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mbedtls/library/x509_crt.c
Manuel Pégourié-Gonnard 1c38550bbd Skip to trusted certs early in the chain 
This helps in the case where an intermediate certificate is directly trusted.
In that case we want to ignore what comes after it in the chain, not only for
performance but also to avoid false negatives (eg an old root being no longer
trusted while the newer intermediate is directly trusted).

see #220

backport of fdbdd72
2015-09-01 18:34:15 +02:00

2197 lines
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/*
* X.509 certificate parsing and verification
*
* Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
*
* This file is part of mbed TLS (https://tls.mbed.org)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* The ITU-T X.509 standard defines a certificate format for PKI.
*
* http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
* http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
* http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
*
* http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
* http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
*/
#if !defined(POLARSSL_CONFIG_FILE)
#include "polarssl/config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif
#if defined(POLARSSL_X509_CRT_PARSE_C)
#include "polarssl/x509_crt.h"
#include "polarssl/oid.h"
#include <stdio.h>
#include <string.h>
#if defined(POLARSSL_PEM_PARSE_C)
#include "polarssl/pem.h"
#endif
#if defined(POLARSSL_PLATFORM_C)
#include "polarssl/platform.h"
#else
#include <stdlib.h>
#define polarssl_free free
#define polarssl_malloc malloc
#define polarssl_snprintf snprintf
#endif
#if defined(POLARSSL_THREADING_C)
#include "polarssl/threading.h"
#endif
#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
#include <windows.h>
#else
#include <time.h>
#endif
#if defined(POLARSSL_FS_IO)
#include <stdio.h>
#if !defined(_WIN32) || defined(EFIX64) || defined(EFI32)
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#endif /* !_WIN32 || EFIX64 || EFI32 */
#endif
/* Implementation that should never be optimized out by the compiler */
static void polarssl_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
/*
* Version ::= INTEGER { v1(0), v2(1), v3(2) }
*/
static int x509_get_version( unsigned char **p,
const unsigned char *end,
int *ver )
{
int ret;
size_t len;
if( ( ret = asn1_get_tag( p, end, &len,
ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0 ) ) != 0 )
{
if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
{
*ver = 0;
return( 0 );
}
return( ret );
}
end = *p + len;
if( ( ret = asn1_get_int( p, end, ver ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_VERSION + ret );
if( *p != end )
return( POLARSSL_ERR_X509_INVALID_VERSION +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* Validity ::= SEQUENCE {
* notBefore Time,
* notAfter Time }
*/
static int x509_get_dates( unsigned char **p,
const unsigned char *end,
x509_time *from,
x509_time *to )
{
int ret;
size_t len;
if( ( ret = asn1_get_tag( p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_DATE + ret );
end = *p + len;
if( ( ret = x509_get_time( p, end, from ) ) != 0 )
return( ret );
if( ( ret = x509_get_time( p, end, to ) ) != 0 )
return( ret );
if( *p != end )
return( POLARSSL_ERR_X509_INVALID_DATE +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* X.509 v2/v3 unique identifier (not parsed)
*/
static int x509_get_uid( unsigned char **p,
const unsigned char *end,
x509_buf *uid, int n )
{
int ret;
if( *p == end )
return( 0 );
uid->tag = **p;
if( ( ret = asn1_get_tag( p, end, &uid->len,
ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | n ) ) != 0 )
{
if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
return( 0 );
return( ret );
}
uid->p = *p;
*p += uid->len;
return( 0 );
}
static int x509_get_basic_constraints( unsigned char **p,
const unsigned char *end,
int *ca_istrue,
int *max_pathlen )
{
int ret;
size_t len;
/*
* BasicConstraints ::= SEQUENCE {
* cA BOOLEAN DEFAULT FALSE,
* pathLenConstraint INTEGER (0..MAX) OPTIONAL }
*/
*ca_istrue = 0; /* DEFAULT FALSE */
*max_pathlen = 0; /* endless */
if( ( ret = asn1_get_tag( p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p == end )
return( 0 );
if( ( ret = asn1_get_bool( p, end, ca_istrue ) ) != 0 )
{
if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
ret = asn1_get_int( p, end, ca_istrue );
if( ret != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( *ca_istrue != 0 )
*ca_istrue = 1;
}
if( *p == end )
return( 0 );
if( ( ret = asn1_get_int( p, end, max_pathlen ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p != end )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
(*max_pathlen)++;
return( 0 );
}
static int x509_get_ns_cert_type( unsigned char **p,
const unsigned char *end,
unsigned char *ns_cert_type)
{
int ret;
x509_bitstring bs = { 0, 0, NULL };
if( ( ret = asn1_get_bitstring( p, end, &bs ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( bs.len != 1 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_INVALID_LENGTH );
/* Get actual bitstring */
*ns_cert_type = *bs.p;
return( 0 );
}
static int x509_get_key_usage( unsigned char **p,
const unsigned char *end,
unsigned char *key_usage)
{
int ret;
x509_bitstring bs = { 0, 0, NULL };
if( ( ret = asn1_get_bitstring( p, end, &bs ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( bs.len < 1 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_INVALID_LENGTH );
/* Get actual bitstring */
*key_usage = *bs.p;
return( 0 );
}
/*
* ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId
*
* KeyPurposeId ::= OBJECT IDENTIFIER
*/
static int x509_get_ext_key_usage( unsigned char **p,
const unsigned char *end,
x509_sequence *ext_key_usage)
{
int ret;
if( ( ret = asn1_get_sequence_of( p, end, ext_key_usage, ASN1_OID ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
/* Sequence length must be >= 1 */
if( ext_key_usage->buf.p == NULL )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_INVALID_LENGTH );
return( 0 );
}
/*
* SubjectAltName ::= GeneralNames
*
* GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
*
* GeneralName ::= CHOICE {
* otherName [0] OtherName,
* rfc822Name [1] IA5String,
* dNSName [2] IA5String,
* x400Address [3] ORAddress,
* directoryName [4] Name,
* ediPartyName [5] EDIPartyName,
* uniformResourceIdentifier [6] IA5String,
* iPAddress [7] OCTET STRING,
* registeredID [8] OBJECT IDENTIFIER }
*
* OtherName ::= SEQUENCE {
* type-id OBJECT IDENTIFIER,
* value [0] EXPLICIT ANY DEFINED BY type-id }
*
* EDIPartyName ::= SEQUENCE {
* nameAssigner [0] DirectoryString OPTIONAL,
* partyName [1] DirectoryString }
*
* NOTE: we only parse and use dNSName at this point.
