Split up X509 files into smaller modules
diff --git a/library/x509_crt.c b/library/x509_crt.c
new file mode 100644
index 0000000..3c88b5e
--- /dev/null
+++ b/library/x509_crt.c
@@ -0,0 +1,1756 @@
+/*
+ *  X.509 certificate and private key decoding
+ *
+ *  Copyright (C) 2006-2013, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  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/rfc3279.txt
+ *  http://www.ietf.org/rfc/rfc3280.txt
+ *
+ *  ftp://ftp.rsasecurity.com/pub/pkcs/ascii/pkcs-1v2.asc
+ *
+ *  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
+ */
+
+#include "polarssl/config.h"
+
+#if defined(POLARSSL_X509_CRT_PARSE_C)
+
+#include "polarssl/x509_crt.h"
+#include "polarssl/oid.h"
+#if defined(POLARSSL_PEM_PARSE_C)
+#include "polarssl/pem.h"
+#endif
+
+#if defined(POLARSSL_MEMORY_C)
+#include "polarssl/memory.h"
+#else
+#define polarssl_malloc     malloc
+#define polarssl_free       free
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+#if defined(_WIN32)
+#include <windows.h>
+#else
+#include <time.h>
+#endif
+
+#if defined(POLARSSL_FS_IO)
+#include <stdio.h>
+#if !defined(_WIN32)
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#endif
+#endif
+
+/*
+ *  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_CERT_INVALID_VERSION + ret );
+
+    if( *p != end )
+        return( POLARSSL_ERR_X509_CERT_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_CERT_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_CERT_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_CERT_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_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+    if( *p != end )
+        return( POLARSSL_ERR_X509_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+    if( bs.len != 1 )
+        return( POLARSSL_ERR_X509_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+    if( bs.len < 1 )
+        return( POLARSSL_ERR_X509_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+    /* Sequence length must be >= 1 */
+    if( ext_key_usage->buf.p == NULL )
+        return( POLARSSL_ERR_X509_CERT_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: PolarSSL only parses and uses 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_CERT_INVALID_EXTENSIONS + ret );
+
+    if( *p + len != end )
+        return( POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS +
+                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
+
+    while( *p < end )
+    {
+        if( ( end - *p ) < 1 )
+            return( POLARSSL_ERR_X509_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+        if( ( tag & ASN1_CONTEXT_SPECIFIC ) != ASN1_CONTEXT_SPECIFIC )
+            return( POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS +
+                    POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
+
+        if( tag != ( ASN1_CONTEXT_SPECIFIC | 2 ) )
+        {
+            *p += tag_len;
+            continue;
+        }
+
+        buf = &(cur->buf);
+        buf->tag = tag;
+        buf->p = *p;
+        buf->len = tag_len;
+        *p += buf->len;
+
+        /* Allocate and assign next pointer */
+        if (*p < end)
+        {
+            cur->next = (asn1_sequence *) polarssl_malloc(
+                 sizeof( asn1_sequence ) );
+
+            if( cur->next == NULL )
+                return( POLARSSL_ERR_X509_CERT_INVALID_EXTENSIONS +
+                        POLARSSL_ERR_ASN1_MALLOC_FAILED );
+
+            memset( cur->next, 0, sizeof( asn1_sequence ) );
+            cur = cur->next;
+        }
+    }
+
+    /* Set final sequence entry's next pointer to NULL */
+    cur->next = NULL;
+
+    if( *p != end )
+        return( POLARSSL_ERR_X509_CERT_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_cert *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_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+        extn_oid.p = *p;
+        *p += extn_oid.len;
