diff options
Diffstat (limited to 'thirdparty/openssl/ssl/s3_cbc.c')
| -rw-r--r-- | thirdparty/openssl/ssl/s3_cbc.c | 820 |
1 files changed, 0 insertions, 820 deletions
diff --git a/thirdparty/openssl/ssl/s3_cbc.c b/thirdparty/openssl/ssl/s3_cbc.c deleted file mode 100644 index 557622f513..0000000000 --- a/thirdparty/openssl/ssl/s3_cbc.c +++ /dev/null @@ -1,820 +0,0 @@ -/* ssl/s3_cbc.c */ -/* ==================================================================== - * Copyright (c) 2012 The OpenSSL Project. All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * 3. All advertising materials mentioning features or use of this - * software must display the following acknowledgment: - * "This product includes software developed by the OpenSSL Project - * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" - * - * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to - * endorse or promote products derived from this software without - * prior written permission. For written permission, please contact - * openssl-core@openssl.org. - * - * 5. Products derived from this software may not be called "OpenSSL" - * nor may "OpenSSL" appear in their names without prior written - * permission of the OpenSSL Project. - * - * 6. Redistributions of any form whatsoever must retain the following - * acknowledgment: - * "This product includes software developed by the OpenSSL Project - * for use in the OpenSSL Toolkit (http://www.openssl.org/)" - * - * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY - * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR - * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR - * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT - * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; - * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, - * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED - * OF THE POSSIBILITY OF SUCH DAMAGE. - * ==================================================================== - * - * This product includes cryptographic software written by Eric Young - * (eay@cryptsoft.com). This product includes software written by Tim - * Hudson (tjh@cryptsoft.com). - * - */ - -#include "../crypto/constant_time_locl.h" -#include "ssl_locl.h" - -#include <openssl/md5.h> -#include <openssl/sha.h> - -/* - * MAX_HASH_BIT_COUNT_BYTES is the maximum number of bytes in the hash's - * length field. (SHA-384/512 have 128-bit length.) - */ -#define MAX_HASH_BIT_COUNT_BYTES 16 - -/* - * MAX_HASH_BLOCK_SIZE is the maximum hash block size that we'll support. - * Currently SHA-384/512 has a 128-byte block size and that's the largest - * supported by TLS.) - */ -#define MAX_HASH_BLOCK_SIZE 128 - -/*- - * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC - * record in |rec| by updating |rec->length| in constant time. - * - * block_size: the block size of the cipher used to encrypt the record. - * returns: - * 0: (in non-constant time) if the record is publicly invalid. - * 1: if the padding was valid - * -1: otherwise. - */ -int ssl3_cbc_remove_padding(const SSL *s, - SSL3_RECORD *rec, - unsigned block_size, unsigned mac_size) -{ - unsigned padding_length, good; - const unsigned overhead = 1 /* padding length byte */ + mac_size; - - /* - * These lengths are all public so we can test them in non-constant time. - */ - if (overhead > rec->length) - return 0; - - padding_length = rec->data[rec->length - 1]; - good = constant_time_ge(rec->length, padding_length + overhead); - /* SSLv3 requires that the padding is minimal. */ - good &= constant_time_ge(block_size, padding_length + 1); - padding_length = good & (padding_length + 1); - rec->length -= padding_length; - rec->type |= padding_length << 8; /* kludge: pass padding length */ - return constant_time_select_int(good, 1, -1); -} - -/*- - * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC - * record in |rec| in constant time and returns 1 if the padding is