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mbedtls/library/x509_crt.c
Hanno Becker 1a65dcd44f Add a new X.509 API call for copy-less parsing of CRTs 
Context:
The existing API `mbedtls_x509_parse_crt_der()` for parsing DER
encoded X.509 CRTs unconditionally makes creates a copy of the
input buffer in RAM. While this comes at the benefit of easy use,
-- specifically: allowing the user to free or re-use the input
buffer right after the call -- it creates a significant memory
overhead, as the CRT is duplicated in memory (at least temporarily).
This might not be tolerable a resource constrained device.

As a remedy, this commit adds a new X.509 API call

   `mbedtls_x509_parse_crt_der_nocopy()`

which has the same signature as `mbedtls_x509_parse_crt_der()`
and almost the same semantics, with one difference: The input
buffer must persist and be unmodified for the lifetime of the
established instance of `mbedtls_x509_crt`, that is, until
`mbedtls_x509_crt_free()` is called.
2019-02-08 14:24:58 +00:00

2755 lines
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/*
* X.509 certificate parsing and verification
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
/*
* 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
*
* [SIRO] https://cabforum.org/wp-content/uploads/Chunghwatelecom201503cabforumV4.pdf
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#include "mbedtls/x509_crt.h"
#include "mbedtls/oid.h"
#include "mbedtls/platform_util.h"
#include <string.h>
#if defined(MBEDTLS_PEM_PARSE_C)
#include "mbedtls/pem.h"
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#include <stdlib.h>
#define mbedtls_free free
#define mbedtls_calloc calloc
#define mbedtls_snprintf snprintf
#endif
#if defined(MBEDTLS_THREADING_C)
#include "mbedtls/threading.h"
#endif
#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
#include <windows.h>
#else
#include <time.h>
#endif
#if defined(MBEDTLS_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
/*
* Item in a verification chain: cert and flags for it
*/
typedef struct {
mbedtls_x509_crt *crt;
uint32_t flags;
} x509_crt_verify_chain_item;
/*
* Max size of verification chain: end-entity + intermediates + trusted root
*/
#define X509_MAX_VERIFY_CHAIN_SIZE ( MBEDTLS_X509_MAX_INTERMEDIATE_CA + 2 )
/*
* Default profile
*/
const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default =
{
#if defined(MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_CERTIFICATES)
/* Allow SHA-1 (weak, but still safe in controlled environments) */
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA1 ) |
#endif
/* Only SHA-2 hashes */
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
0xFFFFFFF, /* Any PK alg */
0xFFFFFFF, /* Any curve */
2048,
};
/*
* Next-default profile
*/
const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
{
/* Hashes from SHA-256 and above */
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
0xFFFFFFF, /* Any PK alg */
#if defined(MBEDTLS_ECP_C)
/* Curves at or above 128-bit security level */
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP384R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP521R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP256R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP384R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_BP512R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256K1 ),
#else
0,
#endif
2048,
};
/*
* NSA Suite B Profile
*/
const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_suiteb =
{
/* Only SHA-256 and 384 */
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ),
/* Only ECDSA */
MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_ECDSA ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_PK_ECKEY ),
#if defined(MBEDTLS_ECP_C)
/* Only NIST P-256 and P-384 */
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP256R1 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_ECP_DP_SECP384R1 ),
#else
0,
#endif
0,
};
/*
* Check md_alg against profile
* Return 0 if md_alg is acceptable for this profile, -1 otherwise
*/
static int x509_profile_check_md_alg( const mbedtls_x509_crt_profile *profile,
mbedtls_md_type_t md_alg )
{
if( md_alg == MBEDTLS_MD_NONE )
return( -1 );
if( ( profile->allowed_mds & MBEDTLS_X509_ID_FLAG( md_alg ) ) != 0 )
return( 0 );
return( -1 );
}
/*
* Check pk_alg against profile
* Return 0 if pk_alg is acceptable for this profile, -1 otherwise
*/
static int x509_profile_check_pk_alg( const mbedtls_x509_crt_profile *profile,
mbedtls_pk_type_t pk_alg )
{
if( pk_alg == MBEDTLS_PK_NONE )
return( -1 );
if( ( profile->allowed_pks & MBEDTLS_X509_ID_FLAG( pk_alg ) ) != 0 )
return( 0 );
return( -1 );
}
/*
* Check key against profile
* Return 0 if pk is acceptable for this profile, -1 otherwise
*/
static int x509_profile_check_key( const mbedtls_x509_crt_profile *profile,
const mbedtls_pk_context *pk )
{
const mbedtls_pk_type_t pk_alg = mbedtls_pk_get_type( pk );
#if defined(MBEDTLS_RSA_C)
if( pk_alg == MBEDTLS_PK_RSA || pk_alg == MBEDTLS_PK_RSASSA_PSS )
{
if( mbedtls_pk_get_bitlen( pk ) >= profile->rsa_min_bitlen )
return( 0 );
return( -1 );
}
#endif
#if defined(MBEDTLS_ECP_C)
if( pk_alg == MBEDTLS_PK_ECDSA ||
pk_alg == MBEDTLS_PK_ECKEY ||
pk_alg == MBEDTLS_PK_ECKEY_DH )
{
const mbedtls_ecp_group_id gid = mbedtls_pk_ec( *pk )->grp.id;
if( gid == MBEDTLS_ECP_DP_NONE )
return( -1 );
if( ( profile->allowed_curves & MBEDTLS_X509_ID_FLAG( gid ) ) != 0 )
return( 0 );
return( -1 );
}
#endif
return( -1 );
}
/*
* 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 0 if name matches wildcard, -1 otherwise
*/
static int x509_check_wildcard( const char *cn, const mbedtls_x509_buf *name )
{
size_t i;
size_t cn_idx = 0, cn_len = strlen( cn );
/* We can't have a match if there is no wildcard to match */
if( name->len < 3 || name->p[0] != '*' || name->p[1] != '.' )
return( -1 );
for( i = 0; i < cn_len; ++i )
{
if( cn[i] == '.' )
{
cn_idx = i;
break;
}
}
if( cn_idx == 0 )
return( -1 );
if( cn_len - cn_idx == name->len - 1 &&
x509_memcasecmp( name->p + 1, cn + cn_idx, name->len - 1 ) == 0 )
{
return( 0 );
}
return( -1 );
}
/*
* 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 mbedtls_x509_buf *a, const mbedtls_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 == MBEDTLS_ASN1_UTF8_STRING || a->tag == MBEDTLS_ASN1_PRINTABLE_STRING ) &&
( b->tag == MBEDTLS_ASN1_UTF8_STRING || b->tag == MBEDTLS_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 mbedtls_x509_name *a, const mbedtls_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 );
}
/*
* Reset (init or clear) a verify_chain
*/
static void x509_crt_verify_chain_reset(
mbedtls_x509_crt_verify_chain *ver_chain )
{
size_t i;
for( i = 0; i < MBEDTLS_X509_MAX_VERIFY_CHAIN_SIZE; i++ )
{
ver_chain->items[i].crt = NULL;
ver_chain->items[i].flags = (uint32_t) -1;
}
ver_chain->len = 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 = mbedtls_asn1_get_tag( p, end, &len,
MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ) != 0 )
{
if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
{
*ver = 0;
return( 0 );
}
return( ret );
}
end = *p + len;
if( ( ret = mbedtls_asn1_get_int( p, end, ver ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_VERSION + ret );