+
+        if( ( end - *p ) < 1 )
+            return( POLARSSL_ERR_X509_CERT_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_CERT_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_CERT_INVALID_EXTENSIONS + ret );
+
+        end_ext_octet = *p + len;
+
+        if( end_ext_octet != end_ext_data )
+            return( POLARSSL_ERR_X509_CERT_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_CERT_INVALID_EXTENSIONS +
+                        POLARSSL_ERR_ASN1_UNEXPECTED_TAG );
+            }
+#endif
+            continue;
+        }
+
+        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_CERT_INVALID_EXTENSIONS +
+                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
+
+    return( 0 );
+}
+
+/*
+ * Parse and fill a single X.509 certificate in DER format
+ */
+static int x509parse_crt_der_core( x509_cert *crt, const unsigned char *buf,
+                                   size_t buflen )
+{
+    int ret;
+    size_t len;
+    unsigned char *p, *end, *crt_end;
+
+    /*
+     * Check for valid input
+     */
+    if( crt == NULL || buf == NULL )
+        return( POLARSSL_ERR_X509_INVALID_INPUT );
+
+    p = (unsigned char *) polarssl_malloc( len = buflen );
+
+    if( p == NULL )
+        return( POLARSSL_ERR_X509_MALLOC_FAILED );
+
+    memcpy( p, buf, buflen );
+
+    buflen = 0;
+
+    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_CERT_INVALID_FORMAT );
+    }
+
+    if( len > (size_t) ( end - p ) )
+    {
+        x509_crt_free( crt );
+        return( POLARSSL_ERR_X509_CERT_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_CERT_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_null( &p, end, &crt->sig_oid1 ) ) != 0 )
+    {
+        x509_crt_free( crt );
+        return( ret );
+    }
+
+    crt->version++;
+
+    if( crt->version > 3 )
+    {
+        x509_crt_free( crt );
+        return( POLARSSL_ERR_X509_CERT_UNKNOWN_VERSION );
+    }
+
+    if( ( ret = x509_get_sig_alg( &crt->sig_oid1, &crt->sig_md,
+                                  &crt->sig_pk ) ) != 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_CERT_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_CERT_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_get_pubkey( &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( crt->version == 3 )
+    {
+        ret = x509_get_crt_ext( &p, end, crt);
+        if( ret != 0 )
+        {
+            x509_crt_free( crt );
+            return( ret );
+        }
+    }
+
+    if( p != end )
+    {
+        x509_crt_free( crt );
+        return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT +
+                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
+    }
+
+    end = crt_end;
+
+    /*
+     *  }
+     *  -- end of TBSCertificate
+     *
+     *  signatureAlgorithm   AlgorithmIdentifier,
+     *  signatureValue       BIT STRING
+     */
+    if( ( ret = x509_get_alg_null( &p, end, &crt->sig_oid2 ) ) != 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 )
+    {
+        x509_crt_free( crt );
+        return( POLARSSL_ERR_X509_CERT_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_CERT_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 x509parse_crt_der( x509_cert *chain, const unsigned char *buf, size_t buflen )
+{
+    int ret;
+    x509_cert *crt = chain, *prev = NULL;
+
+    /*
+     * Check for valid input
+     */
+    if( crt == NULL || buf == NULL )
+        return( POLARSSL_ERR_X509_INVALID_INPUT );
+
+    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 = (x509_cert *) polarssl_malloc( sizeof( x509_cert ) );
+
+        if( crt->next == NULL )
+            return( POLARSSL_ERR_X509_MALLOC_FAILED );
+
+        prev = crt;
+        crt = crt->next;
+        memset( crt, 0, sizeof( x509_cert ) );
+    }
+
+    if( ( ret = x509parse_crt_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 x509parse_crt( x509_cert *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_INVALID_INPUT );
