/* * 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 #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( len <= 0xFFFFFFFF ) { 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 ); } return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); } 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; // TODO negative values and values larger than 128 // DER format assumes 2s complement for numbers, so the leftmost bit // should be 0 for positive numbers and 1 for negative numbers. // 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_printable_string( unsigned char **p, unsigned char *start, 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, MBEDTLS_ASN1_PRINTABLE_STRING ) ); return( (int) len ); } int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start, 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, MBEDTLS_ASN1_IA5_STRING ) ); return( (int) 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; size = ( bits / 8 ) + ( ( bits % 8 ) ? 1 : 0 ); // Calculate byte length // if( *p < start || (size_t)( *p - start ) < size + 1 ) return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); len = size + 1; (*p) -= size; memcpy( *p, buf, size ); // Write unused bits // *--(*p) = (unsigned char) (size * 8 - 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 ); } 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 = mbedtls_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 = (unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)(unsigned char*)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 = (unsigned char*)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 = (unsigned char*)p; cur->val.len = val_len; } if( val != NULL ) memcpy( cur->val.p, val, val_len ); return( cur ); } #endif /* MBEDTLS_ASN1_WRITE_C */