mbedtls/library/pkcs7.c

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/*
* 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.
*/
#include "common.h"
#include "mbedtls/build_info.h"
#if defined(MBEDTLS_PKCS7_C)
#include "mbedtls/pkcs7.h"
#include "mbedtls/x509.h"
#include "mbedtls/asn1.h"
#include "mbedtls/x509_crt.h"
#include "mbedtls/x509_crl.h"
#include "mbedtls/oid.h"
#include "mbedtls/error.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#if defined(MBEDTLS_FS_IO)
#include <sys/types.h>
#include <sys/stat.h>
#endif
#include "mbedtls/platform.h"
#include "mbedtls/platform_util.h"
#if defined(MBEDTLS_HAVE_TIME)
#include "mbedtls/platform_time.h"
#endif
#if defined(MBEDTLS_HAVE_TIME_DATE)
#include <time.h>
#endif
/**
* Initializes the pkcs7 structure.
*/
void mbedtls_pkcs7_init( mbedtls_pkcs7 *pkcs7 )
{
memset( pkcs7, 0, sizeof( *pkcs7 ) );
}
static int pkcs7_get_next_content_len( unsigned char **p, unsigned char *end,
size_t *len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_CONTEXT_SPECIFIC );
if( ret != 0 )
{
ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret );
}
return( ret );
}
/**
* version Version
* Version ::= INTEGER
**/
static int pkcs7_get_version( unsigned char **p, unsigned char *end, int *ver )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
ret = mbedtls_asn1_get_int( p, end, ver );
if( ret != 0 )
ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_VERSION, ret );
/* If version != 1, return invalid version */
if( *ver != MBEDTLS_PKCS7_SUPPORTED_VERSION )
ret = MBEDTLS_ERR_PKCS7_INVALID_VERSION;
return( ret );
}
/**
* ContentInfo ::= SEQUENCE {
* contentType ContentType,
* content
* [0] EXPLICIT ANY DEFINED BY contentType OPTIONAL }
**/
static int pkcs7_get_content_info_type( unsigned char **p, unsigned char *end,
mbedtls_pkcs7_buf *pkcs7 )
{
size_t len = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *start = *p;
ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SEQUENCE );
if( ret != 0 ) {
*p = start;
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret ) );
}
ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_OID );
if( ret != 0 ) {
*p = start;
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret ) );
}
pkcs7->tag = MBEDTLS_ASN1_OID;
pkcs7->len = len;
pkcs7->p = *p;
*p += len;
return( ret );
}
/**
* DigestAlgorithmIdentifier ::= AlgorithmIdentifier
*
* This is from x509.h
**/
static int pkcs7_get_digest_algorithm( unsigned char **p, unsigned char *end,
mbedtls_x509_buf *alg )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
if( ( ret = mbedtls_asn1_get_alg_null( p, end, alg ) ) != 0 )
ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_ALG, ret );
return( ret );
}
/**
* DigestAlgorithmIdentifiers :: SET of DigestAlgorithmIdentifier
**/
static int pkcs7_get_digest_algorithm_set( unsigned char **p,
unsigned char *end,
mbedtls_x509_buf *alg )
{
size_t len = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SET );
if( ret != 0 )
{
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_ALG, ret ) );
}
end = *p + len;
ret = mbedtls_asn1_get_alg_null( p, end, alg );
if( ret != 0 )
{
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_ALG, ret ) );
}
/** For now, it assumes there is only one digest algorithm specified **/
if ( *p != end )
return( MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE );
return( 0 );
}
/**
* certificates :: SET OF ExtendedCertificateOrCertificate,
* ExtendedCertificateOrCertificate ::= CHOICE {
* certificate Certificate -- x509,
* extendedCertificate[0] IMPLICIT ExtendedCertificate }
* Return number of certificates added to the signed data,
* 0 or higher is valid.
* Return negative error code for failure.
**/
static int pkcs7_get_certificates( unsigned char **p, unsigned char *end,
mbedtls_x509_crt *certs )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len1 = 0;
size_t len2 = 0;
unsigned char *end_set, *end_cert, *start;
if( ( ret = mbedtls_asn1_get_tag( p, end, &len1, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ) != 0 )
{
if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
return( 0 );
else
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret ) );
}
start = *p;
end_set = *p + len1;
ret = mbedtls_asn1_get_tag( p, end_set, &len2, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SEQUENCE );
if( ret != 0 )
{
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_CERT, ret ) );
}
end_cert = *p + len2;
/*
* This is to verify that there is only one signer certificate. It seems it is
* not easy to differentiate between the chain vs different signer's certificate.
* So, we support only the root certificate and the single signer.
* The behaviour would be improved with addition of multiple signer support.