+
+    /*
+     * 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 x509parse_crt_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;
+
+                continue;
+            }
+            else
+                break;
+
+            ret = x509parse_crt_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
+
+    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 x509parse_crtfile( x509_cert *chain, const char *path )
+{
+    int ret;
+    size_t n;
+    unsigned char *buf;
+
+    if ( ( ret = x509_load_file( path, &buf, &n ) ) != 0 )
+        return( ret );
+
+    ret = x509parse_crt( chain, buf, n );
+
+    memset( buf, 0, n + 1 );
+    polarssl_free( buf );
+
+    return( ret );
+}
+
+int x509parse_crtpath( x509_cert *chain, const char *path )
+{
+    int ret = 0;
+#if defined(_WIN32)
+    int w_ret;
+    WCHAR szDir[MAX_PATH];
+    char filename[MAX_PATH];
+	char *p;
+    int len = strlen( path );
+
+	WIN32_FIND_DATAW file_data;
+    HANDLE hFind;
+
+    if( len > MAX_PATH - 3 )
+        return( POLARSSL_ERR_X509_INVALID_INPUT );
+
+	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, path, len, szDir, MAX_PATH - 3 );
+
+    hFind = FindFirstFileW( szDir, &file_data );
+    if (hFind == INVALID_HANDLE_VALUE) 
+        return( POLARSSL_ERR_X509_FILE_IO_ERROR );
+
+    len = MAX_PATH - len;
+    do
+    {
+		memset( p, 0, len );
+
+        if( file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY )
+            continue;
+
+		w_ret = WideCharToMultiByte( CP_ACP, 0, file_data.cFileName,
+									 lstrlenW(file_data.cFileName),
+									 p, len - 1,
+									 NULL, NULL );
+
+        w_ret = x509parse_crtfile( chain, filename );
+        if( w_ret < 0 )
+            ret++;
+        else
+            ret += w_ret;
+    }
+    while( FindNextFileW( hFind, &file_data ) != 0 );
+
+    if (GetLastError() != ERROR_NO_MORE_FILES) 
+        ret = POLARSSL_ERR_X509_FILE_IO_ERROR;
+
+cleanup:
+    FindClose( hFind );
+#else
+    int t_ret, i;
+    struct stat sb;
+    struct dirent entry, *result = NULL;
+    char entry_name[255];
+    DIR *dir = opendir( path );
+
+    if( dir == NULL)
+        return( POLARSSL_ERR_X509_FILE_IO_ERROR );
+
+    while( ( t_ret = readdir_r( dir, &entry, &result ) ) == 0 )
+    {
+        if( result == NULL )
+            break;
+
+        snprintf( entry_name, sizeof(entry_name), "%s/%s", path, entry.d_name );
+
+        i = stat( entry_name, &sb );
+
+        if( i == -1 )
+        {
+            closedir( dir );
+            return( POLARSSL_ERR_X509_FILE_IO_ERROR );
+        }
+
+        if( !S_ISREG( sb.st_mode ) )
+            continue;
+
+        // Ignore parse errors
+        //
+        t_ret = x509parse_crtfile( chain, entry_name );
+        if( t_ret < 0 )
+            ret++;
+        else
+            ret += t_ret;
+    }
+    closedir( dir );
+#endif
+
+    return( ret );
+}
+#endif /* POLARSSL_FS_IO */
+
+#if defined _MSC_VER && !defined snprintf
+#include <stdarg.h>
+
+#if !defined vsnprintf
+#define vsnprintf _vsnprintf
+#endif // vsnprintf
+
+/*
+ * Windows _snprintf and _vsnprintf are not compatible to linux versions.
+ * Result value is not size of buffer needed, but -1 if no fit is possible.
+ *
+ * This fuction tries to 'fix' this by at least suggesting enlarging the
+ * size by 20.
+ */
+static int compat_snprintf(char *str, size_t size, const char *format, ...)
+{
+    va_list ap;
+    int res = -1;
+
+    va_start( ap, format );
+
+    res = vsnprintf( str, size, format, ap );
+
+    va_end( ap );
+
+    // No quick fix possible
+    if ( res < 0 )
+        return( (int) size + 20 );
+
+    return res;
+}
+
+#define snprintf compat_snprintf
+#endif
+
+#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;                    \
+}
+
+/*
+ * Return an informational string about the certificate.
