diff options
Diffstat (limited to 'thirdparty/mbedtls/library/ssl_msg.c')
| -rw-r--r-- | thirdparty/mbedtls/library/ssl_msg.c | 5922 |
1 files changed, 5922 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/ssl_msg.c b/thirdparty/mbedtls/library/ssl_msg.c new file mode 100644 index 0000000000..0b696dd561 --- /dev/null +++ b/thirdparty/mbedtls/library/ssl_msg.c @@ -0,0 +1,5922 @@ +/* + * Generic SSL/TLS messaging layer functions + * (record layer + retransmission state machine) + * + * Copyright The Mbed TLS Contributors + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/* + * The SSL 3.0 specification was drafted by Netscape in 1996, + * and became an IETF standard in 1999. + * + * http://wp.netscape.com/eng/ssl3/ + * http://www.ietf.org/rfc/rfc2246.txt + * http://www.ietf.org/rfc/rfc4346.txt + */ + +#include "common.h" + +#if defined(MBEDTLS_SSL_TLS_C) + +#if defined(MBEDTLS_PLATFORM_C) +#include "mbedtls/platform.h" +#else +#include <stdlib.h> +#define mbedtls_calloc calloc +#define mbedtls_free free +#endif + +#include "mbedtls/ssl.h" +#include "mbedtls/ssl_internal.h" +#include "mbedtls/debug.h" +#include "mbedtls/error.h" +#include "mbedtls/platform_util.h" +#include "mbedtls/version.h" +#include "constant_time_internal.h" +#include "mbedtls/constant_time.h" + +#include <string.h> + +#if defined(MBEDTLS_USE_PSA_CRYPTO) +#include "mbedtls/psa_util.h" +#include "psa/crypto.h" +#endif + +#if defined(MBEDTLS_X509_CRT_PARSE_C) +#include "mbedtls/oid.h" +#endif + +static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ); + +/* + * Start a timer. + * Passing millisecs = 0 cancels a running timer. + */ +void mbedtls_ssl_set_timer( mbedtls_ssl_context *ssl, uint32_t millisecs ) +{ + if( ssl->f_set_timer == NULL ) + return; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "set_timer to %d ms", (int) millisecs ) ); + ssl->f_set_timer( ssl->p_timer, millisecs / 4, millisecs ); +} + +/* + * Return -1 is timer is expired, 0 if it isn't. + */ +int mbedtls_ssl_check_timer( mbedtls_ssl_context *ssl ) +{ + if( ssl->f_get_timer == NULL ) + return( 0 ); + + if( ssl->f_get_timer( ssl->p_timer ) == 2 ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "timer expired" ) ); + return( -1 ); + } + + return( 0 ); +} + +#if defined(MBEDTLS_SSL_RECORD_CHECKING) +static int ssl_parse_record_header( mbedtls_ssl_context const *ssl, + unsigned char *buf, + size_t len, + mbedtls_record *rec ); + +int mbedtls_ssl_check_record( mbedtls_ssl_context const *ssl, + unsigned char *buf, + size_t buflen ) +{ + int ret = 0; + MBEDTLS_SSL_DEBUG_MSG( 1, ( "=> mbedtls_ssl_check_record" ) ); + MBEDTLS_SSL_DEBUG_BUF( 3, "record buffer", buf, buflen ); + + /* We don't support record checking in TLS because + * (a) there doesn't seem to be a usecase for it, and + * (b) In SSLv3 and TLS 1.0, CBC record decryption has state + * and we'd need to backup the transform here. + */ + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_STREAM ) + { + ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE; + goto exit; + } +#if defined(MBEDTLS_SSL_PROTO_DTLS) + else + { + mbedtls_record rec; + + ret = ssl_parse_record_header( ssl, buf, buflen, &rec ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 3, "ssl_parse_record_header", ret ); + goto exit; + } + + if( ssl->transform_in != NULL ) + { + ret = mbedtls_ssl_decrypt_buf( ssl, ssl->transform_in, &rec ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 3, "mbedtls_ssl_decrypt_buf", ret ); + goto exit; + } + } + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +exit: + /* On success, we have decrypted the buffer in-place, so make + * sure we don't leak any plaintext data. */ + mbedtls_platform_zeroize( buf, buflen ); + + /* For the purpose of this API, treat messages with unexpected CID + * as well as such from future epochs as unexpected. */ + if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_CID || + ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) + { + ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD; + } + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "<= mbedtls_ssl_check_record" ) ); + return( ret ); +} +#endif /* MBEDTLS_SSL_RECORD_CHECKING */ + +#define SSL_DONT_FORCE_FLUSH 0 +#define SSL_FORCE_FLUSH 1 + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +/* Forward declarations for functions related to message buffering. */ +static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, + uint8_t slot ); +static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ); +static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ); +static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ); +static int ssl_buffer_message( mbedtls_ssl_context *ssl ); +static int ssl_buffer_future_record( mbedtls_ssl_context *ssl, + mbedtls_record const *rec ); +static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ); + +static size_t ssl_get_maximum_datagram_size( mbedtls_ssl_context const *ssl ) +{ + size_t mtu = mbedtls_ssl_get_current_mtu( ssl ); +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t out_buf_len = ssl->out_buf_len; +#else + size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN; +#endif + + if( mtu != 0 && mtu < out_buf_len ) + return( mtu ); + + return( out_buf_len ); +} + +static int ssl_get_remaining_space_in_datagram( mbedtls_ssl_context const *ssl ) +{ + size_t const bytes_written = ssl->out_left; + size_t const mtu = ssl_get_maximum_datagram_size( ssl ); + + /* Double-check that the write-index hasn't gone + * past what we can transmit in a single datagram. */ + if( bytes_written > mtu ) + { + /* Should never happen... */ + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + return( (int) ( mtu - bytes_written ) ); +} + +static int ssl_get_remaining_payload_in_datagram( mbedtls_ssl_context const *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t remaining, expansion; + size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN; + +#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) + const size_t mfl = mbedtls_ssl_get_output_max_frag_len( ssl ); + + if( max_len > mfl ) + max_len = mfl; + + /* By the standard (RFC 6066 Sect. 4), the MFL extension + * only limits the maximum record payload size, so in theory + * we would be allowed to pack multiple records of payload size + * MFL into a single datagram. However, this would mean that there's + * no way to explicitly communicate MTU restrictions to the peer. + * + * The following reduction of max_len makes sure that we never + * write datagrams larger than MFL + Record Expansion Overhead. + */ + if( max_len <= ssl->out_left ) + return( 0 ); + + max_len -= ssl->out_left; +#endif + + ret = ssl_get_remaining_space_in_datagram( ssl ); + if( ret < 0 ) + return( ret ); + remaining = (size_t) ret; + + ret = mbedtls_ssl_get_record_expansion( ssl ); + if( ret < 0 ) + return( ret ); + expansion = (size_t) ret; + + if( remaining <= expansion ) + return( 0 ); + + remaining -= expansion; + if( remaining >= max_len ) + remaining = max_len; + + return( (int) remaining ); +} + +/* + * Double the retransmit timeout value, within the allowed range, + * returning -1 if the maximum value has already been reached. + */ +static int ssl_double_retransmit_timeout( mbedtls_ssl_context *ssl ) +{ + uint32_t new_timeout; + + if( ssl->handshake->retransmit_timeout >= ssl->conf->hs_timeout_max ) + return( -1 ); + + /* Implement the final paragraph of RFC 6347 section 4.1.1.1 + * in the following way: after the initial transmission and a first + * retransmission, back off to a temporary estimated MTU of 508 bytes. + * This value is guaranteed to be deliverable (if not guaranteed to be + * delivered) of any compliant IPv4 (and IPv6) network, and should work + * on most non-IP stacks too. */ + if( ssl->handshake->retransmit_timeout != ssl->conf->hs_timeout_min ) + { + ssl->handshake->mtu = 508; + MBEDTLS_SSL_DEBUG_MSG( 2, ( "mtu autoreduction to %d bytes", ssl->handshake->mtu ) ); + } + + new_timeout = 2 * ssl->handshake->retransmit_timeout; + + /* Avoid arithmetic overflow and range overflow */ + if( new_timeout < ssl->handshake->retransmit_timeout || + new_timeout > ssl->conf->hs_timeout_max ) + { + new_timeout = ssl->conf->hs_timeout_max; + } + + ssl->handshake->retransmit_timeout = new_timeout; + MBEDTLS_SSL_DEBUG_MSG( 3, ( "update timeout value to %lu millisecs", + (unsigned long) ssl->handshake->retransmit_timeout ) ); + + return( 0 ); +} + +static void ssl_reset_retransmit_timeout( mbedtls_ssl_context *ssl ) +{ + ssl->handshake->retransmit_timeout = ssl->conf->hs_timeout_min; + MBEDTLS_SSL_DEBUG_MSG( 3, ( "update timeout value to %lu millisecs", + (unsigned long) ssl->handshake->retransmit_timeout ) ); +} +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) +int (*mbedtls_ssl_hw_record_init)( mbedtls_ssl_context *ssl, + const unsigned char *key_enc, const unsigned char *key_dec, + size_t keylen, + const unsigned char *iv_enc, const unsigned char *iv_dec, + size_t ivlen, + const unsigned char *mac_enc, const unsigned char *mac_dec, + size_t maclen ) = NULL; +int (*mbedtls_ssl_hw_record_activate)( mbedtls_ssl_context *ssl, int direction) = NULL; +int (*mbedtls_ssl_hw_record_reset)( mbedtls_ssl_context *ssl ) = NULL; +int (*mbedtls_ssl_hw_record_write)( mbedtls_ssl_context *ssl ) = NULL; +int (*mbedtls_ssl_hw_record_read)( mbedtls_ssl_context *ssl ) = NULL; +int (*mbedtls_ssl_hw_record_finish)( mbedtls_ssl_context *ssl ) = NULL; +#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */ + +/* + * Encryption/decryption functions + */ + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) + +static size_t ssl_compute_padding_length( size_t len, + size_t granularity ) +{ + return( ( granularity - ( len + 1 ) % granularity ) % granularity ); +} + +/* This functions transforms a (D)TLS plaintext fragment and a record content + * type into an instance of the (D)TLSInnerPlaintext structure. This is used + * in DTLS 1.2 + CID and within TLS 1.3 to allow flexible padding and to protect + * a record's content type. + * + * struct { + * opaque content[DTLSPlaintext.length]; + * ContentType real_type; + * uint8 zeros[length_of_padding]; + * } (D)TLSInnerPlaintext; + * + * Input: + * - `content`: The beginning of the buffer holding the + * plaintext to be wrapped. + * - `*content_size`: The length of the plaintext in Bytes. + * - `max_len`: The number of Bytes available starting from + * `content`. This must be `>= *content_size`. + * - `rec_type`: The desired record content type. + * + * Output: + * - `content`: The beginning of the resulting (D)TLSInnerPlaintext structure. + * - `*content_size`: The length of the resulting (D)TLSInnerPlaintext structure. + * + * Returns: + * - `0` on success. + * - A negative error code if `max_len` didn't offer enough space + * for the expansion. + */ +static int ssl_build_inner_plaintext( unsigned char *content, + size_t *content_size, + size_t remaining, + uint8_t rec_type, + size_t pad ) +{ + size_t len = *content_size; + + /* Write real content type */ + if( remaining == 0 ) + return( -1 ); + content[ len ] = rec_type; + len++; + remaining--; + + if( remaining < pad ) + return( -1 ); + memset( content + len, 0, pad ); + len += pad; + remaining -= pad; + + *content_size = len; + return( 0 ); +} + +/* This function parses a (D)TLSInnerPlaintext structure. + * See ssl_build_inner_plaintext() for details. */ +static int ssl_parse_inner_plaintext( unsigned char const *content, + size_t *content_size, + uint8_t *rec_type ) +{ + size_t remaining = *content_size; + + /* Determine length of padding by skipping zeroes from the back. */ + do + { + if( remaining == 0 ) + return( -1 ); + remaining--; + } while( content[ remaining ] == 0 ); + + *content_size = remaining; + *rec_type = content[ remaining ]; + + return( 0 ); +} +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID || + MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ + +/* `add_data` must have size 13 Bytes if the CID extension is disabled, + * and 13 + 1 + CID-length Bytes if the CID extension is enabled. */ +static void ssl_extract_add_data_from_record( unsigned char* add_data, + size_t *add_data_len, + mbedtls_record *rec, + unsigned minor_ver ) +{ + /* Quoting RFC 5246 (TLS 1.2): + * + * additional_data = seq_num + TLSCompressed.type + + * TLSCompressed.version + TLSCompressed.length; + * + * For the CID extension, this is extended as follows + * (quoting draft-ietf-tls-dtls-connection-id-05, + * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05): + * + * additional_data = seq_num + DTLSPlaintext.type + + * DTLSPlaintext.version + + * cid + + * cid_length + + * length_of_DTLSInnerPlaintext; + * + * For TLS 1.3, the record sequence number is dropped from the AAD + * and encoded within the nonce of the AEAD operation instead. + */ + + unsigned char *cur = add_data; + +#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) + if( minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 ) +#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ + { + ((void) minor_ver); + memcpy( cur, rec->ctr, sizeof( rec->ctr ) ); + cur += sizeof( rec->ctr ); + } + + *cur = rec->type; + cur++; + + memcpy( cur, rec->ver, sizeof( rec->ver ) ); + cur += sizeof( rec->ver ); + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + if( rec->cid_len != 0 ) + { + memcpy( cur, rec->cid, rec->cid_len ); + cur += rec->cid_len; + + *cur = rec->cid_len; + cur++; + + MBEDTLS_PUT_UINT16_BE( rec->data_len, cur, 0 ); + cur += 2; + } + else +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + { + MBEDTLS_PUT_UINT16_BE( rec->data_len, cur, 0 ); + cur += 2; + } + + *add_data_len = cur - add_data; +} + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + +#define SSL3_MAC_MAX_BYTES 20 /* MD-5 or SHA-1 */ + +/* + * SSLv3.0 MAC functions + */ +static int ssl_mac( mbedtls_md_context_t *md_ctx, + const unsigned char *secret, + const unsigned char *buf, size_t len, + const unsigned char *ctr, int type, + unsigned char out[SSL3_MAC_MAX_BYTES] ) +{ + unsigned char header[11]; + unsigned char padding[48]; + int padlen; + int md_size = mbedtls_md_get_size( md_ctx->md_info ); + int md_type = mbedtls_md_get_type( md_ctx->md_info ); + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + /* Only MD5 and SHA-1 supported */ + if( md_type == MBEDTLS_MD_MD5 ) + padlen = 48; + else + padlen = 40; + + memcpy( header, ctr, 8 ); + header[8] = (unsigned char) type; + MBEDTLS_PUT_UINT16_BE( len, header, 9); + + memset( padding, 0x36, padlen ); + ret = mbedtls_md_starts( md_ctx ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, secret, md_size ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, padding, padlen ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, header, 11 ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, buf, len ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_finish( md_ctx, out ); + if( ret != 0 ) + return( ret ); + + memset( padding, 0x5C, padlen ); + ret = mbedtls_md_starts( md_ctx ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, secret, md_size ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, padding, padlen ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_update( md_ctx, out, md_size ); + if( ret != 0 ) + return( ret ); + ret = mbedtls_md_finish( md_ctx, out ); + if( ret != 0 ) + return( ret ); + + return( 0 ); +} +#endif /* MBEDTLS_SSL_PROTO_SSL3 */ + +#if defined(MBEDTLS_GCM_C) || \ + defined(MBEDTLS_CCM_C) || \ + defined(MBEDTLS_CHACHAPOLY_C) +static int ssl_transform_aead_dynamic_iv_is_explicit( + mbedtls_ssl_transform const *transform ) +{ + return( transform->ivlen != transform->fixed_ivlen ); +} + +/* Compute IV := ( fixed_iv || 0 ) XOR ( 0 || dynamic_IV ) + * + * Concretely, this occurs in two variants: + * + * a) Fixed and dynamic IV lengths add up to total IV length, giving + * IV = fixed_iv || dynamic_iv + * + * This variant is used in TLS 1.2 when used with GCM or CCM. + * + * b) Fixed IV lengths matches total IV length, giving + * IV = fixed_iv XOR ( 0 || dynamic_iv ) + * + * This variant occurs in TLS 1.3 and for TLS 1.2 when using ChaChaPoly. + * + * See also the documentation of mbedtls_ssl_transform. + * + * This function has the precondition that + * + * dst_iv_len >= max( fixed_iv_len, dynamic_iv_len ) + * + * which has to be ensured by the caller. If this precondition + * violated, the behavior of this function is undefined. + */ +static void ssl_build_record_nonce( unsigned char *dst_iv, + size_t dst_iv_len, + unsigned char const *fixed_iv, + size_t fixed_iv_len, + unsigned char const *dynamic_iv, + size_t dynamic_iv_len ) +{ + size_t i; + + /* Start with Fixed IV || 0 */ + memset( dst_iv, 0, dst_iv_len ); + memcpy( dst_iv, fixed_iv, fixed_iv_len ); + + dst_iv += dst_iv_len - dynamic_iv_len; + for( i = 0; i < dynamic_iv_len; i++ ) + dst_iv[i] ^= dynamic_iv[i]; +} +#endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C || MBEDTLS_CHACHAPOLY_C */ + +int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl, + mbedtls_ssl_transform *transform, + mbedtls_record *rec, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) +{ + mbedtls_cipher_mode_t mode; + int auth_done = 0; + unsigned char * data; + unsigned char add_data[13 + 1 + MBEDTLS_SSL_CID_OUT_LEN_MAX ]; + size_t add_data_len; + size_t post_avail; + + /* The SSL context is only used for debugging purposes! */ +#if !defined(MBEDTLS_DEBUG_C) + ssl = NULL; /* make sure we don't use it except for debug */ + ((void) ssl); +#endif + + /* The PRNG is used for dynamic IV generation that's used + * for CBC transformations in TLS 1.1 and TLS 1.2. */ +#if !( defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) && \ + ( defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) ) ) + ((void) f_rng); + ((void) p_rng); +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> encrypt buf" ) ); + + if( transform == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "no transform provided to encrypt_buf" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + if( rec == NULL + || rec->buf == NULL + || rec->buf_len < rec->data_offset + || rec->buf_len - rec->data_offset < rec->data_len +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + || rec->cid_len != 0 +#endif + ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad record structure provided to encrypt_buf" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + data = rec->buf + rec->data_offset; + post_avail = rec->buf_len - ( rec->data_len + rec->data_offset ); + MBEDTLS_SSL_DEBUG_BUF( 4, "before encrypt: output payload", + data, rec->data_len ); + + mode = mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ); + + if( rec->data_len > MBEDTLS_SSL_OUT_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record content %" MBEDTLS_PRINTF_SIZET + " too large, maximum %" MBEDTLS_PRINTF_SIZET, + rec->data_len, + (size_t) MBEDTLS_SSL_OUT_CONTENT_LEN ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + + /* The following two code paths implement the (D)TLSInnerPlaintext + * structure present in TLS 1.3 and DTLS 1.2 + CID. + * + * See ssl_build_inner_plaintext() for more information. + * + * Note that this changes `rec->data_len`, and hence + * `post_avail` needs to be recalculated afterwards. + * + * Note also that the two code paths cannot occur simultaneously + * since they apply to different versions of the protocol. There + * is hence no risk of double-addition of the inner plaintext. + */ +#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) + if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 ) + { + size_t padding = + ssl_compute_padding_length( rec->data_len, + MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY ); + if( ssl_build_inner_plaintext( data, + &rec->data_len, + post_avail, + rec->type, + padding ) != 0 ) + { + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + rec->type = MBEDTLS_SSL_MSG_APPLICATION_DATA; + } +#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + /* + * Add CID information + */ + rec->cid_len = transform->out_cid_len; + memcpy( rec->cid, transform->out_cid, transform->out_cid_len ); + MBEDTLS_SSL_DEBUG_BUF( 3, "CID", rec->cid, rec->cid_len ); + + if( rec->cid_len != 0 ) + { + size_t padding = + ssl_compute_padding_length( rec->data_len, + MBEDTLS_SSL_CID_PADDING_GRANULARITY ); + /* + * Wrap plaintext into DTLSInnerPlaintext structure. + * See ssl_build_inner_plaintext() for more information. + * + * Note that this changes `rec->data_len`, and hence + * `post_avail` needs to be recalculated afterwards. + */ + if( ssl_build_inner_plaintext( data, + &rec->data_len, + post_avail, + rec->type, + padding ) != 0 ) + { + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + rec->type = MBEDTLS_SSL_MSG_CID; + } +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + post_avail = rec->buf_len - ( rec->data_len + rec->data_offset ); + + /* + * Add MAC before if needed + */ +#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) + if( mode == MBEDTLS_MODE_STREAM || + ( mode == MBEDTLS_MODE_CBC +#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) + && transform->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED +#endif + ) ) + { + if( post_avail < transform->maclen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) + { + unsigned char mac[SSL3_MAC_MAX_BYTES]; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + ret = ssl_mac( &transform->md_ctx_enc, transform->mac_enc, + data, rec->data_len, rec->ctr, rec->type, mac ); + if( ret == 0 ) + memcpy( data + rec->data_len, mac, transform->maclen ); + mbedtls_platform_zeroize( mac, transform->maclen ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_mac", ret ); + return( ret ); + } + } + else +#endif +#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 ) + { + unsigned char mac[MBEDTLS_SSL_MAC_ADD]; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + ssl_extract_add_data_from_record( add_data, &add_data_len, rec, + transform->minor_ver ); + + ret = mbedtls_md_hmac_update( &transform->md_ctx_enc, + add_data, add_data_len ); + if( ret != 0 ) + goto hmac_failed_etm_disabled; + ret = mbedtls_md_hmac_update( &transform->md_ctx_enc, + data, rec->data_len ); + if( ret != 0 ) + goto hmac_failed_etm_disabled; + ret = mbedtls_md_hmac_finish( &transform->md_ctx_enc, mac ); + if( ret != 0 ) + goto hmac_failed_etm_disabled; + ret = mbedtls_md_hmac_reset( &transform->md_ctx_enc ); + if( ret != 0 ) + goto hmac_failed_etm_disabled; + + memcpy( data + rec->data_len, mac, transform->maclen ); + + hmac_failed_etm_disabled: + mbedtls_platform_zeroize( mac, transform->maclen ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_hmac_xxx", ret ); + return( ret ); + } + } + else +#endif + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + MBEDTLS_SSL_DEBUG_BUF( 4, "computed mac", data + rec->data_len, + transform->maclen ); + + rec->data_len += transform->maclen; + post_avail -= transform->maclen; + auth_done++; + } +#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */ + + /* + * Encrypt + */ +#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER) + if( mode == MBEDTLS_MODE_STREAM ) + { + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t olen; + MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " + "including %d bytes of padding", + rec->data_len, 0 ) ); + + if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_enc, + transform->iv_enc, transform->ivlen, + data, rec->data_len, + data, &olen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); + return( ret ); + } + + if( rec->data_len != olen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } + else +#endif /* MBEDTLS_ARC4_C || MBEDTLS_CIPHER_NULL_CIPHER */ + +#if defined(MBEDTLS_GCM_C) || \ + defined(MBEDTLS_CCM_C) || \ + defined(MBEDTLS_CHACHAPOLY_C) + if( mode == MBEDTLS_MODE_GCM || + mode == MBEDTLS_MODE_CCM || + mode == MBEDTLS_MODE_CHACHAPOLY ) + { + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char iv[12]; + unsigned char *dynamic_iv; + size_t dynamic_iv_len; + int dynamic_iv_is_explicit = + ssl_transform_aead_dynamic_iv_is_explicit( transform ); + + /* Check that there's space for the authentication tag. */ + if( post_avail < transform->taglen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + /* + * Build nonce for AEAD encryption. + * + * Note: In the case of CCM and GCM in TLS 1.2, the dynamic + * part of the IV is prepended to the ciphertext and + * can be chosen freely - in particular, it need not + * agree with the record sequence number. + * However, since ChaChaPoly as well as all AEAD modes + * in TLS 1.3 use the record sequence number as the + * dynamic part of the nonce, we uniformly use the + * record sequence number here in all cases. + */ + dynamic_iv = rec->ctr; + dynamic_iv_len = sizeof( rec->ctr ); + + ssl_build_record_nonce( iv, sizeof( iv ), + transform->iv_enc, + transform->fixed_ivlen, + dynamic_iv, + dynamic_iv_len ); + + /* + * Build additional data for AEAD encryption. + * This depends on the TLS version. + */ + ssl_extract_add_data_from_record( add_data, &add_data_len, rec, + transform->minor_ver ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "IV used (internal)", + iv, transform->ivlen ); + MBEDTLS_SSL_DEBUG_BUF( 4, "IV used (transmitted)", + dynamic_iv, + dynamic_iv_is_explicit ? dynamic_iv_len : 0 ); + MBEDTLS_SSL_DEBUG_BUF( 4, "additional data used for AEAD", + add_data, add_data_len ); + MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " + "including 0 bytes of padding", + rec->data_len ) ); + + /* + * Encrypt and authenticate + */ + + if( ( ret = mbedtls_cipher_auth_encrypt_ext( &transform->cipher_ctx_enc, + iv, transform->ivlen, + add_data, add_data_len, + data, rec->data_len, /* src */ + data, rec->buf_len - (data - rec->buf), /* dst */ + &rec->data_len, + transform->taglen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_encrypt", ret ); + return( ret ); + } + MBEDTLS_SSL_DEBUG_BUF( 4, "after encrypt: tag", + data + rec->data_len - transform->taglen, + transform->taglen ); + /* Account for authentication tag. */ + post_avail -= transform->taglen; + + /* + * Prefix record content with dynamic IV in case it is explicit. + */ + if( dynamic_iv_is_explicit != 0 ) + { + if( rec->data_offset < dynamic_iv_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + memcpy( data - dynamic_iv_len, dynamic_iv, dynamic_iv_len ); + rec->data_offset -= dynamic_iv_len; + rec->data_len += dynamic_iv_len; + } + + auth_done++; + } + else +#endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C || MBEDTLS_CHACHAPOLY_C */ +#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) + if( mode == MBEDTLS_MODE_CBC ) + { + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t padlen, i; + size_t olen; + + /* Currently we're always using minimal padding + * (up to 255 bytes would be allowed). */ + padlen = transform->ivlen - ( rec->data_len + 1 ) % transform->ivlen; + if( padlen == transform->ivlen ) + padlen = 0; + + /* Check there's enough space in the buffer for the padding. */ + if( post_avail < padlen + 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + for( i = 0; i <= padlen; i++ ) + data[rec->data_len + i] = (unsigned char) padlen; + + rec->data_len += padlen + 1; + post_avail -= padlen + 1; + +#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) + /* + * Prepend per-record IV for block cipher in TLS v1.1 and up as per + * Method 1 (6.2.3.2. in RFC4346 and RFC5246) + */ + if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) + { + if( f_rng == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "No PRNG provided to encrypt_record routine" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + if( rec->data_offset < transform->ivlen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + /* + * Generate IV + */ + ret = f_rng( p_rng, transform->iv_enc, transform->ivlen ); + if( ret != 0 ) + return( ret ); + + memcpy( data - transform->ivlen, transform->iv_enc, + transform->ivlen ); + + } +#endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "before encrypt: msglen = %" MBEDTLS_PRINTF_SIZET ", " + "including %" MBEDTLS_PRINTF_SIZET + " bytes of IV and %" MBEDTLS_PRINTF_SIZET " bytes of padding", + rec->data_len, transform->ivlen, + padlen + 1 ) ); + + if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_enc, + transform->iv_enc, + transform->ivlen, + data, rec->data_len, + data, &olen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); + return( ret ); + } + + if( rec->data_len != olen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) + if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) + { + /* + * Save IV in SSL3 and TLS1 + */ + memcpy( transform->iv_enc, transform->cipher_ctx_enc.iv, + transform->ivlen ); + } + else +#endif + { + data -= transform->ivlen; + rec->data_offset -= transform->ivlen; + rec->data_len += transform->ivlen; + } + +#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) + if( auth_done == 0 ) + { + unsigned char mac[MBEDTLS_SSL_MAC_ADD]; + + /* + * MAC(MAC_write_key, seq_num + + * TLSCipherText.type + + * TLSCipherText.version + + * length_of( (IV +) ENC(...) ) + + * IV + // except for TLS 1.0 + * ENC(content + padding + padding_length)); + */ + + if( post_avail < transform->maclen) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Buffer provided for encrypted record not large enough" ) ); + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + } + + ssl_extract_add_data_from_record( add_data, &add_data_len, + rec, transform->minor_ver ); + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) ); + MBEDTLS_SSL_DEBUG_BUF( 4, "MAC'd meta-data", add_data, + add_data_len ); + + ret = mbedtls_md_hmac_update( &transform->md_ctx_enc, add_data, + add_data_len ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_update( &transform->md_ctx_enc, + data, rec->data_len ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_finish( &transform->md_ctx_enc, mac ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_reset( &transform->md_ctx_enc ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + + memcpy( data + rec->data_len, mac, transform->maclen ); + + rec->data_len += transform->maclen; + post_avail -= transform->maclen; + auth_done++; + + hmac_failed_etm_enabled: + mbedtls_platform_zeroize( mac, transform->maclen ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "HMAC calculation failed", ret ); + return( ret ); + } + } +#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ + } + else +#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC) */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* Make extra sure authentication was performed, exactly once */ + if( auth_done != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= encrypt buf" ) ); + + return( 0 ); +} + +int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl, + mbedtls_ssl_transform *transform, + mbedtls_record *rec ) +{ + size_t olen; + mbedtls_cipher_mode_t mode; + int ret, auth_done = 0; +#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) + size_t padlen = 0, correct = 1; +#endif + unsigned char* data; + unsigned char add_data[13 + 1 + MBEDTLS_SSL_CID_IN_LEN_MAX ]; + size_t add_data_len; + +#if !defined(MBEDTLS_DEBUG_C) + ssl = NULL; /* make sure we don't use it except for debug */ + ((void) ssl); +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> decrypt buf" ) ); + if( rec == NULL || + rec->buf == NULL || + rec->buf_len < rec->data_offset || + rec->buf_len - rec->data_offset < rec->data_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad record structure provided to decrypt_buf" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + data = rec->buf + rec->data_offset; + mode = mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_dec ); + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + /* + * Match record's CID with incoming CID. + */ + if( rec->cid_len != transform->in_cid_len || + memcmp( rec->cid, transform->in_cid, rec->cid_len ) != 0 ) + { + return( MBEDTLS_ERR_SSL_UNEXPECTED_CID ); + } +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + +#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER) + if( mode == MBEDTLS_MODE_STREAM ) + { + padlen = 0; + if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_dec, + transform->iv_dec, + transform->ivlen, + data, rec->data_len, + data, &olen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); + return( ret ); + } + + if( rec->data_len != olen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } + else +#endif /* MBEDTLS_ARC4_C || MBEDTLS_CIPHER_NULL_CIPHER */ +#if defined(MBEDTLS_GCM_C) || \ + defined(MBEDTLS_CCM_C) || \ + defined(MBEDTLS_CHACHAPOLY_C) + if( mode == MBEDTLS_MODE_GCM || + mode == MBEDTLS_MODE_CCM || + mode == MBEDTLS_MODE_CHACHAPOLY ) + { + unsigned char iv[12]; + unsigned char *dynamic_iv; + size_t dynamic_iv_len; + + /* + * Extract dynamic part of nonce for AEAD decryption. + * + * Note: In the case of CCM and GCM in TLS 1.2, the dynamic + * part of the IV is prepended to the ciphertext and + * can be chosen freely - in particular, it need not + * agree with the record sequence number. + */ + dynamic_iv_len = sizeof( rec->ctr ); + if( ssl_transform_aead_dynamic_iv_is_explicit( transform ) == 1 ) + { + if( rec->data_len < dynamic_iv_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET + " ) < explicit_iv_len (%" MBEDTLS_PRINTF_SIZET ") ", + rec->data_len, + dynamic_iv_len ) ); + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } + dynamic_iv = data; + + data += dynamic_iv_len; + rec->data_offset += dynamic_iv_len; + rec->data_len -= dynamic_iv_len; + } + else + { + dynamic_iv = rec->ctr; + } + + /* Check that there's space for the authentication tag. */ + if( rec->data_len < transform->taglen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET + ") < taglen (%" MBEDTLS_PRINTF_SIZET ") ", + rec->data_len, + transform->taglen ) ); + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } + rec->data_len -= transform->taglen; + + /* + * Prepare nonce from dynamic and static parts. + */ + ssl_build_record_nonce( iv, sizeof( iv ), + transform->iv_dec, + transform->fixed_ivlen, + dynamic_iv, + dynamic_iv_len ); + + /* + * Build additional data for AEAD encryption. + * This depends on the TLS version. + */ + ssl_extract_add_data_from_record( add_data, &add_data_len, rec, + transform->minor_ver ); + MBEDTLS_SSL_DEBUG_BUF( 4, "additional data used for AEAD", + add_data, add_data_len ); + + /* Because of the check above, we know that there are + * explicit_iv_len Bytes preceeding data, and taglen + * bytes following data + data_len. This justifies + * the debug message and the invocation of + * mbedtls_cipher_auth_decrypt() below. */ + + MBEDTLS_SSL_DEBUG_BUF( 4, "IV used", iv, transform->ivlen ); + MBEDTLS_SSL_DEBUG_BUF( 4, "TAG used", data + rec->data_len, + transform->taglen ); + + /* + * Decrypt and authenticate + */ + if( ( ret = mbedtls_cipher_auth_decrypt_ext( &transform->cipher_ctx_dec, + iv, transform->ivlen, + add_data, add_data_len, + data, rec->data_len + transform->taglen, /* src */ + data, rec->buf_len - (data - rec->buf), &olen, /* dst */ + transform->taglen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_auth_decrypt", ret ); + + if( ret == MBEDTLS_ERR_CIPHER_AUTH_FAILED ) + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + + return( ret ); + } + auth_done++; + + /* Double-check that AEAD decryption doesn't change content length. */ + if( olen != rec->data_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } + else +#endif /* MBEDTLS_GCM_C || MBEDTLS_CCM_C */ +#if defined(MBEDTLS_SSL_SOME_SUITES_USE_CBC) + if( mode == MBEDTLS_MODE_CBC ) + { + size_t minlen = 0; + + /* + * Check immediate ciphertext sanity + */ +#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) + { + /* The ciphertext is prefixed with the CBC IV. */ + minlen += transform->ivlen; + } +#endif + + /* Size considerations: + * + * - The CBC cipher text must not be empty and hence + * at least of size transform->ivlen. + * + * Together with the potential IV-prefix, this explains + * the first of the two checks below. + * + * - The record must contain a MAC, either in plain or + * encrypted, depending on whether Encrypt-then-MAC + * is used or not. + * - If it is, the message contains the IV-prefix, + * the CBC ciphertext, and the MAC. + * - If it is not, the padded plaintext, and hence + * the CBC ciphertext, has at least length maclen + 1 + * because there is at least the padding length byte. + * + * As the CBC ciphertext is not empty, both cases give the + * lower bound minlen + maclen + 1 on the record size, which + * we test for in the second check below. + */ + if( rec->data_len < minlen + transform->ivlen || + rec->data_len < minlen + transform->maclen + 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET + ") < max( ivlen(%" MBEDTLS_PRINTF_SIZET + "), maclen (%" MBEDTLS_PRINTF_SIZET ") " + "+ 1 ) ( + expl IV )", rec->data_len, + transform->ivlen, + transform->maclen ) ); + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } + + /* + * Authenticate before decrypt if enabled + */ +#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC) + if( transform->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED ) + { + unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD]; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) ); + + /* Update data_len in tandem with add_data. + * + * The subtraction is safe because of the previous check + * data_len >= minlen + maclen + 1. + * + * Afterwards, we know that data + data_len is followed by at + * least maclen Bytes, which justifies the call to + * mbedtls_ct_memcmp() below. + * + * Further, we still know that data_len > minlen */ + rec->data_len -= transform->maclen; + ssl_extract_add_data_from_record( add_data, &add_data_len, rec, + transform->minor_ver ); + + /* Calculate expected MAC. */ + MBEDTLS_SSL_DEBUG_BUF( 4, "MAC'd meta-data", add_data, + add_data_len ); + ret = mbedtls_md_hmac_update( &transform->md_ctx_dec, add_data, + add_data_len ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_update( &transform->md_ctx_dec, + data, rec->data_len ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_finish( &transform->md_ctx_dec, mac_expect ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + ret = mbedtls_md_hmac_reset( &transform->md_ctx_dec ); + if( ret != 0 ) + goto hmac_failed_etm_enabled; + + MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", data + rec->data_len, + transform->maclen ); + MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect, + transform->maclen ); + + /* Compare expected MAC with MAC at the end of the record. */ + if( mbedtls_ct_memcmp( data + rec->data_len, mac_expect, + transform->maclen ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) ); + ret = MBEDTLS_ERR_SSL_INVALID_MAC; + goto hmac_failed_etm_enabled; + } + auth_done++; + + hmac_failed_etm_enabled: + mbedtls_platform_zeroize( mac_expect, transform->maclen ); + if( ret != 0 ) + { + if( ret != MBEDTLS_ERR_SSL_INVALID_MAC ) + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_hmac_xxx", ret ); + return( ret ); + } + } +#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */ + + /* + * Check length sanity + */ + + /* We know from above that data_len > minlen >= 0, + * so the following check in particular implies that + * data_len >= minlen + ivlen ( = minlen or 2 * minlen ). */ + if( rec->data_len % transform->ivlen != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET + ") %% ivlen (%" MBEDTLS_PRINTF_SIZET ") != 0", + rec->data_len, transform->ivlen ) ); + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } + +#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) + /* + * Initialize for prepended IV for block cipher in TLS v1.1 and up + */ + if( transform->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) + { + /* Safe because data_len >= minlen + ivlen = 2 * ivlen. */ + memcpy( transform->iv_dec, data, transform->ivlen ); + + data += transform->ivlen; + rec->data_offset += transform->ivlen; + rec->data_len -= transform->ivlen; + } +#endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ + + /* We still have data_len % ivlen == 0 and data_len >= ivlen here. */ + + if( ( ret = mbedtls_cipher_crypt( &transform->cipher_ctx_dec, + transform->iv_dec, transform->ivlen, + data, rec->data_len, data, &olen ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_cipher_crypt", ret ); + return( ret ); + } + + /* Double-check that length hasn't changed during decryption. */ + if( rec->data_len != olen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) + if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) + { + /* + * Save IV in SSL3 and TLS1, where CBC decryption of consecutive + * records is equivalent to CBC decryption of the concatenation + * of the records; in other words, IVs are maintained across + * record decryptions. + */ + memcpy( transform->iv_dec, transform->cipher_ctx_dec.iv, + transform->ivlen ); + } +#endif + + /* Safe since data_len >= minlen + maclen + 1, so after having + * subtracted at most minlen and maclen up to this point, + * data_len > 0 (because of data_len % ivlen == 0, it's actually + * >= ivlen ). */ + padlen = data[rec->data_len - 1]; + + if( auth_done == 1 ) + { + const size_t mask = mbedtls_ct_size_mask_ge( + rec->data_len, + padlen + 1 ); + correct &= mask; + padlen &= mask; + } + else + { +#if defined(MBEDTLS_SSL_DEBUG_ALL) + if( rec->data_len < transform->maclen + padlen + 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "msglen (%" MBEDTLS_PRINTF_SIZET + ") < maclen (%" MBEDTLS_PRINTF_SIZET + ") + padlen (%" MBEDTLS_PRINTF_SIZET ")", + rec->data_len, + transform->maclen, + padlen + 1 ) ); + } +#endif + + const size_t mask = mbedtls_ct_size_mask_ge( + rec->data_len, + transform->maclen + padlen + 1 ); + correct &= mask; + padlen &= mask; + } + + padlen++; + + /* Regardless of the validity of the padding, + * we have data_len >= padlen here. */ + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) + { + /* This is the SSL 3.0 path, we don't have to worry about Lucky + * 13, because there's a strictly worse padding attack built in + * the protocol (known as part of POODLE), so we don't care if the + * code is not constant-time, in particular branches are OK. */ + if( padlen > transform->ivlen ) + { +#if defined(MBEDTLS_SSL_DEBUG_ALL) + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding length: is %" MBEDTLS_PRINTF_SIZET ", " + "should be no more than %" MBEDTLS_PRINTF_SIZET, + padlen, transform->ivlen ) ); +#endif + correct = 0; + } + } + else +#endif /* MBEDTLS_SSL_PROTO_SSL3 */ +#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( transform->minor_ver > MBEDTLS_SSL_MINOR_VERSION_0 ) + { + /* The padding check involves a series of up to 256 + * consecutive memory reads at the end of the record + * plaintext buffer. In order to hide the length and + * validity of the padding, always perform exactly + * `min(256,plaintext_len)` reads (but take into account + * only the last `padlen` bytes for the padding check). */ + size_t pad_count = 0; + volatile unsigned char* const check = data; + + /* Index of first padding byte; it has been ensured above + * that the subtraction is safe. */ + size_t const padding_idx = rec->data_len - padlen; + size_t const num_checks = rec->data_len <= 256 ? rec->data_len : 256; + size_t const start_idx = rec->data_len - num_checks; + size_t idx; + + for( idx = start_idx; idx < rec->data_len; idx++ ) + { + /* pad_count += (idx >= padding_idx) && + * (check[idx] == padlen - 1); + */ + const size_t mask = mbedtls_ct_size_mask_ge( idx, padding_idx ); + const size_t equal = mbedtls_ct_size_bool_eq( check[idx], + padlen - 1 ); + pad_count += mask & equal; + } + correct &= mbedtls_ct_size_bool_eq( pad_count, padlen ); + +#if defined(MBEDTLS_SSL_DEBUG_ALL) + if( padlen > 0 && correct == 0 ) + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) ); +#endif + padlen &= mbedtls_ct_size_mask( correct ); + } + else +#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ + MBEDTLS_SSL_PROTO_TLS1_2 */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* If the padding was found to be invalid, padlen == 0 + * and the subtraction is safe. If the padding was found valid, + * padlen hasn't been changed and the previous assertion + * data_len >= padlen still holds. */ + rec->data_len -= padlen; + } + else +#endif /* MBEDTLS_SSL_SOME_SUITES_USE_CBC */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_DEBUG_ALL) + MBEDTLS_SSL_DEBUG_BUF( 4, "raw buffer after decryption", + data, rec->data_len ); +#endif + + /* + * Authenticate if not done yet. + * Compute the MAC regardless of the padding result (RFC4346, CBCTIME). + */ +#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) + if( auth_done == 0 ) + { + unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD]; + unsigned char mac_peer[MBEDTLS_SSL_MAC_ADD]; + + /* If the initial value of padlen was such that + * data_len < maclen + padlen + 1, then padlen + * got reset to 1, and the initial check + * data_len >= minlen + maclen + 1 + * guarantees that at this point we still + * have at least data_len >= maclen. + * + * If the initial value of padlen was such that + * data_len >= maclen + padlen + 1, then we have + * subtracted either padlen + 1 (if the padding was correct) + * or 0 (if the padding was incorrect) since then, + * hence data_len >= maclen in any case. + */ + rec->data_len -= transform->maclen; + ssl_extract_add_data_from_record( add_data, &add_data_len, rec, + transform->minor_ver ); + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) + { + ret = ssl_mac( &transform->md_ctx_dec, + transform->mac_dec, + data, rec->data_len, + rec->ctr, rec->type, + mac_expect ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_mac", ret ); + goto hmac_failed_etm_disabled; + } + memcpy( mac_peer, data + rec->data_len, transform->maclen ); + } + else +#endif /* MBEDTLS_SSL_PROTO_SSL3 */ +#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( transform->minor_ver > MBEDTLS_SSL_MINOR_VERSION_0 ) + { + /* + * The next two sizes are the minimum and maximum values of + * data_len over all padlen values. + * + * They're independent of padlen, since we previously did + * data_len -= padlen. + * + * Note that max_len + maclen is never more than the buffer + * length, as we previously did in_msglen -= maclen too. + */ + const size_t max_len = rec->data_len + padlen; + const size_t min_len = ( max_len > 256 ) ? max_len - 256 : 0; + + ret = mbedtls_ct_hmac( &transform->md_ctx_dec, + add_data, add_data_len, + data, rec->data_len, min_len, max_len, + mac_expect ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ct_hmac", ret ); + goto hmac_failed_etm_disabled; + } + + mbedtls_ct_memcpy_offset( mac_peer, data, + rec->data_len, + min_len, max_len, + transform->maclen ); + } + else +#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ + MBEDTLS_SSL_PROTO_TLS1_2 */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_DEBUG_ALL) + MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect, transform->maclen ); + MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", mac_peer, transform->maclen ); +#endif + + if( mbedtls_ct_memcmp( mac_peer, mac_expect, + transform->maclen ) != 0 ) + { +#if defined(MBEDTLS_SSL_DEBUG_ALL) + MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) ); +#endif + correct = 0; + } + auth_done++; + + hmac_failed_etm_disabled: + mbedtls_platform_zeroize( mac_peer, transform->maclen ); + mbedtls_platform_zeroize( mac_expect, transform->maclen ); + if( ret != 0 ) + return( ret ); + } + + /* + * Finally check the correct flag + */ + if( correct == 0 ) + return( MBEDTLS_ERR_SSL_INVALID_MAC ); +#endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */ + + /* Make extra sure authentication was performed, exactly once */ + if( auth_done != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) + if( transform->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 ) + { + /* Remove inner padding and infer true content type. */ + ret = ssl_parse_inner_plaintext( data, &rec->data_len, + &rec->type ); + + if( ret != 0 ) + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */ + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + if( rec->cid_len != 0 ) + { + ret = ssl_parse_inner_plaintext( data, &rec->data_len, + &rec->type ); + if( ret != 0 ) + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= decrypt buf" ) ); + + return( 0 ); +} + +#undef MAC_NONE +#undef MAC_PLAINTEXT +#undef MAC_CIPHERTEXT + +#if defined(MBEDTLS_ZLIB_SUPPORT) +/* + * Compression/decompression functions + */ +static int ssl_compress_buf( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *msg_post = ssl->out_msg; + ptrdiff_t bytes_written = ssl->out_msg - ssl->out_buf; + size_t len_pre = ssl->out_msglen; + unsigned char *msg_pre = ssl->compress_buf; +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t out_buf_len = ssl->out_buf_len; +#else + size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN; +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> compress buf" ) ); + + if( len_pre == 0 ) + return( 0 ); + + memcpy( msg_pre, ssl->out_msg, len_pre ); + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "before compression: msglen = %" MBEDTLS_PRINTF_SIZET ", ", + ssl->out_msglen ) ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "before compression: output payload", + ssl->out_msg, ssl->out_msglen ); + + ssl->transform_out->ctx_deflate.next_in = msg_pre; + ssl->transform_out->ctx_deflate.avail_in = len_pre; + ssl->transform_out->ctx_deflate.next_out = msg_post; + ssl->transform_out->ctx_deflate.avail_out = out_buf_len - bytes_written; + + ret = deflate( &ssl->transform_out->ctx_deflate, Z_SYNC_FLUSH ); + if( ret != Z_OK ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "failed to perform compression (%d)", ret ) ); + return( MBEDTLS_ERR_SSL_COMPRESSION_FAILED ); + } + + ssl->out_msglen = out_buf_len - + ssl->transform_out->ctx_deflate.avail_out - bytes_written; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "after compression: msglen = %" MBEDTLS_PRINTF_SIZET ", ", + ssl->out_msglen ) ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "after compression: output payload", + ssl->out_msg, ssl->out_msglen ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= compress buf" ) ); + + return( 0 ); +} + +static int ssl_decompress_buf( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *msg_post = ssl->in_msg; + ptrdiff_t header_bytes = ssl->in_msg - ssl->in_buf; + size_t len_pre = ssl->in_msglen; + unsigned char *msg_pre = ssl->compress_buf; +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t in_buf_len = ssl->in_buf_len; +#else + size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN; +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> decompress buf" ) ); + + if( len_pre == 0 ) + return( 0 ); + + memcpy( msg_pre, ssl->in_msg, len_pre ); + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "before decompression: msglen = %" MBEDTLS_PRINTF_SIZET ", ", + ssl->in_msglen ) ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "before decompression: input payload", + ssl->in_msg, ssl->in_msglen ); + + ssl->transform_in->ctx_inflate.next_in = msg_pre; + ssl->transform_in->ctx_inflate.avail_in = len_pre; + ssl->transform_in->ctx_inflate.next_out = msg_post; + ssl->transform_in->ctx_inflate.avail_out = in_buf_len - header_bytes; + + ret = inflate( &ssl->transform_in->ctx_inflate, Z_SYNC_FLUSH ); + if( ret != Z_OK ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "failed to perform decompression (%d)", ret ) ); + return( MBEDTLS_ERR_SSL_COMPRESSION_FAILED ); + } + + ssl->in_msglen = in_buf_len - + ssl->transform_in->ctx_inflate.avail_out - header_bytes; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "after decompression: msglen = %" MBEDTLS_PRINTF_SIZET ", ", + ssl->in_msglen ) ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "after decompression: input payload", + ssl->in_msg, ssl->in_msglen ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= decompress buf" ) ); + + return( 0 ); +} +#endif /* MBEDTLS_ZLIB_SUPPORT */ + +/* + * Fill the input message buffer by appending data to it. + * The amount of data already fetched is in ssl->in_left. + * + * If we return 0, is it guaranteed that (at least) nb_want bytes are + * available (from this read and/or a previous one). Otherwise, an error code + * is returned (possibly EOF or WANT_READ). + * + * With stream transport (TLS) on success ssl->in_left == nb_want, but + * with datagram transport (DTLS) on success ssl->in_left >= nb_want, + * since we always read a whole datagram at once. + * + * For DTLS, it is up to the caller to set ssl->next_record_offset when + * they're done reading a record. + */ +int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t len; +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t in_buf_len = ssl->in_buf_len; +#else + size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN; +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> fetch input" ) ); + + if( ssl->f_recv == NULL && ssl->f_recv_timeout == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Bad usage of mbedtls_ssl_set_bio() " + "or mbedtls_ssl_set_bio()" ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + + if( nb_want > in_buf_len - (size_t)( ssl->in_hdr - ssl->in_buf ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "requesting more data than fits" ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + uint32_t timeout; + + /* + * The point is, we need to always read a full datagram at once, so we + * sometimes read more then requested, and handle the additional data. + * It could be the rest of the current record (while fetching the + * header) and/or some other records in the same datagram. + */ + + /* + * Move to the next record in the already read datagram if applicable + */ + if( ssl->next_record_offset != 0 ) + { + if( ssl->in_left < ssl->next_record_offset ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + ssl->in_left -= ssl->next_record_offset; + + if( ssl->in_left != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "next record in same datagram, offset: %" + MBEDTLS_PRINTF_SIZET, + ssl->next_record_offset ) ); + memmove( ssl->in_hdr, + ssl->in_hdr + ssl->next_record_offset, + ssl->in_left ); + } + + ssl->next_record_offset = 0; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET + ", nb_want: %" MBEDTLS_PRINTF_SIZET, + ssl->in_left, nb_want ) ); + + /* + * Done if we already have enough data. + */ + if( nb_want <= ssl->in_left) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= fetch input" ) ); + return( 0 ); + } + + /* + * A record can't be split across datagrams. If we need to read but + * are not at the beginning of a new record, the caller did something + * wrong. + */ + if( ssl->in_left != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* + * Don't even try to read if time's out already. + * This avoids by-passing the timer when repeatedly receiving messages + * that will end up being dropped. + */ + if( mbedtls_ssl_check_timer( ssl ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "timer has expired" ) ); + ret = MBEDTLS_ERR_SSL_TIMEOUT; + } + else + { + len = in_buf_len - ( ssl->in_hdr - ssl->in_buf ); + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) + timeout = ssl->handshake->retransmit_timeout; + else + timeout = ssl->conf->read_timeout; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "f_recv_timeout: %lu ms", (unsigned long) timeout ) ); + + if( ssl->f_recv_timeout != NULL ) + ret = ssl->f_recv_timeout( ssl->p_bio, ssl->in_hdr, len, + timeout ); + else + ret = ssl->f_recv( ssl->p_bio, ssl->in_hdr, len ); + + MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_recv(_timeout)", ret ); + + if( ret == 0 ) + return( MBEDTLS_ERR_SSL_CONN_EOF ); + } + + if( ret == MBEDTLS_ERR_SSL_TIMEOUT ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "timeout" ) ); + mbedtls_ssl_set_timer( ssl, 0 ); + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) + { + if( ssl_double_retransmit_timeout( ssl ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake timeout" ) ); + return( MBEDTLS_ERR_SSL_TIMEOUT ); + } + + if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend", ret ); + return( ret ); + } + + return( MBEDTLS_ERR_SSL_WANT_READ ); + } +#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_RENEGOTIATION) + else if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && + ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) + { + if( ( ret = mbedtls_ssl_resend_hello_request( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend_hello_request", + ret ); + return( ret ); + } + + return( MBEDTLS_ERR_SSL_WANT_READ ); + } +#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_RENEGOTIATION */ + } + + if( ret < 0 ) + return( ret ); + + ssl->in_left = ret; + } + else +#endif + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET + ", nb_want: %" MBEDTLS_PRINTF_SIZET, + ssl->in_left, nb_want ) ); + + while( ssl->in_left < nb_want ) + { + len = nb_want - ssl->in_left; + + if( mbedtls_ssl_check_timer( ssl ) != 0 ) + ret = MBEDTLS_ERR_SSL_TIMEOUT; + else + { + if( ssl->f_recv_timeout != NULL ) + { + ret = ssl->f_recv_timeout( ssl->p_bio, + ssl->in_hdr + ssl->in_left, len, + ssl->conf->read_timeout ); + } + else + { + ret = ssl->f_recv( ssl->p_bio, + ssl->in_hdr + ssl->in_left, len ); + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "in_left: %" MBEDTLS_PRINTF_SIZET + ", nb_want: %" MBEDTLS_PRINTF_SIZET, + ssl->in_left, nb_want ) ); + MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_recv(_timeout)", ret ); + + if( ret == 0 ) + return( MBEDTLS_ERR_SSL_CONN_EOF ); + + if( ret < 0 ) + return( ret ); + + if ( (size_t)ret > len || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, + ( "f_recv returned %d bytes but only %" MBEDTLS_PRINTF_SIZET " were requested", + ret, len ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + ssl->in_left += ret; + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= fetch input" ) ); + + return( 0 ); +} + +/* + * Flush any data not yet written + */ +int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *buf; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> flush output" ) ); + + if( ssl->f_send == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Bad usage of mbedtls_ssl_set_bio() " + "or mbedtls_ssl_set_bio()" ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + + /* Avoid incrementing counter if data is flushed */ + if( ssl->out_left == 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) ); + return( 0 ); + } + + while( ssl->out_left > 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "message length: %" MBEDTLS_PRINTF_SIZET + ", out_left: %" MBEDTLS_PRINTF_SIZET, + mbedtls_ssl_out_hdr_len( ssl ) + ssl->out_msglen, ssl->out_left ) ); + + buf = ssl->out_hdr - ssl->out_left; + ret = ssl->f_send( ssl->p_bio, buf, ssl->out_left ); + + MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", ret ); + + if( ret <= 0 ) + return( ret ); + + if( (size_t)ret > ssl->out_left || ( INT_MAX > SIZE_MAX && ret > (int)SIZE_MAX ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, + ( "f_send returned %d bytes but only %" MBEDTLS_PRINTF_SIZET " bytes were sent", + ret, ssl->out_left ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + ssl->out_left -= ret; + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + ssl->out_hdr = ssl->out_buf; + } + else +#endif + { + ssl->out_hdr = ssl->out_buf + 8; + } + mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) ); + + return( 0 ); +} + +/* + * Functions to handle the DTLS retransmission state machine + */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) +/* + * Append current handshake message to current outgoing flight + */ +static int ssl_flight_append( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_flight_item *msg; + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_flight_append" ) ); + MBEDTLS_SSL_DEBUG_BUF( 4, "message appended to flight", + ssl->out_msg, ssl->out_msglen ); + + /* Allocate space for current message */ + if( ( msg = mbedtls_calloc( 1, sizeof( mbedtls_ssl_flight_item ) ) ) == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc %" MBEDTLS_PRINTF_SIZET " bytes failed", + sizeof( mbedtls_ssl_flight_item ) ) ); + return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); + } + + if( ( msg->p = mbedtls_calloc( 1, ssl->out_msglen ) ) == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc %" MBEDTLS_PRINTF_SIZET " bytes failed", + ssl->out_msglen ) ); + mbedtls_free( msg ); + return( MBEDTLS_ERR_SSL_ALLOC_FAILED ); + } + + /* Copy current handshake message with headers */ + memcpy( msg->p, ssl->out_msg, ssl->out_msglen ); + msg->len = ssl->out_msglen; + msg->type = ssl->out_msgtype; + msg->next = NULL; + + /* Append to the current flight */ + if( ssl->handshake->flight == NULL ) + ssl->handshake->flight = msg; + else + { + mbedtls_ssl_flight_item *cur = ssl->handshake->flight; + while( cur->next != NULL ) + cur = cur->next; + cur->next = msg; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_flight_append" ) ); + return( 0 ); +} + +/* + * Free the current flight of handshake messages + */ +void mbedtls_ssl_flight_free( mbedtls_ssl_flight_item *flight ) +{ + mbedtls_ssl_flight_item *cur = flight; + mbedtls_ssl_flight_item *next; + + while( cur != NULL ) + { + next = cur->next; + + mbedtls_free( cur->p ); + mbedtls_free( cur ); + + cur = next; + } +} + +/* + * Swap transform_out and out_ctr with the alternative ones + */ +static int ssl_swap_epochs( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_transform *tmp_transform; + unsigned char tmp_out_ctr[8]; + + if( ssl->transform_out == ssl->handshake->alt_transform_out ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "skip swap epochs" ) ); + return( 0 ); + } + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "swap epochs" ) ); + + /* Swap transforms */ + tmp_transform = ssl->transform_out; + ssl->transform_out = ssl->handshake->alt_transform_out; + ssl->handshake->alt_transform_out = tmp_transform; + + /* Swap epoch + sequence_number */ + memcpy( tmp_out_ctr, ssl->cur_out_ctr, 8 ); + memcpy( ssl->cur_out_ctr, ssl->handshake->alt_out_ctr, 8 ); + memcpy( ssl->handshake->alt_out_ctr, tmp_out_ctr, 8 ); + + /* Adjust to the newly activated transform */ + mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); + +#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) + if( mbedtls_ssl_hw_record_activate != NULL ) + { + int ret = mbedtls_ssl_hw_record_activate( ssl, MBEDTLS_SSL_CHANNEL_OUTBOUND ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_activate", ret ); + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + } + } +#endif + + return( 0 ); +} + +/* + * Retransmit the current flight of messages. + */ +int mbedtls_ssl_resend( mbedtls_ssl_context *ssl ) +{ + int ret = 0; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_resend" ) ); + + ret = mbedtls_ssl_flight_transmit( ssl ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_resend" ) ); + + return( ret ); +} + +/* + * Transmit or retransmit the current flight of messages. + * + * Need to remember the current message in case flush_output returns + * WANT_WRITE, causing us to exit this function and come back later. + * This function must be called until state is no longer SENDING. + */ +int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_flight_transmit" ) ); + + if( ssl->handshake->retransmit_state != MBEDTLS_SSL_RETRANS_SENDING ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialise flight transmission" ) ); + + ssl->handshake->cur_msg = ssl->handshake->flight; + ssl->handshake->cur_msg_p = ssl->handshake->flight->p + 12; + ret = ssl_swap_epochs( ssl ); + if( ret != 0 ) + return( ret ); + + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_SENDING; + } + + while( ssl->handshake->cur_msg != NULL ) + { + size_t max_frag_len; + const mbedtls_ssl_flight_item * const cur = ssl->handshake->cur_msg; + + int const is_finished = + ( cur->type == MBEDTLS_SSL_MSG_HANDSHAKE && + cur->p[0] == MBEDTLS_SSL_HS_FINISHED ); + + uint8_t const force_flush = ssl->disable_datagram_packing == 1 ? + SSL_FORCE_FLUSH : SSL_DONT_FORCE_FLUSH; + + /* Swap epochs before sending Finished: we can't do it after + * sending ChangeCipherSpec, in case write returns WANT_READ. + * Must be done before copying, may change out_msg pointer */ + if( is_finished && ssl->handshake->cur_msg_p == ( cur->p + 12 ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "swap epochs to send finished message" ) ); + ret = ssl_swap_epochs( ssl ); + if( ret != 0 ) + return( ret ); + } + + ret = ssl_get_remaining_payload_in_datagram( ssl ); + if( ret < 0 ) + return( ret ); + max_frag_len = (size_t) ret; + + /* CCS is copied as is, while HS messages may need fragmentation */ + if( cur->type == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) + { + if( max_frag_len == 0 ) + { + if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + return( ret ); + + continue; + } + + memcpy( ssl->out_msg, cur->p, cur->len ); + ssl->out_msglen = cur->len; + ssl->out_msgtype = cur->type; + + /* Update position inside current message */ + ssl->handshake->cur_msg_p += cur->len; + } + else + { + const unsigned char * const p = ssl->handshake->cur_msg_p; + const size_t hs_len = cur->len - 12; + const size_t frag_off = p - ( cur->p + 12 ); + const size_t rem_len = hs_len - frag_off; + size_t cur_hs_frag_len, max_hs_frag_len; + + if( ( max_frag_len < 12 ) || ( max_frag_len == 12 && hs_len != 0 ) ) + { + if( is_finished ) + { + ret = ssl_swap_epochs( ssl ); + if( ret != 0 ) + return( ret ); + } + + if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + return( ret ); + + continue; + } + max_hs_frag_len = max_frag_len - 12; + + cur_hs_frag_len = rem_len > max_hs_frag_len ? + max_hs_frag_len : rem_len; + + if( frag_off == 0 && cur_hs_frag_len != hs_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "fragmenting handshake message (%u > %u)", + (unsigned) cur_hs_frag_len, + (unsigned) max_hs_frag_len ) ); + } + + /* Messages are stored with handshake headers as if not fragmented, + * copy beginning of headers then fill fragmentation fields. + * Handshake headers: type(1) len(3) seq(2) f_off(3) f_len(3) */ + memcpy( ssl->out_msg, cur->p, 6 ); + + ssl->out_msg[6] = MBEDTLS_BYTE_2( frag_off ); + ssl->out_msg[7] = MBEDTLS_BYTE_1( frag_off ); + ssl->out_msg[8] = MBEDTLS_BYTE_0( frag_off ); + + ssl->out_msg[ 9] = MBEDTLS_BYTE_2( cur_hs_frag_len ); + ssl->out_msg[10] = MBEDTLS_BYTE_1( cur_hs_frag_len ); + ssl->out_msg[11] = MBEDTLS_BYTE_0( cur_hs_frag_len ); + + MBEDTLS_SSL_DEBUG_BUF( 3, "handshake header", ssl->out_msg, 12 ); + + /* Copy the handshake message content and set records fields */ + memcpy( ssl->out_msg + 12, p, cur_hs_frag_len ); + ssl->out_msglen = cur_hs_frag_len + 12; + ssl->out_msgtype = cur->type; + + /* Update position inside current message */ + ssl->handshake->cur_msg_p += cur_hs_frag_len; + } + + /* If done with the current message move to the next one if any */ + if( ssl->handshake->cur_msg_p >= cur->p + cur->len ) + { + if( cur->next != NULL ) + { + ssl->handshake->cur_msg = cur->next; + ssl->handshake->cur_msg_p = cur->next->p + 12; + } + else + { + ssl->handshake->cur_msg = NULL; + ssl->handshake->cur_msg_p = NULL; + } + } + + /* Actually send the message out */ + if( ( ret = mbedtls_ssl_write_record( ssl, force_flush ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); + return( ret ); + } + } + + if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + return( ret ); + + /* Update state and set timer */ + if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; + else + { + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING; + mbedtls_ssl_set_timer( ssl, ssl->handshake->retransmit_timeout ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_flight_transmit" ) ); + + return( 0 ); +} + +/* + * To be called when the last message of an incoming flight is received. + */ +void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl ) +{ + /* We won't need to resend that one any more */ + mbedtls_ssl_flight_free( ssl->handshake->flight ); + ssl->handshake->flight = NULL; + ssl->handshake->cur_msg = NULL; + + /* The next incoming flight will start with this msg_seq */ + ssl->handshake->in_flight_start_seq = ssl->handshake->in_msg_seq; + + /* We don't want to remember CCS's across flight boundaries. */ + ssl->handshake->buffering.seen_ccs = 0; + + /* Clear future message buffering structure. */ + mbedtls_ssl_buffering_free( ssl ); + + /* Cancel timer */ + mbedtls_ssl_set_timer( ssl, 0 ); + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + ssl->in_msg[0] == MBEDTLS_SSL_HS_FINISHED ) + { + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; + } + else + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_PREPARING; +} + +/* + * To be called when the last message of an outgoing flight is send. + */ +void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl ) +{ + ssl_reset_retransmit_timeout( ssl ); + mbedtls_ssl_set_timer( ssl, ssl->handshake->retransmit_timeout ); + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + ssl->in_msg[0] == MBEDTLS_SSL_HS_FINISHED ) + { + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED; + } + else + ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_WAITING; +} +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +/* + * Handshake layer functions + */ + +/* + * Write (DTLS: or queue) current handshake (including CCS) message. + * + * - fill in handshake headers + * - update handshake checksum + * - DTLS: save message for resending + * - then pass to the record layer + * + * DTLS: except for HelloRequest, messages are only queued, and will only be + * actually sent when calling flight_transmit() or resend(). + * + * Inputs: + * - ssl->out_msglen: 4 + actual handshake message len + * (4 is the size of handshake headers for TLS) + * - ssl->out_msg[0]: the handshake type (ClientHello, ServerHello, etc) + * - ssl->out_msg + 4: the handshake message body + * + * Outputs, ie state before passing to flight_append() or write_record(): + * - ssl->out_msglen: the length of the record contents + * (including handshake headers but excluding record headers) + * - ssl->out_msg: the record contents (handshake headers + content) + */ +int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + const size_t hs_len = ssl->out_msglen - 4; + const unsigned char hs_type = ssl->out_msg[0]; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write handshake message" ) ); + + /* + * Sanity checks + */ + if( ssl->out_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE && + ssl->out_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) + { + /* In SSLv3, the client might send a NoCertificate alert. */ +#if defined(MBEDTLS_SSL_PROTO_SSL3) && defined(MBEDTLS_SSL_CLI_C) + if( ! ( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 && + ssl->out_msgtype == MBEDTLS_SSL_MSG_ALERT && + ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ) ) +#endif /* MBEDTLS_SSL_PROTO_SSL3 && MBEDTLS_SSL_SRV_C */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } + + /* Whenever we send anything different from a + * HelloRequest we should be in a handshake - double check. */ + if( ! ( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + hs_type == MBEDTLS_SSL_HS_HELLO_REQUEST ) && + ssl->handshake == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->handshake != NULL && + ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } +#endif + + /* Double-check that we did not exceed the bounds + * of the outgoing record buffer. + * This should never fail as the various message + * writing functions must obey the bounds of the + * outgoing record buffer, but better be safe. + * + * Note: We deliberately do not check for the MTU or MFL here. + */ + if( ssl->out_msglen > MBEDTLS_SSL_OUT_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record too large: " + "size %" MBEDTLS_PRINTF_SIZET + ", maximum %" MBEDTLS_PRINTF_SIZET, + ssl->out_msglen, + (size_t) MBEDTLS_SSL_OUT_CONTENT_LEN ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* + * Fill handshake headers + */ + if( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) + { + ssl->out_msg[1] = MBEDTLS_BYTE_2( hs_len ); + ssl->out_msg[2] = MBEDTLS_BYTE_1( hs_len ); + ssl->out_msg[3] = MBEDTLS_BYTE_0( hs_len ); + + /* + * DTLS has additional fields in the Handshake layer, + * between the length field and the actual payload: + * uint16 message_seq; + * uint24 fragment_offset; + * uint24 fragment_length; + */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* Make room for the additional DTLS fields */ + if( MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen < 8 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS handshake message too large: " + "size %" MBEDTLS_PRINTF_SIZET ", maximum %" MBEDTLS_PRINTF_SIZET, + hs_len, + (size_t) ( MBEDTLS_SSL_OUT_CONTENT_LEN - 12 ) ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + + memmove( ssl->out_msg + 12, ssl->out_msg + 4, hs_len ); + ssl->out_msglen += 8; + + /* Write message_seq and update it, except for HelloRequest */ + if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) + { + MBEDTLS_PUT_UINT16_BE( ssl->handshake->out_msg_seq, ssl->out_msg, 4 ); + ++( ssl->handshake->out_msg_seq ); + } + else + { + ssl->out_msg[4] = 0; + ssl->out_msg[5] = 0; + } + + /* Handshake hashes are computed without fragmentation, + * so set frag_offset = 0 and frag_len = hs_len for now */ + memset( ssl->out_msg + 6, 0x00, 3 ); + memcpy( ssl->out_msg + 9, ssl->out_msg + 1, 3 ); + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + /* Update running hashes of handshake messages seen */ + if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) + ssl->handshake->update_checksum( ssl, ssl->out_msg, ssl->out_msglen ); + } + + /* Either send now, or just save to be sent (and resent) later */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ! ( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + hs_type == MBEDTLS_SSL_HS_HELLO_REQUEST ) ) + { + if( ( ret = ssl_flight_append( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_flight_append", ret ); + return( ret ); + } + } + else +#endif + { + if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_record", ret ); + return( ret ); + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write handshake message" ) ); + + return( 0 ); +} + +/* + * Record layer functions + */ + +/* + * Write current record. + * + * Uses: + * - ssl->out_msgtype: type of the message (AppData, Handshake, Alert, CCS) + * - ssl->out_msglen: length of the record content (excl headers) + * - ssl->out_msg: record content + */ +int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush ) +{ + int ret, done = 0; + size_t len = ssl->out_msglen; + uint8_t flush = force_flush; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write record" ) ); + +#if defined(MBEDTLS_ZLIB_SUPPORT) + if( ssl->transform_out != NULL && + ssl->session_out->compression == MBEDTLS_SSL_COMPRESS_DEFLATE ) + { + if( ( ret = ssl_compress_buf( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_compress_buf", ret ); + return( ret ); + } + + len = ssl->out_msglen; + } +#endif /*MBEDTLS_ZLIB_SUPPORT */ + +#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) + if( mbedtls_ssl_hw_record_write != NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "going for mbedtls_ssl_hw_record_write()" ) ); + + ret = mbedtls_ssl_hw_record_write( ssl ); + if( ret != 0 && ret != MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_write", ret ); + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + } + + if( ret == 0 ) + done = 1; + } +#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */ + if( !done ) + { + unsigned i; + size_t protected_record_size; +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t out_buf_len = ssl->out_buf_len; +#else + size_t out_buf_len = MBEDTLS_SSL_OUT_BUFFER_LEN; +#endif + /* Skip writing the record content type to after the encryption, + * as it may change when using the CID extension. */ + + mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, + ssl->conf->transport, ssl->out_hdr + 1 ); + + memcpy( ssl->out_ctr, ssl->cur_out_ctr, 8 ); + MBEDTLS_PUT_UINT16_BE( len, ssl->out_len, 0); + + if( ssl->transform_out != NULL ) + { + mbedtls_record rec; + + rec.buf = ssl->out_iv; + rec.buf_len = out_buf_len - ( ssl->out_iv - ssl->out_buf ); + rec.data_len = ssl->out_msglen; + rec.data_offset = ssl->out_msg - rec.buf; + + memcpy( &rec.ctr[0], ssl->out_ctr, 8 ); + mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver, + ssl->conf->transport, rec.ver ); + rec.type = ssl->out_msgtype; + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + /* The CID is set by mbedtls_ssl_encrypt_buf(). */ + rec.cid_len = 0; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + if( ( ret = mbedtls_ssl_encrypt_buf( ssl, ssl->transform_out, &rec, + ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_encrypt_buf", ret ); + return( ret ); + } + + if( rec.data_offset != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* Update the record content type and CID. */ + ssl->out_msgtype = rec.type; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID ) + memcpy( ssl->out_cid, rec.cid, rec.cid_len ); +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->out_msglen = len = rec.data_len; + MBEDTLS_PUT_UINT16_BE( rec.data_len, ssl->out_len, 0 ); + } + + protected_record_size = len + mbedtls_ssl_out_hdr_len( ssl ); + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + /* In case of DTLS, double-check that we don't exceed + * the remaining space in the datagram. */ + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + ret = ssl_get_remaining_space_in_datagram( ssl ); + if( ret < 0 ) + return( ret ); + + if( protected_record_size > (size_t) ret ) + { + /* Should never happen */ + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + /* Now write the potentially updated record content type. */ + ssl->out_hdr[0] = (unsigned char) ssl->out_msgtype; + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "output record: msgtype = %u, " + "version = [%u:%u], msglen = %" MBEDTLS_PRINTF_SIZET, + ssl->out_hdr[0], ssl->out_hdr[1], + ssl->out_hdr[2], len ) ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network", + ssl->out_hdr, protected_record_size ); + + ssl->out_left += protected_record_size; + ssl->out_hdr += protected_record_size; + mbedtls_ssl_update_out_pointers( ssl, ssl->transform_out ); + + for( i = 8; i > mbedtls_ssl_ep_len( ssl ); i-- ) + if( ++ssl->cur_out_ctr[i - 1] != 0 ) + break; + + /* The loop goes to its end iff the counter is wrapping */ + if( i == mbedtls_ssl_ep_len( ssl ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) ); + return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); + } + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + flush == SSL_DONT_FORCE_FLUSH ) + { + size_t remaining; + ret = ssl_get_remaining_payload_in_datagram( ssl ); + if( ret < 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_get_remaining_payload_in_datagram", + ret ); + return( ret ); + } + + remaining = (size_t) ret; + if( remaining == 0 ) + { + flush = SSL_FORCE_FLUSH; + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Still %u bytes available in current datagram", (unsigned) remaining ) ); + } + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + if( ( flush == SSL_FORCE_FLUSH ) && + ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret ); + return( ret ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write record" ) ); + + return( 0 ); +} + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl ) +{ + if( ssl->in_msglen < ssl->in_hslen || + memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 || + memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 ) + { + return( 1 ); + } + return( 0 ); +} + +static uint32_t ssl_get_hs_frag_len( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[9] << 16 ) | + ( ssl->in_msg[10] << 8 ) | + ssl->in_msg[11] ); +} + +static uint32_t ssl_get_hs_frag_off( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[6] << 16 ) | + ( ssl->in_msg[7] << 8 ) | + ssl->in_msg[8] ); +} + +static int ssl_check_hs_header( mbedtls_ssl_context const *ssl ) +{ + uint32_t msg_len, frag_off, frag_len; + + msg_len = ssl_get_hs_total_len( ssl ); + frag_off = ssl_get_hs_frag_off( ssl ); + frag_len = ssl_get_hs_frag_len( ssl ); + + if( frag_off > msg_len ) + return( -1 ); + + if( frag_len > msg_len - frag_off ) + return( -1 ); + + if( frag_len + 12 > ssl->in_msglen ) + return( -1 ); + + return( 0 ); +} + +/* + * Mark bits in bitmask (used for DTLS HS reassembly) + */ +static void ssl_bitmask_set( unsigned char *mask, size_t offset, size_t len ) +{ + unsigned int start_bits, end_bits; + + start_bits = 8 - ( offset % 8 ); + if( start_bits != 8 ) + { + size_t first_byte_idx = offset / 8; + + /* Special case */ + if( len <= start_bits ) + { + for( ; len != 0; len-- ) + mask[first_byte_idx] |= 1 << ( start_bits - len ); + + /* Avoid potential issues with offset or len becoming invalid */ + return; + } + + offset += start_bits; /* Now offset % 8 == 0 */ + len -= start_bits; + + for( ; start_bits != 0; start_bits-- ) + mask[first_byte_idx] |= 1 << ( start_bits - 1 ); + } + + end_bits = len % 8; + if( end_bits != 0 ) + { + size_t last_byte_idx = ( offset + len ) / 8; + + len -= end_bits; /* Now len % 8 == 0 */ + + for( ; end_bits != 0; end_bits-- ) + mask[last_byte_idx] |= 1 << ( 8 - end_bits ); + } + + memset( mask + offset / 8, 0xFF, len / 8 ); +} + +/* + * Check that bitmask is full + */ +static int ssl_bitmask_check( unsigned char *mask, size_t len ) +{ + size_t i; + + for( i = 0; i < len / 8; i++ ) + if( mask[i] != 0xFF ) + return( -1 ); + + for( i = 0; i < len % 8; i++ ) + if( ( mask[len / 8] & ( 1 << ( 7 - i ) ) ) == 0 ) + return( -1 ); + + return( 0 ); +} + +/* msg_len does not include the handshake header */ +static size_t ssl_get_reassembly_buffer_size( size_t msg_len, + unsigned add_bitmap ) +{ + size_t alloc_len; + + alloc_len = 12; /* Handshake header */ + alloc_len += msg_len; /* Content buffer */ + + if( add_bitmap ) + alloc_len += msg_len / 8 + ( msg_len % 8 != 