Subversion Repositories Kolibri OS

/*

 *  X.509 common functions for parsing and verification

 *

 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved

 *  SPDX-License-Identifier: GPL-2.0

 *

 *  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.

 *

 *  This file is part of mbed TLS (https://tls.mbed.org)

 */

/*

 *  The ITU-T X.509 standard defines a certificate format for PKI.

 *

 *  http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)

 *  http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)

 *  http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)

 *

 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf

 *  http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf

 */

#if !defined(MBEDTLS_CONFIG_FILE)

#include "mbedtls/config.h"

#else

#include MBEDTLS_CONFIG_FILE

#endif

#if defined(MBEDTLS_X509_USE_C)

#include "mbedtls/x509.h"

#include "mbedtls/asn1.h"

#include "mbedtls/oid.h"

#include 

#include 

#if defined(MBEDTLS_PEM_PARSE_C)

#include "mbedtls/pem.h"

#endif

#if defined(MBEDTLS_PLATFORM_C)

#include "mbedtls/platform.h"

#else

#include 

#include 

#define mbedtls_free      free

#define mbedtls_calloc    calloc

#define mbedtls_printf    printf

#define mbedtls_snprintf  snprintf

#endif

#if defined(MBEDTLS_HAVE_TIME)

#include "mbedtls/platform_time.h"

#endif

#if defined(MBEDTLS_HAVE_TIME_DATE)

#include "mbedtls/platform_util.h"

#include 

#endif

#define CHECK(code) if( ( ret = ( code ) ) != 0 ){ return( ret ); }

#define CHECK_RANGE(min, max, val)                      \

    do                                                  \

    {                                                   \

        if( ( val ) < ( min ) || ( val ) > ( max ) )    \

        {                                               \

            return( ret );                              \

        }                                               \

    } while( 0 )

/*

 *  CertificateSerialNumber  ::=  INTEGER

 */

int mbedtls_x509_get_serial( unsigned char **p, const unsigned char *end,

                     mbedtls_x509_buf *serial )

{

    int ret;

    if( ( end - *p ) < 1 )

        return( MBEDTLS_ERR_X509_INVALID_SERIAL +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    if( **p != ( MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_PRIMITIVE | 2 ) &&

        **p !=   MBEDTLS_ASN1_INTEGER )

        return( MBEDTLS_ERR_X509_INVALID_SERIAL +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    serial->tag = *(*p)++;

    if( ( ret = mbedtls_asn1_get_len( p, end, &serial->len ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_SERIAL + ret );

    serial->p = *p;

    *p += serial->len;

    return( 0 );

}

/* Get an algorithm identifier without parameters (eg for signatures)

 *

 *  AlgorithmIdentifier  ::=  SEQUENCE  {

 *       algorithm               OBJECT IDENTIFIER,

 *       parameters              ANY DEFINED BY algorithm OPTIONAL  }

 */

int mbedtls_x509_get_alg_null( unsigned char **p, const unsigned char *end,

                       mbedtls_x509_buf *alg )

{

    int ret;

    if( ( ret = mbedtls_asn1_get_alg_null( p, end, alg ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    return( 0 );

}

/*

 * Parse an algorithm identifier with (optional) parameters

 */

int mbedtls_x509_get_alg( unsigned char **p, const unsigned char *end,

                  mbedtls_x509_buf *alg, mbedtls_x509_buf *params )

{

    int ret;

    if( ( ret = mbedtls_asn1_get_alg( p, end, alg, params ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    return( 0 );

}

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)

/*

 * HashAlgorithm ::= AlgorithmIdentifier

 *

 * AlgorithmIdentifier  ::=  SEQUENCE  {

 *      algorithm               OBJECT IDENTIFIER,

 *      parameters              ANY DEFINED BY algorithm OPTIONAL  }

 *

 * For HashAlgorithm, parameters MUST be NULL or absent.