+ */
+#define BEFORE_COLON    14
+#define BC              "14"
+int x509parse_cert_info( char *buf, size_t size, const char *prefix,
+                         const x509_cert *crt )
+{
+    int ret;
+    size_t n;
+    char *p;
+    const char *desc = NULL;
+    char key_size_str[BEFORE_COLON];
+
+    p = buf;
+    n = size;
+
+    ret = snprintf( p, n, "%scert. version : %d\n",
+                               prefix, crt->version );
+    SAFE_SNPRINTF();
+    ret = snprintf( p, n, "%sserial number : ",
+                               prefix );
+    SAFE_SNPRINTF();
+
+    ret = x509parse_serial_gets( p, n, &crt->serial);
+    SAFE_SNPRINTF();
+
+    ret = snprintf( p, n, "\n%sissuer name   : ", prefix );
+    SAFE_SNPRINTF();
+    ret = x509parse_dn_gets( p, n, &crt->issuer  );
+    SAFE_SNPRINTF();
+
+    ret = snprintf( p, n, "\n%ssubject name  : ", prefix );
+    SAFE_SNPRINTF();
+    ret = x509parse_dn_gets( p, n, &crt->subject );
+    SAFE_SNPRINTF();
+
+    ret = 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 = 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 = snprintf( p, n, "\n%ssigned using  : ", prefix );
+    SAFE_SNPRINTF();
+
+    ret = oid_get_sig_alg_desc( &crt->sig_oid1, &desc );
+    if( ret != 0 )
+        ret = snprintf( p, n, "???"  );
+    else
+        ret = snprintf( p, n, "%s", desc );
+    SAFE_SNPRINTF();
+
+    if( ( ret = x509_key_size_helper( key_size_str, BEFORE_COLON,
+                                      pk_get_name( &crt->pk ) ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    ret = snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,
+                          (int) pk_get_size( &crt->pk ) );
+    SAFE_SNPRINTF();
+
+    return( (int) ( size - n ) );
+}
+
+#if defined(POLARSSL_X509_CRL_PARSE_C)
+/*
+ * Return 1 if the certificate is revoked, or 0 otherwise.
+ */
+int x509parse_revoked( const x509_cert *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( x509parse_time_expired( &cur->revocation_date ) )
+                return( 1 );
+        }
+
+        cur = cur->next;
+    }
+
+    return( 0 );
+}
+
+/*
+ * Check that the given certificate is valid accoring to the CRL.
+ */
+static int x509parse_verifycrl(x509_cert *crt, x509_cert *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 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_can_do( &ca->pk, crl_list->sig_pk ) == 0 ||
+            pk_verify( &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( x509parse_time_expired( &crl_list->next_update ) )
+            flags |= BADCRL_EXPIRED;
+
+        /*
+         * Check if certificate is revoked
+         */
+        if( x509parse_revoked(crt, crl_list) )
+        {
+            flags |= BADCERT_REVOKED;
+            break;
+        }
+
+        crl_list = crl_list->next;
+    }
+    return flags;
+}
+#endif /* POLARSSL_X509_CRL_PARSE_C */
+
+// Equal == 0, inequal == 1
+static int x509_name_cmp( 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( ( n1[i] >= 'a' || n1[i] <= 'z' ) && ( diff == 0 || diff == 32 ) )
+            continue;
+
+        if( ( n1[i] >= 'A' || n1[i] <= 'Z' ) && ( diff == 0 || diff == 32 ) )
+            continue;
+
+        return( 1 );
+    }
+
+    return( 0 );
+}
+
+static int x509_wildcard_verify( const char *cn, x509_buf *name )
+{
+    size_t i;
+    size_t cn_idx = 0;
+
+    if( name->len < 3 || name->p[0] != '*' || name->p[1] != '.' )
+        return( 0 );
+
+    for( i = 0; i < strlen( cn ); ++i )
+    {
+        if( cn[i] == '.' )
+        {
+            cn_idx = i;
+            break;
+        }
+    }
+
+    if( cn_idx == 0 )
+        return( 0 );
+
+    if( strlen( cn ) - cn_idx == name->len - 1 &&
+        x509_name_cmp( name->p + 1, cn + cn_idx, name->len - 1 ) == 0 )
+    {
+        return( 1 );
+    }
+
+    return( 0 );
+}
+
+static int x509parse_verify_top(
+                x509_cert *child, x509_cert *trust_ca,
+                x509_crl *ca_crl, int path_cnt, int *flags,
+                int (*f_vrfy)(void *, x509_cert *, int, int *),
+                void *p_vrfy )
+{
+    int ret;
+    int ca_flags = 0, check_path_cnt = path_cnt + 1;
+    unsigned char hash[POLARSSL_MD_MAX_SIZE];
+    const md_info_t *md_info;
+
+    if( x509parse_time_expired( &child->valid_to ) )
