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/*

 * ASN.1 buffer writing functionality

 *

 *  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)

 */

#if !defined(MBEDTLS_CONFIG_FILE)

#include "mbedtls/config.h"

#else

#include MBEDTLS_CONFIG_FILE

#endif

#if defined(MBEDTLS_ASN1_WRITE_C)

#include "mbedtls/asn1write.h"

#include 

#if defined(MBEDTLS_PLATFORM_C)

#include "mbedtls/platform.h"

#else

#include 

#define mbedtls_calloc    calloc

#define mbedtls_free       free

#endif

int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )

{

    if( len < 0x80 )

    {

        if( *p - start < 1 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = (unsigned char) len;

        return( 1 );

    }

    if( len <= 0xFF )

    {

        if( *p - start < 2 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = (unsigned char) len;

        *--(*p) = 0x81;

        return( 2 );

    }

    if( len <= 0xFFFF )

    {

        if( *p - start < 3 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = ( len       ) & 0xFF;

        *--(*p) = ( len >>  8 ) & 0xFF;

        *--(*p) = 0x82;

        return( 3 );

    }

    if( len <= 0xFFFFFF )

    {

        if( *p - start < 4 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = ( len       ) & 0xFF;

        *--(*p) = ( len >>  8 ) & 0xFF;

        *--(*p) = ( len >> 16 ) & 0xFF;

        *--(*p) = 0x83;

        return( 4 );

    }

#if SIZE_MAX > 0xFFFFFFFF

    if( len <= 0xFFFFFFFF )

#endif

    {

        if( *p - start < 5 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = ( len       ) & 0xFF;

        *--(*p) = ( len >>  8 ) & 0xFF;

        *--(*p) = ( len >> 16 ) & 0xFF;

        *--(*p) = ( len >> 24 ) & 0xFF;

        *--(*p) = 0x84;

        return( 5 );

    }

#if SIZE_MAX > 0xFFFFFFFF

    return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );

#endif

}

int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )

{

    if( *p - start < 1 )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    *--(*p) = tag;

    return( 1 );

}

int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,

                           const unsigned char *buf, size_t size )

{

    size_t len = 0;

    if( *p < start || (size_t)( *p - start ) < size )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    len = size;

    (*p) -= len;

    memcpy( *p, buf, len );

    return( (int) len );

}

#if defined(MBEDTLS_BIGNUM_C)

int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X )

{

    int ret;

    size_t len = 0;

    // Write the MPI

    //

    len = mbedtls_mpi_size( X );

    if( *p < start || (size_t)( *p - start ) < len )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    (*p) -= len;

    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) );

    // DER format assumes 2s complement for numbers, so the leftmost bit

    // should be 0 for positive numbers and 1 for negative numbers.

    //

    if( X->s ==1 && **p & 0x80 )

    {

        if( *p - start < 1 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = 0x00;

        len += 1;

    }

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );

    ret = (int) len;

cleanup:

    return( ret );

}

#endif /* MBEDTLS_BIGNUM_C */

int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start )

{

    int ret;

    size_t len = 0;

    // Write NULL

    //

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) );

    return( (int) len );

}

int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,

                    const char *oid, size_t oid_len )

{

    int ret;

    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,

                                  (const unsigned char *) oid, oid_len ) );

    MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );

    return( (int) len );

}

int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,

                                     const char *oid, size_t oid_len,

                                     size_t par_len )

{

    int ret;

    size_t len = 0;

    if( par_len == 0 )

        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) );

    else

        len += par_len;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,

                                       MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );

    return( (int) len );

}

int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )

{

    int ret;

    size_t len = 0;

    if( *p - start < 1 )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    *--(*p) = (boolean) ? 255 : 0;

    len++;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) );

    return( (int) len );

}

int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val )

{

    int ret;

    size_t len = 0;

    if( *p - start < 1 )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    len += 1;

    *--(*p) = val;

    if( val > 0 && **p & 0x80 )

    {

        if( *p - start < 1 )

            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

        *--(*p) = 0x00;

        len += 1;

    }

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );

    return( (int) len );

}

int mbedtls_asn1_write_tagged_string( unsigned char **p, unsigned char *start, int tag,

    const char *text, size_t text_len )

{

    int ret;

    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,

        (const unsigned char *) text, text_len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, tag ) );

    return( (int) len );

}

int mbedtls_asn1_write_utf8_string( unsigned char **p, unsigned char *start,

    const char *text, size_t text_len )

{

    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len) );

}

int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start,

                                 const char *text, size_t text_len )

{

    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text, text_len) );

}

int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,

                           const char *text, size_t text_len )

{

    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len) );

}

int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,

                          const unsigned char *buf, size_t bits )

{

    int ret;

    size_t len = 0;

    size_t unused_bits, byte_len;

    byte_len = ( bits + 7 ) / 8;

    unused_bits = ( byte_len * 8 ) - bits;

    if( *p < start || (size_t)( *p - start ) < byte_len + 1 )

        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );

    len = byte_len + 1;

    /* Write the bitstring. Ensure the unused bits are zeroed */

    if( byte_len > 0 )

    {

        byte_len--;

        *--( *p ) = buf[byte_len] & ~( ( 0x1 << unused_bits ) - 1 );

        ( *p ) -= byte_len;

        memcpy( *p, buf, byte_len );

    }

    /* Write unused bits */

    *--( *p ) = (unsigned char)unused_bits;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );

    return( (int) len );

}

int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,

                             const unsigned char *buf, size_t size )

{

    int ret;

    size_t len = 0;

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );

    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );

    return( (int) len );

}

/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),

 * which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */

static mbedtls_asn1_named_data *asn1_find_named_data(

                                               mbedtls_asn1_named_data *list,

                                               const char *oid, size_t len )

{

    while( list != NULL )

    {

        if( list->oid.len == len &&

            memcmp( list->oid.p, oid, len ) == 0 )

        {

            break;

        }

        list = list->next;

    }

    return( list );

}

mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(

                                        mbedtls_asn1_named_data **head,

                                        const char *oid, size_t oid_len,

                                        const unsigned char *val,

                                        size_t val_len )

{

    mbedtls_asn1_named_data *cur;

    if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL )

    {

        // Add new entry if not present yet based on OID

        //

        cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1,

                                            sizeof(mbedtls_asn1_named_data) );

        if( cur == NULL )

            return( NULL );

        cur->oid.len = oid_len;

        cur->oid.p = mbedtls_calloc( 1, oid_len );

        if( cur->oid.p == NULL )

        {

            mbedtls_free( cur );

            return( NULL );

        }

        memcpy( cur->oid.p, oid, oid_len );

        cur->val.len = val_len;

        cur->val.p = mbedtls_calloc( 1, val_len );

        if( cur->val.p == NULL )

        {

            mbedtls_free( cur->oid.p );

            mbedtls_free( cur );

            return( NULL );

        }

        cur->next = *head;

        *head = cur;

    }

    else if( cur->val.len < val_len )

    {

        /*

         * Enlarge existing value buffer if needed

         * Preserve old data until the allocation succeeded, to leave list in

         * a consistent state in case allocation fails.

         */

        void *p = mbedtls_calloc( 1, val_len );

        if( p == NULL )

            return( NULL );

        mbedtls_free( cur->val.p );

        cur->val.p = p;

        cur->val.len = val_len;

    }

    if( val != NULL )

        memcpy( cur->val.p, val, val_len );

    return( cur );

}

#endif /* MBEDTLS_ASN1_WRITE_C */