*/
if ( end_cert != end_set )
{
return( MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE );
}
*p = start;
if( ( ret = mbedtls_x509_crt_parse_der( certs, *p, len1 ) ) < 0 )
{
return( MBEDTLS_ERR_PKCS7_INVALID_CERT );
}
*p = *p + len1;
/*
* Since in this version we strictly support single certificate, and reaching
* here implies we have parsed successfully, we return 1.
*/
return( 1 );
}
/**
* EncryptedDigest ::= OCTET STRING
**/
static int pkcs7_get_signature( unsigned char **p, unsigned char *end,
mbedtls_pkcs7_buf *signature )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_OCTET_STRING );
if( ret != 0 )
return( ret );
signature->tag = MBEDTLS_ASN1_OCTET_STRING;
signature->len = len;
signature->p = *p;
*p = *p + len;
return( 0 );
}
/**
* SignerInfo ::= SEQUENCE {
* version Version;
* issuerAndSerialNumber IssuerAndSerialNumber,
* digestAlgorithm DigestAlgorithmIdentifier,
* authenticatedAttributes
* [0] IMPLICIT Attributes OPTIONAL,
* digestEncryptionAlgorithm DigestEncryptionAlgorithmIdentifier,
* encryptedDigest EncryptedDigest,
* unauthenticatedAttributes
* [1] IMPLICIT Attributes OPTIONAL,
* Returns 0 if the signerInfo is valid.
* Return negative error code for failure.
* Structure must not contain vales for authenticatedAttributes
* and unauthenticatedAttributes.
**/
static int pkcs7_get_signer_info( unsigned char **p, unsigned char *end,
mbedtls_pkcs7_signer_info *signer )
{
unsigned char *end_signer;
int asn1_ret = 0, ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
asn1_ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SEQUENCE );
if( asn1_ret != 0 )
goto out;
end_signer = *p + len;
ret = pkcs7_get_version( p, end_signer, &signer->version );
if( ret != 0 )
goto out;
asn1_ret = mbedtls_asn1_get_tag( p, end_signer, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE );
if( asn1_ret != 0 )
goto out;
/* Parsing IssuerAndSerialNumber */
signer->issuer_raw.p = *p;
asn1_ret = mbedtls_asn1_get_tag( p, end_signer, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE );
if( asn1_ret != 0 )
goto out;
ret = mbedtls_x509_get_name( p, *p + len, &signer->issuer );
if( ret != 0 )
goto out;
signer->issuer_raw.len = *p - signer->issuer_raw.p;
ret = mbedtls_x509_get_serial( p, end_signer, &signer->serial );
if( ret != 0 )
goto out;
ret = pkcs7_get_digest_algorithm( p, end_signer, &signer->alg_identifier );
if( ret != 0 )
goto out;
/* Asssume authenticatedAttributes is nonexistent */
ret = pkcs7_get_digest_algorithm( p, end_signer, &signer->sig_alg_identifier );
if( ret != 0 )
goto out;
ret = pkcs7_get_signature( p, end_signer, &signer->sig );
if( ret != 0 )
goto out;
/* Do not permit any unauthenticated attributes */
if( *p != end_signer )
ret = MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO;
out:
if( asn1_ret != 0 )
ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO,
asn1_ret );
else if( ret != 0 )
ret = MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO;
return( ret );
}
static void pkcs7_free_signer_info( mbedtls_pkcs7_signer_info *signer )
{
mbedtls_x509_name *name_cur;
mbedtls_x509_name *name_prv;
if( signer == NULL )
return;
name_cur = signer->issuer.next;
while( name_cur != NULL )
{
name_prv = name_cur;
name_cur = name_cur->next;
mbedtls_free( name_prv );
}
}
/**
* SignerInfos ::= SET of SignerInfo
* Return number of signers added to the signed data,
* 0 or higher is valid.
* Return negative error code for failure.