*/
static int x509_get_subject_alt_name( unsigned char **p,
const unsigned char *end,
x509_sequence *subject_alt_name )
{
int ret;
size_t len, tag_len;
asn1_buf *buf;
unsigned char tag;
asn1_sequence *cur = subject_alt_name;
/* Get main sequence tag */
if( ( ret = asn1_get_tag( p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p + len != end )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
while( *p < end )
{
if( ( end - *p ) < 1 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_OUT_OF_DATA );
tag = **p;
(*p)++;
if( ( ret = asn1_get_len( p, end, &tag_len ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
if( ( tag & ASN1_CONTEXT_SPECIFIC ) != ASN1_CONTEXT_SPECIFIC )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
/* Skip everything but DNS name */
if( tag != ( ASN1_CONTEXT_SPECIFIC | 2 ) )
{
*p += tag_len;
continue;
}
/* Allocate and assign next pointer */
if( cur->buf.p != NULL )
{
if( cur->next != NULL )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS );
cur->next = polarssl_malloc( sizeof( asn1_sequence ) );
if( cur->next == NULL )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_MALLOC_FAILED );
memset( cur->next, 0, sizeof( asn1_sequence ) );
cur = cur->next;
}
buf = &(cur->buf);
buf->tag = tag;
buf->p = *p;
buf->len = tag_len;
*p += buf->len;
}
/* Set final sequence entry's next pointer to NULL */
cur->next = NULL;
if( *p != end )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* X.509 v3 extensions
*
* TODO: Perform all of the basic constraints tests required by the RFC
* TODO: Set values for undetected extensions to a sane default?
*
*/
static int x509_get_crt_ext( unsigned char **p,
const unsigned char *end,
x509_crt *crt )
{
int ret;
size_t len;
unsigned char *end_ext_data, *end_ext_octet;
if( ( ret = x509_get_ext( p, end, &crt->v3_ext, 3 ) ) != 0 )
{
if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
return( 0 );
return( ret );
}
while( *p < end )
{
/*
* Extension ::= SEQUENCE {
* extnID OBJECT IDENTIFIER,
* critical BOOLEAN DEFAULT FALSE,
* extnValue OCTET STRING }
*/
x509_buf extn_oid = {0, 0, NULL};
int is_critical = 0; /* DEFAULT FALSE */
int ext_type = 0;
if( ( ret = asn1_get_tag( p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
end_ext_data = *p + len;
/* Get extension ID */
extn_oid.tag = **p;
if( ( ret = asn1_get_tag( p, end, &extn_oid.len, ASN1_OID ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
extn_oid.p = *p;
*p += extn_oid.len;
if( ( end - *p ) < 1 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_OUT_OF_DATA );
/* Get optional critical */
if( ( ret = asn1_get_bool( p, end_ext_data, &is_critical ) ) != 0 &&
( ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG ) )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
/* Data should be octet string type */
if( ( ret = asn1_get_tag( p, end_ext_data, &len,
ASN1_OCTET_STRING ) ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS + ret );
end_ext_octet = *p + len;
if( end_ext_octet != end_ext_data )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
/*
* Detect supported extensions
*/
ret = oid_get_x509_ext_type( &extn_oid, &ext_type );
if( ret != 0 )
{
/* No parser found, skip extension */
*p = end_ext_octet;
#if !defined(POLARSSL_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION)
if( is_critical )
{
/* Data is marked as critical: fail */
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
}
#endif
continue;
}
/* Forbid repeated extensions */
if( ( crt->ext_types & ext_type ) != 0 )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS );
crt->ext_types |= ext_type;
switch( ext_type )
{
case EXT_BASIC_CONSTRAINTS:
/* Parse basic constraints */
if( ( ret = x509_get_basic_constraints( p, end_ext_octet,
&crt->ca_istrue, &crt->max_pathlen ) ) != 0 )
return( ret );
break;
case EXT_KEY_USAGE:
/* Parse key usage */
if( ( ret = x509_get_key_usage( p, end_ext_octet,
&crt->key_usage ) ) != 0 )
return( ret );
break;
case EXT_EXTENDED_KEY_USAGE:
/* Parse extended key usage */
if( ( ret = x509_get_ext_key_usage( p, end_ext_octet,
&crt->ext_key_usage ) ) != 0 )
return( ret );
break;
case EXT_SUBJECT_ALT_NAME:
/* Parse subject alt name */
if( ( ret = x509_get_subject_alt_name( p, end_ext_octet,
&crt->subject_alt_names ) ) != 0 )
return( ret );
break;
case EXT_NS_CERT_TYPE:
/* Parse netscape certificate type */
if( ( ret = x509_get_ns_cert_type( p, end_ext_octet,
&crt->ns_cert_type ) ) != 0 )
return( ret );
break;
default:
return( POLARSSL_ERR_X509_FEATURE_UNAVAILABLE );
}
}
if( *p != end )
return( POLARSSL_ERR_X509_INVALID_EXTENSIONS +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* Parse and fill a single X.509 certificate in DER format
*/
static int x509_crt_parse_der_core( x509_crt *crt, const unsigned char *buf,
size_t buflen )
{
int ret;
size_t len;
unsigned char *p, *end, *crt_end;
x509_buf sig_params1, sig_params2;
memset( &sig_params1, 0, sizeof( x509_buf ) );
memset( &sig_params2, 0, sizeof( x509_buf ) );
/*
* Check for valid input
*/
if( crt == NULL || buf == NULL )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
p = polarssl_malloc( len = buflen );
if( p == NULL )
return( POLARSSL_ERR_X509_MALLOC_FAILED );
memcpy( p, buf, buflen );
crt->raw.p = p;
crt->raw.len = len;
end = p + len;
/*
* Certificate ::= SEQUENCE {
* tbsCertificate TBSCertificate,
* signatureAlgorithm AlgorithmIdentifier,
* signatureValue BIT STRING }
*/
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT );
}
if( len > (size_t) ( end - p ) )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
}
crt_end = p + len;
/*
* TBSCertificate ::= SEQUENCE {
*/
crt->tbs.p = p;
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
end = p + len;
crt->tbs.len = end - crt->tbs.p;
/*
* Version ::= INTEGER { v1(0), v2(1), v3(2) }
*
* CertificateSerialNumber ::= INTEGER
*
* signature AlgorithmIdentifier
*/
if( ( ret = x509_get_version( &p, end, &crt->version ) ) != 0 ||
( ret = x509_get_serial( &p, end, &crt->serial ) ) != 0 ||
( ret = x509_get_alg( &p, end, &crt->sig_oid1,