0 ); /* Bitmap */ + + return( alloc_len ); +} + +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl ) +{ + return( ( ssl->in_msg[1] << 16 ) | + ( ssl->in_msg[2] << 8 ) | + ssl->in_msg[3] ); +} + +int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl ) +{ + if( ssl->in_msglen < mbedtls_ssl_hs_hdr_len( ssl ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake message too short: %" MBEDTLS_PRINTF_SIZET, + ssl->in_msglen ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ssl_get_hs_total_len( ssl ); + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "handshake message: msglen =" + " %" MBEDTLS_PRINTF_SIZET ", type = %u, hslen = %" MBEDTLS_PRINTF_SIZET, + ssl->in_msglen, ssl->in_msg[0], ssl->in_hslen ) ); + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned int recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; + + if( ssl_check_hs_header( ssl ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid handshake header" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + if( ssl->handshake != NULL && + ( ( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && + recv_msg_seq != ssl->handshake->in_msg_seq ) || + ( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && + ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) ) + { + if( recv_msg_seq > ssl->handshake->in_msg_seq ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)", + recv_msg_seq, + ssl->handshake->in_msg_seq ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + + /* Retransmit only on last message from previous flight, to avoid + * too many retransmissions. + * Besides, No sane server ever retransmits HelloVerifyRequest */ + if( recv_msg_seq == ssl->handshake->in_flight_start_seq - 1 && + ssl->in_msg[0] != MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "received message from last flight, " + "message_seq = %u, start_of_flight = %u", + recv_msg_seq, + ssl->handshake->in_flight_start_seq ) ); + + if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend", ret ); + return( ret ); + } + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "dropping out-of-sequence message: " + "message_seq = %u, expected = %u", + recv_msg_seq, + ssl->handshake->in_msg_seq ) ); + } + + return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); + } + /* Wait until message completion to increment in_msg_seq */ + + /* Message reassembly is handled alongside buffering of future + * messages; the commonality is that both handshake fragments and + * future messages cannot be forwarded immediately to the + * handshake logic layer. */ + if( ssl_hs_is_proper_fragment( ssl ) == 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + } + else +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + /* With TLS we don't handle fragmentation (for now) */ + if( ssl->in_msglen < ssl->in_hslen ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS handshake fragmentation not supported" ) ); + return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); + } + + return( 0 ); +} + +void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && hs != NULL ) + { + ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen ); + } + + /* Handshake message is complete, increment counter */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->handshake != NULL ) + { + unsigned offset; + mbedtls_ssl_hs_buffer *hs_buf; + + /* Increment handshake sequence number */ + hs->in_msg_seq++; + + /* + * Clear up handshake buffering and reassembly structure. + */ + + /* Free first entry */ + ssl_buffering_free_slot( ssl, 0 ); + + /* Shift all other entries */ + for( offset = 0, hs_buf = &hs->buffering.hs[0]; + offset + 1 < MBEDTLS_SSL_MAX_BUFFERED_HS; + offset++, hs_buf++ ) + { + *hs_buf = *(hs_buf + 1); + } + + /* Create a fresh last entry */ + memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); + } +#endif +} + +/* + * DTLS anti-replay: RFC 6347 4.1.2.6 + * + * in_window is a field of bits numbered from 0 (lsb) to 63 (msb). + * Bit n is set iff record number in_window_top - n has been seen. + * + * Usually, in_window_top is the last record number seen and the lsb of + * in_window is set. The only exception is the initial state (record number 0 + * not seen yet). + */ +#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) +void mbedtls_ssl_dtls_replay_reset( mbedtls_ssl_context *ssl ) +{ + ssl->in_window_top = 0; + ssl->in_window = 0; +} + +static inline uint64_t ssl_load_six_bytes( unsigned char *buf ) +{ + return( ( (uint64_t) buf[0] << 40 ) | + ( (uint64_t) buf[1] << 32 ) | + ( (uint64_t) buf[2] << 24 ) | + ( (uint64_t) buf[3] << 16 ) | + ( (uint64_t) buf[4] << 8 ) | + ( (uint64_t) buf[5] ) ); +} + +static int mbedtls_ssl_dtls_record_replay_check( mbedtls_ssl_context *ssl, uint8_t *record_in_ctr ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *original_in_ctr; + + // save original in_ctr + original_in_ctr = ssl->in_ctr; + + // use counter from record + ssl->in_ctr = record_in_ctr; + + ret = mbedtls_ssl_dtls_replay_check( (mbedtls_ssl_context const *) ssl ); + + // restore the counter + ssl->in_ctr = original_in_ctr; + + return ret; +} + +/* + * Return 0 if sequence number is acceptable, -1 otherwise + */ +int mbedtls_ssl_dtls_replay_check( mbedtls_ssl_context const *ssl ) +{ + uint64_t rec_seqnum = ssl_load_six_bytes( ssl->in_ctr + 2 ); + uint64_t bit; + + if( ssl->conf->anti_replay == MBEDTLS_SSL_ANTI_REPLAY_DISABLED ) + return( 0 ); + + if( rec_seqnum > ssl->in_window_top ) + return( 0 ); + + bit = ssl->in_window_top - rec_seqnum; + + if( bit >= 64 ) + return( -1 ); + + if( ( ssl->in_window & ( (uint64_t) 1 << bit ) ) != 0 ) + return( -1 ); + + return( 0 ); +} + +/* + * Update replay window on new validated record + */ +void mbedtls_ssl_dtls_replay_update( mbedtls_ssl_context *ssl ) +{ + uint64_t rec_seqnum = ssl_load_six_bytes( ssl->in_ctr + 2 ); + + if( ssl->conf->anti_replay == MBEDTLS_SSL_ANTI_REPLAY_DISABLED ) + return; + + if( rec_seqnum > ssl->in_window_top ) + { + /* Update window_top and the contents of the window */ + uint64_t shift = rec_seqnum - ssl->in_window_top; + + if( shift >= 64 ) + ssl->in_window = 1; + else + { + ssl->in_window <<= shift; + ssl->in_window |= 1; + } + + ssl->in_window_top = rec_seqnum; + } + else + { + /* Mark that number as seen in the current window */ + uint64_t bit = ssl->in_window_top - rec_seqnum; + + if( bit < 64 ) /* Always true, but be extra sure */ + ssl->in_window |= (uint64_t) 1 << bit; + } +} +#endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */ + +#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) +/* + * Without any SSL context, check if a datagram looks like a ClientHello with + * a valid cookie, and if it doesn't, generate a HelloVerifyRequest message. + * Both input and output include full DTLS headers. + * + * - if cookie is valid, return 0 + * - if ClientHello looks superficially valid but cookie is not, + * fill obuf and set olen, then + * return MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED + * - otherwise return a specific error code + */ +static int ssl_check_dtls_clihlo_cookie( + mbedtls_ssl_cookie_write_t *f_cookie_write, + mbedtls_ssl_cookie_check_t *f_cookie_check, + void *p_cookie, + const unsigned char *cli_id, size_t cli_id_len, + const unsigned char *in, size_t in_len, + unsigned char *obuf, size_t buf_len, size_t *olen ) +{ + size_t sid_len, cookie_len; + unsigned char *p; + + /* + * Structure of ClientHello with record and handshake headers, + * and expected values. We don't need to check a lot, more checks will be + * done when actually parsing the ClientHello - skipping those checks + * avoids code duplication and does not make cookie forging any easier. + * + * 0-0 ContentType type; copied, must be handshake + * 1-2 ProtocolVersion version; copied + * 3-4 uint16 epoch; copied, must be 0 + * 5-10 uint48 sequence_number; copied + * 11-12 uint16 length; (ignored) + * + * 13-13 HandshakeType msg_type; (ignored) + * 14-16 uint24 length; (ignored) + * 17-18 uint16 message_seq; copied + * 19-21 uint24 fragment_offset; copied, must be 0 + * 22-24 uint24 fragment_length; (ignored) + * + * 25-26 ProtocolVersion client_version; (ignored) + * 27-58 Random random; (ignored) + * 59-xx SessionID session_id; 1 byte len + sid_len content + * 60+ opaque cookie<0..2^8-1>; 1 byte len + content + * ... + * + * Minimum length is 61 bytes. + */ + if( in_len < 61 || + in[0] != MBEDTLS_SSL_MSG_HANDSHAKE || + in[3] != 0 || in[4] != 0 || + in[19] != 0 || in[20] != 0 || in[21] != 0 ) + { + return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); + } + + sid_len = in[59]; + if( sid_len > in_len - 61 ) + return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); + + cookie_len = in[60 + sid_len]; + if( cookie_len > in_len - 60 ) + return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); + + if( f_cookie_check( p_cookie, in + sid_len + 61, cookie_len, + cli_id, cli_id_len ) == 0 ) + { + /* Valid cookie */ + return( 0 ); + } + + /* + * If we get here, we've got an invalid cookie, let's prepare HVR. + * + * 0-0 ContentType type; copied + * 1-2 ProtocolVersion version; copied + * 3-4 uint16 epoch; copied + * 5-10 uint48 sequence_number; copied + * 11-12 uint16 length; olen - 13 + * + * 13-13 HandshakeType msg_type; hello_verify_request + * 14-16 uint24 length; olen - 25 + * 17-18 uint16 message_seq; copied + * 19-21 uint24 fragment_offset; copied + * 22-24 uint24 fragment_length; olen - 25 + * + * 25-26 ProtocolVersion server_version; 0xfe 0xff + * 27-27 opaque cookie<0..2^8-1>; cookie_len = olen - 27, cookie + * + * Minimum length is 28. + */ + if( buf_len < 28 ) + return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL ); + + /* Copy most fields and adapt others */ + memcpy( obuf, in, 25 ); + obuf[13] = MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST; + obuf[25] = 0xfe; + obuf[26] = 0xff; + + /* Generate and write actual cookie */ + p = obuf + 28; + if( f_cookie_write( p_cookie, + &p, obuf + buf_len, cli_id, cli_id_len ) != 0 ) + { + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + *olen = p - obuf; + + /* Go back and fill length fields */ + obuf[27] = (unsigned char)( *olen - 28 ); + + obuf[14] = obuf[22] = MBEDTLS_BYTE_2( *olen - 25 ); + obuf[15] = obuf[23] = MBEDTLS_BYTE_1( *olen - 25 ); + obuf[16] = obuf[24] = MBEDTLS_BYTE_0( *olen - 25 ); + + MBEDTLS_PUT_UINT16_BE( *olen - 13, obuf, 11 ); + + return( MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED ); +} + +/* + * Handle possible client reconnect with the same UDP quadruplet + * (RFC 6347 Section 4.2.8). + * + * Called by ssl_parse_record_header() in case we receive an epoch 0 record + * that looks like a ClientHello. + * + * - if the input looks like a ClientHello without cookies, + * send back HelloVerifyRequest, then return 0 + * - if the input looks like a ClientHello with a valid cookie, + * reset the session of the current context, and + * return MBEDTLS_ERR_SSL_CLIENT_RECONNECT + * - if anything goes wrong, return a specific error code + * + * This function is called (through ssl_check_client_reconnect()) when an + * unexpected record is found in ssl_get_next_record(), which will discard the + * record if we return 0, and bubble up the return value otherwise (this + * includes the case of MBEDTLS_ERR_SSL_CLIENT_RECONNECT and of unexpected + * errors, and is the right thing to do in both cases). + */ +static int ssl_handle_possible_reconnect( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t len; + + if( ssl->conf->f_cookie_write == NULL || + ssl->conf->f_cookie_check == NULL ) + { + /* If we can't use cookies to verify reachability of the peer, + * drop the record. */ + MBEDTLS_SSL_DEBUG_MSG( 1, ( "no cookie callbacks, " + "can't check reconnect validity" ) ); + return( 0 ); + } + + ret = ssl_check_dtls_clihlo_cookie( + ssl->conf->f_cookie_write, + ssl->conf->f_cookie_check, + ssl->conf->p_cookie, + ssl->cli_id, ssl->cli_id_len, + ssl->in_buf, ssl->in_left, + ssl->out_buf, MBEDTLS_SSL_OUT_CONTENT_LEN, &len ); + + MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_dtls_clihlo_cookie", ret ); + + if( ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED ) + { + int send_ret; + MBEDTLS_SSL_DEBUG_MSG( 1, ( "sending HelloVerifyRequest" ) ); + MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network", + ssl->out_buf, len ); + /* Don't check write errors as we can't do anything here. + * If the error is permanent we'll catch it later, + * if it's not, then hopefully it'll work next time. */ + send_ret = ssl->f_send( ssl->p_bio, ssl->out_buf, len ); + MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", send_ret ); + (void) send_ret; + + return( 0 ); + } + + if( ret == 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "cookie is valid, resetting context" ) ); + if( ( ret = mbedtls_ssl_session_reset_int( ssl, 1 ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "reset", ret ); + return( ret ); + } + + return( MBEDTLS_ERR_SSL_CLIENT_RECONNECT ); + } + + return( ret ); +} +#endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */ + +static int ssl_check_record_type( uint8_t record_type ) +{ + if( record_type != MBEDTLS_SSL_MSG_HANDSHAKE && + record_type != MBEDTLS_SSL_MSG_ALERT && + record_type != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC && + record_type != MBEDTLS_SSL_MSG_APPLICATION_DATA ) + { + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + return( 0 ); +} + +/* + * ContentType type; + * ProtocolVersion version; + * uint16 epoch; // DTLS only + * uint48 sequence_number; // DTLS only + * uint16 length; + * + * Return 0 if header looks sane (and, for DTLS, the record is expected) + * MBEDTLS_ERR_SSL_INVALID_RECORD if the header looks bad, + * MBEDTLS_ERR_SSL_UNEXPECTED_RECORD (DTLS only) if sane but unexpected. + * + * With DTLS, mbedtls_ssl_read_record() will: + * 1. proceed with the record if this function returns 0 + * 2. drop only the current record if this function returns UNEXPECTED_RECORD + * 3. return CLIENT_RECONNECT if this function return that value + * 4. drop the whole datagram if this function returns anything else. + * Point 2 is needed when the peer is resending, and we have already received + * the first record from a datagram but are still waiting for the others. + */ +static int ssl_parse_record_header( mbedtls_ssl_context const *ssl, + unsigned char *buf, + size_t len, + mbedtls_record *rec ) +{ + int major_ver, minor_ver; + + size_t const rec_hdr_type_offset = 0; + size_t const rec_hdr_type_len = 1; + + size_t const rec_hdr_version_offset = rec_hdr_type_offset + + rec_hdr_type_len; + size_t const rec_hdr_version_len = 2; + + size_t const rec_hdr_ctr_len = 8; +#if defined(MBEDTLS_SSL_PROTO_DTLS) + uint32_t rec_epoch; + size_t const rec_hdr_ctr_offset = rec_hdr_version_offset + + rec_hdr_version_len; + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + size_t const rec_hdr_cid_offset = rec_hdr_ctr_offset + + rec_hdr_ctr_len; + size_t rec_hdr_cid_len = 0; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + size_t rec_hdr_len_offset; /* To be determined */ + size_t const rec_hdr_len_len = 2; + + /* + * Check minimum lengths for record header. + */ + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + rec_hdr_len_offset = rec_hdr_ctr_offset + rec_hdr_ctr_len; + } + else +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + { + rec_hdr_len_offset = rec_hdr_version_offset + rec_hdr_version_len; + } + + if( len < rec_hdr_len_offset + rec_hdr_len_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "datagram of length %u too small to hold DTLS record header of length %u", + (unsigned) len, + (unsigned)( rec_hdr_len_len + rec_hdr_len_len ) ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + /* + * Parse and validate record content type + */ + + rec->type = buf[ rec_hdr_type_offset ]; + + /* Check record content type */ +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + rec->cid_len = 0; + + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->conf->cid_len != 0 && + rec->type == MBEDTLS_SSL_MSG_CID ) + { + /* Shift pointers to account for record header including CID + * struct { + * ContentType special_type = tls12_cid; + * ProtocolVersion version; + * uint16 epoch; + * uint48 sequence_number; + * opaque cid[cid_length]; // Additional field compared to + * // default DTLS record format + * uint16 length; + * opaque enc_content[DTLSCiphertext.length]; + * } DTLSCiphertext; + */ + + /* So far, we only support static CID lengths + * fixed in the configuration. */ + rec_hdr_cid_len = ssl->conf->cid_len; + rec_hdr_len_offset += rec_hdr_cid_len; + + if( len < rec_hdr_len_offset + rec_hdr_len_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "datagram of length %u too small to hold DTLS record header including CID, length %u", + (unsigned) len, + (unsigned)( rec_hdr_len_offset + rec_hdr_len_len ) ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + /* configured CID len is guaranteed at most 255, see + * MBEDTLS_SSL_CID_OUT_LEN_MAX in check_config.h */ + rec->cid_len = (uint8_t) rec_hdr_cid_len; + memcpy( rec->cid, buf + rec_hdr_cid_offset, rec_hdr_cid_len ); + } + else +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + { + if( ssl_check_record_type( rec->type ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "unknown record type %u", + (unsigned) rec->type ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + } + + /* + * Parse and validate record version + */ + + rec->ver[0] = buf[ rec_hdr_version_offset + 0 ]; + rec->ver[1] = buf[ rec_hdr_version_offset + 1 ]; + mbedtls_ssl_read_version( &major_ver, &minor_ver, + ssl->conf->transport, + &rec->ver[0] ); + + if( major_ver != ssl->major_ver ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "major version mismatch" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + if( minor_ver > ssl->conf->max_minor_ver ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "minor version mismatch" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + /* + * Parse/Copy record sequence number. + */ + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* Copy explicit record sequence number from input buffer. */ + memcpy( &rec->ctr[0], buf + rec_hdr_ctr_offset, + rec_hdr_ctr_len ); + } + else +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + { + /* Copy implicit record sequence number from SSL context structure. */ + memcpy( &rec->ctr[0], ssl->in_ctr, rec_hdr_ctr_len ); + } + + /* + * Parse record length. + */ + + rec->data_offset = rec_hdr_len_offset + rec_hdr_len_len; + rec->data_len = ( (size_t) buf[ rec_hdr_len_offset + 0 ] << 8 ) | + ( (size_t) buf[ rec_hdr_len_offset + 1 ] << 0 ); + MBEDTLS_SSL_DEBUG_BUF( 4, "input record header", buf, rec->data_offset ); + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "input record: msgtype = %u, " + "version = [%d:%d], msglen = %" MBEDTLS_PRINTF_SIZET, + rec->type, + major_ver, minor_ver, rec->data_len ) ); + + rec->buf = buf; + rec->buf_len = rec->data_offset + rec->data_len; + + if( rec->data_len == 0 ) + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + + /* + * DTLS-related tests. + * Check epoch before checking length constraint because + * the latter varies with the epoch. E.g., if a ChangeCipherSpec + * message gets duplicated before the corresponding Finished message, + * the second ChangeCipherSpec should be discarded because it belongs + * to an old epoch, but not because its length is shorter than + * the minimum record length for packets using the new record transform. + * Note that these two kinds of failures are handled differently, + * as an unexpected record is silently skipped but an invalid + * record leads to the entire datagram being dropped. + */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + rec_epoch = ( rec->ctr[0] << 8 ) | rec->ctr[1]; + + /* Check that the datagram is large enough to contain a record + * of the advertised length. */ + if( len < rec->data_offset + rec->data_len ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Datagram of length %u too small to contain record of advertised length %u.", + (unsigned) len, + (unsigned)( rec->data_offset + rec->data_len ) ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + /* Records from other, non-matching epochs are silently discarded. + * (The case of same-port Client reconnects must be considered in + * the caller). */ + if( rec_epoch != ssl->in_epoch ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "record from another epoch: " + "expected %u, received %lu", + ssl->in_epoch, (unsigned long) rec_epoch ) ); + + /* Records from the