 */

static int x509_get_hash_alg( const mbedtls_x509_buf *alg, mbedtls_md_type_t *md_alg )

{

    int ret;

    unsigned char *p;

    const unsigned char *end;

    mbedtls_x509_buf md_oid;

    size_t len;

    /* Make sure we got a SEQUENCE and setup bounds */

    if( alg->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )

        return( MBEDTLS_ERR_X509_INVALID_ALG +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    p = (unsigned char *) alg->p;

    end = p + alg->len;

    if( p >= end )

        return( MBEDTLS_ERR_X509_INVALID_ALG +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    /* Parse md_oid */

    md_oid.tag = *p;

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &md_oid.len, MBEDTLS_ASN1_OID ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    md_oid.p = p;

    p += md_oid.len;

    /* Get md_alg from md_oid */

    if( ( ret = mbedtls_oid_get_md_alg( &md_oid, md_alg ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    /* Make sure params is absent of NULL */

    if( p == end )

        return( 0 );

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_NULL ) ) != 0 || len != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    if( p != end )

        return( MBEDTLS_ERR_X509_INVALID_ALG +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    return( 0 );

}

/*

 *    RSASSA-PSS-params  ::=  SEQUENCE  {

 *       hashAlgorithm     [0] HashAlgorithm DEFAULT sha1Identifier,

 *       maskGenAlgorithm  [1] MaskGenAlgorithm DEFAULT mgf1SHA1Identifier,

 *       saltLength        [2] INTEGER DEFAULT 20,

 *       trailerField      [3] INTEGER DEFAULT 1  }

 *    -- Note that the tags in this Sequence are explicit.

 *

 * RFC 4055 (which defines use of RSASSA-PSS in PKIX) states that the value

 * of trailerField MUST be 1, and PKCS#1 v2.2 doesn't even define any other

 * option. Enfore this at parsing time.

 */

int mbedtls_x509_get_rsassa_pss_params( const mbedtls_x509_buf *params,

                                mbedtls_md_type_t *md_alg, mbedtls_md_type_t *mgf_md,

                                int *salt_len )

{

    int ret;

    unsigned char *p;

    const unsigned char *end, *end2;

    size_t len;

    mbedtls_x509_buf alg_id, alg_params;

    /* First set everything to defaults */

    *md_alg = MBEDTLS_MD_SHA1;

    *mgf_md = MBEDTLS_MD_SHA1;

    *salt_len = 20;

    /* Make sure params is a SEQUENCE and setup bounds */

    if( params->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )

        return( MBEDTLS_ERR_X509_INVALID_ALG +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    p = (unsigned char *) params->p;

    end = p + params->len;

    if( p == end )

        return( 0 );

    /*

     * HashAlgorithm

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                    MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0 ) ) == 0 )

    {

        end2 = p + len;

        /* HashAlgorithm ::= AlgorithmIdentifier (without parameters) */

        if( ( ret = mbedtls_x509_get_alg_null( &p, end2, &alg_id ) ) != 0 )

            return( ret );

        if( ( ret = mbedtls_oid_get_md_alg( &alg_id, md_alg ) ) != 0 )

            return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

        if( p != end2 )

            return( MBEDTLS_ERR_X509_INVALID_ALG +

                    MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    }

    else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    if( p == end )

        return( 0 );

    /*

     * MaskGenAlgorithm

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                    MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 1 ) ) == 0 )

    {

        end2 = p + len;

        /* MaskGenAlgorithm ::= AlgorithmIdentifier (params = HashAlgorithm) */

        if( ( ret = mbedtls_x509_get_alg( &p, end2, &alg_id, &alg_params ) ) != 0 )

            return( ret );

        /* Only MFG1 is recognised for now */

        if( MBEDTLS_OID_CMP( MBEDTLS_OID_MGF1, &alg_id ) != 0 )

            return( MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE +

                    MBEDTLS_ERR_OID_NOT_FOUND );

        /* Parse HashAlgorithm */

        if( ( ret = x509_get_hash_alg( &alg_params, mgf_md ) ) != 0 )

            return( ret );

        if( p != end2 )

            return( MBEDTLS_ERR_X509_INVALID_ALG +

                    MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    }

    else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    if( p == end )

        return( 0 );

    /*

     * salt_len

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                    MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 2 ) ) == 0 )

    {

        end2 = p + len;

        if( ( ret = mbedtls_asn1_get_int( &p, end2, salt_len ) ) != 0 )

            return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

        if( p != end2 )

            return( MBEDTLS_ERR_X509_INVALID_ALG +

                    MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    }

    else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    if( p == end )

        return( 0 );

    /*

     * trailer_field (if present, must be 1)

     */

    if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,

                    MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 3 ) ) == 0 )