&sig_params1 ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
crt->version++;
if( crt->version > 3 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_UNKNOWN_VERSION );
}
if( ( ret = x509_get_sig_alg( &crt->sig_oid1, &sig_params1,
&crt->sig_md, &crt->sig_pk,
&crt->sig_opts ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
/*
* issuer Name
*/
crt->issuer_raw.p = p;
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
if( ( ret = x509_get_name( &p, p + len, &crt->issuer ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
crt->issuer_raw.len = p - crt->issuer_raw.p;
/*
* Validity ::= SEQUENCE {
* notBefore Time,
* notAfter Time }
*
*/
if( ( ret = x509_get_dates( &p, end, &crt->valid_from,
&crt->valid_to ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
/*
* subject Name
*/
crt->subject_raw.p = p;
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
if( len && ( ret = x509_get_name( &p, p + len, &crt->subject ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
crt->subject_raw.len = p - crt->subject_raw.p;
/*
* SubjectPublicKeyInfo
*/
if( ( ret = pk_parse_subpubkey( &p, end, &crt->pk ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
/*
* issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL,
* -- If present, version shall be v2 or v3
* subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL,
* -- If present, version shall be v2 or v3
* extensions [3] EXPLICIT Extensions OPTIONAL
* -- If present, version shall be v3
*/
if( crt->version == 2 || crt->version == 3 )
{
ret = x509_get_uid( &p, end, &crt->issuer_id, 1 );
if( ret != 0 )
{
x509_crt_free( crt );
return( ret );
}
}
if( crt->version == 2 || crt->version == 3 )
{
ret = x509_get_uid( &p, end, &crt->subject_id, 2 );
if( ret != 0 )
{
x509_crt_free( crt );
return( ret );
}
}
#if !defined(POLARSSL_X509_ALLOW_EXTENSIONS_NON_V3)
if( crt->version == 3 )
{
#endif
ret = x509_get_crt_ext( &p, end, crt );
if( ret != 0 )
{
x509_crt_free( crt );
return( ret );
}
#if !defined(POLARSSL_X509_ALLOW_EXTENSIONS_NON_V3)
}
#endif
if( p != end )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
}
end = crt_end;
/*
* }
* -- end of TBSCertificate
*
* signatureAlgorithm AlgorithmIdentifier,
* signatureValue BIT STRING
*/
if( ( ret = x509_get_alg( &p, end, &crt->sig_oid2, &sig_params2 ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
if( crt->sig_oid1.len != crt->sig_oid2.len ||
memcmp( crt->sig_oid1.p, crt->sig_oid2.p, crt->sig_oid1.len ) != 0 ||
sig_params1.len != sig_params2.len ||
( sig_params1.len != 0 &&
memcmp( sig_params1.p, sig_params2.p, sig_params1.len ) != 0 ) )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_SIG_MISMATCH );
}
if( ( ret = x509_get_sig( &p, end, &crt->sig ) ) != 0 )
{
x509_crt_free( crt );
return( ret );
}
if( p != end )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_INVALID_FORMAT +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
}
return( 0 );
}
/*
* Parse one X.509 certificate in DER format from a buffer and add them to a
* chained list
*/
int x509_crt_parse_der( x509_crt *chain, const unsigned char *buf,
size_t buflen )
{
int ret;
x509_crt *crt = chain, *prev = NULL;
/*
* Check for valid input
*/
if( crt == NULL || buf == NULL )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
while( crt->version != 0 && crt->next != NULL )
{
prev = crt;
crt = crt->next;
}
/*
* Add new certificate on the end of the chain if needed.
*/
if( crt->version != 0 && crt->next == NULL )
{
crt->next = polarssl_malloc( sizeof( x509_crt ) );
if( crt->next == NULL )
return( POLARSSL_ERR_X509_MALLOC_FAILED );
prev = crt;
x509_crt_init( crt->next );
crt = crt->next;
}
if( ( ret = x509_crt_parse_der_core( crt, buf, buflen ) ) != 0 )
{
if( prev )
prev->next = NULL;
if( crt != chain )
polarssl_free( crt );
return( ret );
}
return( 0 );
}
/*
* Parse one or more PEM certificates from a buffer and add them to the chained
* list
*/
int x509_crt_parse( x509_crt *chain, const unsigned char *buf, size_t buflen )
{
int success = 0, first_error = 0, total_failed = 0;
int buf_format = X509_FORMAT_DER;
/*
* Check for valid input
*/
if( chain == NULL || buf == NULL )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
/*
* Determine buffer content. Buffer contains either one DER certificate or
* one or more PEM certificates.
*/
#if defined(POLARSSL_PEM_PARSE_C)
if( strstr( (const char *) buf, "-----BEGIN CERTIFICATE-----" ) != NULL )
buf_format = X509_FORMAT_PEM;
#endif
if( buf_format == X509_FORMAT_DER )
return x509_crt_parse_der( chain, buf, buflen );
#if defined(POLARSSL_PEM_PARSE_C)
if( buf_format == X509_FORMAT_PEM )
{
int ret;
pem_context pem;
while( buflen > 0 )
{
size_t use_len;
pem_init( &pem );
ret = pem_read_buffer( &pem,
"-----BEGIN CERTIFICATE-----",
"-----END CERTIFICATE-----",
buf, NULL, 0, &use_len );
if( ret == 0 )
{
/*
* Was PEM encoded
*/
buflen -= use_len;
buf += use_len;
}
else if( ret == POLARSSL_ERR_PEM_BAD_INPUT_DATA )
{
return( ret );
}
else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
{
pem_free( &pem );
/*
* PEM header and footer were found
*/
buflen -= use_len;
buf += use_len;
if( first_error == 0 )
first_error = ret;
total_failed++;
continue;
}
else
break;
ret = x509_crt_parse_der( chain, pem.buf, pem.buflen );
pem_free( &pem );
if( ret != 0 )
{
/*
* Quit parsing on a memory error
*/
if( ret == POLARSSL_ERR_X509_MALLOC_FAILED )
return( ret );
if( first_error == 0 )
first_error = ret;
total_failed++;
continue;
}
success = 1;
}
}
#endif /* POLARSSL_PEM_PARSE_C */
if( success )
return( total_failed );
else if( first_error )
return( first_error );
else
return( POLARSSL_ERR_X509_CERT_UNKNOWN_FORMAT );
}
#if defined(POLARSSL_FS_IO)
/*
* Load one or more certificates and add them to the chained list
*/
int x509_crt_parse_file( x509_crt *chain, const char *path )
{
int ret;
size_t n;
unsigned char *buf;
if( ( ret = pk_load_file( path, &buf, &n ) ) != 0 )
return( ret );
ret = x509_crt_parse( chain, buf, n );
polarssl_zeroize( buf, n + 1 );
polarssl_free( buf );