if( *p != end )
return( MBEDTLS_ERR_X509_INVALID_VERSION +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* Validity ::= SEQUENCE {
* notBefore Time,
* notAfter Time }
*/
static int x509_get_dates( unsigned char **p,
const unsigned char *end,
mbedtls_x509_time *from,
mbedtls_x509_time *to )
{
int ret;
size_t len;
if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_DATE + ret );
end = *p + len;
if( ( ret = mbedtls_x509_get_time( p, end, from ) ) != 0 )
return( ret );
if( ( ret = mbedtls_x509_get_time( p, end, to ) ) != 0 )
return( ret );
if( *p != end )
return( MBEDTLS_ERR_X509_INVALID_DATE +
MBEDTLS_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,
mbedtls_x509_buf *uid, int n )
{
int ret;
if( *p == end )
return( 0 );
uid->tag = **p;
if( ( ret = mbedtls_asn1_get_tag( p, end, &uid->len,
MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | n ) ) != 0 )
{
if( ret == MBEDTLS_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 = mbedtls_asn1_get_tag( p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p == end )
return( 0 );
if( ( ret = mbedtls_asn1_get_bool( p, end, ca_istrue ) ) != 0 )
{
if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
ret = mbedtls_asn1_get_int( p, end, ca_istrue );
if( ret != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( *ca_istrue != 0 )
*ca_istrue = 1;
}
if( *p == end )
return( 0 );
if( ( ret = mbedtls_asn1_get_int( p, end, max_pathlen ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p != end )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_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;
mbedtls_x509_bitstring bs = { 0, 0, NULL };
if( ( ret = mbedtls_asn1_get_bitstring( p, end, &bs ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( bs.len != 1 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_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 int *key_usage)
{
int ret;
size_t i;
mbedtls_x509_bitstring bs = { 0, 0, NULL };
if( ( ret = mbedtls_asn1_get_bitstring( p, end, &bs ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( bs.len < 1 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_INVALID_LENGTH );
/* Get actual bitstring */
*key_usage = 0;
for( i = 0; i < bs.len && i < sizeof( unsigned int ); i++ )
{
*key_usage |= (unsigned int) bs.p[i] << (8*i);
}
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,
mbedtls_x509_sequence *ext_key_usage)
{
int ret;
if( ( ret = mbedtls_asn1_get_sequence_of( p, end, ext_key_usage, MBEDTLS_ASN1_OID ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
/* Sequence length must be >= 1 */
if( ext_key_usage->buf.p == NULL )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_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,
mbedtls_x509_sequence *subject_alt_name )
{
int ret;
size_t len, tag_len;
mbedtls_asn1_buf *buf;
unsigned char tag;
mbedtls_asn1_sequence *cur = subject_alt_name;
/* Get main sequence tag */
if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( *p + len != end )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
while( *p < end )
{
if( ( end - *p ) < 1 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_OUT_OF_DATA );
tag = **p;
(*p)++;
if( ( ret = mbedtls_asn1_get_len( p, end, &tag_len ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
if( ( tag & MBEDTLS_ASN1_TAG_CLASS_MASK ) !=
MBEDTLS_ASN1_CONTEXT_SPECIFIC )
{
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
}
/* Skip everything but DNS name */
if( tag != ( MBEDTLS_ASN1_CONTEXT_SPECIFIC | 2 ) )
{
*p += tag_len;
continue;
}
/* Allocate and assign next pointer */
if( cur->buf.p != NULL )
{
if( cur->next != NULL )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS );
cur->next = mbedtls_calloc( 1, sizeof( mbedtls_asn1_sequence ) );
if( cur->next == NULL )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_ALLOC_FAILED );
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( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* X.509 v3 extensions
*
*/
static int x509_get_crt_ext( unsigned char **p,
const unsigned char *end,
mbedtls_x509_crt *crt )
{
int ret;
size_t len;
unsigned char *end_ext_data, *end_ext_octet;
if( ( ret = mbedtls_x509_get_ext( p, end, &crt->v3_ext, 3 ) ) != 0 )
{
if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )
return( 0 );
return( ret );
}
while( *p < end )
{
/*
* Extension ::= SEQUENCE {
* extnID OBJECT IDENTIFIER,
* critical BOOLEAN DEFAULT FALSE,
* extnValue OCTET STRING }
*/
mbedtls_x509_buf extn_oid = {0, 0, NULL};
int is_critical = 0; /* DEFAULT FALSE */
int ext_type = 0;
if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
end_ext_data = *p + len;
/* Get extension ID */
if( ( ret = mbedtls_asn1_get_tag( p, end_ext_data, &extn_oid.len,
MBEDTLS_ASN1_OID ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
extn_oid.tag = MBEDTLS_ASN1_OID;
extn_oid.p = *p;
*p += extn_oid.len;
/* Get optional critical */
if( ( ret = mbedtls_asn1_get_bool( p, end_ext_data, &is_critical ) ) != 0 &&
( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ) )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
/* Data should be octet string type */
if( ( ret = mbedtls_asn1_get_tag( p, end_ext_data, &len,
MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
end_ext_octet = *p + len;
if( end_ext_octet != end_ext_data )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
/*
* Detect supported extensions
*/
ret = mbedtls_oid_get_x509_ext_type( &extn_oid, &ext_type );
if( ret != 0 )
{
/* No parser found, skip extension */
*p = end_ext_octet;
#if !defined(MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION)
if( is_critical )
{
/* Data is marked as critical: fail */
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
}
#endif
continue;
}
/* Forbid repeated extensions */
if( ( crt->ext_types & ext_type ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS );
crt->ext_types |= ext_type;
switch( ext_type )
{
case MBEDTLS_X509_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 MBEDTLS_X509_EXT_KEY_USAGE:
/* Parse key usage */
if( ( ret = x509_get_key_usage( p, end_ext_octet,
&crt->key_usage ) ) != 0 )
return( ret );
break;
case MBEDTLS_X509_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 MBEDTLS_X509_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 MBEDTLS_X509_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( MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE );
}
}
if( *p != end )
return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
return( 0 );
}
/*
* Parse and fill a single X.509 certificate in DER format
*/
static int x509_crt_parse_der_core( mbedtls_x509_crt *crt,
const unsigned char *buf,
size_t buflen,
int make_copy )
{
int ret;
size_t len;
unsigned char *p, *end, *crt_end;
mbedtls_x509_buf sig_params1, sig_params2, sig_oid2;
memset( &sig_params1, 0, sizeof( mbedtls_x509_buf ) );
memset( &sig_params2, 0, sizeof( mbedtls_x509_buf ) );
memset( &sig_oid2, 0, sizeof( mbedtls_x509_buf ) );
/*
* Check for valid input
*/
if( crt == NULL || buf == NULL )
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
/* Use the original buffer until we figure out actual length. */
p = (unsigned char*) buf;
len = buflen;
end = p + len;
/*
* Certificate ::= SEQUENCE {