    {

        int trailer_field;

        end2 = p + len;

        if( ( ret = mbedtls_asn1_get_int( &p, end2, &trailer_field ) ) != 0 )

            return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

        if( p != end2 )

            return( MBEDTLS_ERR_X509_INVALID_ALG +

                    MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

        if( trailer_field != 1 )

            return( MBEDTLS_ERR_X509_INVALID_ALG );

    }

    else if( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG )

        return( MBEDTLS_ERR_X509_INVALID_ALG + ret );

    if( p != end )

        return( MBEDTLS_ERR_X509_INVALID_ALG +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    return( 0 );

}

#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */

/*

 *  AttributeTypeAndValue ::= SEQUENCE {

 *    type     AttributeType,

 *    value    AttributeValue }

 *

 *  AttributeType ::= OBJECT IDENTIFIER

 *

 *  AttributeValue ::= ANY DEFINED BY AttributeType

 */

static int x509_get_attr_type_value( unsigned char **p,

                                     const unsigned char *end,

                                     mbedtls_x509_name *cur )

{

    int ret;

    size_t len;

    mbedtls_x509_buf *oid;

    mbedtls_x509_buf *val;

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_NAME + ret );

    end = *p + len;

    if( ( end - *p ) < 1 )

        return( MBEDTLS_ERR_X509_INVALID_NAME +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    oid = &cur->oid;

    oid->tag = **p;

    if( ( ret = mbedtls_asn1_get_tag( p, end, &oid->len, MBEDTLS_ASN1_OID ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_NAME + ret );

    oid->p = *p;

    *p += oid->len;

    if( ( end - *p ) < 1 )

        return( MBEDTLS_ERR_X509_INVALID_NAME +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    if( **p != MBEDTLS_ASN1_BMP_STRING && **p != MBEDTLS_ASN1_UTF8_STRING      &&

        **p != MBEDTLS_ASN1_T61_STRING && **p != MBEDTLS_ASN1_PRINTABLE_STRING &&

        **p != MBEDTLS_ASN1_IA5_STRING && **p != MBEDTLS_ASN1_UNIVERSAL_STRING &&

        **p != MBEDTLS_ASN1_BIT_STRING )

        return( MBEDTLS_ERR_X509_INVALID_NAME +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    val = &cur->val;

    val->tag = *(*p)++;

    if( ( ret = mbedtls_asn1_get_len( p, end, &val->len ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_NAME + ret );

    val->p = *p;

    *p += val->len;

    if( *p != end )

    {

        return( MBEDTLS_ERR_X509_INVALID_NAME +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    }

    cur->next = NULL;

    return( 0 );

}

/*

 *  Name ::= CHOICE { -- only one possibility for now --

 *       rdnSequence  RDNSequence }

 *

 *  RDNSequence ::= SEQUENCE OF RelativeDistinguishedName

 *

 *  RelativeDistinguishedName ::=

 *    SET OF AttributeTypeAndValue

 *

 *  AttributeTypeAndValue ::= SEQUENCE {

 *    type     AttributeType,

 *    value    AttributeValue }

 *

 *  AttributeType ::= OBJECT IDENTIFIER

 *

 *  AttributeValue ::= ANY DEFINED BY AttributeType

 *

 * The data structure is optimized for the common case where each RDN has only

 * one element, which is represented as a list of AttributeTypeAndValue.

 * For the general case we still use a flat list, but we mark elements of the

 * same set so that they are "merged" together in the functions that consume

 * this list, eg mbedtls_x509_dn_gets().

 */

int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end,

                   mbedtls_x509_name *cur )

{

    int ret;

    size_t set_len;

    const unsigned char *end_set;

    /* don't use recursion, we'd risk stack overflow if not optimized */

    while( 1 )

    {

        /*

         * parse SET

         */

        if( ( ret = mbedtls_asn1_get_tag( p, end, &set_len,

                MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET ) ) != 0 )

            return( MBEDTLS_ERR_X509_INVALID_NAME + ret );

        end_set  = *p + set_len;

        while( 1 )

        {

            if( ( ret = x509_get_attr_type_value( p, end_set, cur ) ) != 0 )

                return( ret );

            if( *p == end_set )

                break;

            /* Mark this item as being no the only one in a set */

            cur->next_merged = 1;

            cur->next = mbedtls_calloc( 1, sizeof( mbedtls_x509_name ) );

            if( cur->next == NULL )

                return( MBEDTLS_ERR_X509_ALLOC_FAILED );

            cur = cur->next;