valid and - * -1 otherwise. It also removes any explicit IV from the start of the record - * without leaking any timing about whether there was enough space after the - * padding was removed. - * - * block_size: the block size of the cipher used to encrypt the record. - * returns: - * 0: (in non-constant time) if the record is publicly invalid. - * 1: if the padding was valid - * -1: otherwise. - */ -int tls1_cbc_remove_padding(const SSL *s, - SSL3_RECORD *rec, - unsigned block_size, unsigned mac_size) -{ - unsigned padding_length, good, to_check, i; - const unsigned overhead = 1 /* padding length byte */ + mac_size; - /* Check if version requires explicit IV */ - if (SSL_USE_EXPLICIT_IV(s)) { - /* - * These lengths are all public so we can test them in non-constant - * time. - */ - if (overhead + block_size > rec->length) - return 0; - /* We can now safely skip explicit IV */ - rec->data += block_size; - rec->input += block_size; - rec->length -= block_size; - } else if (overhead > rec->length) - return 0; - - padding_length = rec->data[rec->length - 1]; - - /* - * NB: if compression is in operation the first packet may not be of even - * length so the padding bug check cannot be performed. This bug - * workaround has been around since SSLeay so hopefully it is either - * fixed now or no buggy implementation supports compression [steve] - */ - if ((s->options & SSL_OP_TLS_BLOCK_PADDING_BUG) && !s->expand) { - /* First packet is even in size, so check */ - if ((CRYPTO_memcmp(s->s3->read_sequence, "\0\0\0\0\0\0\0\0", 8) == 0) && - !(padding_length & 1)) { - s->s3->flags |= TLS1_FLAGS_TLS_PADDING_BUG; - } - if ((s->s3->flags & TLS1_FLAGS_TLS_PADDING_BUG) && padding_length > 0) { - padding_length--; - } - } - - if (EVP_CIPHER_flags(s->enc_read_ctx->cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) { - /* padding is already verified */ - rec->length -= padding_length + 1; - return 1; - } - - good = constant_time_ge(rec->length, overhead + padding_length); - /* - * The padding consists of a length byte at the end of the record and - * then that many bytes of padding, all with the same value as the length - * byte. Thus, with the length byte included, there are i+1 bytes of - * padding. We can't check just |padding_length+1| bytes because that - * leaks decrypted information. Therefore we always have to check the - * maximum amount of padding possible. (Again, the length of the record - * is public information so we can use it.) - */ - to_check = 255; /* maximum amount of padding. */ - if (to_check > rec->length - 1) - to_check = rec->length - 1; - - for (i = 0; i < to_check; i++) { - unsigned char mask = constant_time_ge_8(padding_length, i); - unsigned char b = rec->data[rec->length - 1 - i]; - /* - * The final |padding_length+1| bytes should all have the value - * |padding_length|. Therefore the XOR should be zero. - */ - good &= ~(mask & (padding_length ^ b)); - } - - /* - * If any of the final |padding_length+1| bytes had the wrong value, one - * or more of the lower eight bits of |good| will be cleared. - */ - good = constant_time_eq(0xff, good & 0xff); - padding_length = good & (padding_length + 1); - rec->length -= padding_length; - rec->type |= padding_length << 8; /* kludge: pass padding length */ - - return constant_time_select_int(good, 1, -1); -} - -/*- - * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in - * constant time (independent of the concrete value of rec->length, which may - * vary within a 256-byte window). - * - * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to - * this function. - * - * On entry: - * rec->orig_len >= md_size - * md_size <= EVP_MAX_MD_SIZE - * - * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with - * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into - * a single or pair of cache-lines, then the variable memory accesses don't - * actually affect the timing. CPUs with smaller