* tbsCertificate TBSCertificate,
* signatureAlgorithm AlgorithmIdentifier,
* signatureValue BIT STRING }
*/
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_INVALID_FORMAT );
}
end = crt_end = p + len;
crt->raw.len = crt_end - buf;
if( make_copy != 0 )
{
/* Create and populate a new buffer for the raw field. */
crt->raw.p = p = mbedtls_calloc( 1, crt->raw.len );
if( crt->raw.p == NULL )
return( MBEDTLS_ERR_X509_ALLOC_FAILED );
memcpy( crt->raw.p, buf, crt->raw.len );
crt->own_buffer = 1;
p += crt->raw.len - len;
end = crt_end = p + len;
}
else
{
crt->raw.p = (unsigned char*) buf;
crt->own_buffer = 0;
}
/*
* TBSCertificate ::= SEQUENCE {
*/
crt->tbs.p = p;
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_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 = mbedtls_x509_get_serial( &p, end, &crt->serial ) ) != 0 ||
( ret = mbedtls_x509_get_alg( &p, end, &crt->sig_oid,
&sig_params1 ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
if( crt->version < 0 || crt->version > 2 )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_UNKNOWN_VERSION );
}
crt->version++;
if( ( ret = mbedtls_x509_get_sig_alg( &crt->sig_oid, &sig_params1,
&crt->sig_md, &crt->sig_pk,
&crt->sig_opts ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
/*
* issuer Name
*/
crt->issuer_raw.p = p;
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
}
if( ( ret = mbedtls_x509_get_name( &p, p + len, &crt->issuer ) ) != 0 )
{
mbedtls_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 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
/*
* subject Name
*/
crt->subject_raw.p = p;
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret );
}
if( len && ( ret = mbedtls_x509_get_name( &p, p + len, &crt->subject ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
crt->subject_raw.len = p - crt->subject_raw.p;
/*
* SubjectPublicKeyInfo
*/
if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &crt->pk ) ) != 0 )
{
mbedtls_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 )
{
mbedtls_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 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
}
#if !defined(MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3)
if( crt->version == 3 )
#endif
{
ret = x509_get_crt_ext( &p, end, crt );
if( ret != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
}
if( p != end )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_INVALID_FORMAT +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
}
end = crt_end;
/*
* }
* -- end of TBSCertificate
*
* signatureAlgorithm AlgorithmIdentifier,
* signatureValue BIT STRING
*/
if( ( ret = mbedtls_x509_get_alg( &p, end, &sig_oid2, &sig_params2 ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
if( crt->sig_oid.len != sig_oid2.len ||
memcmp( crt->sig_oid.p, sig_oid2.p, crt->sig_oid.len ) != 0 ||
sig_params1.len != sig_params2.len ||
( sig_params1.len != 0 &&
memcmp( sig_params1.p, sig_params2.p, sig_params1.len ) != 0 ) )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_SIG_MISMATCH );
}
if( ( ret = mbedtls_x509_get_sig( &p, end, &crt->sig ) ) != 0 )
{
mbedtls_x509_crt_free( crt );
return( ret );
}
if( p != end )
{
mbedtls_x509_crt_free( crt );
return( MBEDTLS_ERR_X509_INVALID_FORMAT +
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
}
return( 0 );
}
/*
* Parse one X.509 certificate in DER format from a buffer and add them to a
* chained list
*/
static int mbedtls_x509_crt_parse_der_internal( mbedtls_x509_crt *chain,
const unsigned char *buf,
size_t buflen,
int make_copy )
{
int ret;
mbedtls_x509_crt *crt = chain, *prev = NULL;
/*
* Check for valid input
*/
if( crt == NULL || buf == NULL )
return( MBEDTLS_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 = mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) );
if( crt->next == NULL )
return( MBEDTLS_ERR_X509_ALLOC_FAILED );
prev = crt;
mbedtls_x509_crt_init( crt->next );
crt = crt->next;
}
if( ( ret = x509_crt_parse_der_core( crt, buf, buflen, make_copy ) ) != 0 )
{
if( prev )
prev->next = NULL;
if( crt != chain )
mbedtls_free( crt );
return( ret );
}
return( 0 );
}
int mbedtls_x509_crt_parse_der_nocopy( mbedtls_x509_crt *chain,
const unsigned char *buf,
size_t buflen )
{
return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 0 ) );
}
int mbedtls_x509_crt_parse_der( mbedtls_x509_crt *chain,
const unsigned char *buf,
size_t buflen )
{
return( mbedtls_x509_crt_parse_der_internal( chain, buf, buflen, 1 ) );
}
/*
* Parse one or more PEM certificates from a buffer and add them to the chained
* list
*/
int mbedtls_x509_crt_parse( mbedtls_x509_crt *chain,
const unsigned char *buf,
size_t buflen )
{
#if defined(MBEDTLS_PEM_PARSE_C)
int success = 0, first_error = 0, total_failed = 0;
int buf_format = MBEDTLS_X509_FORMAT_DER;
#endif
/*
* Check for valid input
*/
if( chain == NULL || buf == NULL )
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
/*
* Determine buffer content. Buffer contains either one DER certificate or
* one or more PEM certificates.
*/
#if defined(MBEDTLS_PEM_PARSE_C)
if( buflen != 0 && buf[buflen - 1] == '\0' &&
strstr( (const char *) buf, "-----BEGIN CERTIFICATE-----" ) != NULL )
{
buf_format = MBEDTLS_X509_FORMAT_PEM;
}
if( buf_format == MBEDTLS_X509_FORMAT_DER )
return mbedtls_x509_crt_parse_der( chain, buf, buflen );
#else
return mbedtls_x509_crt_parse_der( chain, buf, buflen );
#endif
#if defined(MBEDTLS_PEM_PARSE_C)
if( buf_format == MBEDTLS_X509_FORMAT_PEM )
{
int ret;
mbedtls_pem_context pem;
/* 1 rather than 0 since the terminating NULL byte is counted in */
while( buflen > 1 )
{
size_t use_len;
mbedtls_pem_init( &pem );
/* If we get there, we know the string is null-terminated */
ret = mbedtls_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 == MBEDTLS_ERR_PEM_BAD_INPUT_DATA )
{
return( ret );
}
else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
{
mbedtls_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 = mbedtls_x509_crt_parse_der( chain, pem.buf, pem.buflen );
mbedtls_pem_free( &pem );
if( ret != 0 )
{
/*
* Quit parsing on a memory error
*/
if( ret == MBEDTLS_ERR_X509_ALLOC_FAILED )
return( ret );
if( first_error == 0 )
first_error = ret;
total_failed++;
continue;
}
success = 1;
}
}
if( success )
return( total_failed );
else if( first_error )
return( first_error );
else
return( MBEDTLS_ERR_X509_CERT_UNKNOWN_FORMAT );
#endif /* MBEDTLS_PEM_PARSE_C */
}
#if defined(MBEDTLS_FS_IO)
/*
* Load one or more certificates and add them to the chained list
*/
int mbedtls_x509_crt_parse_file( mbedtls_x509_crt *chain, const char *path )
{
int ret;
size_t n;
unsigned char *buf;
if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )
return( ret );
ret = mbedtls_x509_crt_parse( chain, buf, n );
mbedtls_platform_zeroize( buf, n );
mbedtls_free( buf );
return( ret );
}
int mbedtls_x509_crt_parse_path( mbedtls_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( MBEDTLS_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( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
hFind = FindFirstFileW( szDir, &file_data );
if( hFind == INVALID_HANDLE_VALUE )
return( MBEDTLS_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 = MBEDTLS_ERR_X509_FILE_IO_ERROR;
goto cleanup;
}