        }

        /*

         * continue until end of SEQUENCE is reached

         */

        if( *p == end )

            return( 0 );

        cur->next = mbedtls_calloc( 1, sizeof( mbedtls_x509_name ) );

        if( cur->next == NULL )

            return( MBEDTLS_ERR_X509_ALLOC_FAILED );

        cur = cur->next;

    }

}

static int x509_parse_int( unsigned char **p, size_t n, int *res )

{

    *res = 0;

    for( ; n > 0; --n )

    {

        if( ( **p < '0') || ( **p > '9' ) )

            return ( MBEDTLS_ERR_X509_INVALID_DATE );

        *res *= 10;

        *res += ( *(*p)++ - '0' );

    }

    return( 0 );

}

static int x509_date_is_valid(const mbedtls_x509_time *t )

{

    int ret = MBEDTLS_ERR_X509_INVALID_DATE;

    int month_len;

    CHECK_RANGE( 0, 9999, t->year );

    CHECK_RANGE( 0, 23,   t->hour );

    CHECK_RANGE( 0, 59,   t->min  );

    CHECK_RANGE( 0, 59,   t->sec  );

    switch( t->mon )

    {

        case 1: case 3: case 5: case 7: case 8: case 10: case 12:

            month_len = 31;

            break;

        case 4: case 6: case 9: case 11:

            month_len = 30;

            break;

        case 2:

            if( ( !( t->year % 4 ) && t->year % 100 ) ||

                !( t->year % 400 ) )

                month_len = 29;

            else

                month_len = 28;

            break;

        default:

            return( ret );

    }

    CHECK_RANGE( 1, month_len, t->day );

    return( 0 );

}

/*

 * Parse an ASN1_UTC_TIME (yearlen=2) or ASN1_GENERALIZED_TIME (yearlen=4)

 * field.

 */

static int x509_parse_time( unsigned char **p, size_t len, size_t yearlen,

                            mbedtls_x509_time *tm )

{

    int ret;

    /*

     * Minimum length is 10 or 12 depending on yearlen

     */

    if ( len < yearlen + 8 )

        return ( MBEDTLS_ERR_X509_INVALID_DATE );

    len -= yearlen + 8;

    /*

     * Parse year, month, day, hour, minute

     */

    CHECK( x509_parse_int( p, yearlen, &tm->year ) );

    if ( 2 == yearlen )

    {

        if ( tm->year < 50 )

            tm->year += 100;

        tm->year += 1900;

    }

    CHECK( x509_parse_int( p, 2, &tm->mon ) );

    CHECK( x509_parse_int( p, 2, &tm->day ) );

    CHECK( x509_parse_int( p, 2, &tm->hour ) );

    CHECK( x509_parse_int( p, 2, &tm->min ) );

    /*

     * Parse seconds if present

     */

    if ( len >= 2 )

    {

        CHECK( x509_parse_int( p, 2, &tm->sec ) );

        len -= 2;

    }

    else

        return ( MBEDTLS_ERR_X509_INVALID_DATE );

    /*

     * Parse trailing 'Z' if present

     */

    if ( 1 == len && 'Z' == **p )

    {

        (*p)++;

        len--;

    }

    /*

     * We should have parsed all characters at this point

     */

    if ( 0 != len )

        return ( MBEDTLS_ERR_X509_INVALID_DATE );

    CHECK( x509_date_is_valid( tm ) );

    return ( 0 );

}

/*

 *  Time ::= CHOICE {

 *       utcTime        UTCTime,

 *       generalTime    GeneralizedTime }

 */

int mbedtls_x509_get_time( unsigned char **p, const unsigned char *end,

                           mbedtls_x509_time *tm )

{

    int ret;

    size_t len, year_len;

    unsigned char tag;

    if( ( end - *p ) < 1 )

        return( MBEDTLS_ERR_X509_INVALID_DATE +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    tag = **p;

    if( tag == MBEDTLS_ASN1_UTC_TIME )

        year_len = 2;

    else if( tag == MBEDTLS_ASN1_GENERALIZED_TIME )

        year_len = 4;

    else

        return( MBEDTLS_ERR_X509_INVALID_DATE +

                MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );

    (*p)++;

    ret = mbedtls_asn1_get_len( p, end, &len );

    if( ret != 0 )

        return( MBEDTLS_ERR_X509_INVALID_DATE + ret );

    return x509_parse_time( p, len, year_len, tm );

}

int mbedtls_x509_get_sig( unsigned char **p, const unsigned char *end, mbedtls_x509_buf *sig )

{

    int ret;

    size_t len;

    int tag_type;

    if( ( end - *p ) < 1 )

        return( MBEDTLS_ERR_X509_INVALID_SIGNATURE +

                MBEDTLS_ERR_ASN1_OUT_OF_DATA );

    tag_type = **p;

    if( ( ret = mbedtls_asn1_get_bitstring_null( p, end, &len ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_SIGNATURE + ret );

    sig->tag = tag_type;

    sig->len = len;

    sig->p = *p;

    *p += len;

    return( 0 );

}

/*

 * Get signature algorithm from alg OID and optional parameters

 */

int mbedtls_x509_get_sig_alg( const mbedtls_x509_buf *sig_oid, const mbedtls_x509_buf *sig_params,

                      mbedtls_md_type_t *md_alg, mbedtls_pk_type_t *pk_alg,

                      void **sig_opts )

{

    int ret;

    if( *sig_opts != NULL )

        return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );

    if( ( ret = mbedtls_oid_get_sig_alg( sig_oid, md_alg, pk_alg ) ) != 0 )

        return( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + ret );

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)

    if( *pk_alg == MBEDTLS_PK_RSASSA_PSS )

    {

        mbedtls_pk_rsassa_pss_options *pss_opts;

        pss_opts = mbedtls_calloc( 1, sizeof( mbedtls_pk_rsassa_pss_options ) );

        if( pss_opts == NULL )

            return( MBEDTLS_ERR_X509_ALLOC_FAILED );

        ret = mbedtls_x509_get_rsassa_pss_params( sig_params,

                                          md_alg,

                                          &pss_opts->mgf1_hash_id,

                                          &pss_opts->expected_salt_len );

        if( ret != 0 )

        {

            mbedtls_free( pss_opts );

            return( ret );

        }

        *sig_opts = (void *) pss_opts;

    }

    else

#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */

    {

        /* Make sure parameters are absent or NULL */

        if( ( sig_params->tag != MBEDTLS_ASN1_NULL && sig_params->tag != 0 ) ||

              sig_params->len != 0 )

        return( MBEDTLS_ERR_X509_INVALID_ALG );

    }

    return( 0 );

}

/*

 * X.509 Extensions (No parsing of extensions, pointer should

 * be either manually updated or extensions should be parsed!)

 */

int mbedtls_x509_get_ext( unsigned char **p, const unsigned char *end,

                          mbedtls_x509_buf *ext, int tag )

{

    int ret;

    size_t len;

    /* Extension structure use EXPLICIT tagging. That is, the actual

     * `Extensions` structure is wrapped by a tag-length pair using

     * the respective context-specific tag. */

    ret = mbedtls_asn1_get_tag( p, end, &ext->len,

              MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | tag );

    if( ret != 0 )

        return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );

    ext->tag = MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | tag;

    ext->p   = *p;

    end      = *p + ext->len;

    /*

     * Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension

     */

    if( ( ret = mbedtls_asn1_get_tag( p, end, &len,

            MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )

        return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );

    if( end != *p + len )

        return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +

                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );

    return( 0 );

}

/*

 * Store the name in printable form into buf; no more

 * than size characters will be written

 */

int mbedtls_x509_dn_gets( char *buf, size_t size, const mbedtls_x509_name *dn )

{

    int ret;

    size_t i, n;

    unsigned char c, merge = 0;

    const mbedtls_x509_name *name;

    const char *short_name = NULL;

    char s[MBEDTLS_X509_MAX_DN_NAME_SIZE], *p;

    memset( s, 0, sizeof( s ) );

    name = dn;

    p = buf;

    n = size;

    while( name != NULL )

    {

        if( !name->oid.p )

        {

            name = name->next;

            continue;

        }

        if( name != dn )

        {

            ret = mbedtls_snprintf( p, n, merge ? " + " : ", " );

            MBEDTLS_X509_SAFE_SNPRINTF;

