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