w_ret = mbedtls_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 = MBEDTLS_ERR_X509_FILE_IO_ERROR;
cleanup:
FindClose( hFind );
#else /* _WIN32 */
int t_ret;
int snp_ret;
struct stat sb;
struct dirent *entry;
char entry_name[MBEDTLS_X509_MAX_FILE_PATH_LEN];
DIR *dir = opendir( path );
if( dir == NULL )
return( MBEDTLS_ERR_X509_FILE_IO_ERROR );
#if defined(MBEDTLS_THREADING_C)
if( ( ret = mbedtls_mutex_lock( &mbedtls_threading_readdir_mutex ) ) != 0 )
{
closedir( dir );
return( ret );
}
#endif /* MBEDTLS_THREADING_C */
while( ( entry = readdir( dir ) ) != NULL )
{
snp_ret = mbedtls_snprintf( entry_name, sizeof entry_name,
"%s/%s", path, entry->d_name );
if( snp_ret < 0 || (size_t)snp_ret >= sizeof entry_name )
{
ret = MBEDTLS_ERR_X509_BUFFER_TOO_SMALL;
goto cleanup;
}
else if( stat( entry_name, &sb ) == -1 )
{
ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
goto cleanup;
}
if( !S_ISREG( sb.st_mode ) )
continue;
// Ignore parse errors
//
t_ret = mbedtls_x509_crt_parse_file( chain, entry_name );
if( t_ret < 0 )
ret++;
else
ret += t_ret;
}
cleanup:
closedir( dir );
#if defined(MBEDTLS_THREADING_C)
if( mbedtls_mutex_unlock( &mbedtls_threading_readdir_mutex ) != 0 )
ret = MBEDTLS_ERR_THREADING_MUTEX_ERROR;
#endif /* MBEDTLS_THREADING_C */
#endif /* _WIN32 */
return( ret );
}
#endif /* MBEDTLS_FS_IO */
static int x509_info_subject_alt_name( char **buf, size_t *size,
const mbedtls_x509_sequence *subject_alt_name )
{
size_t i;
size_t n = *size;
char *p = *buf;
const mbedtls_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( MBEDTLS_ERR_X509_BUFFER_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 = mbedtls_snprintf( p, n, "%s" i, sep ); \
MBEDTLS_X509_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( MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT, "SSL Client" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER, "SSL Server" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_EMAIL, "Email" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_OBJECT_SIGNING, "Object Signing" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_RESERVED, "Reserved" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_SSL_CA, "SSL CA" );
CERT_TYPE( MBEDTLS_X509_NS_CERT_TYPE_EMAIL_CA, "Email CA" );
CERT_TYPE( MBEDTLS_X509_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 int key_usage )
{
int ret;
size_t n = *size;
char *p = *buf;
const char *sep = "";
KEY_USAGE( MBEDTLS_X509_KU_DIGITAL_SIGNATURE, "Digital Signature" );
KEY_USAGE( MBEDTLS_X509_KU_NON_REPUDIATION, "Non Repudiation" );
KEY_USAGE( MBEDTLS_X509_KU_KEY_ENCIPHERMENT, "Key Encipherment" );
KEY_USAGE( MBEDTLS_X509_KU_DATA_ENCIPHERMENT, "Data Encipherment" );
KEY_USAGE( MBEDTLS_X509_KU_KEY_AGREEMENT, "Key Agreement" );
KEY_USAGE( MBEDTLS_X509_KU_KEY_CERT_SIGN, "Key Cert Sign" );
KEY_USAGE( MBEDTLS_X509_KU_CRL_SIGN, "CRL Sign" );
KEY_USAGE( MBEDTLS_X509_KU_ENCIPHER_ONLY, "Encipher Only" );
KEY_USAGE( MBEDTLS_X509_KU_DECIPHER_ONLY, "Decipher Only" );
*size = n;
*buf = p;
return( 0 );
}
static int x509_info_ext_key_usage( char **buf, size_t *size,
const mbedtls_x509_sequence *extended_key_usage )
{
int ret;
const char *desc;
size_t n = *size;
char *p = *buf;
const mbedtls_x509_sequence *cur = extended_key_usage;
const char *sep = "";
while( cur != NULL )
{
if( mbedtls_oid_get_extended_key_usage( &cur->buf, &desc ) != 0 )
desc = "???";
ret = mbedtls_snprintf( p, n, "%s%s", sep, desc );
MBEDTLS_X509_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 mbedtls_x509_crt_info( char *buf, size_t size, const char *prefix,
const mbedtls_x509_crt *crt )
{
int ret;
size_t n;
char *p;
char key_size_str[BEFORE_COLON];
p = buf;
n = size;
if( NULL == crt )
{
ret = mbedtls_snprintf( p, n, "\nCertificate is uninitialised!\n" );
MBEDTLS_X509_SAFE_SNPRINTF;
return( (int) ( size - n ) );
}
ret = mbedtls_snprintf( p, n, "%scert. version : %d\n",
prefix, crt->version );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_snprintf( p, n, "%sserial number : ",
prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_x509_serial_gets( p, n, &crt->serial );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_snprintf( p, n, "\n%sissuer name : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_x509_dn_gets( p, n, &crt->issuer );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_snprintf( p, n, "\n%ssubject name : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_x509_dn_gets( p, n, &crt->subject );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_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 );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_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 );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_snprintf( p, n, "\n%ssigned using : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
ret = mbedtls_x509_sig_alg_gets( p, n, &crt->sig_oid, crt->sig_pk,
crt->sig_md, crt->sig_opts );
MBEDTLS_X509_SAFE_SNPRINTF;
/* Key size */
if( ( ret = mbedtls_x509_key_size_helper( key_size_str, BEFORE_COLON,
mbedtls_pk_get_name( &crt->pk ) ) ) != 0 )
{
return( ret );
}
ret = mbedtls_snprintf( p, n, "\n%s%-" BC "s: %d bits", prefix, key_size_str,
(int) mbedtls_pk_get_bitlen( &crt->pk ) );
MBEDTLS_X509_SAFE_SNPRINTF;
/*
* Optional extensions
*/
if( crt->ext_types & MBEDTLS_X509_EXT_BASIC_CONSTRAINTS )
{
ret = mbedtls_snprintf( p, n, "\n%sbasic constraints : CA=%s", prefix,
crt->ca_istrue ? "true" : "false" );
MBEDTLS_X509_SAFE_SNPRINTF;
if( crt->max_pathlen > 0 )
{
ret = mbedtls_snprintf( p, n, ", max_pathlen=%d", crt->max_pathlen - 1 );
MBEDTLS_X509_SAFE_SNPRINTF;
}
}
if( crt->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME )
{
ret = mbedtls_snprintf( p, n, "\n%ssubject alt name : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
if( ( ret = x509_info_subject_alt_name( &p, &n,
&crt->subject_alt_names ) ) != 0 )
return( ret );
}
if( crt->ext_types & MBEDTLS_X509_EXT_NS_CERT_TYPE )
{
ret = mbedtls_snprintf( p, n, "\n%scert. type : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
if( ( ret = x509_info_cert_type( &p, &n, crt->ns_cert_type ) ) != 0 )
return( ret );
}
if( crt->ext_types & MBEDTLS_X509_EXT_KEY_USAGE )
{
ret = mbedtls_snprintf( p, n, "\n%skey usage : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
if( ( ret = x509_info_key_usage( &p, &n, crt->key_usage ) ) != 0 )
return( ret );
}
if( crt->ext_types & MBEDTLS_X509_EXT_EXTENDED_KEY_USAGE )
{
ret = mbedtls_snprintf( p, n, "\n%sext key usage : ", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
if( ( ret = x509_info_ext_key_usage( &p, &n,
&crt->ext_key_usage ) ) != 0 )
return( ret );
}
ret = mbedtls_snprintf( p, n, "\n" );
MBEDTLS_X509_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[] = {
{ MBEDTLS_X509_BADCERT_EXPIRED, "The certificate validity has expired" },
{ MBEDTLS_X509_BADCERT_REVOKED, "The certificate has been revoked (is on a CRL)" },
{ MBEDTLS_X509_BADCERT_CN_MISMATCH, "The certificate Common Name (CN) does not match with the expected CN" },
{ MBEDTLS_X509_BADCERT_NOT_TRUSTED, "The certificate is not correctly signed by the trusted CA" },
{ MBEDTLS_X509_BADCRL_NOT_TRUSTED, "The CRL is not correctly signed by the trusted CA" },
{ MBEDTLS_X509_BADCRL_EXPIRED, "The CRL is expired" },
