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/*

 *  X.509 Certificate Signing Request writing

 *

 *  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)

 */

/*

 * References:

 * - CSRs: PKCS#10 v1.7 aka RFC 2986

 * - attributes: PKCS#9 v2.0 aka RFC 2985

 */

#if !defined(MBEDTLS_CONFIG_FILE)

#include "mbedtls/config.h"

#else

#include MBEDTLS_CONFIG_FILE

#endif

#if defined(MBEDTLS_X509_CSR_WRITE_C)

#include "mbedtls/x509_csr.h"

#include "mbedtls/oid.h"

#include "mbedtls/asn1write.h"

#include "mbedtls/platform_util.h"

#include 

#include 

#if defined(MBEDTLS_PEM_WRITE_C)

#include "mbedtls/pem.h"

#endif

/*

 * For the currently used signature algorithms the buffer to store any signature

 * must be at least of size MAX(MBEDTLS_ECDSA_MAX_LEN, MBEDTLS_MPI_MAX_SIZE)

 */

#if MBEDTLS_ECDSA_MAX_LEN > MBEDTLS_MPI_MAX_SIZE

#define SIGNATURE_MAX_SIZE MBEDTLS_ECDSA_MAX_LEN

#else

#define SIGNATURE_MAX_SIZE MBEDTLS_MPI_MAX_SIZE

#endif

void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )

{

    memset( ctx, 0, sizeof( mbedtls_x509write_csr ) );

}

void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx )

{

    mbedtls_asn1_free_named_data_list( &ctx->subject );

    mbedtls_asn1_free_named_data_list( &ctx->extensions );

    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_csr ) );

}

void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg )

{

    ctx->md_alg = md_alg;

}

void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key )

{

    ctx->key = key;

}

int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx,

                                    const char *subject_name )

{

    return mbedtls_x509_string_to_names( &ctx->subject, subject_name );

}

int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx,

                                 const char *oid, size_t oid_len,

                                 const unsigned char *val, size_t val_len )

{

    return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,

                               0, val, val_len );

}

static size_t csr_get_unused_bits_for_named_bitstring( unsigned char bitstring,

                                                       size_t bit_offset )

{

    size_t unused_bits;

     /* Count the unused bits removing trailing 0s */

    for( unused_bits = bit_offset; unused_bits < 8; unused_bits++ )

        if( ( ( bitstring >> unused_bits ) & 0x1 ) != 0 )

            break;

     return( unused_bits );

}

int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage )

{

    unsigned char buf[4];

    unsigned char *c;

    size_t unused_bits;

    int ret;

    c = buf + 4;

    unused_bits = csr_get_unused_bits_for_named_bitstring( key_usage, 0 );

    ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 8 - unused_bits );

    if( ret < 0 )

        return( ret );

    else if( ret < 3 || ret > 4 )

        return( MBEDTLS_ERR_X509_INVALID_FORMAT );

    ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,

                                       MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),

                                       c, (size_t)ret );

    if( ret != 0 )

        return( ret );

    return( 0 );

}

int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx,

                                    unsigned char ns_cert_type )

{

    unsigned char buf[4];

    unsigned char *c;

    size_t unused_bits;

    int ret;

    c = buf + 4;

    unused_bits = csr_get_unused_bits_for_named_bitstring( ns_cert_type, 0 );

    ret = mbedtls_asn1_write_bitstring( &c,

                                        buf,

                                        &ns_cert_type,

                                        8 - unused_bits );

    if( ret < 0 )

        return( ret );

    else if( ret < 3 || ret > 4 )

        return( ret );

    ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,

                                       MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),

                                       c, (size_t)ret );

    if( ret != 0 )

        return( ret );

    return( 0 );

}

int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,

                       int (*f_rng)(void *, unsigned char *, size_t),

                       void *p_rng )

{

    int ret;

    const char *sig_oid;

    size_t sig_oid_len = 0;

    unsigned char *c, *c2;

    unsigned char hash[64];

    unsigned char sig[SIGNATURE_MAX_SIZE];

    unsigned char tmp_buf[2048];

    size_t pub_len = 0, sig_and_oid_len = 0, sig_len;

    size_t len = 0;

    mbedtls_pk_type_t pk_alg;

    /*

     * Prepare data to be signed in tmp_buf

     */

    c = tmp_buf + sizeof( tmp_buf );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );

    if( len )

    {

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                        MBEDTLS_ASN1_SEQUENCE ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                        MBEDTLS_ASN1_SET ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ,

                                          MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                        MBEDTLS_ASN1_SEQUENCE ) );

    }

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                    MBEDTLS_ASN1_CONTEXT_SPECIFIC ) );

    MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key,

                                                tmp_buf, c - tmp_buf ) );

    c -= pub_len;

    len += pub_len;

    /*

     *  Subject  ::=  Name

     */

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) );

    /*

     *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }

     */

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                    MBEDTLS_ASN1_SEQUENCE ) );

    /*

     * Prepare signature

     */

    ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );

    if( ret != 0 )

        return( ret );

    if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,

                                 f_rng, p_rng ) ) != 0 )

    {

        return( ret );

    }

    if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) )

        pk_alg = MBEDTLS_PK_RSA;

    else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) )

        pk_alg = MBEDTLS_PK_ECDSA;

    else

        return( MBEDTLS_ERR_X509_INVALID_ALG );

    if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,

                                                &sig_oid, &sig_oid_len ) ) != 0 )

    {

        return( ret );

    }

    /*

     * Write data to output buffer

     */

    c2 = buf + size;

    MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf,

                                        sig_oid, sig_oid_len, sig, sig_len ) );

    if( len > (size_t)( c2 - buf ) )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    c2 -= len;

    memcpy( c2, c, len );

    len += sig_and_oid_len;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED |

                                                 MBEDTLS_ASN1_SEQUENCE ) );

    return( (int) len );

}

#define PEM_BEGIN_CSR           "-----BEGIN CERTIFICATE REQUEST-----\n"

#define PEM_END_CSR             "-----END CERTIFICATE REQUEST-----\n"

#if defined(MBEDTLS_PEM_WRITE_C)

int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size,

                       int (*f_rng)(void *, unsigned char *, size_t),

                       void *p_rng )

{

    int ret;

    unsigned char output_buf[4096];

    size_t olen = 0;

    if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf),

                                   f_rng, p_rng ) ) < 0 )

    {

        return( ret );

    }

    if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,

                                  output_buf + sizeof(output_buf) - ret,

                                  ret, buf, size, &olen ) ) != 0 )

    {

        return( ret );

    }

    return( 0 );

}

#endif /* MBEDTLS_PEM_WRITE_C */

#endif /* MBEDTLS_X509_CSR_WRITE_C */