| /** |
| * \file cipher.c |
| * |
| * \brief Generic cipher wrapper for mbed TLS |
| * |
| * \author Adriaan de Jong <dejong@fox-it.com> |
| * |
| * 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_CIPHER_C) |
| |
| #include "mbedtls/cipher.h" |
| #include "mbedtls/cipher_internal.h" |
| #include "mbedtls/platform_util.h" |
| |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| #include "mbedtls/chachapoly.h" |
| #endif |
| |
| #if defined(MBEDTLS_GCM_C) |
| #include "mbedtls/gcm.h" |
| #endif |
| |
| #if defined(MBEDTLS_CCM_C) |
| #include "mbedtls/ccm.h" |
| #endif |
| |
| #if defined(MBEDTLS_CHACHA20_C) |
| #include "mbedtls/chacha20.h" |
| #endif |
| |
| #if defined(MBEDTLS_CMAC_C) |
| #include "mbedtls/cmac.h" |
| #endif |
| |
| #if defined(MBEDTLS_PLATFORM_C) |
| #include "mbedtls/platform.h" |
| #else |
| #define mbedtls_calloc calloc |
| #define mbedtls_free free |
| #endif |
| |
| #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) |
| /* Compare the contents of two buffers in constant time. |
| * Returns 0 if the contents are bitwise identical, otherwise returns |
| * a non-zero value. |
| * This is currently only used by GCM and ChaCha20+Poly1305. |
| */ |
| static int mbedtls_constant_time_memcmp( const void *v1, const void *v2, size_t len ) |
| { |
| const unsigned char *p1 = (const unsigned char*) v1; |
| const unsigned char *p2 = (const unsigned char*) v2; |
| size_t i; |
| unsigned char diff; |
| |
| for( diff = 0, i = 0; i < len; i++ ) |
| diff |= p1[i] ^ p2[i]; |
| |
| return (int)diff; |
| } |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ |
| |
| static int supported_init = 0; |
| |
| const int *mbedtls_cipher_list( void ) |
| { |
| const mbedtls_cipher_definition_t *def; |
| int *type; |
| |
| if( ! supported_init ) |
| { |
| def = mbedtls_cipher_definitions; |
| type = mbedtls_cipher_supported; |
| |
| while( def->type != 0 ) |
| *type++ = (*def++).type; |
| |
| *type = 0; |
| |
| supported_init = 1; |
| } |
| |
| return( mbedtls_cipher_supported ); |
| } |
| |
| const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type ) |
| { |
| const mbedtls_cipher_definition_t *def; |
| |
| for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) |
| if( def->type == cipher_type ) |
| return( def->info ); |
| |
| return( NULL ); |
| } |
| |
| const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name ) |
| { |
| const mbedtls_cipher_definition_t *def; |
| |
| if( NULL == cipher_name ) |
| return( NULL ); |
| |
| for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) |
| if( ! strcmp( def->info->name, cipher_name ) ) |
| return( def->info ); |
| |
| return( NULL ); |
| } |
| |
| const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id, |
| int key_bitlen, |
| const mbedtls_cipher_mode_t mode ) |
| { |
| const mbedtls_cipher_definition_t *def; |
| |
| for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) |
| if( def->info->base->cipher == cipher_id && |
| def->info->key_bitlen == (unsigned) key_bitlen && |
| def->info->mode == mode ) |
| return( def->info ); |
| |
| return( NULL ); |
| } |
| |
| void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx ) |
| { |
| memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) ); |
| } |
| |
| void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx ) |
| { |
| if( ctx == NULL ) |
| return; |
| |
| #if defined(MBEDTLS_CMAC_C) |
| if( ctx->cmac_ctx ) |
| { |
| mbedtls_platform_zeroize( ctx->cmac_ctx, |
| sizeof( mbedtls_cmac_context_t ) ); |
| mbedtls_free( ctx->cmac_ctx ); |
| } |
| #endif |
| |
| if( ctx->cipher_ctx ) |
| ctx->cipher_info->base->ctx_free_func( ctx->cipher_ctx ); |
| |
| mbedtls_platform_zeroize( ctx, sizeof(mbedtls_cipher_context_t) ); |
| } |
| |
| int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info ) |
| { |
| if( NULL == cipher_info || NULL == ctx ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) ); |
| |
| if( NULL == ( ctx->cipher_ctx = cipher_info->base->ctx_alloc_func() ) ) |
| return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED ); |
| |
| ctx->cipher_info = cipher_info; |
| |
| #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) |
| /* |
| * Ignore possible errors caused by a cipher mode that doesn't use padding |
| */ |
| #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) |
| (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_PKCS7 ); |
| #else |
| (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_NONE ); |
| #endif |
| #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key, |