return( ret );
}
#if defined(POLARSSL_THREADING_PTHREAD)
static threading_mutex_t readdir_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
int x509_crt_parse_path( x509_crt *chain, const char *path )
{
int ret = 0;
#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
int w_ret;
WCHAR szDir[MAX_PATH];
char filename[MAX_PATH];
char *p;
int len = (int) strlen( path );
WIN32_FIND_DATAW file_data;
HANDLE hFind;
if( len > MAX_PATH - 3 )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
memset( szDir, 0, sizeof(szDir) );
memset( filename, 0, MAX_PATH );
memcpy( filename, path, len );
filename[len++] = '\\';
p = filename + len;
filename[len++] = '*';
w_ret = MultiByteToWideChar( CP_ACP, 0, filename, len, szDir,
MAX_PATH - 3 );
if( w_ret == 0 )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
hFind = FindFirstFileW( szDir, &file_data );
if( hFind == INVALID_HANDLE_VALUE )
return( POLARSSL_ERR_X509_FILE_IO_ERROR );
len = MAX_PATH - len;
do
{
memset( p, 0, len );
if( file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY )
continue;
w_ret = WideCharToMultiByte( CP_ACP, 0, file_data.cFileName,
lstrlenW( file_data.cFileName ),
p, len - 1,
NULL, NULL );
if( w_ret == 0 )
return( POLARSSL_ERR_X509_FILE_IO_ERROR );
w_ret = x509_crt_parse_file( chain, filename );
if( w_ret < 0 )
ret++;
else
ret += w_ret;
}
while( FindNextFileW( hFind, &file_data ) != 0 );
if( GetLastError() != ERROR_NO_MORE_FILES )
ret = POLARSSL_ERR_X509_FILE_IO_ERROR;
FindClose( hFind );
#else /* _WIN32 */
int t_ret;
struct stat sb;
struct dirent *entry;
char entry_name[255];
DIR *dir = opendir( path );
if( dir == NULL )
return( POLARSSL_ERR_X509_FILE_IO_ERROR );
#if defined(POLARSSL_THREADING_PTHREAD)
if( ( ret = polarssl_mutex_lock( &readdir_mutex ) ) != 0 )
return( ret );
#endif
while( ( entry = readdir( dir ) ) != NULL )
{
polarssl_snprintf( entry_name, sizeof entry_name, "%s/%s", path, entry->d_name );
if( stat( entry_name, &sb ) == -1 )
{
closedir( dir );
ret = POLARSSL_ERR_X509_FILE_IO_ERROR;
goto cleanup;
}
if( !S_ISREG( sb.st_mode ) )
continue;
// Ignore parse errors
//
t_ret = x509_crt_parse_file( chain, entry_name );
if( t_ret < 0 )
ret++;
else
ret += t_ret;
}
closedir( dir );
cleanup:
#if defined(POLARSSL_THREADING_PTHREAD)
if( polarssl_mutex_unlock( &readdir_mutex ) != 0 )
ret = POLARSSL_ERR_THREADING_MUTEX_ERROR;
#endif
#endif /* _WIN32 */
return( ret );
}
#endif /* POLARSSL_FS_IO */
#if defined(_MSC_VER) && !defined snprintf && !defined(EFIX64) && \
!defined(EFI32)
#include <stdarg.h>
#if !defined vsnprintf
#define vsnprintf _vsnprintf
#endif // vsnprintf
/*
* Windows _snprintf and _vsnprintf are not compatible to linux versions.
* Result value is not size of buffer needed, but -1 if no fit is possible.
*
* This fuction tries to 'fix' this by at least suggesting enlarging the
* size by 20.
*/
static int compat_snprintf( char *str, size_t size, const char *format, ... )
{
va_list ap;
int res = -1;
va_start( ap, format );
res = vsnprintf( str, size, format, ap );
va_end( ap );
// No quick fix possible
if( res < 0 )
return( (int) size + 20 );
return( res );
}
#define snprintf compat_snprintf
#endif /* _MSC_VER && !snprintf && !EFIX64 && !EFI32 */
#define POLARSSL_ERR_DEBUG_BUF_TOO_SMALL -2
#define SAFE_SNPRINTF() \
{ \
if( ret == -1 ) \
return( -1 ); \
\
if( (unsigned int) ret > n ) { \
p[n - 1] = '\0'; \
return( POLARSSL_ERR_DEBUG_BUF_TOO_SMALL ); \
} \
\
n -= (unsigned int) ret; \
p += (unsigned int) ret; \
}
static int x509_info_subject_alt_name( char **buf, size_t *size,
const x509_sequence *subject_alt_name )
{
size_t i;
size_t n = *size;
char *p = *buf;
const x509_sequence *cur = subject_alt_name;
const char *sep = "";
size_t sep_len = 0;
while( cur != NULL )
{
if( cur->buf.len + sep_len >= n )
{
*p = '\0';
return( POLARSSL_ERR_DEBUG_BUF_TOO_SMALL );
}
n -= cur->buf.len + sep_len;
for( i = 0; i < sep_len; i++ )
*p++ = sep[i];
for( i = 0; i < cur->buf.len; i++ )
*p++ = cur->buf.p[i];
sep = ", ";
sep_len = 2;
cur = cur->next;
}
*p = '\0';
*size = n;
*buf = p;
return( 0 );
}
#define PRINT_ITEM(i) \
{ \
ret = polarssl_snprintf( p, n, "%s" i, sep ); \
SAFE_SNPRINTF(); \
sep = ", "; \
}
#define CERT_TYPE(type,name) \
if( ns_cert_type & type ) \
PRINT_ITEM( name );
static int x509_info_cert_type( char **buf, size_t *size,
unsigned char ns_cert_type )
{
int ret;
size_t n = *size;
char *p = *buf;
const char *sep = "";
CERT_TYPE( NS_CERT_TYPE_SSL_CLIENT, "SSL Client" );
CERT_TYPE( NS_CERT_TYPE_SSL_SERVER, "SSL Server" );
CERT_TYPE( NS_CERT_TYPE_EMAIL, "Email" );
CERT_TYPE( NS_CERT_TYPE_OBJECT_SIGNING, "Object Signing" );
CERT_TYPE( NS_CERT_TYPE_RESERVED, "Reserved" );
CERT_TYPE( NS_CERT_TYPE_SSL_CA, "SSL CA" );
CERT_TYPE( NS_CERT_TYPE_EMAIL_CA, "Email CA" );
CERT_TYPE( NS_CERT_TYPE_OBJECT_SIGNING_CA, "Object Signing CA" );
*size = n;
*buf = p;
return( 0 );
}
#define KEY_USAGE(code,name) \
if( key_usage & code ) \
PRINT_ITEM( name );
static int x509_info_key_usage( char **buf, size_t *size,
unsigned char key_usage )
{
int ret;
size_t n = *size;
char *p = *buf;
const char *sep = "";
KEY_USAGE( KU_DIGITAL_SIGNATURE, "Digital Signature" );
KEY_USAGE( KU_NON_REPUDIATION, "Non Repudiation" );
KEY_USAGE( KU_KEY_ENCIPHERMENT, "Key Encipherment" );
KEY_USAGE( KU_DATA_ENCIPHERMENT, "Data Encipherment" );
KEY_USAGE( KU_KEY_AGREEMENT, "Key Agreement" );
KEY_USAGE( KU_KEY_CERT_SIGN, "Key Cert Sign" );
KEY_USAGE( KU_CRL_SIGN, "CRL Sign" );
*size = n;
*buf = p;
return( 0 );
}
static int x509_info_ext_key_usage( char **buf, size_t *size,
const x509_sequence *extended_key_usage )
{
int ret;
const char *desc;
size_t n = *size;
char *p = *buf;
const x509_sequence *cur = extended_key_usage;
const char *sep = "";
while( cur != NULL )
{
if( oid_get_extended_key_usage( &cur->buf, &desc ) != 0 )
desc = "???";
ret = polarssl_snprintf( p, n, "%s%s", sep, desc );
SAFE_SNPRINTF();
sep = ", ";
cur = cur->next;
}
*size = n;
*buf = p;
return( 0 );
}
/*
* Return an informational string about the certificate.
