mirror of
https://github.com/yuzu-emu/mbedtls.git
synced 2024-11-27 12:44:21 +01:00
8730610ae0
This commit adds a new function `mbedtls_asn1_traverse_sequence_of()` which traverses an ASN.1 SEQUENCE and calls a user-provided callback for each entry. It allows to put the following constraints on the tags allowed in the SEQUENCE: - A tag mask and mandatory tag value w.r.t. that mask. A non-matching tag leads to an MBEDTLS_ERR_ASN1_UNEXPECTED_TAG error. For example, it the mask if 0xFF, this means that only a single tag will be allowed in the SEQUENCE. - A tag mask and optional tag value w.r.t. that mask. A non-matching tag is silently ignored. The main use for this flexibility is the traversal of the `SubjectAlternativeNames` extension, where some parts of the tag are fixed but some are flexible to indicate which type of name the entry describes.
436 lines
10 KiB
C
436 lines
10 KiB
C
/*
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* Generic ASN.1 parsing
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_ASN1_PARSE_C)
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#include "mbedtls/asn1.h"
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#include "mbedtls/platform_util.h"
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#include <string.h>
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#if defined(MBEDTLS_BIGNUM_C)
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#include "mbedtls/bignum.h"
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#endif
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdlib.h>
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#define mbedtls_calloc calloc
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#define mbedtls_free free
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#endif
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/*
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* ASN.1 DER decoding routines
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*/
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int mbedtls_asn1_get_len( unsigned char **p,
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const unsigned char *end,
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size_t *len )
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{
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if( ( end - *p ) < 1 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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if( ( **p & 0x80 ) == 0 )
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*len = *(*p)++;
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else
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{
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switch( **p & 0x7F )
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{
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case 1:
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if( ( end - *p ) < 2 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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*len = (*p)[1];
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(*p) += 2;
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break;
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case 2:
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if( ( end - *p ) < 3 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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*len = ( (size_t)(*p)[1] << 8 ) | (*p)[2];
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(*p) += 3;
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break;
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case 3:
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if( ( end - *p ) < 4 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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*len = ( (size_t)(*p)[1] << 16 ) |
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( (size_t)(*p)[2] << 8 ) | (*p)[3];
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(*p) += 4;
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break;
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case 4:
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if( ( end - *p ) < 5 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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*len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) |
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( (size_t)(*p)[3] << 8 ) | (*p)[4];
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(*p) += 5;
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break;
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default:
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return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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}
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}
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if( *len > (size_t) ( end - *p ) )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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return( 0 );
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}
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int mbedtls_asn1_get_tag( unsigned char **p,
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const unsigned char *end,
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size_t *len, int tag )
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{
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if( ( end - *p ) < 1 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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if( **p != tag )
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return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
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(*p)++;
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return( mbedtls_asn1_get_len( p, end, len ) );
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}
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int mbedtls_asn1_get_bool( unsigned char **p,
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const unsigned char *end,
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int *val )
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{
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int ret;
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size_t len;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_BOOLEAN ) ) != 0 )
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return( ret );
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if( len != 1 )
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return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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*val = ( **p != 0 ) ? 1 : 0;
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(*p)++;
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return( 0 );
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}
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int mbedtls_asn1_get_int( unsigned char **p,
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const unsigned char *end,
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int *val )
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{
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int ret;
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size_t len;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
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return( ret );
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if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 )
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return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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*val = 0;
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while( len-- > 0 )
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{
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*val = ( *val << 8 ) | **p;
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(*p)++;
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}
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return( 0 );
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}
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#if defined(MBEDTLS_BIGNUM_C)
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int mbedtls_asn1_get_mpi( unsigned char **p,
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const unsigned char *end,
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mbedtls_mpi *X )
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{
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int ret;
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size_t len;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 )
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return( ret );
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ret = mbedtls_mpi_read_binary( X, *p, len );
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*p += len;
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return( ret );
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}
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#endif /* MBEDTLS_BIGNUM_C */
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int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
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mbedtls_asn1_bitstring *bs)
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{
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int ret;
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/* Certificate type is a single byte bitstring */
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if( ( ret = mbedtls_asn1_get_tag( p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
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return( ret );
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/* Check length, subtract one for actual bit string length */
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if( bs->len < 1 )
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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bs->len -= 1;
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/* Get number of unused bits, ensure unused bits <= 7 */
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bs->unused_bits = **p;
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if( bs->unused_bits > 7 )
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return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
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(*p)++;
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/* Get actual bitstring */
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bs->p = *p;
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*p += bs->len;
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if( *p != end )
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return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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return( 0 );
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}
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/*
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* Get a bit string without unused bits
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*/
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int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
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size_t *len )
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{
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int ret;
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if( ( ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 )
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return( ret );
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if( (*len)-- < 2 || *(*p)++ != 0 )
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return( MBEDTLS_ERR_ASN1_INVALID_DATA );
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return( 0 );
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}
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/*
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* Traverse an ASN.1 "SEQUENCE OF <tag>"
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* and call a callback for each entry found.
