/* * Generic ASN.1 parsing * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * 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. * * This file is part of mbed TLS (https://tls.mbed.org) */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_ASN1_PARSE_C) #include "mbedtls/asn1.h" #include <string.h> #if defined(MBEDTLS_BIGNUM_C) #include "mbedtls/bignum.h" #endif #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include <stdlib.h> #define mbedtls_calloc calloc #define mbedtls_free free #endif /* Implementation that should never be optimized out by the compiler */ static void mbedtls_zeroize( void *v, size_t n ) { volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0; } /* * ASN.1 DER decoding routines */ int mbedtls_asn1_get_len( unsigned char **p, const unsigned char *end, size_t *len ) { if( ( end - *p ) < 1 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); if( ( **p & 0x80 ) == 0 ) *len = *(*p)++; else { switch( **p & 0x7F ) { case 1: if( ( end - *p ) < 2 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); *len = (*p)[1]; (*p) += 2; break; case 2: if( ( end - *p ) < 3 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); *len = ( (size_t)(*p)[1] << 8 ) | (*p)[2]; (*p) += 3; break; case 3: if( ( end - *p ) < 4 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); *len = ( (size_t)(*p)[1] << 16 ) | ( (size_t)(*p)[2] << 8 ) | (*p)[3]; (*p) += 4; break; case 4: if( ( end - *p ) < 5 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); *len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) | ( (size_t)(*p)[3] << 8 ) | (*p)[4]; (*p) += 5; break; default: return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); } } if( *len > (size_t) ( end - *p ) ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); return( 0 ); } int mbedtls_asn1_get_tag( unsigned char **p, const unsigned char *end, size_t *len, int tag ) { if( ( end - *p ) < 1 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); if( **p != tag ) return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ); (*p)++; return( mbedtls_asn1_get_len( p, end, len ) ); } int mbedtls_asn1_get_bool( unsigned char **p, const unsigned char *end, int *val ) { int ret; size_t len; if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_BOOLEAN ) ) != 0 ) return( ret ); if( len != 1 ) return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); *val = ( **p != 0 ) ? 1 : 0; (*p)++; return( 0 ); } int mbedtls_asn1_get_int( unsigned char **p, const unsigned char *end, int *val ) { int ret; size_t len; if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 ) return( ret ); if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 ) return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); *val = 0; while( len-- > 0 ) { *val = ( *val << 8 ) | **p; (*p)++; } return( 0 ); } #if defined(MBEDTLS_BIGNUM_C) int mbedtls_asn1_get_mpi( unsigned char **p, const unsigned char *end, mbedtls_mpi *X ) { int ret; size_t len; if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 ) return( ret ); ret = mbedtls_mpi_read_binary( X, *p, len ); *p += len; return( ret ); } #endif /* MBEDTLS_BIGNUM_C */ int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end, mbedtls_asn1_bitstring *bs) { int ret; /* Certificate type is a single byte bitstring */ if( ( ret = mbedtls_asn1_get_tag( p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 ) return( ret ); /* Check length, subtract one for actual bit string length */ if( bs->len < 1 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); bs->len -= 1; /* Get number of unused bits, ensure unused bits <= 7 */ bs->unused_bits = **p; if( bs->unused_bits > 7 ) return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); (*p)++; /* Get actual bitstring */ bs->p = *p; *p += bs->len; if( *p != end ) return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); return( 0 ); } /* * Get a bit string without unused bits */ int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end, size_t *len ) { int ret; if( ( ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 ) return( ret ); if( (*len)-- < 2 || *(*p)++ != 0 ) return( MBEDTLS_ERR_ASN1_INVALID_DATA ); return( 0 ); } /* * Parses and splits an ASN.1 "SEQUENCE OF <tag>" */ int mbedtls_asn1_get_sequence_of( unsigned char **p, const unsigned char *end, mbedtls_asn1_sequence *cur, int tag) { int ret; size_t len; mbedtls_asn1_buf *buf; /* Get main sequence tag */ if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) return( ret ); if( *p + len != end ) return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); while( *p < end ) { buf = &(cur->buf); buf->tag = **p; if( ( ret = mbedtls_asn1_get_tag( p, end, &buf->len, tag ) ) != 0 ) return( ret ); buf->p = *p; *p += buf->len; /* Allocate and assign next pointer */ if( *p < end ) { cur->next = (mbedtls_asn1_sequence*)mbedtls_calloc( 1, sizeof( mbedtls_asn1_sequence ) ); if( cur->next == NULL ) return( MBEDTLS_ERR_ASN1_ALLOC_FAILED ); cur = cur->next; } } /* Set final sequence entry's next pointer to NULL */ cur->next = NULL; if( *p != end ) return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); return( 0 ); } int mbedtls_asn1_get_alg( unsigned char **p, const unsigned char *end, mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params ) { int ret; size_t len; if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) return( ret ); if( ( end - *p ) < 1 ) return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); alg->tag = **p; end = *p + len; if( ( ret = mbedtls_asn1_get_tag( p, end, &alg->len, MBEDTLS_ASN1_OID ) ) != 0 ) return( ret ); alg->p = *p; *p += alg->len; if( *p == end ) { mbedtls_zeroize( params, sizeof(mbedtls_asn1_buf) ); return( 0 ); } params->tag = **p; (*p)++; if( ( ret = mbedtls_asn1_get_len( p, end, ¶ms->len ) ) != 0 ) return( ret ); params->p = *p; *p += params->len; if( *p != end ) return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); return( 0 ); } int mbedtls_asn1_get_alg_null( unsigned char **p, const unsigned char *end, mbedtls_asn1_buf *alg ) { int ret; mbedtls_asn1_buf params; memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) ); if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 ) return( ret ); if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 ) return( MBEDTLS_ERR_ASN1_INVALID_DATA ); return( 0 ); } void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *cur ) { if( cur == NULL ) return; mbedtls_free( cur->oid.p ); mbedtls_free( cur->val.p ); mbedtls_zeroize( cur, sizeof( mbedtls_asn1_named_data ) ); } void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head ) { mbedtls_asn1_named_data *cur; while( ( cur = *head ) != NULL ) { *head = cur->next; mbedtls_asn1_free_named_data( cur ); mbedtls_free( cur ); } } mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list, const char *oid, size_t len ) { while( list != NULL ) { if( list->oid.len == len && memcmp( list->oid.p, oid, len ) == 0 ) { break; } list = list->next; } return( list ); } #endif /* MBEDTLS_ASN1_PARSE_C */