*/
#define BEFORE_COLON 18
#define BC "18"
int x509_crt_info( char *buf, size_t size, const char *prefix,
const x509_crt *crt )
{
int ret;
size_t n;
char *p;
char key_size_str[BEFORE_COLON];
p = buf;
n = size;
ret = polarssl_snprintf( p, n, "%scert. version : %d\n",
prefix, crt->version );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "%sserial number : ",
prefix );
SAFE_SNPRINTF();
ret = x509_serial_gets( p, n, &crt->serial );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%sissuer name : ", prefix );
SAFE_SNPRINTF();
ret = x509_dn_gets( p, n, &crt->issuer );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%ssubject name : ", prefix );
SAFE_SNPRINTF();
ret = x509_dn_gets( p, n, &crt->subject );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%sissued on : " \
"%04d-%02d-%02d %02d:%02d:%02d", prefix,
crt->valid_from.year, crt->valid_from.mon,
crt->valid_from.day, crt->valid_from.hour,
crt->valid_from.min, crt->valid_from.sec );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%sexpires on : " \
"%04d-%02d-%02d %02d:%02d:%02d", prefix,
crt->valid_to.year, crt->valid_to.mon,
crt->valid_to.day, crt->valid_to.hour,
crt->valid_to.min, crt->valid_to.sec );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%ssigned using : ", prefix );
SAFE_SNPRINTF();
ret = x509_sig_alg_gets( p, n, &crt->sig_oid1, crt->sig_pk,
crt->sig_md, crt->sig_opts );
SAFE_SNPRINTF();
/* Key size */
if( ( ret = x509_key_size_helper( key_size_str, BEFORE_COLON,
pk_get_name( &crt->pk ) ) ) != 0 )
{
return( ret );
}
ret = polarssl_snprintf( p, n, "\n%s%-" BC "s: %d bits", prefix, key_size_str,
(int) pk_get_size( &crt->pk ) );
SAFE_SNPRINTF();
/*
* Optional extensions
*/
if( crt->ext_types & EXT_BASIC_CONSTRAINTS )
{
ret = polarssl_snprintf( p, n, "\n%sbasic constraints : CA=%s", prefix,
crt->ca_istrue ? "true" : "false" );
SAFE_SNPRINTF();
if( crt->max_pathlen > 0 )
{
ret = polarssl_snprintf( p, n, ", max_pathlen=%d", crt->max_pathlen - 1 );
SAFE_SNPRINTF();
}
}
if( crt->ext_types & EXT_SUBJECT_ALT_NAME )
{
ret = polarssl_snprintf( p, n, "\n%ssubject alt name : ", prefix );
SAFE_SNPRINTF();
if( ( ret = x509_info_subject_alt_name( &p, &n,
&crt->subject_alt_names ) ) != 0 )
return( ret );
}
if( crt->ext_types & EXT_NS_CERT_TYPE )
{
ret = polarssl_snprintf( p, n, "\n%scert. type : ", prefix );
SAFE_SNPRINTF();
if( ( ret = x509_info_cert_type( &p, &n, crt->ns_cert_type ) ) != 0 )
return( ret );
}
if( crt->ext_types & EXT_KEY_USAGE )
{
ret = polarssl_snprintf( p, n, "\n%skey usage : ", prefix );
SAFE_SNPRINTF();
if( ( ret = x509_info_key_usage( &p, &n, crt->key_usage ) ) != 0 )
return( ret );
}
if( crt->ext_types & EXT_EXTENDED_KEY_USAGE )
{
ret = polarssl_snprintf( p, n, "\n%sext key usage : ", prefix );
SAFE_SNPRINTF();
if( ( ret = x509_info_ext_key_usage( &p, &n,
&crt->ext_key_usage ) ) != 0 )
return( ret );
}
ret = polarssl_snprintf( p, n, "\n" );
SAFE_SNPRINTF();
return( (int) ( size - n ) );
}
struct x509_crt_verify_string {
int code;
const char *string;
};
static const struct x509_crt_verify_string x509_crt_verify_strings[] = {
{ BADCERT_EXPIRED, "The certificate validity has expired" },
{ BADCERT_REVOKED, "The certificate has been revoked (is on a CRL)" },
{ BADCERT_CN_MISMATCH, "The certificate Common Name (CN) does not match with the expected CN" },
{ BADCERT_NOT_TRUSTED, "The certificate is not correctly signed by the trusted CA" },
{ BADCRL_NOT_TRUSTED, "The CRL is not correctly signed by the trusted CA" },
{ BADCRL_EXPIRED, "The CRL is expired" },
{ BADCERT_MISSING, "Certificate was missing" },
{ BADCERT_SKIP_VERIFY, "Certificate verification was skipped" },
{ BADCERT_OTHER, "Other reason (can be used by verify callback)" },
{ BADCERT_FUTURE, "The certificate validity starts in the future" },
{ BADCRL_FUTURE, "The CRL is from the future" },
{ BADCERT_KEY_USAGE, "Usage does not match the keyUsage extension" },
{ BADCERT_EXT_KEY_USAGE, "Usage does not match the extendedKeyUsage extension" },
{ BADCERT_NS_CERT_TYPE, "Usage does not match the nsCertType extension" },
{ 0, NULL }
};
int x509_crt_verify_info( char *buf, size_t size, const char *prefix,
int flags )
{
int ret;
const struct x509_crt_verify_string *cur;
char *p = buf;
size_t n = size;
for( cur = x509_crt_verify_strings; cur->string != NULL ; cur++ )
{
if( ( flags & cur->code ) == 0 )
continue;
ret = polarssl_snprintf( p, n, "%s%s\n", prefix, cur->string );
SAFE_SNPRINTF();
flags ^= cur->code;
}
if( flags != 0 )
{