        }

        ret = mbedtls_oid_get_attr_short_name( &name->oid, &short_name );

        if( ret == 0 )

            ret = mbedtls_snprintf( p, n, "%s=", short_name );

        else

            ret = mbedtls_snprintf( p, n, "\?\?=" );

        MBEDTLS_X509_SAFE_SNPRINTF;

        for( i = 0; i < name->val.len; i++ )

        {

            if( i >= sizeof( s ) - 1 )

                break;

            c = name->val.p[i];

            if( c < 32 || c == 127 || ( c > 128 && c < 160 ) )

                 s[i] = '?';

            else s[i] = c;

        }

        s[i] = '\0';

        ret = mbedtls_snprintf( p, n, "%s", s );

        MBEDTLS_X509_SAFE_SNPRINTF;

        merge = name->next_merged;

        name = name->next;

    }

    return( (int) ( size - n ) );

}

/*

 * Store the serial in printable form into buf; no more

 * than size characters will be written

 */

int mbedtls_x509_serial_gets( char *buf, size_t size, const mbedtls_x509_buf *serial )

{

    int ret;

    size_t i, n, nr;

    char *p;

    p = buf;

    n = size;

    nr = ( serial->len <= 32 )

        ? serial->len  : 28;

    for( i = 0; i < nr; i++ )

    {

        if( i == 0 && nr > 1 && serial->p[i] == 0x0 )

            continue;

        ret = mbedtls_snprintf( p, n, "%02X%s",

                serial->p[i], ( i < nr - 1 ) ? ":" : "" );

        MBEDTLS_X509_SAFE_SNPRINTF;

    }

    if( nr != serial->len )

    {

        ret = mbedtls_snprintf( p, n, "...." );

        MBEDTLS_X509_SAFE_SNPRINTF;

    }

    return( (int) ( size - n ) );

}

/*

 * Helper for writing signature algorithms

 */

int mbedtls_x509_sig_alg_gets( char *buf, size_t size, const mbedtls_x509_buf *sig_oid,

                       mbedtls_pk_type_t pk_alg, mbedtls_md_type_t md_alg,

                       const void *sig_opts )

{

    int ret;

    char *p = buf;

    size_t n = size;

    const char *desc = NULL;

    ret = mbedtls_oid_get_sig_alg_desc( sig_oid, &desc );

    if( ret != 0 )

        ret = mbedtls_snprintf( p, n, "???"  );

    else

        ret = mbedtls_snprintf( p, n, "%s", desc );

    MBEDTLS_X509_SAFE_SNPRINTF;

#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)

    if( pk_alg == MBEDTLS_PK_RSASSA_PSS )

    {

        const mbedtls_pk_rsassa_pss_options *pss_opts;

        const mbedtls_md_info_t *md_info, *mgf_md_info;

        pss_opts = (const mbedtls_pk_rsassa_pss_options *) sig_opts;

        md_info = mbedtls_md_info_from_type( md_alg );

        mgf_md_info = mbedtls_md_info_from_type( pss_opts->mgf1_hash_id );

        ret = mbedtls_snprintf( p, n, " (%s, MGF1-%s, 0x%02X)",

                              md_info ? mbedtls_md_get_name( md_info ) : "???",

                              mgf_md_info ? mbedtls_md_get_name( mgf_md_info ) : "???",

                              pss_opts->expected_salt_len );

        MBEDTLS_X509_SAFE_SNPRINTF;

    }

#else

    ((void) pk_alg);

    ((void) md_alg);

    ((void) sig_opts);

#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */

    return( (int)( size - n ) );

}

/*

 * Helper for writing "RSA key size", "EC key size", etc

 */

int mbedtls_x509_key_size_helper( char *buf, size_t buf_size, const char *name )

{

    char *p = buf;

    size_t n = buf_size;

    int ret;

    ret = mbedtls_snprintf( p, n, "%s key size", name );

    MBEDTLS_X509_SAFE_SNPRINTF;

    return( 0 );

}

#if defined(MBEDTLS_HAVE_TIME_DATE)

/*

 * Set the time structure to the current time.

 * Return 0 on success, non-zero on failure.