{ MBEDTLS_X509_BADCERT_MISSING, "Certificate was missing" },
{ MBEDTLS_X509_BADCERT_SKIP_VERIFY, "Certificate verification was skipped" },
{ MBEDTLS_X509_BADCERT_OTHER, "Other reason (can be used by verify callback)" },
{ MBEDTLS_X509_BADCERT_FUTURE, "The certificate validity starts in the future" },
{ MBEDTLS_X509_BADCRL_FUTURE, "The CRL is from the future" },
{ MBEDTLS_X509_BADCERT_KEY_USAGE, "Usage does not match the keyUsage extension" },
{ MBEDTLS_X509_BADCERT_EXT_KEY_USAGE, "Usage does not match the extendedKeyUsage extension" },
{ MBEDTLS_X509_BADCERT_NS_CERT_TYPE, "Usage does not match the nsCertType extension" },
{ MBEDTLS_X509_BADCERT_BAD_MD, "The certificate is signed with an unacceptable hash." },
{ MBEDTLS_X509_BADCERT_BAD_PK, "The certificate is signed with an unacceptable PK alg (eg RSA vs ECDSA)." },
{ MBEDTLS_X509_BADCERT_BAD_KEY, "The certificate is signed with an unacceptable key (eg bad curve, RSA too short)." },
{ MBEDTLS_X509_BADCRL_BAD_MD, "The CRL is signed with an unacceptable hash." },
{ MBEDTLS_X509_BADCRL_BAD_PK, "The CRL is signed with an unacceptable PK alg (eg RSA vs ECDSA)." },
{ MBEDTLS_X509_BADCRL_BAD_KEY, "The CRL is signed with an unacceptable key (eg bad curve, RSA too short)." },
{ 0, NULL }
};
int mbedtls_x509_crt_verify_info( char *buf, size_t size, const char *prefix,
uint32_t 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 = mbedtls_snprintf( p, n, "%s%s\n", prefix, cur->string );
MBEDTLS_X509_SAFE_SNPRINTF;
flags ^= cur->code;
}
if( flags != 0 )
{
ret = mbedtls_snprintf( p, n, "%sUnknown reason "
"(this should not happen)\n", prefix );
MBEDTLS_X509_SAFE_SNPRINTF;
}
return( (int) ( size - n ) );
}
#if defined(MBEDTLS_X509_CHECK_KEY_USAGE)
int mbedtls_x509_crt_check_key_usage( const mbedtls_x509_crt *crt,
unsigned int usage )
{
unsigned int usage_must, usage_may;
unsigned int may_mask = MBEDTLS_X509_KU_ENCIPHER_ONLY
| MBEDTLS_X509_KU_DECIPHER_ONLY;
if( ( crt->ext_types & MBEDTLS_X509_EXT_KEY_USAGE ) == 0 )
return( 0 );
usage_must = usage & ~may_mask;
if( ( ( crt->key_usage & ~may_mask ) & usage_must ) != usage_must )
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
usage_may = usage & may_mask;
if( ( ( crt->key_usage & may_mask ) | usage_may ) != usage_may )
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
return( 0 );
}
#endif
#if defined(MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE)
int mbedtls_x509_crt_check_extended_key_usage( const mbedtls_x509_crt *crt,
const char *usage_oid,
size_t usage_len )
{
const mbedtls_x509_sequence *cur;
/* Extension is not mandatory, absent means no restriction */
if( ( crt->ext_types & MBEDTLS_X509_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 mbedtls_x509_buf *cur_oid = &cur->buf;
if( cur_oid->len == usage_len &&
memcmp( cur_oid->p, usage_oid, usage_len ) == 0 )
{
return( 0 );
}
if( MBEDTLS_OID_CMP( MBEDTLS_OID_ANY_EXTENDED_KEY_USAGE, cur_oid ) == 0 )
return( 0 );
}
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
}
#endif /* MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE */
#if defined(MBEDTLS_X509_CRL_PARSE_C)
/*
* Return 1 if the certificate is revoked, or 0 otherwise.
*/
int mbedtls_x509_crt_is_revoked( const mbedtls_x509_crt *crt, const mbedtls_x509_crl *crl )
{
const mbedtls_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( mbedtls_x509_time_is_past( &cur->revocation_date ) )
return( 1 );
}
cur = cur->next;
}
return( 0 );
}
/*
* Check that the given certificate is not revoked according to the CRL.
* Skip validation if no CRL for the given CA is present.
*/
static int x509_crt_verifycrl( mbedtls_x509_crt *crt, mbedtls_x509_crt *ca,
mbedtls_x509_crl *crl_list,
const mbedtls_x509_crt_profile *profile )
{
int flags = 0;
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
const mbedtls_md_info_t *md_info;
if( ca == NULL )
return( flags );
while( crl_list != NULL )
{
if( crl_list->version == 0 ||
x509_name_cmp( &crl_list->issuer, &ca->subject ) != 0 )
{
crl_list = crl_list->next;
continue;
}
/*
* Check if the CA is configured to sign CRLs
*/
#if defined(MBEDTLS_X509_CHECK_KEY_USAGE)
if( mbedtls_x509_crt_check_key_usage( ca,
MBEDTLS_X509_KU_CRL_SIGN ) != 0 )
{
flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
break;
}
#endif
/*
* Check if CRL is correctly signed by the trusted CA
*/
if( x509_profile_check_md_alg( profile, crl_list->sig_md ) != 0 )
flags |= MBEDTLS_X509_BADCRL_BAD_MD;
if( x509_profile_check_pk_alg( profile, crl_list->sig_pk ) != 0 )
flags |= MBEDTLS_X509_BADCRL_BAD_PK;
md_info = mbedtls_md_info_from_type( crl_list->sig_md );
if( mbedtls_md( md_info, crl_list->tbs.p, crl_list->tbs.len, hash ) != 0 )
{
/* Note: this can't happen except after an internal error */
flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
break;
}
if( x509_profile_check_key( profile, &ca->pk ) != 0 )
flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
if( mbedtls_pk_verify_ext( crl_list->sig_pk, crl_list->sig_opts, &ca->pk,
crl_list->sig_md, hash, mbedtls_md_get_size( md_info ),
crl_list->sig.p, crl_list->sig.len ) != 0 )
{
flags |= MBEDTLS_X509_BADCRL_NOT_TRUSTED;
break;
}
/*
* Check for validity of CRL (Do not drop out)
*/
if( mbedtls_x509_time_is_past( &crl_list->next_update ) )
flags |= MBEDTLS_X509_BADCRL_EXPIRED;
if( mbedtls_x509_time_is_future( &crl_list->this_update ) )
flags |= MBEDTLS_X509_BADCRL_FUTURE;
/*
* Check if certificate is revoked
*/
if( mbedtls_x509_crt_is_revoked( crt, crl_list ) )
{
flags |= MBEDTLS_X509_BADCERT_REVOKED;
break;
}
crl_list = crl_list->next;
}
return( flags );
}
#endif /* MBEDTLS_X509_CRL_PARSE_C */
/*
* Check the signature of a certificate by its parent
*/
static int x509_crt_check_signature( const mbedtls_x509_crt *child,
mbedtls_x509_crt *parent,
mbedtls_x509_crt_restart_ctx *rs_ctx )
{
const mbedtls_md_info_t *md_info;
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
md_info = mbedtls_md_info_from_type( child->sig_md );
if( mbedtls_md( md_info, child->tbs.p, child->tbs.len, hash ) != 0 )
{
/* Note: this can't happen except after an internal error */
return( -1 );
}
/* Skip expensive computation on obvious mismatch */
if( ! mbedtls_pk_can_do( &parent->pk, child->sig_pk ) )
return( -1 );
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && child->sig_pk == MBEDTLS_PK_ECDSA )
{
return( mbedtls_pk_verify_restartable( &parent->pk,
child->sig_md, hash, mbedtls_md_get_size( md_info ),
child->sig.p, child->sig.len, &rs_ctx->pk ) );
}
#else
(void) rs_ctx;
#endif
return( mbedtls_pk_verify_ext( child->sig_pk, child->sig_opts, &parent->pk,
child->sig_md, hash, mbedtls_md_get_size( md_info ),
child->sig.p, child->sig.len ) );
}
/*
* 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
*/
static int x509_crt_check_parent( const mbedtls_x509_crt *child,
const mbedtls_x509_crt *parent,
int top )
{
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;
if( need_ca_bit && ! parent->ca_istrue )
return( -1 );
#if defined(MBEDTLS_X509_CHECK_KEY_USAGE)
if( need_ca_bit &&
mbedtls_x509_crt_check_key_usage( parent, MBEDTLS_X509_KU_KEY_CERT_SIGN ) != 0 )
{
return( -1 );
}
#endif
return( 0 );
}
/*
* Find a suitable parent for child in candidates, or return NULL.