ret = polarssl_snprintf( p, n, "%sUnknown reason "
"(this should not happen)\n", prefix );
SAFE_SNPRINTF();
}
return( (int) ( size - n ) );
}
#if defined(POLARSSL_X509_CHECK_KEY_USAGE)
int x509_crt_check_key_usage( const x509_crt *crt, int usage )
{
if( ( crt->ext_types & EXT_KEY_USAGE ) != 0 &&
( crt->key_usage & usage ) != usage )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
return( 0 );
}
#endif
#if defined(POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE)
int x509_crt_check_extended_key_usage( const x509_crt *crt,
const char *usage_oid,
size_t usage_len )
{
const x509_sequence *cur;
/* Extension is not mandatory, absent means no restriction */
if( ( crt->ext_types & EXT_EXTENDED_KEY_USAGE ) == 0 )
return( 0 );
/*
* Look for the requested usage (or wildcard ANY) in our list
*/
for( cur = &crt->ext_key_usage; cur != NULL; cur = cur->next )
{
const x509_buf *cur_oid = &cur->buf;
if( cur_oid->len == usage_len &&
memcmp( cur_oid->p, usage_oid, usage_len ) == 0 )
{
return( 0 );
}
if( OID_CMP( OID_ANY_EXTENDED_KEY_USAGE, cur_oid ) )
return( 0 );
}
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
}
#endif /* POLARSSL_X509_CHECK_EXTENDED_KEY_USAGE */
#if defined(POLARSSL_X509_CRL_PARSE_C)
/*
* Return 1 if the certificate is revoked, or 0 otherwise.
*/
int x509_crt_revoked( const x509_crt *crt, const x509_crl *crl )
{
const x509_crl_entry *cur = &crl->entry;
while( cur != NULL && cur->serial.len != 0 )
{
if( crt->serial.len == cur->serial.len &&
memcmp( crt->serial.p, cur->serial.p, crt->serial.len ) == 0 )
{
if( x509_time_expired( &cur->revocation_date ) )
return( 1 );
}
cur = cur->next;
}
return( 0 );
}
/*
* Check that the given certificate is valid according to the CRL.
*/
static int x509_crt_verifycrl( x509_crt *crt, x509_crt *ca,
x509_crl *crl_list)
{
int flags = 0;
unsigned char hash[POLARSSL_MD_MAX_SIZE];
const md_info_t *md_info;
if( ca == NULL )
return( flags );
/*
* TODO: What happens if no CRL is present?
* Suggestion: Revocation state should be unknown if no CRL is present.
* For backwards compatibility this is not yet implemented.
*/
while( crl_list != NULL )
{
if( crl_list->version == 0 ||
crl_list->issuer_raw.len != ca->subject_raw.len ||
memcmp( crl_list->issuer_raw.p, ca->subject_raw.p,
crl_list->issuer_raw.len ) != 0 )
{
crl_list = crl_list->next;
continue;
}
/*
* Check if the CA is configured to sign CRLs
*/
#if defined(POLARSSL_X509_CHECK_KEY_USAGE)
if( x509_crt_check_key_usage( ca, KU_CRL_SIGN ) != 0 )
{
flags |= BADCRL_NOT_TRUSTED;
break;
}
#endif
/*
* Check if CRL is correctly signed by the trusted CA
*/
md_info = md_info_from_type( crl_list->sig_md );
if( md_info == NULL )
{
/*
* Cannot check 'unknown' hash
*/
flags |= BADCRL_NOT_TRUSTED;
break;
}
md( md_info, crl_list->tbs.p, crl_list->tbs.len, hash );
if( pk_verify_ext( crl_list->sig_pk, crl_list->sig_opts, &ca->pk,
crl_list->sig_md, hash, md_info->size,
crl_list->sig.p, crl_list->sig.len ) != 0 )
{
flags |= BADCRL_NOT_TRUSTED;
break;
}
/*
* Check for validity of CRL (Do not drop out)
*/
if( x509_time_expired( &crl_list->next_update ) )
flags |= BADCRL_EXPIRED;
if( x509_time_future( &crl_list->this_update ) )
flags |= BADCRL_FUTURE;
/*
* Check if certificate is revoked
*/
if( x509_crt_revoked( crt, crl_list ) )
{
flags |= BADCERT_REVOKED;
break;
}
crl_list = crl_list->next;
}
return( flags );
}
#endif /* POLARSSL_X509_CRL_PARSE_C */
/*
* Like memcmp, but case-insensitive and always returns -1 if different
*/
static int x509_memcasecmp( const void *s1, const void *s2, size_t len )
{
size_t i;
unsigned char diff;
const unsigned char *n1 = s1, *n2 = s2;
for( i = 0; i < len; i++ )
{
diff = n1[i] ^ n2[i];
if( diff == 0 )
continue;
if( diff == 32 &&
( ( n1[i] >= 'a' && n1[i] <= 'z' ) ||
( n1[i] >= 'A' && n1[i] <= 'Z' ) ) )
{
continue;
}
return( -1 );
}
return( 0 );
}
/*
* Return 1 if match, 0 if not
* TODO: inverted return value!
*/
static int x509_wildcard_verify( const char *cn, x509_buf *name )
{
size_t i;
size_t cn_idx = 0, cn_len = strlen( cn );
if( name->len < 3 || name->p[0] != '*' || name->p[1] != '.' )
return( 0 );
for( i = 0; i < cn_len; ++i )
{
if( cn[i] == '.' )
{
cn_idx = i;
break;
}
}
if( cn_idx == 0 )
return( 0 );
if( cn_len - cn_idx == name->len - 1 &&
x509_memcasecmp( name->p + 1, cn + cn_idx, name->len - 1 ) == 0 )
{
return( 1 );
}
return( 0 );
}
/*
* Compare two X.509 strings, case-insensitive, and allowing for some encoding
* variations (but not all).
*
* Return 0 if equal, -1 otherwise.