cache-lines [if any] are - * not multi-core and are not considered vulnerable to cache-timing attacks. - */ -#define CBC_MAC_ROTATE_IN_PLACE - -void ssl3_cbc_copy_mac(unsigned char *out, - const SSL3_RECORD *rec, - unsigned md_size, unsigned orig_len) -{ -#if defined(CBC_MAC_ROTATE_IN_PLACE) - unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE]; - unsigned char *rotated_mac; -#else - unsigned char rotated_mac[EVP_MAX_MD_SIZE]; -#endif - - /* - * mac_end is the index of |rec->data| just after the end of the MAC. - */ - unsigned mac_end = rec->length; - unsigned mac_start = mac_end - md_size; - /* - * scan_start contains the number of bytes that we can ignore because the - * MAC's position can only vary by 255 bytes. - */ - unsigned scan_start = 0; - unsigned i, j; - unsigned div_spoiler; - unsigned rotate_offset; - - OPENSSL_assert(orig_len >= md_size); - OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE); - -#if defined(CBC_MAC_ROTATE_IN_PLACE) - rotated_mac = rotated_mac_buf + ((0 - (size_t)rotated_mac_buf) & 63); -#endif - - /* This information is public so it's safe to branch based on it. */ - if (orig_len > md_size + 255 + 1) - scan_start = orig_len - (md_size + 255 + 1); - /* - * div_spoiler contains a multiple of md_size that is used to cause the - * modulo operation to be constant time. Without this, the time varies - * based on the amount of padding when running on Intel chips at least. - * The aim of right-shifting md_size is so that the compiler doesn't - * figure out that it can remove div_spoiler as that would require it to - * prove that md_size is always even, which I hope is beyond it. - */ - div_spoiler = md_size >> 1; - div_spoiler <<= (sizeof(div_spoiler) - 1) * 8; - rotate_offset = (div_spoiler + mac_start - scan_start) % md_size; - - memset(rotated_mac, 0, md_size); - for (i = scan_start, j = 0; i < orig_len; i++) { - unsigned char mac_started = constant_time_ge_8(i, mac_start); - unsigned char mac_ended = constant_time_ge_8(i, mac_end); - unsigned char b = rec->data[i]; - rotated_mac[j++] |= b & mac_started & ~mac_ended; - j &= constant_time_lt(j, md_size); - } - - /* Now rotate the MAC */ -#if defined(CBC_MAC_ROTATE_IN_PLACE) - j = 0; - for (i = 0; i < md_size; i++) { - /* in case cache-line is 32 bytes, touch second line */ - ((volatile unsigned char *)rotated_mac)[rotate_offset ^ 32]; - out[j++] = rotated_mac[rotate_offset++]; - rotate_offset &= constant_time_lt(rotate_offset, md_size); - } -#else - memset(out, 0, md_size); - rotate_offset = md_size - rotate_offset; - rotate_offset &= constant_time_lt(rotate_offset, md_size); - for (i = 0; i < md_size; i++) { - for (j = 0; j < md_size; j++) - out[j] |= rotated_mac[i] & constant_time_eq_8(j, rotate_offset); - rotate_offset++; - rotate_offset &= constant_time_lt(rotate_offset, md_size); - } -#endif -} - -/* - * u32toLE serialises an unsigned, 32-bit number (n) as four bytes at (p) in - * little-endian order. The value of p is advanced by four. - */ -#define u32toLE(n, p) \ - (*((p)++)=(unsigned char)(n), \ - *((p)++)=(unsigned char)(n>>8), \ - *((p)++)=(unsigned char)(n>>16), \ - *((p)++)=(unsigned char)(n>>24)) - -/* - * These functions serialize the state of a hash and thus perform the - * standard "final" operation without adding the padding and length that such - * a function typically does. - */ -static void tls1_md5_final_raw(void *ctx, unsigned char *md_out) -{ - MD5_CTX *md5 = ctx; - u32toLE(md5->A, md_out); - u32toLE(md5->B, md_out); - u32toLE(md5->C, md_out); - u32toLE(md5->D, md_out); -} - -static void tls1_sha1_final_raw(void *ctx, unsigned char *md_out) -{ - SHA_CTX *sha1 = ctx; - l2n(sha1->h0, md_out); - l2n(sha1->h1, md_out); - l2n(sha1->h2, md_out); - l2n(sha1->h3, md_out); - l2n(sha1->h4, md_out); -} - -#define LARGEST_DIGEST_CTX SHA_CTX - -#ifndef OPENSSL_NO_SHA256 -static void tls1_sha256_final_raw(void *ctx, unsigned char *md_out) -{ - SHA256_CTX *sha256 = ctx; - unsigned i; - - for (i = 0; i < 8; i++) { - l2n(sha256->h[i], md_out); - } -} - -# undef LARGEST_DIGEST_CTX -# define LARGEST_DIGEST_CTX SHA256_CTX -#endif - -#ifndef OPENSSL_NO_SHA512 -static void tls1_sha512_final_raw(void *ctx, unsigned char *md_out) -{ - SHA512_CTX *sha512 = ctx; - unsigned i; - - for (i = 0; i < 8; i++) { - l2n8(sha512->h[i], md_out); - } -} - -# undef LARGEST_DIGEST_CTX -# define LARGEST_DIGEST_CTX SHA512_CTX -#endif - -/* - * ssl3_cbc_record_digest_supported returns 1 iff |ctx| uses a hash function - * which ssl3_cbc_digest_record supports. - */ -char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx) -{ -#ifdef OPENSSL_FIPS - if (FIPS_mode()) - return 0; -#endif - switch (EVP_MD_CTX_type(ctx)) { - case NID_md5: - case NID_sha1: -#ifndef OPENSSL_NO_SHA256 - case NID_sha224: - case NID_sha256: -#endif -#ifndef OPENSSL_NO_SHA512 - case NID_sha384: - case NID_sha512: -#endif - return 1; - default: - return 0; - } -} - -/*- - * ssl3_cbc_digest_record computes the MAC of a decrypted, padded SSLv3/TLS - * record. - * - * ctx: the EVP_MD_CTX from which we take the hash function. - * ssl3_cbc_record_digest_supported must return true for this EVP_MD_CTX. - * md_out: the digest output. At most EVP_MAX_MD_SIZE bytes will be written. - * md_out_size: if non-NULL, the number of output bytes is written here. - * header: the 13-byte, TLS record header. - * data: the record data itself, less any preceeding explicit IV. - * data_plus_mac_size: the secret, reported length of the data and MAC - * once the padding has been removed. - * data_plus_mac_plus_padding_size: the public length of the whole - * record, including padding. - * is_sslv3: non-zero if we are to use SSLv3. Otherwise, TLS. - * - * On entry: by virtue of having been through one of the remove_padding - * functions, above, we know that data_plus_mac_size is large enough to contain - * a padding byte and MAC. (If the padding was invalid, it might contain the - * padding too. ) - * Returns 1 on success or 0 on error - */ -int ssl3_cbc_digest_record(const EVP_MD_CTX *ctx, - unsigned char *md_out, - size_t *md_out_size, - const unsigned char header[13], - const unsigned char *data, - size_t data_plus_mac_size, - size_t data_plus_mac_plus_padding_size, - const unsigned char *mac_secret, - unsigned mac_secret_length, char is_sslv3) -{ - union { - double align; - unsigned char c[sizeof(LARGEST_DIGEST_CTX)]; - } md_state; - void (*md_final_raw) (void *ctx, unsigned char *md_out); - void (*md_transform) (void *ctx, const unsigned char *block); - unsigned md_size, md_block_size = 64; - unsigned sslv3_pad_length = 40, header_length, variance_blocks, - len, max_mac_bytes, num_blocks, - num_starting_blocks, k, mac_end_offset, c, index_a, index_b; - unsigned int bits; /* at most 18 bits */ - unsigned char length_bytes[MAX_HASH_BIT_COUNT_BYTES]; - /* hmac_pad is the masked HMAC key. */ - unsigned char hmac_pad[MAX_HASH_BLOCK_SIZE]; - unsigned char first_block[MAX_HASH_BLOCK_SIZE]; - unsigned char mac_out[EVP_MAX_MD_SIZE]; - unsigned i, j, md_out_size_u; - EVP_MD_CTX md_ctx; - /* - * mdLengthSize is the number of bytes in the length field that - * terminates * the hash. - */ - unsigned md_length_size = 8; - char length_is_big_endian = 1; - - /* - * This is a, hopefully redundant, check that allows us to forget about - * many possible overflows later in this function. - */ - OPENSSL_assert(data_plus_mac_plus_padding_size < 1024 * 1024); - - switch (EVP_MD_CTX_type(ctx)) { - case NID_md5: - if (MD5_Init((MD5_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_md5_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))MD5_Transform; - md_size = 16; - sslv3_pad_length = 48; - length_is_big_endian = 0; - break; - case NID_sha1: - if (SHA1_Init((SHA_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_sha1_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))SHA1_Transform; - md_size = 20; - break; -#ifndef OPENSSL_NO_SHA256 - case NID_sha224: - if (SHA224_Init((SHA256_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_sha256_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))SHA256_Transform; - md_size = 224 / 8; - break; - case NID_sha256: - if (SHA256_Init((SHA256_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_sha256_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))SHA256_Transform; - md_size = 32; - break; -#endif -#ifndef OPENSSL_NO_SHA512 - case NID_sha384: - if (SHA384_Init((SHA512_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_sha512_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))SHA512_Transform; - md_size = 384 / 8; - md_block_size = 128; - md_length_size = 16; - break; - case NID_sha512: - if (SHA512_Init((SHA512_CTX *)md_state.c) <= 0) - return 0; - md_final_raw = tls1_sha512_final_raw; - md_transform = - (void (*)(void *ctx, const unsigned char *block))SHA512_Transform; - md_size = 64; - md_block_size = 128; - md_length_size = 16; - break; -#endif - default: - /* - * ssl3_cbc_record_digest_supported should have been called first to - * check that the hash function is supported. - */ - OPENSSL_assert(0); - if (md_out_size) - *md_out_size = 0; - return 0; - } - - OPENSSL_assert(md_length_size <= MAX_HASH_BIT_COUNT_BYTES); - OPENSSL_assert(md_block_size <= MAX_HASH_BLOCK_SIZE); - OPENSSL_assert(md_size <= EVP_MAX_MD_SIZE); - - header_length = 13; - if (is_sslv3) { - header_length = mac_secret_length + sslv3_pad_length + 8 /* sequence - * number */ + - 1 /* record type */ + - 2 /* record length */ ; - } - - /* - * variance_blocks is the number of blocks of the hash that we have to - * calculate in constant time because they could be altered by the - * padding value. In SSLv3, the padding must be minimal so the end of - * the plaintext varies by, at most, 15+20 = 35 bytes. (We conservatively - * assume that the MAC size varies from 0..20 bytes.) In case the 9 bytes - * of hash termination (0x80 + 64-bit length) don't fit in the final - * block, we say that the final two blocks can vary based on the padding. - * TLSv1 has MACs up to 48 bytes long (SHA-384) and the padding is not - * required to be minimal. Therefore we say that the final six blocks can - * vary based on the padding. Later in the function, if the message is - * short and there obviously cannot be this many blocks then - * variance_blocks can be reduced. - */ - variance_blocks = is_sslv3 ? 2 : 6; - /* - * From now on we're dealing with the MAC, which conceptually has 13 - * bytes of `header' before the start of the data (TLS) or 71/75 bytes - * (SSLv3) - */ - len = data_plus_mac_plus_padding_size + header_length; - /* - * max_mac_bytes contains the maximum bytes of bytes in the MAC, - * including * |header|, assuming that there's no padding. - */ - max_mac_bytes = len - md_size - 1; - /* num_blocks is the maximum number of hash blocks. */ - num_blocks = - (max_mac_bytes + 1 + md_length_size + md_block_size - - 1) / md_block_size; - /* - * In order to calculate the MAC in constant time we have to handle the - * final blocks specially because the padding value could cause the end - * to appear somewhere in the final |variance_blocks| blocks and we can't - * leak where. However, |num_starting_blocks| worth of data can be hashed - * right away because no padding value can affect whether they are - * plaintext. - */ - num_starting_blocks = 0; - /* - * k is the starting byte offset into the conceptual header||data where - * we start processing. - */ - k = 0; - /* - * mac_end_offset is the index just past the end of the data to be MACed. - */ - mac_end_offset = data_plus_mac_size + header_length - md_size; - /* - * c is the index of the 0x80 byte in the final hash block that contains - * application data. - */ - c = mac_end_offset % md_block_size; - /* - * index_a is the hash block number that contains