*
* Here suitable is defined as:
* 1. subject name matches child's issuer
* 2. if necessary, the CA bit is set and key usage allows signing certs
* 3. for trusted roots, the signature is correct
* (for intermediates, the signature is checked and the result reported)
* 4. pathlen constraints are satisfied
*
* If there's a suitable candidate which is also time-valid, return the first
* such. Otherwise, return the first suitable candidate (or NULL if there is
* none).
*
* The rationale for this rule is that someone could have a list of trusted
* roots with two versions on the same root with different validity periods.
* (At least one user reported having such a list and wanted it to just work.)
* The reason we don't just require time-validity is that generally there is
* only one version, and if it's expired we want the flags to state that
* rather than NOT_TRUSTED, as would be the case if we required it here.
*
* The rationale for rule 3 (signature for trusted roots) is that users might
* have two versions of the same CA with different keys in their list, and the
* way we select the correct one is by checking the signature (as we don't
* rely on key identifier extensions). (This is one way users might choose to
* handle key rollover, another relies on self-issued certs, see [SIRO].)
*
* Arguments:
* - [in] child: certificate for which we're looking for a parent
* - [in] candidates: chained list of potential parents
* - [out] r_parent: parent found (or NULL)
* - [out] r_signature_is_good: 1 if child signature by parent is valid, or 0
* - [in] top: 1 if candidates consists of trusted roots, ie we're at the top
* of the chain, 0 otherwise
* - [in] path_cnt: number of intermediates seen so far
* - [in] self_cnt: number of self-signed intermediates seen so far
* (will never be greater than path_cnt)
* - [in-out] rs_ctx: context for restarting operations
*
* Return value:
* - 0 on success
* - MBEDTLS_ERR_ECP_IN_PROGRESS otherwise
*/
static int x509_crt_find_parent_in(
mbedtls_x509_crt *child,
mbedtls_x509_crt *candidates,
mbedtls_x509_crt **r_parent,
int *r_signature_is_good,
int top,
unsigned path_cnt,
unsigned self_cnt,
mbedtls_x509_crt_restart_ctx *rs_ctx )
{
int ret;
mbedtls_x509_crt *parent, *fallback_parent;
int signature_is_good, fallback_signature_is_good;
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/* did we have something in progress? */
if( rs_ctx != NULL && rs_ctx->parent != NULL )
{
/* restore saved state */
parent = rs_ctx->parent;
fallback_parent = rs_ctx->fallback_parent;
fallback_signature_is_good = rs_ctx->fallback_signature_is_good;
/* clear saved state */
rs_ctx->parent = NULL;
rs_ctx->fallback_parent = NULL;
rs_ctx->fallback_signature_is_good = 0;
/* resume where we left */
goto check_signature;
}
#endif
fallback_parent = NULL;
fallback_signature_is_good = 0;
for( parent = candidates; parent != NULL; parent = parent->next )
{
/* basic parenting skills (name, CA bit, key usage) */
if( x509_crt_check_parent( child, parent, top ) != 0 )
continue;
/* +1 because stored max_pathlen is 1 higher that the actual value */
if( parent->max_pathlen > 0 &&
(size_t) parent->max_pathlen < 1 + path_cnt - self_cnt )
{
continue;
}
/* Signature */
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
check_signature:
#endif
ret = x509_crt_check_signature( child, parent, rs_ctx );
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
{
/* save state */
rs_ctx->parent = parent;
rs_ctx->fallback_parent = fallback_parent;
rs_ctx->fallback_signature_is_good = fallback_signature_is_good;
return( ret );
}
#else
(void) ret;
#endif
signature_is_good = ret == 0;
if( top && ! signature_is_good )
continue;
/* optional time check */
if( mbedtls_x509_time_is_past( &parent->valid_to ) ||
mbedtls_x509_time_is_future( &parent->valid_from ) )
{
if( fallback_parent == NULL )
{
fallback_parent = parent;
fallback_signature_is_good = signature_is_good;
}
continue;
}
break;
}
if( parent != NULL )
{
*r_parent = parent;
*r_signature_is_good = signature_is_good;
}
else
{
*r_parent = fallback_parent;
*r_signature_is_good = fallback_signature_is_good;
}
return( 0 );
}
/*
* Find a parent in trusted CAs or the provided chain, or return NULL.
*
* Searches in trusted CAs first, and return the first suitable parent found
* (see find_parent_in() for definition of suitable).
*
* Arguments:
* - [in] child: certificate for which we're looking for a parent, followed
* by a chain of possible intermediates
* - [in] trust_ca: list of locally trusted certificates
* - [out] parent: parent found (or NULL)
* - [out] parent_is_trusted: 1 if returned `parent` is trusted, or 0
* - [out] signature_is_good: 1 if child signature by parent is valid, or 0
* - [in] path_cnt: number of links in the chain so far (EE -> ... -> child)
* - [in] self_cnt: number of self-signed certs in the chain so far
* (will always be no greater than path_cnt)
* - [in-out] rs_ctx: context for restarting operations
*
* Return value:
* - 0 on success
* - MBEDTLS_ERR_ECP_IN_PROGRESS otherwise
*/
static int x509_crt_find_parent(
mbedtls_x509_crt *child,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crt **parent,
int *parent_is_trusted,
int *signature_is_good,
unsigned path_cnt,
unsigned self_cnt,
mbedtls_x509_crt_restart_ctx *rs_ctx )
{
int ret;
mbedtls_x509_crt *search_list;
*parent_is_trusted = 1;
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/* restore then clear saved state if we have some stored */
if( rs_ctx != NULL && rs_ctx->parent_is_trusted != -1 )
{
*parent_is_trusted = rs_ctx->parent_is_trusted;
rs_ctx->parent_is_trusted = -1;
}
#endif
while( 1 ) {
search_list = *parent_is_trusted ? trust_ca : child->next;
ret = x509_crt_find_parent_in( child, search_list,
parent, signature_is_good,
*parent_is_trusted,
path_cnt, self_cnt, rs_ctx );
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
{
/* save state */
rs_ctx->parent_is_trusted = *parent_is_trusted;
return( ret );
}
#else
(void) ret;
#endif
/* stop here if found or already in second iteration */
if( *parent != NULL || *parent_is_trusted == 0 )
break;
/* prepare second iteration */
*parent_is_trusted = 0;
}
/* extra precaution against mistakes in the caller */
if( *parent == NULL )
{
*parent_is_trusted = 0;
*signature_is_good = 0;
}
return( 0 );
}
/*
* Check if an end-entity certificate is locally trusted
*
* Currently we require such certificates to be self-signed (actually only
* check for self-issued as self-signatures are not checked)
*/
static int x509_crt_check_ee_locally_trusted(
mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca )
{
mbedtls_x509_crt *cur;
/* must be self-issued */
if( x509_name_cmp( &crt->issuer, &crt->subject ) != 0 )
return( -1 );
/* look for an exact match with trusted cert */
for( cur = trust_ca; cur != NULL; cur = cur->next )
{
if( crt->raw.len == cur->raw.len &&
memcmp( crt->raw.p, cur->raw.p, crt->raw.len ) == 0 )
{
return( 0 );
}
}
/* too bad */
return( -1 );
}
/*
* Build and verify a certificate chain
*
* Given a peer-provided list of certificates EE, C1, ..., Cn and
* a list of trusted certs R1, ... Rp, try to build and verify a chain
* EE, Ci1, ... Ciq [, Rj]
* such that every cert in the chain is a child of the next one,
* jumping to a trusted root as early as possible.
