/* | |
* ASN.1 buffer writing functionality | |
* | |
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | |
* SPDX-License-Identifier: Apache-2.0 | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); you may | |
* not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | |
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
* | |
* 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 <string.h> | |
#if defined(MBEDTLS_PLATFORM_C) | |
#include "mbedtls/platform.h" | |
#else | |
#include <stdlib.h> | |
#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_named_bitstring( unsigned char **p, | |
unsigned char *start, | |
const unsigned char *buf, | |
size_t bits ) | |
{ | |
size_t unused_bits, byte_len; | |
const unsigned char *cur_byte; | |
unsigned char cur_byte_shifted; | |
unsigned char bit; | |
byte_len = ( bits + 7 ) / 8; | |
unused_bits = ( byte_len * 8 ) - bits; | |
/* | |
* Named bitstrings require that trailing 0s are excluded in the encoding | |
* of the bitstring. Trailing 0s are considered part of the 'unused' bits | |
* when encoding this value in the first content octet | |
*/ | |
if( bits != 0 ) | |
{ | |
cur_byte = buf + byte_len - 1; | |
cur_byte_shifted = *cur_byte >> unused_bits; | |
for( ; ; ) | |
{ | |
bit = cur_byte_shifted & 0x1; | |
cur_byte_shifted >>= 1; | |
if( bit != 0 ) | |
break; | |
bits--; | |
if( bits == 0 ) | |
break; | |
if( bits % 8 == 0 ) | |
cur_byte_shifted = *--cur_byte; | |
} | |
} | |
return( mbedtls_asn1_write_bitstring( p, start, buf, bits ) ); | |
} | |
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 */ |