*/
static int x509_string_cmp( const x509_buf *a, const x509_buf *b )
{
if( a->tag == b->tag &&
a->len == b->len &&
memcmp( a->p, b->p, b->len ) == 0 )
{
return( 0 );
}
if( ( a->tag == ASN1_UTF8_STRING || a->tag == ASN1_PRINTABLE_STRING ) &&
( b->tag == ASN1_UTF8_STRING || b->tag == ASN1_PRINTABLE_STRING ) &&
a->len == b->len &&
x509_memcasecmp( a->p, b->p, b->len ) == 0 )
{
return( 0 );
}
return( -1 );
}
/*
* Compare two X.509 Names (aka rdnSequence).
*
* See RFC 5280 section 7.1, though we don't implement the whole algorithm:
* we sometimes return unequal when the full algorithm would return equal,
* but never the other way. (In particular, we don't do Unicode normalisation
* or space folding.)
*
* Return 0 if equal, -1 otherwise.
*/
static int x509_name_cmp( const x509_name *a, const x509_name *b )
{
/* Avoid recursion, it might not be optimised by the compiler */
while( a != NULL || b != NULL )
{
if( a == NULL || b == NULL )
return( -1 );
/* type */
if( a->oid.tag != b->oid.tag ||
a->oid.len != b->oid.len ||
memcmp( a->oid.p, b->oid.p, b->oid.len ) != 0 )
{
return( -1 );
}
/* value */
if( x509_string_cmp( &a->val, &b->val ) != 0 )
return( -1 );
/* structure of the list of sets */
if( a->next_merged != b->next_merged )
return( -1 );
a = a->next;
b = b->next;
}
/* a == NULL == b */
return( 0 );
}
/*
* Check if 'parent' is a suitable parent (signing CA) for 'child'.
* Return 0 if yes, -1 if not.
*
* top means parent is a locally-trusted certificate
* bottom means child is the end entity cert
*/
static int x509_crt_check_parent( const x509_crt *child,
const x509_crt *parent,
int top, int bottom )
{
int need_ca_bit;
/* Parent must be the issuer */
if( x509_name_cmp( &child->issuer, &parent->subject ) != 0 )
return( -1 );
/* Parent must have the basicConstraints CA bit set as a general rule */
need_ca_bit = 1;
/* Exception: v1/v2 certificates that are locally trusted. */
if( top && parent->version < 3 )
need_ca_bit = 0;
/* Exception: self-signed end-entity certs that are locally trusted. */
if( top && bottom &&
child->raw.len == parent->raw.len &&
memcmp( child->raw.p, parent->raw.p, child->raw.len ) == 0 )
{
need_ca_bit = 0;
}
if( need_ca_bit && ! parent->ca_istrue )
return( -1 );
#if defined(POLARSSL_X509_CHECK_KEY_USAGE)
if( need_ca_bit &&
x509_crt_check_key_usage( parent, KU_KEY_CERT_SIGN ) != 0 )
{
return( -1 );
}
#endif
return( 0 );
}
static int x509_crt_verify_top(
x509_crt *child, x509_crt *trust_ca,
x509_crl *ca_crl, int path_cnt, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
int ret;
int ca_flags = 0, check_path_cnt;
unsigned char hash[POLARSSL_MD_MAX_SIZE];
const md_info_t *md_info;
if( x509_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
if( x509_time_future( &child->valid_from ) )
*flags |= BADCERT_FUTURE;
/*
* Child is the top of the chain. Check against the trust_ca list.
*/
*flags |= BADCERT_NOT_TRUSTED;
md_info = md_info_from_type( child->sig_md );
if( md_info == NULL )
{
/*
* Cannot check 'unknown', no need to try any CA
*/
trust_ca = NULL;
}
else
md( md_info, child->tbs.p, child->tbs.len, hash );
for( /* trust_ca */ ; trust_ca != NULL; trust_ca = trust_ca->next )
{
if( x509_crt_check_parent( child, trust_ca, 1, path_cnt == 0 ) != 0 )
continue;
check_path_cnt = path_cnt + 1;
/*
* Reduce check_path_cnt to check against if top of the chain is
* the same as the trusted CA
*/
if( child->subject_raw.len == trust_ca->subject_raw.len &&
memcmp( child->subject_raw.p, trust_ca->subject_raw.p,
child->issuer_raw.len ) == 0 )
{
check_path_cnt--;
}
if( trust_ca->max_pathlen > 0 &&
trust_ca->max_pathlen < check_path_cnt )
{
continue;
}
if( pk_verify_ext( child->sig_pk, child->sig_opts, &trust_ca->pk,
child->sig_md, hash, md_info->size,
child->sig.p, child->sig.len ) != 0 )
{
continue;
}
/*
* Top of chain is signed by a trusted CA
*/
*flags &= ~BADCERT_NOT_TRUSTED;
break;
}
/*
* If top of chain is not the same as the trusted CA send a verify request
* to the callback for any issues with validity and CRL presence for the
* trusted CA certificate.
*/
if( trust_ca != NULL &&
( child->subject_raw.len != trust_ca->subject_raw.len ||
memcmp( child->subject_raw.p, trust_ca->subject_raw.p,
child->issuer_raw.len ) != 0 ) )
{
#if defined(POLARSSL_X509_CRL_PARSE_C)
/* Check trusted CA's CRL for the chain's top crt */
*flags |= x509_crt_verifycrl( child, trust_ca, ca_crl );
#else
((void) ca_crl);
#endif
if( x509_time_expired( &trust_ca->valid_to ) )
ca_flags |= BADCERT_EXPIRED;
if( x509_time_future( &trust_ca->valid_from ) )
ca_flags |= BADCERT_FUTURE;
if( NULL != f_vrfy )
{
if( ( ret = f_vrfy( p_vrfy, trust_ca, path_cnt + 1,
&ca_flags ) ) != 0 )
{
return( ret );
}
}
}
/* Call callback on top cert */
if( NULL != f_vrfy )
{
if( ( ret = f_vrfy( p_vrfy, child, path_cnt, flags ) ) != 0 )
return( ret );
}
*flags |= ca_flags;
return( 0 );
}
static int x509_crt_verify_child(
x509_crt *child, x509_crt *parent, x509_crt *trust_ca,
x509_crl *ca_crl, int path_cnt, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
int ret;
int parent_flags = 0;
unsigned char hash[POLARSSL_MD_MAX_SIZE];
x509_crt *grandparent;
const md_info_t *md_info;
/* path_cnt is 0 for the first intermediate CA */
if( 1 + path_cnt > POLARSSL_X509_MAX_INTERMEDIATE_CA )
{
*flags |= BADCERT_NOT_TRUSTED;
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
}
if( x509_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
if( x509_time_future( &child->valid_from ) )