*
* Verify that chain and return it with flags for all issues found.
*
* Special cases:
* - EE == Rj -> return a one-element list containing it
* - EE, Ci1, ..., Ciq cannot be continued with a trusted root
* -> return that chain with NOT_TRUSTED set on Ciq
*
* Tests for (aspects of) this function should include at least:
* - trusted EE
* - EE -> trusted root
* - EE -> intermediate CA -> trusted root
* - if relevant: EE untrusted
* - if relevant: EE -> intermediate, untrusted
* with the aspect under test checked at each relevant level (EE, int, root).
* For some aspects longer chains are required, but usually length 2 is
* enough (but length 1 is not in general).
*
* Arguments:
* - [in] crt: the cert list EE, C1, ..., Cn
* - [in] trust_ca: the trusted list R1, ..., Rp
* - [in] ca_crl, profile: as in verify_with_profile()
* - [out] ver_chain: the built and verified chain
* Only valid when return value is 0, may contain garbage otherwise!
* Restart note: need not be the same when calling again to resume.
* - [in-out] rs_ctx: context for restarting operations
*
* Return value:
* - non-zero if the chain could not be fully built and examined
* - 0 is the chain was successfully built and examined,
* even if it was found to be invalid
*/
static int x509_crt_verify_chain(
mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crl *ca_crl,
const mbedtls_x509_crt_profile *profile,
mbedtls_x509_crt_verify_chain *ver_chain,
mbedtls_x509_crt_restart_ctx *rs_ctx )
{
/* Don't initialize any of those variables here, so that the compiler can
* catch potential issues with jumping ahead when restarting */
int ret;
uint32_t *flags;
mbedtls_x509_crt_verify_chain_item *cur;
mbedtls_x509_crt *child;
mbedtls_x509_crt *parent;
int parent_is_trusted;
int child_is_trusted;
int signature_is_good;
unsigned self_cnt;
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/* resume if we had an operation in progress */
if( rs_ctx != NULL && rs_ctx->in_progress == x509_crt_rs_find_parent )
{
/* restore saved state */
*ver_chain = rs_ctx->ver_chain; /* struct copy */
self_cnt = rs_ctx->self_cnt;
/* restore derived state */
cur = &ver_chain->items[ver_chain->len - 1];
child = cur->crt;
flags = &cur->flags;
goto find_parent;
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
child = crt;
self_cnt = 0;
parent_is_trusted = 0;
child_is_trusted = 0;
while( 1 ) {
/* Add certificate to the verification chain */
cur = &ver_chain->items[ver_chain->len];
cur->crt = child;
cur->flags = 0;
ver_chain->len++;
flags = &cur->flags;
/* Check time-validity (all certificates) */
if( mbedtls_x509_time_is_past( &child->valid_to ) )
*flags |= MBEDTLS_X509_BADCERT_EXPIRED;
if( mbedtls_x509_time_is_future( &child->valid_from ) )
*flags |= MBEDTLS_X509_BADCERT_FUTURE;
/* Stop here for trusted roots (but not for trusted EE certs) */
if( child_is_trusted )
return( 0 );
/* Check signature algorithm: MD & PK algs */
if( x509_profile_check_md_alg( profile, child->sig_md ) != 0 )
*flags |= MBEDTLS_X509_BADCERT_BAD_MD;
if( x509_profile_check_pk_alg( profile, child->sig_pk ) != 0 )
*flags |= MBEDTLS_X509_BADCERT_BAD_PK;
/* Special case: EE certs that are locally trusted */
if( ver_chain->len == 1 &&
x509_crt_check_ee_locally_trusted( child, trust_ca ) == 0 )
{
return( 0 );
}
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
find_parent:
#endif
/* Look for a parent in trusted CAs or up the chain */
ret = x509_crt_find_parent( child, trust_ca, &parent,
&parent_is_trusted, &signature_is_good,
ver_chain->len - 1, self_cnt, rs_ctx );
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && ret == MBEDTLS_ERR_ECP_IN_PROGRESS )
{
/* save state */
rs_ctx->in_progress = x509_crt_rs_find_parent;
rs_ctx->self_cnt = self_cnt;
rs_ctx->ver_chain = *ver_chain; /* struct copy */
return( ret );
}
#else
(void) ret;
#endif
/* No parent? We're done here */
if( parent == NULL )
{
*flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED;
return( 0 );
}
/* Count intermediate self-issued (not necessarily self-signed) certs.
* These can occur with some strategies for key rollover, see [SIRO],
* and should be excluded from max_pathlen checks. */
if( ver_chain->len != 1 &&
x509_name_cmp( &child->issuer, &child->subject ) == 0 )
{
self_cnt++;
}
/* path_cnt is 0 for the first intermediate CA,
* and if parent is trusted it's not an intermediate CA */
if( ! parent_is_trusted &&
ver_chain->len > MBEDTLS_X509_MAX_INTERMEDIATE_CA )
{
/* return immediately to avoid overflow the chain array */
return( MBEDTLS_ERR_X509_FATAL_ERROR );
}
/* signature was checked while searching parent */
if( ! signature_is_good )
*flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED;
/* check size of signing key */
if( x509_profile_check_key( profile, &parent->pk ) != 0 )
*flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
#if defined(MBEDTLS_X509_CRL_PARSE_C)
/* Check trusted CA's CRL for the given crt */
*flags |= x509_crt_verifycrl( child, parent, ca_crl, profile );
#else
(void) ca_crl;
#endif
/* prepare for next iteration */
child = parent;
parent = NULL;
child_is_trusted = parent_is_trusted;
signature_is_good = 0;
}
}
/*
* Check for CN match
*/
static int x509_crt_check_cn( const mbedtls_x509_buf *name,
const char *cn, size_t cn_len )
{
/* try exact match */
if( name->len == cn_len &&
x509_memcasecmp( cn, name->p, cn_len ) == 0 )
{
return( 0 );
}
/* try wildcard match */
if( x509_check_wildcard( cn, name ) == 0 )
{
return( 0 );
}
return( -1 );
}
/*
* Verify the requested CN - only call this if cn is not NULL!
