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mbedtls/library/x509_crt.c
Janos Follath 5308f47038 Fix implementation-defined integer conversion 
"When an integer is demoted to a signed integer with smaller size, or an
unsigned integer is converted to its corresponding signed integer, if
the value cannot be represented the result is implementation-defined."
2017-07-28 13:15:57 +01:00

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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
#if !defined(POLARSSL_X509_MIN_VERIFY_MD_ALG)
#define POLARSSL_X509_MIN_VERIFY_MD_ALG POLARSSL_MD_SHA1
#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 );
}
if( crt->version < 0 || crt->version > 2 )
{
x509_crt_free( crt );
return( POLARSSL_ERR_X509_UNKNOWN_VERSION );
}
crt->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;
size_t len = 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, (int)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, (int) len - 1,
NULL, NULL );
if( w_ret == 0 )
{
ret = POLARSSL_ERR_X509_FILE_IO_ERROR;
goto cleanup;
}
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;
cleanup:
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_C)
if( ( ret = polarssl_mutex_lock( &readdir_mutex ) ) != 0 )
return( ret );
#endif /* POLARSSL_THREADING_C */
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_C)
if( polarssl_mutex_unlock( &readdir_mutex ) != 0 )
ret = POLARSSL_ERR_THREADING_MUTEX_ERROR;
#endif /* POLARSSL_THREADING_C */
#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" },
{ BADCERT_BAD_KEY, "The certificate uses an invalid key (e.g. unsupported elliptic curve)" },
{ 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 ) );
}
/*
* Check md_alg against profile
* Return 0 if md_alg acceptable for this profile, -1 otherwise
*/
static int x509_check_md_alg( md_type_t md_alg )
{
if( md_alg >= POLARSSL_X509_MIN_VERIFY_MD_ALG )
return( 0 );
return( -1 );
}
#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 signed with a valid MD
*/
if( x509_check_md_alg( crl_list->sig_md ) != 0 )
{
flags |= BADCRL_NOT_TRUSTED;
break;
}
/*
* 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 self_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;
x509_crt *future_past_ca = NULL;
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;
/*
* Check if certificate is signed with a valid MD
*/
if( x509_check_md_alg( child->sig_md ) != 0 )
{
*flags |= BADCERT_NOT_TRUSTED;
/*
* not signed with a valid MD, no need to check trust_ca
*/
trust_ca = NULL;
}
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--;
}
/* Self signed certificates do not count towards the limit */
if( trust_ca->max_pathlen > 0 &&
trust_ca->max_pathlen < check_path_cnt - self_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;
}
if( x509_time_expired( &trust_ca->valid_to ) ||
x509_time_future( &trust_ca->valid_from ) )
{
if( future_past_ca == NULL )
future_past_ca = trust_ca;
continue;
}
break;
}
if( trust_ca != NULL || ( trust_ca = future_past_ca ) != NULL )
{
/*
* Top of chain is signed by a trusted CA
*/
*flags &= ~BADCERT_NOT_TRUSTED;
}
/*
* 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 self_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;
/* Counting intermediate self signed certificates */
if( ( path_cnt != 0 ) && x509_name_cmp( &child->issuer, &child->subject ) == 0 )
self_cnt++;
/* path_cnt is 0 for the first intermediate CA */
if( 1 + path_cnt > POLARSSL_X509_MAX_INTERMEDIATE_CA )
{
/* return immediately as the goal is to avoid unbounded recursion */
return( POLARSSL_ERR_X509_FATAL_ERROR );
}
if( x509_time_expired( &child->valid_to ) )
*flags |= BADCERT_EXPIRED;
if( x509_time_future( &child->valid_from ) )
*flags |= BADCERT_FUTURE;
/*
* Check if certificate is signed with a valid MD
*/
if( x509_check_md_alg( child->sig_md ) != 0 )
*flags |= BADCERT_NOT_TRUSTED;
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, self_cnt, &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 )
{
/* +2 because the current step is not yet accounted for
* and because max_pathlen is one higher than it should be.
* Also self signed certificates do not count to the limit. */
if( grandparent->max_pathlen > 0 &&
grandparent->max_pathlen < 2 + path_cnt - self_cnt )
{
continue;
}
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, self_cnt, &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, self_cnt, &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;
int selfsigned = 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, selfsigned, flags, f_vrfy, p_vrfy );
if( ret != 0 )
goto exit;
}
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, selfsigned, flags, f_vrfy, p_vrfy );
if( ret != 0 )
goto exit;
}
else
{
ret = x509_crt_verify_top( crt, trust_ca, ca_crl,
pathlen, selfsigned, flags, f_vrfy, p_vrfy );
if( ret != 0 )
goto exit;
}
}
exit:
/* prevent misuse of the vrfy callback - VERIFY_FAILED would be ignored by
* the SSL module for authmode optional, but non-zero return from the
* callback means a fatal error so it shouldn't be ignored */
if( ret == POLARSSL_ERR_X509_CERT_VERIFY_FAILED )
ret = POLARSSL_ERR_X509_FATAL_ERROR;
if( ret != 0 )
{
*flags = -1;
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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