| int key_bitlen, const mbedtls_operation_t operation ) |
| { |
| if( NULL == ctx || NULL == ctx->cipher_info ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_KEY_LEN ) == 0 && |
| (int) ctx->cipher_info->key_bitlen != key_bitlen ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| ctx->key_bitlen = key_bitlen; |
| ctx->operation = operation; |
| |
| /* |
| * For OFB, CFB and CTR mode always use the encryption key schedule |
| */ |
| if( MBEDTLS_ENCRYPT == operation || |
| MBEDTLS_MODE_CFB == ctx->cipher_info->mode || |
| MBEDTLS_MODE_OFB == ctx->cipher_info->mode || |
| MBEDTLS_MODE_CTR == ctx->cipher_info->mode ) |
| { |
| return ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key, |
| ctx->key_bitlen ); |
| } |
| |
| if( MBEDTLS_DECRYPT == operation ) |
| return ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key, |
| ctx->key_bitlen ); |
| |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx, |
| const unsigned char *iv, size_t iv_len ) |
| { |
| size_t actual_iv_size; |
| |
| if( NULL == ctx || NULL == ctx->cipher_info || NULL == iv ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| /* avoid buffer overflow in ctx->iv */ |
| if( iv_len > MBEDTLS_MAX_IV_LENGTH ) |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| |
| if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_IV_LEN ) != 0 ) |
| actual_iv_size = iv_len; |
| else |
| { |
| actual_iv_size = ctx->cipher_info->iv_size; |
| |
| /* avoid reading past the end of input buffer */ |
| if( actual_iv_size > iv_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| #if defined(MBEDTLS_CHACHA20_C) |
| if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20 ) |
| { |
| if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx, |
| iv, |
| 0U ) ) /* Initial counter value */ |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| } |
| #endif |
| |
| memcpy( ctx->iv, iv, actual_iv_size ); |
| ctx->iv_size = actual_iv_size; |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx ) |
| { |
| if( NULL == ctx || NULL == ctx->cipher_info ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| ctx->unprocessed_len = 0; |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) |
| int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx, |
| const unsigned char *ad, size_t ad_len ) |
| { |
| if( NULL == ctx || NULL == ctx->cipher_info ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_GCM_C) |
| if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) |
| { |
| return mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation, |
| ctx->iv, ctx->iv_size, ad, ad_len ); |
| } |
| #endif |
| |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if (MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) |
| { |
| int result; |
| mbedtls_chachapoly_mode_t mode; |
| |
| mode = ( ctx->operation == MBEDTLS_ENCRYPT ) |
| ? MBEDTLS_CHACHAPOLY_ENCRYPT |
| : MBEDTLS_CHACHAPOLY_DECRYPT; |
| |
| result = mbedtls_chachapoly_starts( (mbedtls_chachapoly_context*) ctx->cipher_ctx, |
| ctx->iv, |
| mode ); |
| if ( result != 0 ) |
| return( result ); |
| |
| return mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx, |
| ad, ad_len ); |
| } |
| #endif |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ |
| |
| int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input, |
| size_t ilen, unsigned char *output, size_t *olen ) |
| { |
| int ret; |
| size_t block_size = 0; |
| |
| if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| *olen = 0; |
| block_size = mbedtls_cipher_get_block_size( ctx ); |
| |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_ECB ) |
| { |
| if( ilen != block_size ) |
| return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); |
| |
| *olen = ilen; |
| |
| if( 0 != ( ret = ctx->cipher_info->base->ecb_func( ctx->cipher_ctx, |
| ctx->operation, input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_GCM_C) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_GCM ) |
| { |
| *olen = ilen; |
| return mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input, |
| output ); |
| } |
| #endif |
| |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 ) |
| { |
| *olen = ilen; |
| return mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx, |
| ilen, input, output ); |
| } |
| #endif |
| |
| if ( 0 == block_size ) |
| { |
| return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT; |
| } |
| |
| if( input == output && |