**/
static int pkcs7_get_signers_info_set( unsigned char **p, unsigned char *end,
mbedtls_pkcs7_signer_info *signers_set )
{
unsigned char *end_set;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
int count = 0;
size_t len = 0;
ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SET );
if( ret != 0 )
{
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO, ret ) );
}
/* Detect zero signers */
if( len == 0 )
{
return( 0 );
}
end_set = *p + len;
ret = pkcs7_get_signer_info( p, end_set, signers_set );
if( ret != 0 )
return( ret );
count++;
mbedtls_pkcs7_signer_info *prev = signers_set;
while( *p != end_set )
{
mbedtls_pkcs7_signer_info *signer =
mbedtls_calloc( 1, sizeof( mbedtls_pkcs7_signer_info ) );
if( !signer )
{
ret = MBEDTLS_ERR_PKCS7_ALLOC_FAILED;
goto cleanup;
}
ret = pkcs7_get_signer_info( p, end_set, signer );
if( ret != 0 ) {
mbedtls_free( signer );
goto cleanup;
}
prev->next = signer;
prev = signer;
count++;
}
return( count );
cleanup:
pkcs7_free_signer_info( signers_set );
mbedtls_pkcs7_signer_info *signer = signers_set->next;
while( signer != NULL )
{
prev = signer;
signer = signer->next;
pkcs7_free_signer_info( prev );
mbedtls_free( prev );
}
signers_set->next = NULL;
return( ret );
}
/**
* SignedData ::= SEQUENCE {
* version Version,
* digestAlgorithms DigestAlgorithmIdentifiers,
* contentInfo ContentInfo,
* certificates
* [0] IMPLICIT ExtendedCertificatesAndCertificates
* OPTIONAL,
* crls
* [0] IMPLICIT CertificateRevocationLists OPTIONAL,
* signerInfos SignerInfos }
*/
static int pkcs7_get_signed_data( unsigned char *buf, size_t buflen,
mbedtls_pkcs7_signed_data *signed_data )
{
unsigned char *p = buf;
unsigned char *end = buf + buflen;
unsigned char *end_set;
size_t len = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_md_type_t md_alg;
ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
| MBEDTLS_ASN1_SEQUENCE );
if( ret != 0 )
{
return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret ) );
}
end_set = p + len;
/* Get version of signed data */
ret = pkcs7_get_version( &p, end_set, &signed_data->version );
if( ret != 0 )
return( ret );
/* Get digest algorithm */
ret = pkcs7_get_digest_algorithm_set( &p, end_set,
&signed_data->digest_alg_identifiers );
if( ret != 0 )
return( ret );
ret = mbedtls_oid_get_md_alg( &signed_data->digest_alg_identifiers, &md_alg );
if( ret != 0 )
{
return( MBEDTLS_ERR_PKCS7_INVALID_ALG );
}
/* Do not expect any content */
ret = pkcs7_get_content_info_type( &p, end_set, &signed_data->content.oid );
if( ret != 0 )
return( ret );
if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_DATA, &signed_data->content.oid ) )
{
return( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO );
}
/* Look for certificates, there may or may not be any */
mbedtls_x509_crt_init( &signed_data->certs );
ret = pkcs7_get_certificates( &p, end_set, &signed_data->certs );
if( ret < 0 )
return( ret );
signed_data->no_of_certs = ret;
/*
* Currently CRLs are not supported. If CRL exist, the parsing will fail
* at next step of getting signers info and return error as invalid
* signer info.
*/
signed_data->no_of_crls = 0;
/* Get signers info */
ret = pkcs7_get_signers_info_set( &p, end_set, &signed_data->signers );
if( ret < 0 )
return( ret );
signed_data->no_of_signers = ret;
/* Don't permit trailing data */
if ( p != end )
return( MBEDTLS_ERR_PKCS7_INVALID_FORMAT );
return( 0 );
}
int mbedtls_pkcs7_parse_der( mbedtls_pkcs7 *pkcs7, const unsigned char *buf,
const size_t buflen )
{
unsigned char *p;
unsigned char *end;
size_t len = 0;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
int isoidset = 0;
if( pkcs7 == NULL )
{
return( MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA );
}
/* make an internal copy of the buffer for parsing */
pkcs7->raw.p = p = mbedtls_calloc( 1, buflen );
if( pkcs7->raw.p == NULL )
{
ret = MBEDTLS_ERR_PKCS7_ALLOC_FAILED;
goto out;
}
memcpy( p, buf, buflen );
pkcs7->raw.len = buflen;
end = p + buflen;
ret = pkcs7_get_content_info_type( &p, end, &pkcs7->content_type_oid );
if( ret != 0 )
{
len = buflen;
goto try_data;
}
if( ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_DATA, &pkcs7->content_type_oid )
|| ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_ENCRYPTED_DATA, &pkcs7->content_type_oid )
|| ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_ENVELOPED_DATA, &pkcs7->content_type_oid )
|| ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_SIGNED_AND_ENVELOPED_DATA, &pkcs7->content_type_oid )
|| ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_DIGESTED_DATA, &pkcs7->content_type_oid )
|| ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_ENCRYPTED_DATA, &pkcs7->content_type_oid ) )
{
ret = MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
goto out;
}
if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_SIGNED_DATA, &pkcs7->content_type_oid ) )
{
ret = MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
goto out;
}
isoidset = 1;
ret = pkcs7_get_next_content_len( &p, end, &len );
if( ret != 0 )
goto out;
try_data:
ret = pkcs7_get_signed_data( p, len, &pkcs7->signed_data );
if ( ret != 0 )
goto out;
if ( !isoidset )
{
pkcs7->content_type_oid.tag = MBEDTLS_ASN1_OID;
pkcs7->content_type_oid.len = MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS7_SIGNED_DATA );
pkcs7->content_type_oid.p = (unsigned char *)MBEDTLS_OID_PKCS7_SIGNED_DATA;
}
ret = MBEDTLS_PKCS7_SIGNED_DATA;
out:
if ( ret < 0 )
mbedtls_pkcs7_free( pkcs7 );
return( ret );
}
static int mbedtls_pkcs7_data_or_hash_verify( mbedtls_pkcs7 *pkcs7,
const mbedtls_x509_crt *cert,
const unsigned char *data,
size_t datalen,
const int is_data_hash )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *hash;
mbedtls_pk_context pk_cxt = cert->pk;
const mbedtls_md_info_t *md_info;
mbedtls_md_type_t md_alg;
mbedtls_pkcs7_signer_info *signer;
if( pkcs7->signed_data.no_of_signers == 0 )
{
return( MBEDTLS_ERR_PKCS7_INVALID_CERT );
}
if( mbedtls_x509_time_is_past( &cert->valid_to ) ||
mbedtls_x509_time_is_future( &cert->valid_from ))
{
return( MBEDTLS_ERR_PKCS7_CERT_DATE_INVALID );
}
/*
* Potential TODOs
* Currently we iterate over all signers and return success if any of them
* verify.
*
* However, we could make this better by checking against the certificate's
* identification and SignerIdentifier fields first. That would also allow
* us to distinguish between 'no signature for key' and 'signature for key
* failed to validate'.
*
* We could also cache hashes by md, so if there are several sigs all using
* the same algo we don't recalculate the hash each time.
*/
for( signer = &pkcs7->signed_data.signers; signer; signer = signer->next )
{
ret = mbedtls_oid_get_md_alg( &signer->alg_identifier, &md_alg );
if( ret != 0 )
{
ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
continue;
}
md_info = mbedtls_md_info_from_type( md_alg );
if( md_info == NULL )
{
ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
continue;
}
hash = mbedtls_calloc( mbedtls_md_get_size( md_info ), 1 );
if( hash == NULL ) {
return( MBEDTLS_ERR_PKCS7_ALLOC_FAILED );
}
/* BEGIN must free hash before jumping out */
if( is_data_hash )
{
if( datalen != mbedtls_md_get_size( md_info ))
ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
else
memcpy(hash, data, datalen);
}
else
{
ret = mbedtls_md( md_info, data, datalen, hash );
}
if( ret != 0 )
{
ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
mbedtls_free( hash );
continue;
}
ret = mbedtls_pk_verify( &pk_cxt, md_alg, hash,
mbedtls_md_get_size( md_info ),
signer->sig.p, signer->sig.len );
mbedtls_free( hash );
/* END must free hash before jumping out */
if( ret == 0 )
break;
}
return( ret );
}
int mbedtls_pkcs7_signed_data_verify( mbedtls_pkcs7 *pkcs7,
const mbedtls_x509_crt *cert,
const unsigned char *data,
size_t datalen )
{
return( mbedtls_pkcs7_data_or_hash_verify( pkcs7, cert, data, datalen, 0 ) );
}
int mbedtls_pkcs7_signed_hash_verify( mbedtls_pkcs7 *pkcs7,
const mbedtls_x509_crt *cert,
const unsigned char *hash,
size_t hashlen )
{
return( mbedtls_pkcs7_data_or_hash_verify( pkcs7, cert, hash, hashlen, 1 ) );
}
/*
* Unallocate all pkcs7 data
*/
void mbedtls_pkcs7_free( mbedtls_pkcs7 *pkcs7 )
{
mbedtls_pkcs7_signer_info *signer_cur;
mbedtls_pkcs7_signer_info *signer_prev;
if( pkcs7 == NULL || pkcs7->raw.p == NULL )
return;
mbedtls_free( pkcs7->raw.p );
mbedtls_x509_crt_free( &pkcs7->signed_data.certs );
mbedtls_x509_crl_free( &pkcs7->signed_data.crl );
signer_cur = pkcs7->signed_data.signers.next;
pkcs7_free_signer_info( &pkcs7->signed_data.signers );
while( signer_cur != NULL )
{
signer_prev = signer_cur;
signer_cur = signer_prev->next;
pkcs7_free_signer_info( signer_prev );
mbedtls_free( signer_prev );
}
pkcs7->raw.p = NULL;
}
#endif