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*/
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int mbedtls_asn1_traverse_sequence_of(
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unsigned char **p,
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const unsigned char *end,
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uint8_t tag_must_mask, uint8_t tag_must_val,
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uint8_t tag_may_mask, uint8_t tag_may_val,
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int (*cb)( void *ctx, int tag,
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unsigned char *start, size_t len ),
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void *ctx )
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{
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int ret;
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size_t len;
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/* Get main sequence tag */
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if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
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{
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return( ret );
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}
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if( *p + len != end )
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return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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while( *p < end )
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{
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unsigned char const tag = *(*p)++;
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if( ( tag & tag_must_mask ) != tag_must_val )
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return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
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if( ( tag & tag_may_mask ) == tag_may_val )
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{
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if( ( ret = mbedtls_asn1_get_len( p, end, &len ) ) != 0 )
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return( ret );
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if( cb != NULL )
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{
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ret = cb( ctx, tag, *p, len );
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if( ret != 0 )
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return( ret );
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}
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}
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*p += len;
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}
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return( 0 );
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}
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typedef struct
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{
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int tag;
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mbedtls_asn1_sequence *cur;
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} asn1_get_sequence_of_cb_ctx_t;
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static int asn1_get_sequence_of_cb( void *ctx,
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int tag,
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unsigned char *start,
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size_t len )
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{
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asn1_get_sequence_of_cb_ctx_t *cb_ctx =
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(asn1_get_sequence_of_cb_ctx_t *) ctx;
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mbedtls_asn1_sequence *cur =
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cb_ctx->cur;
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if( cur->buf.p != NULL )
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{
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cur->next =
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mbedtls_calloc( 1, sizeof( mbedtls_asn1_sequence ) );
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if( cur->next == NULL )
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return( MBEDTLS_ERR_ASN1_ALLOC_FAILED );
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cur = cur->next;
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}
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cur->buf.p = start;
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cur->buf.len = len;
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cur->buf.tag = tag;
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cb_ctx->cur = cur;
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return( 0 );
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}
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/*
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* Parses and splits an ASN.1 "SEQUENCE OF <tag>"
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*/
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int mbedtls_asn1_get_sequence_of( unsigned char **p,
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const unsigned char *end,
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mbedtls_asn1_sequence *cur,
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int tag)
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{
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asn1_get_sequence_of_cb_ctx_t cb_ctx = { tag, cur };
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memset( cur, 0, sizeof( mbedtls_asn1_sequence ) );
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return( mbedtls_asn1_traverse_sequence_of(
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p, end, 0xFF, tag, 0, 0,
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asn1_get_sequence_of_cb, &cb_ctx ) );
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}
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int mbedtls_asn1_get_alg( unsigned char **p,
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const unsigned char *end,
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mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params )
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{
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int ret;
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size_t len;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
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return( ret );
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end = *p + len;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &alg->len, MBEDTLS_ASN1_OID ) ) != 0 )
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return( ret );
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alg->tag = MBEDTLS_ASN1_OID;
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alg->p = *p;
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*p += alg->len;
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if( *p == end )
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{
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mbedtls_platform_zeroize( params, sizeof(mbedtls_asn1_buf) );
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return( 0 );
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}
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params->tag = **p;
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(*p)++;
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if( ( ret = mbedtls_asn1_get_len( p, end, ¶ms->len ) ) != 0 )
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return( ret );
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params->p = *p;
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*p += params->len;
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if( *p != end )
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return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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return( 0 );
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}
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int mbedtls_asn1_get_alg_null( unsigned char **p,
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const unsigned char *end,
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mbedtls_asn1_buf *alg )
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{
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int ret;
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mbedtls_asn1_buf params;
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memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) );
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if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 )
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return( ret );
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if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 )
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return( MBEDTLS_ERR_ASN1_INVALID_DATA );
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return( 0 );
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}
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void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *cur )
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{
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if( cur == NULL )
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return;
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mbedtls_free( cur->oid.p );
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mbedtls_free( cur->val.p );
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mbedtls_platform_zeroize( cur, sizeof( mbedtls_asn1_named_data ) );
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}
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void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head )
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{
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mbedtls_asn1_named_data *cur;
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while( ( cur = *head ) != NULL )
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{
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*head = cur->next;
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mbedtls_asn1_free_named_data( cur );
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mbedtls_free( cur );
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}
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}
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mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
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const char *oid, size_t len )
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{
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while( list != NULL )
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{
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if( list->oid.len == len &&
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memcmp( list->oid.p, oid, len ) == 0 )
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{
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break;
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}
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list = list->next;
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}
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return( list );
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}
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#endif /* MBEDTLS_ASN1_PARSE_C */
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