*flags |= BADCERT_FUTURE;
md_info = md_info_from_type( child->sig_md );
if( md_info == NULL )
{
/*
* Cannot check 'unknown' hash
*/
*flags |= BADCERT_NOT_TRUSTED;
}
else
{
md( md_info, child->tbs.p, child->tbs.len, hash );
if( pk_verify_ext( child->sig_pk, child->sig_opts, &parent->pk,
child->sig_md, hash, md_info->size,
child->sig.p, child->sig.len ) != 0 )
{
*flags |= BADCERT_NOT_TRUSTED;
}
}
#if defined(POLARSSL_X509_CRL_PARSE_C)
/* Check trusted CA's CRL for the given crt */
*flags |= x509_crt_verifycrl(child, parent, ca_crl);
#endif
/* Look for a grandparent in trusted CAs */
for( grandparent = trust_ca;
grandparent != NULL;
grandparent = grandparent->next )
{
if( x509_crt_check_parent( parent, grandparent,
0, path_cnt == 0 ) == 0 )
break;
}
if( grandparent != NULL )
{
ret = x509_crt_verify_top( parent, grandparent, ca_crl,
path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
/* Look for a grandparent upwards the chain */
for( grandparent = parent->next;
grandparent != NULL;
grandparent = grandparent->next )
{
if( x509_crt_check_parent( parent, grandparent,
0, path_cnt == 0 ) == 0 )
break;
}
/* Is our parent part of the chain or at the top? */
if( grandparent != NULL )
{
ret = x509_crt_verify_child( parent, grandparent, trust_ca, ca_crl,
path_cnt + 1, &parent_flags,
f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
ret = x509_crt_verify_top( parent, trust_ca, ca_crl,
path_cnt + 1, &parent_flags,
f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
}
/* child is verified to be a child of the parent, call verify callback */
if( NULL != f_vrfy )
if( ( ret = f_vrfy( p_vrfy, child, path_cnt, flags ) ) != 0 )
return( ret );
*flags |= parent_flags;
return( 0 );
}
/*
* Verify the certificate validity
*/
int x509_crt_verify( x509_crt *crt,
x509_crt *trust_ca,
x509_crl *ca_crl,
const char *cn, int *flags,
int (*f_vrfy)(void *, x509_crt *, int, int *),
void *p_vrfy )
{
size_t cn_len;
int ret;
int pathlen = 0;
x509_crt *parent;
x509_name *name;
x509_sequence *cur = NULL;
*flags = 0;
if( cn != NULL )
{
name = &crt->subject;
cn_len = strlen( cn );
if( crt->ext_types & EXT_SUBJECT_ALT_NAME )
{
cur = &crt->subject_alt_names;
while( cur != NULL )
{
if( cur->buf.len == cn_len &&
x509_memcasecmp( cn, cur->buf.p, cn_len ) == 0 )
break;
if( cur->buf.len > 2 &&
memcmp( cur->buf.p, "*.", 2 ) == 0 &&
x509_wildcard_verify( cn, &cur->buf ) )
break;
cur = cur->next;
}
if( cur == NULL )
*flags |= BADCERT_CN_MISMATCH;
}
else
{
while( name != NULL )
{
if( OID_CMP( OID_AT_CN, &name->oid ) )
{
if( name->val.len == cn_len &&
x509_memcasecmp( name->val.p, cn, cn_len ) == 0 )
break;
if( name->val.len > 2 &&
memcmp( name->val.p, "*.", 2 ) == 0 &&
x509_wildcard_verify( cn, &name->val ) )
break;
}
name = name->next;
}
if( name == NULL )
*flags |= BADCERT_CN_MISMATCH;
}
}
/* Look for a parent in trusted CAs */
for( parent = trust_ca; parent != NULL; parent = parent->next )
{
if( x509_crt_check_parent( crt, parent, 0, pathlen == 0 ) == 0 )
break;
}
if( parent != NULL )
{
ret = x509_crt_verify_top( crt, parent, ca_crl,
pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
/* Look for a parent upwards the chain */
for( parent = crt->next; parent != NULL; parent = parent->next )
{
if( x509_crt_check_parent( crt, parent, 0, pathlen == 0 ) == 0 )
break;
}
/* Are we part of the chain or at the top? */
if( parent != NULL )
{
ret = x509_crt_verify_child( crt, parent, trust_ca, ca_crl,
pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
else
{
ret = x509_crt_verify_top( crt, trust_ca, ca_crl,
pathlen, flags, f_vrfy, p_vrfy );
if( ret != 0 )
return( ret );
}
}
if( *flags != 0 )
return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
return( 0 );
}
/*
* Initialize a certificate chain
*/
void x509_crt_init( x509_crt *crt )
{
memset( crt, 0, sizeof(x509_crt) );
}
/*
* Unallocate all certificate data
*/
void x509_crt_free( x509_crt *crt )
{
x509_crt *cert_cur = crt;
x509_crt *cert_prv;
x509_name *name_cur;
x509_name *name_prv;
x509_sequence *seq_cur;
x509_sequence *seq_prv;
if( crt == NULL )
return;
do
{
pk_free( &cert_cur->pk );
#if defined(POLARSSL_X509_RSASSA_PSS_SUPPORT)
polarssl_free( cert_cur->sig_opts );
#endif
name_cur = cert_cur->issuer.next;
while( name_cur != NULL )
{
name_prv = name_cur;
name_cur = name_cur->next;
polarssl_zeroize( name_prv, sizeof( x509_name ) );
polarssl_free( name_prv );
}
name_cur = cert_cur->subject.next;
while( name_cur != NULL )
{
name_prv = name_cur;
name_cur = name_cur->next;
polarssl_zeroize( name_prv, sizeof( x509_name ) );
polarssl_free( name_prv );
}
seq_cur = cert_cur->ext_key_usage.next;
while( seq_cur != NULL )
{
seq_prv = seq_cur;
seq_cur = seq_cur->next;
polarssl_zeroize( seq_prv, sizeof( x509_sequence ) );
polarssl_free( seq_prv );
}
seq_cur = cert_cur->subject_alt_names.next;
while( seq_cur != NULL )
{
seq_prv = seq_cur;
seq_cur = seq_cur->next;
polarssl_zeroize( seq_prv, sizeof( x509_sequence ) );
polarssl_free( seq_prv );
}
if( cert_cur->raw.p != NULL )
{
polarssl_zeroize( cert_cur->raw.p, cert_cur->raw.len );
polarssl_free( cert_cur->raw.p );
}
cert_cur = cert_cur->next;
}
while( cert_cur != NULL );
cert_cur = crt;
do
{
cert_prv = cert_cur;
cert_cur = cert_cur->next;
polarssl_zeroize( cert_prv, sizeof( x509_crt ) );
if( cert_prv != crt )
polarssl_free( cert_prv );
}
while( cert_cur != NULL );
}
#endif /* POLARSSL_X509_CRT_PARSE_C */
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