*/
static void x509_crt_verify_name( const mbedtls_x509_crt *crt,
const char *cn,
uint32_t *flags )
{
const mbedtls_x509_name *name;
const mbedtls_x509_sequence *cur;
size_t cn_len = strlen( cn );
if( crt->ext_types & MBEDTLS_X509_EXT_SUBJECT_ALT_NAME )
{
for( cur = &crt->subject_alt_names; cur != NULL; cur = cur->next )
{
if( x509_crt_check_cn( &cur->buf, cn, cn_len ) == 0 )
break;
}
if( cur == NULL )
*flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
}
else
{
for( name = &crt->subject; name != NULL; name = name->next )
{
if( MBEDTLS_OID_CMP( MBEDTLS_OID_AT_CN, &name->oid ) == 0 &&
x509_crt_check_cn( &name->val, cn, cn_len ) == 0 )
{
break;
}
}
if( name == NULL )
*flags |= MBEDTLS_X509_BADCERT_CN_MISMATCH;
}
}
/*
* Merge the flags for all certs in the chain, after calling callback
*/
static int x509_crt_merge_flags_with_cb(
uint32_t *flags,
const mbedtls_x509_crt_verify_chain *ver_chain,
int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
void *p_vrfy )
{
int ret;
unsigned i;
uint32_t cur_flags;
const mbedtls_x509_crt_verify_chain_item *cur;
for( i = ver_chain->len; i != 0; --i )
{
cur = &ver_chain->items[i-1];
cur_flags = cur->flags;
if( NULL != f_vrfy )
if( ( ret = f_vrfy( p_vrfy, cur->crt, (int) i-1, &cur_flags ) ) != 0 )
return( ret );
*flags |= cur_flags;
}
return( 0 );
}
/*
* Verify the certificate validity (default profile, not restartable)
*/
int mbedtls_x509_crt_verify( mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crl *ca_crl,
const char *cn, uint32_t *flags,
int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
void *p_vrfy )
{
return( mbedtls_x509_crt_verify_restartable( crt, trust_ca, ca_crl,
&mbedtls_x509_crt_profile_default, cn, flags,
f_vrfy, p_vrfy, NULL ) );
}
/*
* Verify the certificate validity (user-chosen profile, not restartable)
*/
int mbedtls_x509_crt_verify_with_profile( mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crl *ca_crl,
const mbedtls_x509_crt_profile *profile,
const char *cn, uint32_t *flags,
int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
void *p_vrfy )
{
return( mbedtls_x509_crt_verify_restartable( crt, trust_ca, ca_crl,
profile, cn, flags, f_vrfy, p_vrfy, NULL ) );
}
/*
* Verify the certificate validity, with profile, restartable version
*
* This function:
* - checks the requested CN (if any)
* - checks the type and size of the EE cert's key,
* as that isn't done as part of chain building/verification currently
* - builds and verifies the chain
* - then calls the callback and merges the flags
*/
int mbedtls_x509_crt_verify_restartable( mbedtls_x509_crt *crt,
mbedtls_x509_crt *trust_ca,
mbedtls_x509_crl *ca_crl,
const mbedtls_x509_crt_profile *profile,
const char *cn, uint32_t *flags,
int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
void *p_vrfy,
mbedtls_x509_crt_restart_ctx *rs_ctx )
{
int ret;
mbedtls_pk_type_t pk_type;
mbedtls_x509_crt_verify_chain ver_chain;
uint32_t ee_flags;
*flags = 0;
ee_flags = 0;
x509_crt_verify_chain_reset( &ver_chain );
if( profile == NULL )
{
ret = MBEDTLS_ERR_X509_BAD_INPUT_DATA;
goto exit;
}
/* check name if requested */
if( cn != NULL )
x509_crt_verify_name( crt, cn, &ee_flags );
/* Check the type and size of the key */
pk_type = mbedtls_pk_get_type( &crt->pk );
if( x509_profile_check_pk_alg( profile, pk_type ) != 0 )
ee_flags |= MBEDTLS_X509_BADCERT_BAD_PK;
if( x509_profile_check_key( profile, &crt->pk ) != 0 )
ee_flags |= MBEDTLS_X509_BADCERT_BAD_KEY;
/* Check the chain */
ret = x509_crt_verify_chain( crt, trust_ca, ca_crl, profile,
&ver_chain, rs_ctx );
if( ret != 0 )
goto exit;
/* Merge end-entity flags */
ver_chain.items[0].flags |= ee_flags;
/* Build final flags, calling callback on the way if any */
ret = x509_crt_merge_flags_with_cb( flags, &ver_chain, f_vrfy, p_vrfy );
exit:
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
if( rs_ctx != NULL && ret != MBEDTLS_ERR_ECP_IN_PROGRESS )
mbedtls_x509_crt_restart_free( rs_ctx );
#endif
/* 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 == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED )
ret = MBEDTLS_ERR_X509_FATAL_ERROR;
if( ret != 0 )
{
*flags = (uint32_t) -1;
return( ret );
}
if( *flags != 0 )
return( MBEDTLS_ERR_X509_CERT_VERIFY_FAILED );
return( 0 );
}
/*
* Initialize a certificate chain
*/
void mbedtls_x509_crt_init( mbedtls_x509_crt *crt )
{
memset( crt, 0, sizeof(mbedtls_x509_crt) );
}
/*
* Unallocate all certificate data
*/
void mbedtls_x509_crt_free( mbedtls_x509_crt *crt )
{
mbedtls_x509_crt *cert_cur = crt;
mbedtls_x509_crt *cert_prv;
mbedtls_x509_name *name_cur;
mbedtls_x509_name *name_prv;
mbedtls_x509_sequence *seq_cur;
mbedtls_x509_sequence *seq_prv;
if( crt == NULL )
return;
do
{
mbedtls_pk_free( &cert_cur->pk );
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
mbedtls_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;
mbedtls_platform_zeroize( name_prv, sizeof( mbedtls_x509_name ) );
mbedtls_free( name_prv );
}
name_cur = cert_cur->subject.next;
while( name_cur != NULL )
{
name_prv = name_cur;
name_cur = name_cur->next;
mbedtls_platform_zeroize( name_prv, sizeof( mbedtls_x509_name ) );
mbedtls_free( name_prv );
}
seq_cur = cert_cur->ext_key_usage.next;
while( seq_cur != NULL )
{
seq_prv = seq_cur;
seq_cur = seq_cur->next;
mbedtls_platform_zeroize( seq_prv,
sizeof( mbedtls_x509_sequence ) );
mbedtls_free( seq_prv );
}
seq_cur = cert_cur->subject_alt_names.next;
while( seq_cur != NULL )
{
seq_prv = seq_cur;
seq_cur = seq_cur->next;
mbedtls_platform_zeroize( seq_prv,
sizeof( mbedtls_x509_sequence ) );
mbedtls_free( seq_prv );
}
if( cert_cur->raw.p != NULL && cert_cur->own_buffer )
{
mbedtls_platform_zeroize( cert_cur->raw.p, cert_cur->raw.len );
mbedtls_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;
mbedtls_platform_zeroize( cert_prv, sizeof( mbedtls_x509_crt ) );
if( cert_prv != crt )
mbedtls_free( cert_prv );
}
while( cert_cur != NULL );
}
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/*
* Initialize a restart context
*/
void mbedtls_x509_crt_restart_init( mbedtls_x509_crt_restart_ctx *ctx )
{
mbedtls_pk_restart_init( &ctx->pk );
ctx->parent = NULL;
ctx->fallback_parent = NULL;
ctx->fallback_signature_is_good = 0;
ctx->parent_is_trusted = -1;
ctx->in_progress = x509_crt_rs_none;
ctx->self_cnt = 0;
x509_crt_verify_chain_reset( &ctx->ver_chain );
}
/*
* Free the components of a restart context
*/
void mbedtls_x509_crt_restart_free( mbedtls_x509_crt_restart_ctx *ctx )
{
if( ctx == NULL )
return;
mbedtls_pk_restart_free( &ctx->pk );
mbedtls_x509_crt_restart_init( ctx );
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
#endif /* MBEDTLS_X509_CRT_PARSE_C */
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