+        *flags |= BADCERT_EXPIRED;
+
+    /*
+     * 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 );
+
+    while( trust_ca != NULL )
+    {
+        if( trust_ca->version == 0 ||
+            child->issuer_raw.len != trust_ca->subject_raw.len ||
+            memcmp( child->issuer_raw.p, trust_ca->subject_raw.p,
+                    child->issuer_raw.len ) != 0 )
+        {
+            trust_ca = trust_ca->next;
+            continue;
+        }
+
+        /*
+         * Reduce path_len to check against if top of the chain is
+         * the same as the trusted CA
+         */
+        if( child->subject_raw.len == trust_ca->subject_raw.len &&
+            memcmp( child->subject_raw.p, trust_ca->subject_raw.p,
+                            child->issuer_raw.len ) == 0 )
+        {
+            check_path_cnt--;
+        }
+
+        if( trust_ca->max_pathlen > 0 &&
+            trust_ca->max_pathlen < check_path_cnt )
+        {
+            trust_ca = trust_ca->next;
+            continue;
+        }
+
+        if( pk_can_do( &trust_ca->pk, child->sig_pk ) == 0 ||
+            pk_verify( &trust_ca->pk, child->sig_md, hash, md_info->size,
+                       child->sig.p, child->sig.len ) != 0 )
+        {
+            trust_ca = trust_ca->next;
+            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 |= x509parse_verifycrl( child, trust_ca, ca_crl );
+#endif
+
+        if( x509parse_time_expired( &trust_ca->valid_to ) )
+            ca_flags |= BADCERT_EXPIRED;
+
+        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 x509parse_verify_child(
+                x509_cert *child, x509_cert *parent, x509_cert *trust_ca,
+                x509_crl *ca_crl, int path_cnt, int *flags,
+                int (*f_vrfy)(void *, x509_cert *, int, int *),
+                void *p_vrfy )
+{
+    int ret;
+    int parent_flags = 0;
+    unsigned char hash[POLARSSL_MD_MAX_SIZE];
+    x509_cert *grandparent;
+    const md_info_t *md_info;
+
+    if( x509parse_time_expired( &child->valid_to ) )
+        *flags |= BADCERT_EXPIRED;
+
+    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_can_do( &parent->pk, child->sig_pk ) == 0 ||
+            pk_verify( &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 |= x509parse_verifycrl(child, parent, ca_crl);
+#endif
+
+    grandparent = parent->next;
+
+    while( grandparent != NULL )
+    {
+        if( grandparent->version == 0 ||
+            grandparent->ca_istrue == 0 ||
+            parent->issuer_raw.len != grandparent->subject_raw.len ||
+            memcmp( parent->issuer_raw.p, grandparent->subject_raw.p,
+                    parent->issuer_raw.len ) != 0 )
+        {
+            grandparent = grandparent->next;
+            continue;
+        }
+        break;
+    }
+
+    if( grandparent != NULL )
+    {
+        /*
+         * Part of the chain
+         */
+        ret = x509parse_verify_child( parent, grandparent, trust_ca, ca_crl, path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
+        if( ret != 0 )
+            return( ret );
+    }
+    else
+    {
+        ret = x509parse_verify_top( parent, trust_ca, ca_crl, path_cnt + 1, &parent_flags, f_vrfy, p_vrfy );
+        if( ret != 0 )
+            return( ret );
+    }
+
+    /* child is verified to be a child of the parent, call verify callback */
+    if( NULL != f_vrfy )
+        if( ( ret = f_vrfy( p_vrfy, child, path_cnt, flags ) ) != 0 )
+            return( ret );
+
+    *flags |= parent_flags;
+
+    return( 0 );
+}
+
+/*
+ * Verify the certificate validity
+ */
+int x509parse_verify( x509_cert *crt,
+                      x509_cert *trust_ca,
+                      x509_crl *ca_crl,
+                      const char *cn, int *flags,
+                      int (*f_vrfy)(void *, x509_cert *, int, int *),
+                      void *p_vrfy )
+{
+    size_t cn_len;
+    int ret;
+    int pathlen = 0;
+    x509_cert *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_name_cmp( 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_name_cmp( 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;
+        }
+    }
+
+    /*
+     * Iterate upwards in the given cert chain, to find our crt parent.