next epoch are considered for buffering + * (concretely: early Finished messages). */ + if( rec_epoch == (unsigned) ssl->in_epoch + 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Consider record for buffering" ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } + + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } +#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) + /* For records from the correct epoch, check whether their + * sequence number has been seen before. */ + else if( mbedtls_ssl_dtls_record_replay_check( (mbedtls_ssl_context *) ssl, + &rec->ctr[0] ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "replayed record" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } +#endif + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + return( 0 ); +} + + +#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) +static int ssl_check_client_reconnect( mbedtls_ssl_context *ssl ) +{ + unsigned int rec_epoch = ( ssl->in_ctr[0] << 8 ) | ssl->in_ctr[1]; + + /* + * Check for an epoch 0 ClientHello. We can't use in_msg here to + * access the first byte of record content (handshake type), as we + * have an active transform (possibly iv_len != 0), so use the + * fact that the record header len is 13 instead. + */ + if( rec_epoch == 0 && + ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && + ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER && + ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + ssl->in_left > 13 && + ssl->in_buf[13] == MBEDTLS_SSL_HS_CLIENT_HELLO ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "possible client reconnect " + "from the same port" ) ); + return( ssl_handle_possible_reconnect( ssl ) ); + } + + return( 0 ); +} +#endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */ + +/* + * If applicable, decrypt record content + */ +static int ssl_prepare_record_content( mbedtls_ssl_context *ssl, + mbedtls_record *rec ) +{ + int ret, done = 0; + + MBEDTLS_SSL_DEBUG_BUF( 4, "input record from network", + rec->buf, rec->buf_len ); + +#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) + if( mbedtls_ssl_hw_record_read != NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "going for mbedtls_ssl_hw_record_read()" ) ); + + ret = mbedtls_ssl_hw_record_read( ssl ); + if( ret != 0 && ret != MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_read", ret ); + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + } + + if( ret == 0 ) + done = 1; + } +#endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */ + if( !done && ssl->transform_in != NULL ) + { + unsigned char const old_msg_type = rec->type; + + if( ( ret = mbedtls_ssl_decrypt_buf( ssl, ssl->transform_in, + rec ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_decrypt_buf", ret ); + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_CID && + ssl->conf->ignore_unexpected_cid + == MBEDTLS_SSL_UNEXPECTED_CID_IGNORE ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ignoring unexpected CID" ) ); + ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING; + } +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + return( ret ); + } + + if( old_msg_type != rec->type ) + { + MBEDTLS_SSL_DEBUG_MSG( 4, ( "record type after decrypt (before %d): %d", + old_msg_type, rec->type ) ); + } + + MBEDTLS_SSL_DEBUG_BUF( 4, "input payload after decrypt", + rec->buf + rec->data_offset, rec->data_len ); + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + /* We have already checked the record content type + * in ssl_parse_record_header(), failing or silently + * dropping the record in the case of an unknown type. + * + * Since with the use of CIDs, the record content type + * might change during decryption, re-check the record + * content type, but treat a failure as fatal this time. */ + if( ssl_check_record_type( rec->type ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "unknown record type" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + if( rec->data_len == 0 ) + { +#if defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 + && rec->type != MBEDTLS_SSL_MSG_APPLICATION_DATA ) + { + /* TLS v1.2 explicitly disallows zero-length messages which are not application data */ + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid zero-length message type: %d", ssl->in_msgtype ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } +#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */ + + ssl->nb_zero++; + + /* + * Three or more empty messages may be a DoS attack + * (excessive CPU consumption). + */ + if( ssl->nb_zero > 3 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "received four consecutive empty " + "messages, possible DoS attack" ) ); + /* Treat the records as if they were not properly authenticated, + * thereby failing the connection if we see more than allowed + * by the configured bad MAC threshold. */ + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } + } + else + ssl->nb_zero = 0; + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + ; /* in_ctr read from peer, not maintained internally */ + } + else +#endif + { + unsigned i; + for( i = 8; i > mbedtls_ssl_ep_len( ssl ); i-- ) + if( ++ssl->in_ctr[i - 1] != 0 ) + break; + + /* The loop goes to its end iff the counter is wrapping */ + if( i == mbedtls_ssl_ep_len( ssl ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "incoming message counter would wrap" ) ); + return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); + } + } + + } + +#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + mbedtls_ssl_dtls_replay_update( ssl ); + } +#endif + + /* Check actual (decrypted) record content length against + * configured maximum. */ + if( ssl->in_msglen > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + return( 0 ); +} + +/* + * Read a record. + * + * Silently ignore non-fatal alert (and for DTLS, invalid records as well, + * RFC 6347 4.1.2.7) and continue reading until a valid record is found. + * + */ + +/* Helper functions for mbedtls_ssl_read_record(). */ +static int ssl_consume_current_message( mbedtls_ssl_context *ssl ); +static int ssl_get_next_record( mbedtls_ssl_context *ssl ); +static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ); + +int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl, + unsigned update_hs_digest ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> read record" ) ); + + if( ssl->keep_current_message == 0 ) + { + do { + + ret = ssl_consume_current_message( ssl ); + if( ret != 0 ) + return( ret ); + + if( ssl_record_is_in_progress( ssl ) == 0 ) + { +#if defined(MBEDTLS_SSL_PROTO_DTLS) + int have_buffered = 0; + + /* We only check for buffered messages if the + * current datagram is fully consumed. */ + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl_next_record_is_in_datagram( ssl ) == 0 ) + { + if( ssl_load_buffered_message( ssl ) == 0 ) + have_buffered = 1; + } + + if( have_buffered == 0 ) +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + { + ret = ssl_get_next_record( ssl ); + if( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ) + continue; + + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_get_next_record" ), ret ); + return( ret ); + } + } + } + + ret = mbedtls_ssl_handle_message_type( ssl ); + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) + { + /* Buffer future message */ + ret = ssl_buffer_message( ssl ); + if( ret != 0 ) + return( ret ); + + ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING; + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + } while( MBEDTLS_ERR_SSL_NON_FATAL == ret || + MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret ); + + if( 0 != ret ) + { + MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret ); + return( ret ); + } + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE && + update_hs_digest == 1 ) + { + mbedtls_ssl_update_handshake_status( ssl ); + } + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "reuse previously read message" ) ); + ssl->keep_current_message = 0; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= read record" ) ); + + return( 0 ); +} + +#if defined(MBEDTLS_SSL_PROTO_DTLS) +static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl ) +{ + if( ssl->in_left > ssl->next_record_offset ) + return( 1 ); + + return( 0 ); +} + +static int ssl_load_buffered_message( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + mbedtls_ssl_hs_buffer * hs_buf; + int ret = 0; + + if( hs == NULL ) + return( -1 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_messsage" ) ); + + if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC || + ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) + { + /* Check if we have seen a ChangeCipherSpec before. + * If yes, synthesize a CCS record. */ + if( !hs->buffering.seen_ccs ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "CCS not seen in the current flight" ) ); + ret = -1; + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Injecting buffered CCS message" ) ); + ssl->in_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC; + ssl->in_msglen = 1; + ssl->in_msg[0] = 1; + + /* As long as they are equal, the exact value doesn't matter. */ + ssl->in_left = 0; + ssl->next_record_offset = 0; + + hs->buffering.seen_ccs = 0; + goto exit; + } + +#if defined(MBEDTLS_DEBUG_C) + /* Debug only */ + { + unsigned offset; + for( offset = 1; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) + { + hs_buf = &hs->buffering.hs[offset]; + if( hs_buf->is_valid == 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Future message with sequence number %u %s buffered.", + hs->in_msg_seq + offset, + hs_buf->is_complete ? "fully" : "partially" ) ); + } + } + } +#endif /* MBEDTLS_DEBUG_C */ + + /* Check if we have buffered and/or fully reassembled the + * next handshake message. */ + hs_buf = &hs->buffering.hs[0]; + if( ( hs_buf->is_valid == 1 ) && ( hs_buf->is_complete == 1 ) ) + { + /* Synthesize a record containing the buffered HS message. */ + size_t msg_len = ( hs_buf->data[1] << 16 ) | + ( hs_buf->data[2] << 8 ) | + hs_buf->data[3]; + + /* Double-check that we haven't accidentally buffered + * a message that doesn't fit into the input buffer. */ + if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message has been buffered - load" ) ); + MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered handshake message (incl. header)", + hs_buf->data, msg_len + 12 ); + + ssl->in_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; + ssl->in_hslen = msg_len + 12; + ssl->in_msglen = msg_len + 12; + memcpy( ssl->in_msg, hs_buf->data, ssl->in_hslen ); + + ret = 0; + goto exit; + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message %u not or only partially bufffered", + hs->in_msg_seq ) ); + } + + ret = -1; + +exit: + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_message" ) ); + return( ret ); +} + +static int ssl_buffer_make_space( mbedtls_ssl_context *ssl, + size_t desired ) +{ + int offset; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Attempt to free buffered messages to have %u bytes available", + (unsigned) desired ) ); + + /* Get rid of future records epoch first, if such exist. */ + ssl_free_buffered_record( ssl ); + + /* Check if we have enough space available now. */ + if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing future epoch record" ) ); + return( 0 ); + } + + /* We don't have enough space to buffer the next expected handshake + * message. Remove buffers used for future messages to gain space, + * starting with the most distant one. */ + for( offset = MBEDTLS_SSL_MAX_BUFFERED_HS - 1; + offset >= 0; offset-- ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Free buffering slot %d to make space for reassembly of next handshake message", + offset ) ); + + ssl_buffering_free_slot( ssl, (uint8_t) offset ); + + /* Check if we have enough space available now. */ + if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing buffered HS messages" ) ); + return( 0 ); + } + } + + return( -1 ); +} + +static int ssl_buffer_message( mbedtls_ssl_context *ssl ) +{ + int ret = 0; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + if( hs == NULL ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_buffer_message" ) ); + + switch( ssl->in_msgtype ) + { + case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC: + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Remember CCS message" ) ); + + hs->buffering.seen_ccs = 1; + break; + + case MBEDTLS_SSL_MSG_HANDSHAKE: + { + unsigned recv_msg_seq_offset; + unsigned recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5]; + mbedtls_ssl_hs_buffer *hs_buf; + size_t msg_len = ssl->in_hslen - 12; + + /* We should never receive an old handshake + * message - double-check nonetheless. */ + if( recv_msg_seq < ssl->handshake->in_msg_seq ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + recv_msg_seq_offset = recv_msg_seq - ssl->handshake->in_msg_seq; + if( recv_msg_seq_offset >= MBEDTLS_SSL_MAX_BUFFERED_HS ) + { + /* Silently ignore -- message too far in the future */ + MBEDTLS_SSL_DEBUG_MSG( 2, + ( "Ignore future HS message with sequence number %u, " + "buffering window %u - %u", + recv_msg_seq, ssl->handshake->in_msg_seq, + ssl->handshake->in_msg_seq + MBEDTLS_SSL_MAX_BUFFERED_HS - 1 ) ); + + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering HS message with sequence number %u, offset %u ", + recv_msg_seq, recv_msg_seq_offset ) ); + + hs_buf = &hs->buffering.hs[ recv_msg_seq_offset ]; + + /* Check if the buffering for this seq nr has already commenced. */ + if( !hs_buf->is_valid ) + { + size_t reassembly_buf_sz; + + hs_buf->is_fragmented = + ( ssl_hs_is_proper_fragment( ssl ) == 1 ); + + /* We copy the message back into the input buffer + * after reassembly, so check that it's not too large. + * This is an implementation-specific limitation + * and not one from the standard, hence it is not + * checked in ssl_check_hs_header(). */ + if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + /* Ignore message */ + goto exit; + } + + /* Check if we have enough space to buffer the message. */ + if( hs->buffering.total_bytes_buffered > + MBEDTLS_SSL_DTLS_MAX_BUFFERING ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + reassembly_buf_sz = ssl_get_reassembly_buffer_size( msg_len, + hs_buf->is_fragmented ); + + if( reassembly_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + if( recv_msg_seq_offset > 0 ) + { + /* If we can't buffer a future message because + * of space limitations -- ignore. */ + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %" MBEDTLS_PRINTF_SIZET + " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET + " (already %" MBEDTLS_PRINTF_SIZET + " bytes buffered) -- ignore\n", + msg_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, + hs->buffering.total_bytes_buffered ) ); + goto exit; + } + else + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %" MBEDTLS_PRINTF_SIZET + " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET + " (already %" MBEDTLS_PRINTF_SIZET + " bytes buffered) -- attempt to make space by freeing buffered future messages\n", + msg_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, + hs->buffering.total_bytes_buffered ) ); + } + + if( ssl_buffer_make_space( ssl, reassembly_buf_sz ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reassembly of next message of size %" MBEDTLS_PRINTF_SIZET + " (%" MBEDTLS_PRINTF_SIZET " with bitmap) would exceed" + " the compile-time limit %" MBEDTLS_PRINTF_SIZET + " (already %" MBEDTLS_PRINTF_SIZET + " bytes buffered) -- fail\n", + msg_len, + reassembly_buf_sz, + (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, + hs->buffering.total_bytes_buffered ) ); + ret = MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL; + goto exit; + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %" MBEDTLS_PRINTF_SIZET, + msg_len ) ); + + hs_buf->data = mbedtls_calloc( 1, reassembly_buf_sz ); + if( hs_buf->data == NULL ) + { + ret = MBEDTLS_ERR_SSL_ALLOC_FAILED; + goto exit; + } + hs_buf->data_len = reassembly_buf_sz; + + /* Prepare final header: copy msg_type, length and message_seq, + * then add standardised fragment_offset and fragment_length */ + memcpy( hs_buf->data, ssl->in_msg, 6 ); + memset( hs_buf->data + 6, 0, 3 ); + memcpy( hs_buf->data + 9, hs_buf->data + 1, 3 ); + + hs_buf->is_valid = 1; + + hs->buffering.total_bytes_buffered += reassembly_buf_sz; + } + else + { + /* Make sure msg_type and length are consistent */ + if( memcmp( hs_buf->data, ssl->in_msg, 4 ) != 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "Fragment header mismatch - ignore" ) ); + /* Ignore */ + goto exit; + } + } + + if( !hs_buf->is_complete ) + { + size_t frag_len, frag_off; + unsigned char * const msg = hs_buf->data + 12; + + /* + * Check and copy current fragment + */ + + /* Validation of header fields already done in + * mbedtls_ssl_prepare_handshake_record(). */ + frag_off = ssl_get_hs_frag_off( ssl ); + frag_len = ssl_get_hs_frag_len( ssl ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %" MBEDTLS_PRINTF_SIZET + ", length = %" MBEDTLS_PRINTF_SIZET, + frag_off, frag_len ) ); + memcpy( msg + frag_off, ssl->in_msg + 12, frag_len ); + + if( hs_buf->is_fragmented ) + { + unsigned char * const bitmask = msg + msg_len; + ssl_bitmask_set( bitmask, frag_off, frag_len ); + hs_buf->is_complete = ( ssl_bitmask_check( bitmask, + msg_len ) == 0 ); + } + else + { + hs_buf->is_complete = 1; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "message %scomplete", + hs_buf->is_complete ? "" : "not yet " ) ); + } + + break; + } + + default: + /* We don't buffer other types of messages. */ + break; + } + +exit: + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_buffer_message" ) ); + return( ret ); +} +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +static int ssl_consume_current_message( mbedtls_ssl_context *ssl ) +{ + /* + * Consume last content-layer message and potentially + * update in_msglen which keeps track of the contents' + * consumption state. + * + * (1) Handshake messages: + * Remove last handshake message, move content + * and adapt in_msglen. + * + * (2) Alert messages: + * Consume whole record content, in_msglen = 0. + * + * (3) Change cipher spec: + * Consume whole record content, in_msglen = 0. + * + * (4) Application data: + * Don't do anything - the record layer provides + * the application data as a stream transport + * and consumes through mbedtls_ssl_read only. + * + */ + + /* Case (1): Handshake messages */ + if( ssl->in_hslen != 0 ) + { + /* Hard assertion to be sure that no application data + * is in flight, as corrupting ssl->in_msglen during + * ssl->in_offt != NULL is fatal. */ + if( ssl->in_offt != NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + /* + * Get next Handshake message in the current record + */ + + /* Notes: + * (1) in_hslen is not necessarily the size of the + * current handshake content: If DTLS handshake + * fragmentation is used, that's the fragment + * size instead. Using the total handshake message + * size here is faulty and should be changed at + * some point. + * (2) While it doesn't seem to cause problems, one + * has to be very careful not to assume that in_hslen + * is always <= in_msglen in a sensible communication. + * Again, it's wrong for DTLS handshake fragmentation. + * The following check is therefore mandatory, and + * should not be treated as a silently corrected assertion. + * Additionally, ssl->in_hslen might be arbitrarily out of + * bounds after handling a DTLS message with an unexpected + * sequence number, see mbedtls_ssl_prepare_handshake_record. + */ + if( ssl->in_hslen < ssl->in_msglen ) + { + ssl->in_msglen -= ssl->in_hslen; + memmove( ssl->in_msg, ssl->in_msg + ssl->in_hslen, + ssl->in_msglen ); + + MBEDTLS_SSL_DEBUG_BUF( 4, "remaining content in record", + ssl->in_msg, ssl->in_msglen ); + } + else + { + ssl->in_msglen = 0; + } + + ssl->in_hslen = 0; + } + /* Case (4): Application data */ + else if( ssl->in_offt != NULL ) + { + return( 0 ); + } + /* Everything else (CCS & Alerts) */ + else + { + ssl->in_msglen = 0; + } + + return( 0 ); +} + +static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl ) +{ + if( ssl->in_msglen > 0 ) + return( 1 ); + + return( 0 ); +} + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +static void ssl_free_buffered_record( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + if( hs == NULL ) + return; + + if( hs->buffering.future_record.data != NULL ) + { + hs->buffering.total_bytes_buffered -= + hs->buffering.future_record.len; + + mbedtls_free( hs->buffering.future_record.data ); + hs->buffering.future_record.data = NULL; + } +} + +static int ssl_load_buffered_record( mbedtls_ssl_context *ssl ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + unsigned char * rec; + size_t rec_len; + unsigned rec_epoch; +#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH) + size_t in_buf_len = ssl->in_buf_len; +#else + size_t in_buf_len = MBEDTLS_SSL_IN_BUFFER_LEN; +#endif + if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + return( 0 ); + + if( hs == NULL ) + return( 0 ); + + rec = hs->buffering.future_record.data; + rec_len = hs->buffering.future_record.len; + rec_epoch = hs->buffering.future_record.epoch; + + if( rec == NULL ) + return( 0 ); + + /* Only consider loading future records if the + * input buffer is empty. */ + if( ssl_next_record_is_in_datagram( ssl ) == 1 ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_record" ) ); + + if( rec_epoch != ssl->in_epoch ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffered record not from current epoch." ) ); + goto exit; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Found buffered record from current epoch - load" ) ); + + /* Double-check that the record is not too large */ + if( rec_len > in_buf_len - (size_t)( ssl->in_hdr - ssl->in_buf ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + + memcpy( ssl->in_hdr, rec, rec_len ); + ssl->in_left = rec_len; + ssl->next_record_offset = 0; + + ssl_free_buffered_record( ssl ); + +exit: + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_record" ) ); + return( 0 ); +} + +static int ssl_buffer_future_record( mbedtls_ssl_context *ssl, + mbedtls_record const *rec ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + /* Don't buffer future records outside handshakes. */ + if( hs == NULL ) + return( 0 ); + + /* Only buffer handshake records (we are only interested + * in Finished messages). */ + if( rec->type != MBEDTLS_SSL_MSG_HANDSHAKE ) + return( 0 ); + + /* Don't buffer more than one future epoch record. */ + if( hs->buffering.future_record.data != NULL ) + return( 0 ); + + /* Don't buffer record if there's not enough buffering space remaining. */ + if( rec->buf_len > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING - + hs->buffering.total_bytes_buffered ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future epoch record of size %" MBEDTLS_PRINTF_SIZET + " would exceed the compile-time limit %" MBEDTLS_PRINTF_SIZET + " (already %" MBEDTLS_PRINTF_SIZET + " bytes buffered) -- ignore\n", + rec->buf_len, (size_t) MBEDTLS_SSL_DTLS_MAX_BUFFERING, + hs->buffering.total_bytes_buffered ) ); + return( 0 ); + } + + /* Buffer record */ + MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffer record from epoch %u", + ssl->in_epoch + 1U ) ); + MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered record", rec->buf, rec->buf_len ); + + /* ssl_parse_record_header() only considers records + * of the next epoch as candidates for buffering. */ + hs->buffering.future_record.epoch = ssl->in_epoch + 1; + hs->buffering.future_record.len = rec->buf_len; + + hs->buffering.future_record.data = + mbedtls_calloc( 1, hs->buffering.future_record.len ); + if( hs->buffering.future_record.data == NULL ) + { + /* If we run out of RAM trying to buffer a + * record from the next epoch, just ignore. */ + return( 0 ); + } + + memcpy( hs->buffering.future_record.data, rec->buf, rec->buf_len ); + + hs->buffering.total_bytes_buffered += rec->buf_len; + return( 0 ); +} + +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +static int ssl_get_next_record( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_record rec; + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + /* We might have buffered a future record; if so, + * and if the epoch matches now, load it. + * On success, this call will set ssl->in_left to + * the length of the buffered record, so that + * the calls to ssl_fetch_input() below will + * essentially be no-ops. */ + ret = ssl_load_buffered_record( ssl ); + if( ret != 0 ) + return( ret ); +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + /* Ensure that we have enough space available for the default form + * of TLS / DTLS record headers (5 Bytes for TLS, 13 Bytes for DTLS, + * with no space for CIDs counted in). */ + ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_in_hdr_len( ssl ) ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); + return( ret ); + } + + ret = ssl_parse_record_header( ssl, ssl->in_hdr, ssl->in_left, &rec ); + if( ret != 0 ) + { +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE ) + { + ret = ssl_buffer_future_record( ssl, &rec ); + if( ret != 0 ) + return( ret ); + + /* Fall through to handling of unexpected records */ + ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD; + } + + if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ) + { +#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C) + /* Reset in pointers to default state for TLS/DTLS records, + * assuming no CID and no offset between record content and + * record plaintext. */ + mbedtls_ssl_update_in_pointers( ssl ); + + /* Setup internal message pointers from record structure. */ + ssl->in_msgtype = rec.type; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->in_len = ssl->in_cid + rec.cid_len; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->in_iv = ssl->in_msg = ssl->in_len + 2; + ssl->in_msglen = rec.data_len; + + ret = ssl_check_client_reconnect( ssl ); + MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_client_reconnect", ret ); + if( ret != 0 ) + return( ret ); +#endif + + /* Skip unexpected record (but not whole datagram) */ + ssl->next_record_offset = rec.buf_len; + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding unexpected record " + "(header)" ) ); + } + else + { + /* Skip invalid record and the rest of the datagram */ + ssl->next_record_offset = 0; + ssl->in_left = 0; + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding invalid record " + "(header)" ) ); + } + + /* Get next record */ + return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); + } + else +#endif + { + return( ret ); + } + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* Remember offset of next record within datagram. */ + ssl->next_record_offset = rec.buf_len; + if( ssl->next_record_offset < ssl->in_left ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "more than one record within datagram" ) ); + } + } + else +#endif + { + /* + * Fetch record contents from underlying transport. + */ + ret = mbedtls_ssl_fetch_input( ssl, rec.buf_len ); + if( ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_fetch_input", ret ); + return( ret ); + } + + ssl->in_left = 0; + } + + /* + * Decrypt record contents. + */ + + if( ( ret = ssl_prepare_record_content( ssl, &rec ) ) != 0 ) + { +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* Silently discard invalid records */ + if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) + { + /* Except when waiting for Finished as a bad mac here + * probably means something went wrong in the handshake + * (eg wrong psk used, mitm downgrade attempt, etc.) */ + if( ssl->state == MBEDTLS_SSL_CLIENT_FINISHED || + ssl->state == MBEDTLS_SSL_SERVER_FINISHED ) + { +#if defined(MBEDTLS_SSL_ALL_ALERT_MESSAGES) + if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) + { + mbedtls_ssl_send_alert_message( ssl, + MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC ); + } +#endif + return( ret ); + } + +#if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT) + if( ssl->conf->badmac_limit != 0 && + ++ssl->badmac_seen >= ssl->conf->badmac_limit ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "too many records with bad MAC" ) ); + return( MBEDTLS_ERR_SSL_INVALID_MAC ); + } +#endif + + /* As above, invalid records cause + * dismissal of the whole datagram. */ + + ssl->next_record_offset = 0; + ssl->in_left = 0; + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "discarding invalid record (mac)" ) ); + return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING ); + } + + return( ret ); + } + else +#endif + { + /* Error out (and send alert) on invalid records */ +#if defined(MBEDTLS_SSL_ALL_ALERT_MESSAGES) + if( ret == MBEDTLS_ERR_SSL_INVALID_MAC ) + { + mbedtls_ssl_send_alert_message( ssl, + MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC ); + } +#endif + return( ret ); + } + } + + + /* Reset in pointers to default state for TLS/DTLS records, + * assuming no CID and no offset between record content and + * record plaintext. */ + mbedtls_ssl_update_in_pointers( ssl ); +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->in_len = ssl->in_cid + rec.cid_len; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->in_iv = ssl->in_len + 2; + + /* The record content type may change during decryption, + * so re-read it. */ + ssl->in_msgtype = rec.type; + /* Also update the input buffer, because unfortunately + * the server-side ssl_parse_client_hello() reparses the + * record header when receiving a ClientHello initiating + * a renegotiation. */ + ssl->in_hdr[0] = rec.type; + ssl->in_msg = rec.buf + rec.data_offset; + ssl->in_msglen = rec.data_len; + MBEDTLS_PUT_UINT16_BE( rec.data_len, ssl->in_len, 0 ); + +#if defined(MBEDTLS_ZLIB_SUPPORT) + if( ssl->transform_in != NULL && + ssl->session_in->compression == MBEDTLS_SSL_COMPRESS_DEFLATE ) + { + if( ( ret = ssl_decompress_buf( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_decompress_buf", ret ); + return( ret ); + } + + /* Check actual (decompress) record content length against + * configured maximum. */ + if( ssl->in_msglen > MBEDTLS_SSL_IN_CONTENT_LEN ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + } +#endif /* MBEDTLS_ZLIB_SUPPORT */ + + return( 0 ); +} + +int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + /* + * Handle particular types of records + */ + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) + { + if( ( ret = mbedtls_ssl_prepare_handshake_record( ssl ) ) != 0 ) + { + return( ret ); + } + } + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) + { + if( ssl->in_msglen != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, len: %" MBEDTLS_PRINTF_SIZET, + ssl->in_msglen ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + if( ssl->in_msg[0] != 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, content: %02x", + ssl->in_msg[0] ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC && + ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC ) + { + if( ssl->handshake == NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping ChangeCipherSpec outside handshake" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD ); + } + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "received out-of-order ChangeCipherSpec - remember" ) ); + return( MBEDTLS_ERR_SSL_EARLY_MESSAGE ); + } +#endif + } + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT ) + { + if( ssl->in_msglen != 2 ) + { + /* Note: Standard allows for more than one 2 byte alert + to be packed in a single message, but Mbed TLS doesn't + currently support this. */ + MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid alert message, len: %" MBEDTLS_PRINTF_SIZET, + ssl->in_msglen ) ); + return( MBEDTLS_ERR_SSL_INVALID_RECORD ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "got an alert message, type: [%u:%u]", + ssl->in_msg[0], ssl->in_msg[1] ) ); + + /* + * Ignore non-fatal alerts, except close_notify and no_renegotiation + */ + if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_FATAL ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "is a fatal alert message (msg %d)", + ssl->in_msg[1] ) ); + return( MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE ); + } + + if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING && + ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "is a close notify message" ) ); + return( MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY ); + } + +#if defined(MBEDTLS_SSL_RENEGOTIATION_ENABLED) + if( ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING && + ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "is a SSLv3 no renegotiation alert" ) ); + /* Will be handled when trying to parse ServerHello */ + return( 0 ); + } +#endif + +#if defined(MBEDTLS_SSL_PROTO_SSL3) && defined(MBEDTLS_SSL_SRV_C) + if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 && + ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && + ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING && + ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_NO_CERT ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "is a SSLv3 no_cert" ) ); + /* Will be handled in mbedtls_ssl_parse_certificate() */ + return( 0 ); + } +#endif /* MBEDTLS_SSL_PROTO_SSL3 && MBEDTLS_SSL_SRV_C */ + + /* Silently ignore: fetch new message */ + return MBEDTLS_ERR_SSL_NON_FATAL; + } + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* Drop unexpected ApplicationData records, + * except at the beginning of renegotiations */ + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA && + ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER +#if defined(MBEDTLS_SSL_RENEGOTIATION) + && ! ( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS && + ssl->state == MBEDTLS_SSL_SERVER_HELLO ) +#endif + ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ApplicationData" ) ); + return( MBEDTLS_ERR_SSL_NON_FATAL ); + } + + if( ssl->handshake != NULL && + ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) + { + mbedtls_ssl_handshake_wrapup_free_hs_transform( ssl ); + } + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + return( 0 ); +} + +int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl ) +{ + return( mbedtls_ssl_send_alert_message( ssl, + MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE ) ); +} + +int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl, + unsigned char level, + unsigned char message ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if( ssl == NULL || ssl->conf == NULL ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> send alert message" ) ); + MBEDTLS_SSL_DEBUG_MSG( 3, ( "send alert level=%u message=%u", level, message )); + + ssl->out_msgtype = MBEDTLS_SSL_MSG_ALERT; + ssl->out_msglen = 2; + ssl->out_msg[0] = level; + ssl->out_msg[1] = message; + + if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); + return( ret ); + } + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= send alert message" ) ); + + return( 0 ); +} + +int mbedtls_ssl_write_change_cipher_spec( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write change cipher spec" ) ); + + ssl->out_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC; + ssl->out_msglen = 1; + ssl->out_msg[0] = 1; + + ssl->state++; + + if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret ); + return( ret ); + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write change cipher spec" ) ); + + return( 0 ); +} + +int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) ); + + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); + return( ret ); + } + + if( ssl->in_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) ); + mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } + + /* CCS records are only accepted if they have length 1 and content '1', + * so we don't need to check this here. */ + + /* + * Switch to our negotiated transform and session parameters for inbound + * data. + */ + MBEDTLS_SSL_DEBUG_MSG( 3, ( "switching to new transform spec for inbound data" ) ); + ssl->transform_in = ssl->transform_negotiate; + ssl->session_in = ssl->session_negotiate; + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { +#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY) + mbedtls_ssl_dtls_replay_reset( ssl ); +#endif + + /* Increment epoch */ + if( ++ssl->in_epoch == 0 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS epoch would wrap" ) ); + /* This is highly unlikely to happen for legitimate reasons, so + treat it as an attack and don't send an alert. */ + return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING ); + } + } + else +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + memset( ssl->in_ctr, 0, 8 ); + + mbedtls_ssl_update_in_pointers( ssl ); + +#if defined(MBEDTLS_SSL_HW_RECORD_ACCEL) + if( mbedtls_ssl_hw_record_activate != NULL ) + { + if( ( ret = mbedtls_ssl_hw_record_activate( ssl, MBEDTLS_SSL_CHANNEL_INBOUND ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_hw_record_activate", ret ); + mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR ); + return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED ); + } + } +#endif + + ssl->state++; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse change cipher spec" ) ); + + return( 0 ); +} + +/* Once ssl->out_hdr as the address of the beginning of the + * next outgoing record is set, deduce the other pointers. + * + * Note: For TLS, we save the implicit record sequence number + * (entering MAC computation) in the 8 bytes before ssl->out_hdr, + * and the caller has to make sure there's space for this. + */ + +static size_t ssl_transform_get_explicit_iv_len( + mbedtls_ssl_transform const *transform ) +{ + if( transform->minor_ver < MBEDTLS_SSL_MINOR_VERSION_2 ) + return( 0 ); + + return( transform->ivlen - transform->fixed_ivlen ); +} + +void mbedtls_ssl_update_out_pointers( mbedtls_ssl_context *ssl, + mbedtls_ssl_transform *transform ) +{ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + ssl->out_ctr = ssl->out_hdr + 3; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->out_cid = ssl->out_ctr + 8; + ssl->out_len = ssl->out_cid; + if( transform != NULL ) + ssl->out_len += transform->out_cid_len; +#else /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->out_len = ssl->out_ctr + 8; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->out_iv = ssl->out_len + 2; + } + else +#endif + { + ssl->out_ctr = ssl->out_hdr - 8; + ssl->out_len = ssl->out_hdr + 3; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->out_cid = ssl->out_len; +#endif + ssl->out_iv = ssl->out_hdr + 5; + } + + ssl->out_msg = ssl->out_iv; + /* Adjust out_msg to make space for explicit IV, if used. */ + if( transform != NULL ) + ssl->out_msg += ssl_transform_get_explicit_iv_len( transform ); +} + +/* Once ssl->in_hdr as the address of the beginning of the + * next incoming record is set, deduce the other pointers. + * + * Note: For TLS, we save the implicit record sequence number + * (entering MAC computation) in the 8 bytes before ssl->in_hdr, + * and the caller has to make sure there's space for this. + */ + +void mbedtls_ssl_update_in_pointers( mbedtls_ssl_context *ssl ) +{ + /* This function sets the pointers to match the case + * of unprotected TLS/DTLS records, with both ssl->in_iv + * and ssl->in_msg pointing to the beginning of the record + * content. + * + * When decrypting a protected record, ssl->in_msg + * will be shifted to point to the beginning of the + * record plaintext. + */ + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + /* This sets the header pointers to match records + * without CID. When we receive a record containing + * a CID, the fields are shifted accordingly in + * ssl_parse_record_header(). */ + ssl->in_ctr = ssl->in_hdr + 3; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->in_cid = ssl->in_ctr + 8; + ssl->in_len = ssl->in_cid; /* Default: no CID */ +#else /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->in_len = ssl->in_ctr + 8; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + ssl->in_iv = ssl->in_len + 2; + } + else +#endif + { + ssl->in_ctr = ssl->in_hdr - 8; + ssl->in_len = ssl->in_hdr + 3; +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + ssl->in_cid = ssl->in_len; +#endif + ssl->in_iv = ssl->in_hdr + 5; + } + + /* This will be adjusted at record decryption time. */ + ssl->in_msg = ssl->in_iv; +} + +/* + * Setup an SSL context + */ + +void mbedtls_ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl ) +{ + /* Set the incoming and outgoing record pointers. */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + ssl->out_hdr = ssl->out_buf; + ssl->in_hdr = ssl->in_buf; + } + else +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + { + ssl->out_hdr = ssl->out_buf + 8; + ssl->in_hdr = ssl->in_buf + 8; + } + + /* Derive other internal pointers. */ + mbedtls_ssl_update_out_pointers( ssl, NULL /* no transform enabled */ ); + mbedtls_ssl_update_in_pointers ( ssl ); +} + +/* + * SSL get accessors + */ +size_t mbedtls_ssl_get_bytes_avail( const mbedtls_ssl_context *ssl ) +{ + return( ssl->in_offt == NULL ? 