 */

static int x509_get_current_time( mbedtls_x509_time *now )

{

    struct tm *lt, tm_buf;

    mbedtls_time_t tt;

    int ret = 0;

    tt = mbedtls_time( NULL );

    lt = mbedtls_platform_gmtime_r( &tt, &tm_buf );

    if( lt == NULL )

        ret = -1;

    else

    {

        now->year = lt->tm_year + 1900;

        now->mon  = lt->tm_mon  + 1;

        now->day  = lt->tm_mday;

        now->hour = lt->tm_hour;

        now->min  = lt->tm_min;

        now->sec  = lt->tm_sec;

    }

    return( ret );

}

/*

 * Return 0 if before <= after, 1 otherwise

 */

static int x509_check_time( const mbedtls_x509_time *before, const mbedtls_x509_time *after )

{

    if( before->year  > after->year )

        return( 1 );

    if( before->year == after->year &&

        before->mon   > after->mon )

        return( 1 );

    if( before->year == after->year &&

        before->mon  == after->mon  &&

        before->day   > after->day )

        return( 1 );

    if( before->year == after->year &&

        before->mon  == after->mon  &&

        before->day  == after->day  &&

        before->hour  > after->hour )

        return( 1 );

    if( before->year == after->year &&

        before->mon  == after->mon  &&

        before->day  == after->day  &&

        before->hour == after->hour &&

        before->min   > after->min  )

        return( 1 );

    if( before->year == after->year &&

        before->mon  == after->mon  &&

        before->day  == after->day  &&

        before->hour == after->hour &&

        before->min  == after->min  &&

        before->sec   > after->sec  )

        return( 1 );

    return( 0 );

}

int mbedtls_x509_time_is_past( const mbedtls_x509_time *to )

{

    mbedtls_x509_time now;

    if( x509_get_current_time( &now ) != 0 )

        return( 1 );

    return( x509_check_time( &now, to ) );

}

int mbedtls_x509_time_is_future( const mbedtls_x509_time *from )

{

    mbedtls_x509_time now;

    if( x509_get_current_time( &now ) != 0 )

        return( 1 );

    return( x509_check_time( from, &now ) );

}

#else  /* MBEDTLS_HAVE_TIME_DATE */

int mbedtls_x509_time_is_past( const mbedtls_x509_time *to )

{

    ((void) to);

    return( 0 );

}

int mbedtls_x509_time_is_future( const mbedtls_x509_time *from )

{

    ((void) from);

    return( 0 );

}

#endif /* MBEDTLS_HAVE_TIME_DATE */

#if defined(MBEDTLS_SELF_TEST)

#include "mbedtls/x509_crt.h"

#include "mbedtls/certs.h"

/*

 * Checkup routine

 */

int mbedtls_x509_self_test( int verbose )

{

    int ret = 0;

#if defined(MBEDTLS_CERTS_C) && defined(MBEDTLS_SHA256_C)

    uint32_t flags;

    mbedtls_x509_crt cacert;

    mbedtls_x509_crt clicert;

    if( verbose != 0 )

        mbedtls_printf( "  X.509 certificate load: " );

    mbedtls_x509_crt_init( &cacert );

    mbedtls_x509_crt_init( &clicert );

    ret = mbedtls_x509_crt_parse( &clicert, (const unsigned char *) mbedtls_test_cli_crt,

                           mbedtls_test_cli_crt_len );

    if( ret != 0 )

    {

        if( verbose != 0 )

            mbedtls_printf( "failed\n" );

        goto cleanup;

    }

    ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_ca_crt,

                          mbedtls_test_ca_crt_len );

    if( ret != 0 )

    {

        if( verbose != 0 )

            mbedtls_printf( "failed\n" );

        goto cleanup;

    }

    if( verbose != 0 )

        mbedtls_printf( "passed\n  X.509 signature verify: ");

    ret = mbedtls_x509_crt_verify( &clicert, &cacert, NULL, NULL, &flags, NULL, NULL );

    if( ret != 0 )

    {

        if( verbose != 0 )

            mbedtls_printf( "failed\n" );

        goto cleanup;

    }

    if( verbose != 0 )

        mbedtls_printf( "passed\n\n");

cleanup:

    mbedtls_x509_crt_free( &cacert  );

    mbedtls_x509_crt_free( &clicert );

#else

    ((void) verbose);

#endif /* MBEDTLS_CERTS_C && MBEDTLS_SHA256_C */

    return( ret );

}

#endif /* MBEDTLS_SELF_TEST */

#endif /* MBEDTLS_X509_USE_C */