+     * Ignore any upper cert with CA != TRUE.
+     */
+    parent = crt->next;
+
+    while( parent != NULL && parent->version != 0 )
+    {
+        if( parent->ca_istrue == 0 ||
+            crt->issuer_raw.len != parent->subject_raw.len ||
+            memcmp( crt->issuer_raw.p, parent->subject_raw.p,
+                    crt->issuer_raw.len ) != 0 )
+        {
+            parent = parent->next;
+            continue;
+        }
+        break;
+    }
+
+    if( parent != NULL )
+    {
+        /*
+         * Part of the chain
+         */
+        ret = x509parse_verify_child( crt, parent, trust_ca, ca_crl, pathlen, flags, f_vrfy, p_vrfy );
+        if( ret != 0 )
+            return( ret );
+    }
+    else
+    {
+        ret = x509parse_verify_top( crt, trust_ca, ca_crl, pathlen, flags, f_vrfy, p_vrfy );
+        if( ret != 0 )
+            return( ret );
+    }
+
+    if( *flags != 0 )
+        return( POLARSSL_ERR_X509_CERT_VERIFY_FAILED );
+
+    return( 0 );
+}
+
+/*
+ * Unallocate all certificate data
+ */
+void x509_crt_free( x509_cert *crt )
+{
+    x509_cert *cert_cur = crt;
+    x509_cert *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 );
+
+        name_cur = cert_cur->issuer.next;
+        while( name_cur != NULL )
+        {
+            name_prv = name_cur;
+            name_cur = name_cur->next;
+            memset( name_prv, 0, 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;
+            memset( name_prv, 0, 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;
+            memset( seq_prv, 0, 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;
+            memset( seq_prv, 0, sizeof( x509_sequence ) );
+            polarssl_free( seq_prv );
+        }
+
+        if( cert_cur->raw.p != NULL )
+        {
+            memset( cert_cur->raw.p, 0, 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;
+
+        memset( cert_prv, 0, sizeof( x509_cert ) );
+        if( cert_prv != crt )
+            polarssl_free( cert_prv );
+    }
+    while( cert_cur != NULL );
+}
+
+#if defined(POLARSSL_SELF_TEST)
+
+#include "polarssl/certs.h"
+
+/*
+ * Checkup routine
+ */
+int x509_self_test( int verbose )
+{
+#if defined(POLARSSL_CERTS_C) && defined(POLARSSL_MD5_C)
+    int ret;
+    int flags;
+    x509_cert cacert;
+    x509_cert clicert;
+    pk_context pkey;
+
+    if( verbose != 0 )
+        printf( "  X.509 certificate load: " );
+
+    memset( &clicert, 0, sizeof( x509_cert ) );
+
+    ret = x509parse_crt( &clicert, (const unsigned char *) test_cli_crt,
+                         strlen( test_cli_crt ) );
+    if( ret != 0 )
+    {
+        if( verbose != 0 )
+            printf( "failed\n" );
+
+        return( ret );
+    }
+
+    memset( &cacert, 0, sizeof( x509_cert ) );
+
+    ret = x509parse_crt( &cacert, (const unsigned char *) test_ca_crt,
+                         strlen( test_ca_crt ) );
+    if( ret != 0 )
+    {
+        if( verbose != 0 )
+            printf( "failed\n" );
+
+        return( ret );
+    }
+
+    if( verbose != 0 )
+        printf( "passed\n  X.509 signature verify: ");
+
+    ret = x509parse_verify( &clicert, &cacert, NULL, NULL, &flags, NULL, NULL );
+    if( ret != 0 )
+    {
+        if( verbose != 0 )
+            printf( "failed\n" );
+
+        printf("ret = %d, &flags = %04x\n", ret, flags);
+
+        return( ret );
+    }
+
+    if( verbose != 0 )
+        printf( "passed\n\n");
+
+    x509_crt_free( &cacert  );
+    x509_crt_free( &clicert );
+    pk_free( &pkey );
+
+    return( 0 );
+#else
+    ((void) verbose);
+    return( POLARSSL_ERR_X509_FEATURE_UNAVAILABLE );
+#endif
+}
+
+#endif
+
+#endif