0 : ssl->in_msglen ); +} + +int mbedtls_ssl_check_pending( const mbedtls_ssl_context *ssl ) +{ + /* + * Case A: We're currently holding back + * a message for further processing. + */ + + if( ssl->keep_current_message == 1 ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: record held back for processing" ) ); + return( 1 ); + } + + /* + * Case B: Further records are pending in the current datagram. + */ + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->in_left > ssl->next_record_offset ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: more records within current datagram" ) ); + return( 1 ); + } +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + + /* + * Case C: A handshake message is being processed. + */ + + if( ssl->in_hslen > 0 && ssl->in_hslen < ssl->in_msglen ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: more handshake messages within current record" ) ); + return( 1 ); + } + + /* + * Case D: An application data message is being processed + */ + if( ssl->in_offt != NULL ) + { + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: application data record is being processed" ) ); + return( 1 ); + } + + /* + * In all other cases, the rest of the message can be dropped. + * As in ssl_get_next_record, this needs to be adapted if + * we implement support for multiple alerts in single records. + */ + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_check_pending: nothing pending" ) ); + return( 0 ); +} + + +int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl ) +{ + size_t transform_expansion = 0; + const mbedtls_ssl_transform *transform = ssl->transform_out; + unsigned block_size; + + size_t out_hdr_len = mbedtls_ssl_out_hdr_len( ssl ); + + if( transform == NULL ) + return( (int) out_hdr_len ); + +#if defined(MBEDTLS_ZLIB_SUPPORT) + if( ssl->session_out->compression != MBEDTLS_SSL_COMPRESS_NULL ) + return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE ); +#endif + + switch( mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ) ) + { + case MBEDTLS_MODE_GCM: + case MBEDTLS_MODE_CCM: + case MBEDTLS_MODE_CHACHAPOLY: + case MBEDTLS_MODE_STREAM: + transform_expansion = transform->minlen; + break; + + case MBEDTLS_MODE_CBC: + + block_size = mbedtls_cipher_get_block_size( + &transform->cipher_ctx_enc ); + + /* Expansion due to the addition of the MAC. */ + transform_expansion += transform->maclen; + + /* Expansion due to the addition of CBC padding; + * Theoretically up to 256 bytes, but we never use + * more than the block size of the underlying cipher. */ + transform_expansion += block_size; + + /* For TLS 1.1 or higher, an explicit IV is added + * after the record header. */ +#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 ) + transform_expansion += block_size; +#endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */ + + break; + + default: + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + +#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) + if( transform->out_cid_len != 0 ) + transform_expansion += MBEDTLS_SSL_MAX_CID_EXPANSION; +#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */ + + return( (int)( out_hdr_len + transform_expansion ) ); +} + +#if defined(MBEDTLS_SSL_RENEGOTIATION) +/* + * Check record counters and renegotiate if they're above the limit. + */ +static int ssl_check_ctr_renegotiate( mbedtls_ssl_context *ssl ) +{ + size_t ep_len = mbedtls_ssl_ep_len( ssl ); + int in_ctr_cmp; + int out_ctr_cmp; + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER || + ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING || + ssl->conf->disable_renegotiation == MBEDTLS_SSL_RENEGOTIATION_DISABLED ) + { + return( 0 ); + } + + in_ctr_cmp = memcmp( ssl->in_ctr + ep_len, + ssl->conf->renego_period + ep_len, 8 - ep_len ); + out_ctr_cmp = memcmp( ssl->cur_out_ctr + ep_len, + ssl->conf->renego_period + ep_len, 8 - ep_len ); + + if( in_ctr_cmp <= 0 && out_ctr_cmp <= 0 ) + { + return( 0 ); + } + + MBEDTLS_SSL_DEBUG_MSG( 1, ( "record counter limit reached: renegotiate" ) ); + return( mbedtls_ssl_renegotiate( ssl ) ); +} +#endif /* MBEDTLS_SSL_RENEGOTIATION */ + +/* + * Receive application data decrypted from the SSL layer + */ +int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t n; + + if( ssl == NULL || ssl->conf == NULL ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> read" ) ); + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + return( ret ); + + if( ssl->handshake != NULL && + ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING ) + { + if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 ) + return( ret ); + } + } +#endif + + /* + * Check if renegotiation is necessary and/or handshake is + * in process. If yes, perform/continue, and fall through + * if an unexpected packet is received while the client + * is waiting for the ServerHello. + * + * (There is no equivalent to the last condition on + * the server-side as it is not treated as within + * a handshake while waiting for the ClientHello + * after a renegotiation request.) + */ + +#if defined(MBEDTLS_SSL_RENEGOTIATION) + ret = ssl_check_ctr_renegotiate( ssl ); + if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && + ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_check_ctr_renegotiate", ret ); + return( ret ); + } +#endif + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) + { + ret = mbedtls_ssl_handshake( ssl ); + if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && + ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_handshake", ret ); + return( ret ); + } + } + + /* Loop as long as no application data record is available */ + while( ssl->in_offt == NULL ) + { + /* Start timer if not already running */ + if( ssl->f_get_timer != NULL && + ssl->f_get_timer( ssl->p_timer ) == -1 ) + { + mbedtls_ssl_set_timer( ssl, ssl->conf->read_timeout ); + } + + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) + { + if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); + return( ret ); + } + + if( ssl->in_msglen == 0 && + ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA ) + { + /* + * OpenSSL sends empty messages to randomize the IV + */ + if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 ) + { + if( ret == MBEDTLS_ERR_SSL_CONN_EOF ) + return( 0 ); + + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret ); + return( ret ); + } + } + + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "received handshake message" ) ); + + /* + * - For client-side, expect SERVER_HELLO_REQUEST. + * - For server-side, expect CLIENT_HELLO. + * - Fail (TLS) or silently drop record (DTLS) in other cases. + */ + +#if defined(MBEDTLS_SSL_CLI_C) + if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT && + ( ssl->in_msg[0] != MBEDTLS_SSL_HS_HELLO_REQUEST || + ssl->in_hslen != mbedtls_ssl_hs_hdr_len( ssl ) ) ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake received (not HelloRequest)" ) ); + + /* With DTLS, drop the packet (probably from last handshake) */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + continue; + } +#endif + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } +#endif /* MBEDTLS_SSL_CLI_C */ + +#if defined(MBEDTLS_SSL_SRV_C) + if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && + ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake received (not ClientHello)" ) ); + + /* With DTLS, drop the packet (probably from last handshake) */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + continue; + } +#endif + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } +#endif /* MBEDTLS_SSL_SRV_C */ + +#if defined(MBEDTLS_SSL_RENEGOTIATION) + /* Determine whether renegotiation attempt should be accepted */ + if( ! ( ssl->conf->disable_renegotiation == MBEDTLS_SSL_RENEGOTIATION_DISABLED || + ( ssl->secure_renegotiation == MBEDTLS_SSL_LEGACY_RENEGOTIATION && + ssl->conf->allow_legacy_renegotiation == + MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION ) ) ) + { + /* + * Accept renegotiation request + */ + + /* DTLS clients need to know renego is server-initiated */ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM && + ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ) + { + ssl->renego_status = MBEDTLS_SSL_RENEGOTIATION_PENDING; + } +#endif + ret = mbedtls_ssl_start_renegotiation( ssl ); + if( ret != MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO && + ret != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_start_renegotiation", + ret ); + return( ret ); + } + } + else +#endif /* MBEDTLS_SSL_RENEGOTIATION */ + { + /* + * Refuse renegotiation + */ + + MBEDTLS_SSL_DEBUG_MSG( 3, ( "refusing renegotiation, sending alert" ) ); + +#if defined(MBEDTLS_SSL_PROTO_SSL3) + if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ) + { + /* SSLv3 does not have a "no_renegotiation" warning, so + we send a fatal alert and abort the connection. */ + mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL, + MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } + else +#endif /* MBEDTLS_SSL_PROTO_SSL3 */ +#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \ + defined(MBEDTLS_SSL_PROTO_TLS1_2) + if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 ) + { + if( ( ret = mbedtls_ssl_send_alert_message( ssl, + MBEDTLS_SSL_ALERT_LEVEL_WARNING, + MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION ) ) != 0 ) + { + return( ret ); + } + } + else +#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || + MBEDTLS_SSL_PROTO_TLS1_2 */ + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) ); + return( MBEDTLS_ERR_SSL_INTERNAL_ERROR ); + } + } + + /* At this point, we don't know whether the renegotiation has been + * completed or not. The cases to consider are the following: + * 1) The renegotiation is complete. In this case, no new record + * has been read yet. + * 2) The renegotiation is incomplete because the client received + * an application data record while awaiting the ServerHello. + * 3) The renegotiation is incomplete because the client received + * a non-handshake, non-application data message while awaiting + * the ServerHello. + * In each of these case, looping will be the proper action: + * - For 1), the next iteration will read a new record and check + * if it's application data. + * - For 2), the loop condition isn't satisfied as application data + * is present, hence continue is the same as break + * - For 3), the loop condition is satisfied and read_record + * will re-deliver the message that was held back by the client + * when expecting the ServerHello. + */ + continue; + } +#if defined(MBEDTLS_SSL_RENEGOTIATION) + else if( ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) + { + if( ssl->conf->renego_max_records >= 0 ) + { + if( ++ssl->renego_records_seen > ssl->conf->renego_max_records ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "renegotiation requested, " + "but not honored by client" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } + } + } +#endif /* MBEDTLS_SSL_RENEGOTIATION */ + + /* Fatal and closure alerts handled by mbedtls_ssl_read_record() */ + if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT ) + { + MBEDTLS_SSL_DEBUG_MSG( 2, ( "ignoring non-fatal non-closure alert" ) ); + return( MBEDTLS_ERR_SSL_WANT_READ ); + } + + if( ssl->in_msgtype != MBEDTLS_SSL_MSG_APPLICATION_DATA ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad application data message" ) ); + return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE ); + } + + ssl->in_offt = ssl->in_msg; + + /* We're going to return something now, cancel timer, + * except if handshake (renegotiation) is in progress */ + if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) + mbedtls_ssl_set_timer( ssl, 0 ); + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + /* If we requested renego but received AppData, resend HelloRequest. + * Do it now, after setting in_offt, to avoid taking this branch + * again if ssl_write_hello_request() returns WANT_WRITE */ +#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_RENEGOTIATION) + if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER && + ssl->renego_status == MBEDTLS_SSL_RENEGOTIATION_PENDING ) + { + if( ( ret = mbedtls_ssl_resend_hello_request( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_resend_hello_request", + ret ); + return( ret ); + } + } +#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_RENEGOTIATION */ +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + } + + n = ( len < ssl->in_msglen ) + ? len : ssl->in_msglen; + + memcpy( buf, ssl->in_offt, n ); + ssl->in_msglen -= n; + + /* Zeroising the plaintext buffer to erase unused application data + from the memory. */ + mbedtls_platform_zeroize( ssl->in_offt, n ); + + if( ssl->in_msglen == 0 ) + { + /* all bytes consumed */ + ssl->in_offt = NULL; + ssl->keep_current_message = 0; + } + else + { + /* more data available */ + ssl->in_offt += n; + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= read" ) ); + + return( (int) n ); +} + +/* + * Send application data to be encrypted by the SSL layer, taking care of max + * fragment length and buffer size. + * + * According to RFC 5246 Section 6.2.1: + * + * Zero-length fragments of Application data MAY be sent as they are + * potentially useful as a traffic analysis countermeasure. + * + * Therefore, it is possible that the input message length is 0 and the + * corresponding return code is 0 on success. + */ +static int ssl_write_real( mbedtls_ssl_context *ssl, + const unsigned char *buf, size_t len ) +{ + int ret = mbedtls_ssl_get_max_out_record_payload( ssl ); + const size_t max_len = (size_t) ret; + + if( ret < 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_max_out_record_payload", ret ); + return( ret ); + } + + if( len > max_len ) + { +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "fragment larger than the (negotiated) " + "maximum fragment length: %" MBEDTLS_PRINTF_SIZET + " > %" MBEDTLS_PRINTF_SIZET, + len, max_len ) ); + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + } + else +#endif + len = max_len; + } + + if( ssl->out_left != 0 ) + { + /* + * The user has previously tried to send the data and + * MBEDTLS_ERR_SSL_WANT_WRITE or the message was only partially + * written. In this case, we expect the high-level write function + * (e.g. mbedtls_ssl_write()) to be called with the same parameters + */ + if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret ); + return( ret ); + } + } + else + { + /* + * The user is trying to send a message the first time, so we need to + * copy the data into the internal buffers and setup the data structure + * to keep track of partial writes + */ + ssl->out_msglen = len; + ssl->out_msgtype = MBEDTLS_SSL_MSG_APPLICATION_DATA; + memcpy( ssl->out_msg, buf, len ); + + if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret ); + return( ret ); + } + } + + return( (int) len ); +} + +/* + * Write application data, doing 1/n-1 splitting if necessary. + * + * With non-blocking I/O, ssl_write_real() may return WANT_WRITE, + * then the caller will call us again with the same arguments, so + * remember whether we already did the split or not. + */ +#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING) +static int ssl_write_split( mbedtls_ssl_context *ssl, + const unsigned char *buf, size_t len ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if( ssl->conf->cbc_record_splitting == + MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED || + len <= 1 || + ssl->minor_ver > MBEDTLS_SSL_MINOR_VERSION_1 || + mbedtls_cipher_get_cipher_mode( &ssl->transform_out->cipher_ctx_enc ) + != MBEDTLS_MODE_CBC ) + { + return( ssl_write_real( ssl, buf, len ) ); + } + + if( ssl->split_done == 0 ) + { + if( ( ret = ssl_write_real( ssl, buf, 1 ) ) <= 0 ) + return( ret ); + ssl->split_done = 1; + } + + if( ( ret = ssl_write_real( ssl, buf + 1, len - 1 ) ) <= 0 ) + return( ret ); + ssl->split_done = 0; + + return( ret + 1 ); +} +#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */ + +/* + * Write application data (public-facing wrapper) + */ +int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write" ) ); + + if( ssl == NULL || ssl->conf == NULL ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + +#if defined(MBEDTLS_SSL_RENEGOTIATION) + if( ( ret = ssl_check_ctr_renegotiate( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "ssl_check_ctr_renegotiate", ret ); + return( ret ); + } +#endif + + if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER ) + { + if( ( ret = mbedtls_ssl_handshake( ssl ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_handshake", ret ); + return( ret ); + } + } + +#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING) + ret = ssl_write_split( ssl, buf, len ); +#else + ret = ssl_write_real( ssl, buf, len ); +#endif + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write" ) ); + + return( ret ); +} + +/* + * Notify the peer that the connection is being closed + */ +int mbedtls_ssl_close_notify( mbedtls_ssl_context *ssl ) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if( ssl == NULL || ssl->conf == NULL ) + return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA ); + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write close notify" ) ); + + if( ssl->out_left != 0 ) + return( mbedtls_ssl_flush_output( ssl ) ); + + if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER ) + { + if( ( ret = mbedtls_ssl_send_alert_message( ssl, + MBEDTLS_SSL_ALERT_LEVEL_WARNING, + MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY ) ) != 0 ) + { + MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_send_alert_message", ret ); + return( ret ); + } + } + + MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write close notify" ) ); + + return( 0 ); +} + +void mbedtls_ssl_transform_free( mbedtls_ssl_transform *transform ) +{ + if( transform == NULL ) + return; + +#if defined(MBEDTLS_ZLIB_SUPPORT) + deflateEnd( &transform->ctx_deflate ); + inflateEnd( &transform->ctx_inflate ); +#endif + + mbedtls_cipher_free( &transform->cipher_ctx_enc ); + mbedtls_cipher_free( &transform->cipher_ctx_dec ); + +#if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) + mbedtls_md_free( &transform->md_ctx_enc ); + mbedtls_md_free( &transform->md_ctx_dec ); +#endif + + mbedtls_platform_zeroize( transform, sizeof( mbedtls_ssl_transform ) ); +} + +#if defined(MBEDTLS_SSL_PROTO_DTLS) + +void mbedtls_ssl_buffering_free( mbedtls_ssl_context *ssl ) +{ + unsigned offset; + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + + if( hs == NULL ) + return; + + ssl_free_buffered_record( ssl ); + + for( offset = 0; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ ) + ssl_buffering_free_slot( ssl, offset ); +} + +static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl, + uint8_t slot ) +{ + mbedtls_ssl_handshake_params * const hs = ssl->handshake; + mbedtls_ssl_hs_buffer * const hs_buf = &hs->buffering.hs[slot]; + + if( slot >= MBEDTLS_SSL_MAX_BUFFERED_HS ) + return; + + if( hs_buf->is_valid == 1 ) + { + hs->buffering.total_bytes_buffered -= hs_buf->data_len; + mbedtls_platform_zeroize( hs_buf->data, hs_buf->data_len ); + mbedtls_free( hs_buf->data ); + memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) ); + } +} + +#endif /* MBEDTLS_SSL_PROTO_DTLS */ + +/* + * Convert version numbers to/from wire format + * and, for DTLS, to/from TLS equivalent. + * + * For TLS this is the identity. + * For DTLS, use 1's complement (v -> 255 - v, and then map as follows: + * 1.0 <-> 3.2 (DTLS 1.0 is based on TLS 1.1) + * 1.x <-> 3.x+1 for x != 0 (DTLS 1.2 based on TLS 1.2) + */ +void mbedtls_ssl_write_version( int major, int minor, int transport, + unsigned char ver[2] ) +{ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + if( minor == MBEDTLS_SSL_MINOR_VERSION_2 ) + --minor; /* DTLS 1.0 stored as TLS 1.1 internally */ + + ver[0] = (unsigned char)( 255 - ( major - 2 ) ); + ver[1] = (unsigned char)( 255 - ( minor - 1 ) ); + } + else +#else + ((void) transport); +#endif + { + ver[0] = (unsigned char) major; + ver[1] = (unsigned char) minor; + } +} + +void mbedtls_ssl_read_version( int *major, int *minor, int transport, + const unsigned char ver[2] ) +{ +#if defined(MBEDTLS_SSL_PROTO_DTLS) + if( transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM ) + { + *major = 255 - ver[0] + 2; + *minor = 255 - ver[1] + 1; + + if( *minor == MBEDTLS_SSL_MINOR_VERSION_1 ) + ++*minor; /* DTLS 1.0 stored as TLS 1.1 internally */ + } + else +#else + ((void) transport); +#endif + { + *major = ver[0]; + *minor = ver[1]; + } +} + +#endif /* MBEDTLS_SSL_TLS_C */ |