the 0x80 terminating - * value. - */ - index_a = mac_end_offset / md_block_size; - /* - * index_b is the hash block number that contains the 64-bit hash length, - * in bits. - */ - index_b = (mac_end_offset + md_length_size) / md_block_size; - /* - * bits is the hash-length in bits. It includes the additional hash block - * for the masked HMAC key, or whole of |header| in the case of SSLv3. - */ - - /* - * For SSLv3, if we're going to have any starting blocks then we need at - * least two because the header is larger than a single block. - */ - if (num_blocks > variance_blocks + (is_sslv3 ? 1 : 0)) { - num_starting_blocks = num_blocks - variance_blocks; - k = md_block_size * num_starting_blocks; - } - - bits = 8 * mac_end_offset; - if (!is_sslv3) { - /* - * Compute the initial HMAC block. For SSLv3, the padding and secret - * bytes are included in |header| because they take more than a - * single block. - */ - bits += 8 * md_block_size; - memset(hmac_pad, 0, md_block_size); - OPENSSL_assert(mac_secret_length <= sizeof(hmac_pad)); - memcpy(hmac_pad, mac_secret, mac_secret_length); - for (i = 0; i < md_block_size; i++) - hmac_pad[i] ^= 0x36; - - md_transform(md_state.c, hmac_pad); - } - - if (length_is_big_endian) { - memset(length_bytes, 0, md_length_size - 4); - length_bytes[md_length_size - 4] = (unsigned char)(bits >> 24); - length_bytes[md_length_size - 3] = (unsigned char)(bits >> 16); - length_bytes[md_length_size - 2] = (unsigned char)(bits >> 8); - length_bytes[md_length_size - 1] = (unsigned char)bits; - } else { - memset(length_bytes, 0, md_length_size); - length_bytes[md_length_size - 5] = (unsigned char)(bits >> 24); - length_bytes[md_length_size - 6] = (unsigned char)(bits >> 16); - length_bytes[md_length_size - 7] = (unsigned char)(bits >> 8); - length_bytes[md_length_size - 8] = (unsigned char)bits; - } - - if (k > 0) { - if (is_sslv3) { - unsigned overhang; - - /* - * The SSLv3 header is larger than a single block. overhang is - * the number of bytes beyond a single block that the header - * consumes: either 7 bytes (SHA1) or 11 bytes (MD5). There are no - * ciphersuites in SSLv3 that are not SHA1 or MD5 based and - * therefore we can be confident that the header_length will be - * greater than |md_block_size|. However we add a sanity check just - * in case - */ - if (header_length <= md_block_size) { - /* Should never happen */ - return 0; - } - overhang = header_length - md_block_size; - md_transform(md_state.c, header); - memcpy(first_block, header + md_block_size, overhang); - memcpy(first_block + overhang, data, md_block_size - overhang); - md_transform(md_state.c, first_block); - for (i = 1; i < k / md_block_size - 1; i++) - md_transform(md_state.c, data + md_block_size * i - overhang); - } else { - /* k is a multiple of md_block_size. */ - memcpy(first_block, header, 13); - memcpy(first_block + 13, data, md_block_size - 13); - md_transform(md_state.c, first_block); - for (i = 1; i < k / md_block_size; i++) - md_transform(md_state.c, data + md_block_size * i - 13); - } - } - - memset(mac_out, 0, sizeof(mac_out)); - - /* - * We now process the final hash blocks. For each block, we construct it - * in constant time. If the |i==index_a| then we'll include the 0x80 - * bytes and zero pad etc. For each block we selectively copy it, in - * constant time, to |mac_out|. - */ - for (i = num_starting_blocks; i <= num_starting_blocks + variance_blocks; - i++) { - unsigned char block[MAX_HASH_BLOCK_SIZE]; - unsigned char is_block_a = constant_time_eq_8(i, index_a); - unsigned char is_block_b = constant_time_eq_8(i, index_b); - for (j = 0; j < md_block_size; j++) { - unsigned char b = 0, is_past_c, is_past_cp1; - if (k < header_length) - b = header[k]; - else if (k < data_plus_mac_plus_padding_size + header_length) - b = data[k - header_length]; - k++; - - is_past_c = is_block_a & constant_time_ge_8(j, c); - is_past_cp1 = is_block_a & constant_time_ge_8(j, c + 1); - /* - * If this is the block containing the end of the application - * data, and we are at the offset for the 0x80 value, then - * overwrite b with 0x80. - */ - b = constant_time_select_8(is_past_c, 0x80, b); - /* - * If this the the block containing the end of the application - * data and we're past the 0x80 value then just write zero. - */ - b = b & ~is_past_cp1; - /* - * If this is index_b (the final block), but not index_a (the end - * of the data), then the 64-bit length didn't fit into index_a - * and we're having to add an extra block of zeros. - */ - b &= ~is_block_b | is_block_a; - - /* - * The final bytes of one of the blocks contains the length. - */ - if (j >= md_block_size - md_length_size) { - /* If this is index_b, write a length byte. */ - b = constant_time_select_8(is_block_b, - length_bytes[j - - (md_block_size - - md_length_size)], b); - } - block[j] = b; - } - - md_transform(md_state.c, block); - md_final_raw(md_state.c, block); - /* If this is index_b, copy the hash value to |mac_out|. */ - for (j = 0; j < md_size; j++) - mac_out[j] |= block[j] & is_block_b; - } - - EVP_MD_CTX_init(&md_ctx); - if (EVP_DigestInit_ex(&md_ctx, ctx->digest, NULL /* engine */ ) <= 0) - goto err; - if (is_sslv3) { - /* We repurpose |hmac_pad| to contain the SSLv3 pad2 block. */ - memset(hmac_pad, 0x5c, sslv3_pad_length); - - if (EVP_DigestUpdate(&md_ctx, mac_secret, mac_secret_length) <= 0 - || EVP_DigestUpdate(&md_ctx, hmac_pad, sslv3_pad_length) <= 0 - || EVP_DigestUpdate(&md_ctx, mac_out, md_size) <= 0) - goto err; - } else { - /* Complete the HMAC in the standard manner. */ - for (i = 0; i < md_block_size; i++) - hmac_pad[i] ^= 0x6a; - - if (EVP_DigestUpdate(&md_ctx, hmac_pad, md_block_size) <= 0 - || EVP_DigestUpdate(&md_ctx, mac_out, md_size) <= 0) - goto err; - } - EVP_DigestFinal(&md_ctx, md_out, &md_out_size_u); - if (md_out_size) - *md_out_size = md_out_size_u; - EVP_MD_CTX_cleanup(&md_ctx); - - return 1; -err: - EVP_MD_CTX_cleanup(&md_ctx); - return 0; -} - -#ifdef OPENSSL_FIPS - -/* - * Due to the need to use EVP in FIPS mode we can't reimplement digests but - * we can ensure the number of blocks processed is equal for all cases by - * digesting additional data. - */ - -void tls_fips_digest_extra(const EVP_CIPHER_CTX *cipher_ctx, - EVP_MD_CTX *mac_ctx, const unsigned char *data, - size_t data_len, size_t orig_len) -{ - size_t block_size, digest_pad, blocks_data, blocks_orig; - if (EVP_CIPHER_CTX_mode(cipher_ctx) != EVP_CIPH_CBC_MODE) - return; - block_size = EVP_MD_CTX_block_size(mac_ctx); - /*- - * We are in FIPS mode if we get this far so we know we have only SHA* - * digests and TLS to deal with. - * Minimum digest padding length is 17 for SHA384/SHA512 and 9 - * otherwise. - * Additional header is 13 bytes. To get the number of digest blocks - * processed round up the amount of data plus padding to the nearest - * block length. Block length is 128 for SHA384/SHA512 and 64 otherwise. - * So we have: - * blocks = (payload_len + digest_pad + 13 + block_size - 1)/block_size - * equivalently: - * blocks = (payload_len + digest_pad + 12)/block_size + 1 - * HMAC adds a constant overhead. - * We're ultimately only interested in differences so this becomes - * blocks = (payload_len + 29)/128 - * for SHA384/SHA512 and - * blocks = (payload_len + 21)/64 - * otherwise. - */ - digest_pad = block_size == 64 ? 21 : 29; - blocks_orig = (orig_len + digest_pad) / block_size; - blocks_data = (data_len + digest_pad) / block_size; - /* - * MAC enough blocks to make up the difference between the original and - * actual lengths plus one extra block to ensure this is never a no op. - * The "data" pointer should always have enough space to perform this - * operation as it is large enough for a maximum length TLS buffer. - */ - EVP_DigestSignUpdate(mac_ctx, data, - (blocks_orig - blocks_data + 1) * block_size); -} -#endif |