| ( ctx->unprocessed_len != 0 || ilen % block_size ) ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| #if defined(MBEDTLS_CIPHER_MODE_CBC) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_CBC ) |
| { |
| size_t copy_len = 0; |
| |
| /* |
| * If there is not enough data for a full block, cache it. |
| */ |
| if( ( ctx->operation == MBEDTLS_DECRYPT && NULL != ctx->add_padding && |
| ilen <= block_size - ctx->unprocessed_len ) || |
| ( ctx->operation == MBEDTLS_DECRYPT && NULL == ctx->add_padding && |
| ilen < block_size - ctx->unprocessed_len ) || |
| ( ctx->operation == MBEDTLS_ENCRYPT && |
| ilen < block_size - ctx->unprocessed_len ) ) |
| { |
| memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, |
| ilen ); |
| |
| ctx->unprocessed_len += ilen; |
| return( 0 ); |
| } |
| |
| /* |
| * Process cached data first |
| */ |
| if( 0 != ctx->unprocessed_len ) |
| { |
| copy_len = block_size - ctx->unprocessed_len; |
| |
| memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, |
| copy_len ); |
| |
| if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, |
| ctx->operation, block_size, ctx->iv, |
| ctx->unprocessed_data, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen += block_size; |
| output += block_size; |
| ctx->unprocessed_len = 0; |
| |
| input += copy_len; |
| ilen -= copy_len; |
| } |
| |
| /* |
| * Cache final, incomplete block |
| */ |
| if( 0 != ilen ) |
| { |
| if( 0 == block_size ) |
| { |
| return MBEDTLS_ERR_CIPHER_INVALID_CONTEXT; |
| } |
| |
| /* Encryption: only cache partial blocks |
| * Decryption w/ padding: always keep at least one whole block |
| * Decryption w/o padding: only cache partial blocks |
| */ |
| copy_len = ilen % block_size; |
| if( copy_len == 0 && |
| ctx->operation == MBEDTLS_DECRYPT && |
| NULL != ctx->add_padding) |
| { |
| copy_len = block_size; |
| } |
| |
| memcpy( ctx->unprocessed_data, &( input[ilen - copy_len] ), |
| copy_len ); |
| |
| ctx->unprocessed_len += copy_len; |
| ilen -= copy_len; |
| } |
| |
| /* |
| * Process remaining full blocks |
| */ |
| if( ilen ) |
| { |
| if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, |
| ctx->operation, ilen, ctx->iv, input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen += ilen; |
| } |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_CBC */ |
| |
| #if defined(MBEDTLS_CIPHER_MODE_CFB) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_CFB ) |
| { |
| if( 0 != ( ret = ctx->cipher_info->base->cfb_func( ctx->cipher_ctx, |
| ctx->operation, ilen, &ctx->unprocessed_len, ctx->iv, |
| input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen = ilen; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_CFB */ |
| |
| #if defined(MBEDTLS_CIPHER_MODE_OFB) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_OFB ) |
| { |
| if( 0 != ( ret = ctx->cipher_info->base->ofb_func( ctx->cipher_ctx, |
| ilen, &ctx->unprocessed_len, ctx->iv, input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen = ilen; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_OFB */ |
| |
| #if defined(MBEDTLS_CIPHER_MODE_CTR) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_CTR ) |
| { |
| if( 0 != ( ret = ctx->cipher_info->base->ctr_func( ctx->cipher_ctx, |
| ilen, &ctx->unprocessed_len, ctx->iv, |
| ctx->unprocessed_data, input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen = ilen; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_CTR */ |
| |
| #if defined(MBEDTLS_CIPHER_MODE_XTS) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_XTS ) |
| { |
| if( ctx->unprocessed_len > 0 ) { |
| /* We can only process an entire data unit at a time. */ |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| |
| ret = ctx->cipher_info->base->xts_func( ctx->cipher_ctx, |
| ctx->operation, ilen, ctx->iv, input, output ); |
| if( ret != 0 ) |
| { |
| return( ret ); |
| } |
| |
| *olen = ilen; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_XTS */ |
| |
| #if defined(MBEDTLS_CIPHER_MODE_STREAM) |
| if( ctx->cipher_info->mode == MBEDTLS_MODE_STREAM ) |
| { |
| if( 0 != ( ret = ctx->cipher_info->base->stream_func( ctx->cipher_ctx, |
| ilen, input, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| *olen = ilen; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_STREAM */ |
| |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| |
| #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) |
| #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) |
| /* |
| * PKCS7 (and PKCS5) padding: fill with ll bytes, with ll = padding_len |
| */ |
| static void add_pkcs_padding( unsigned char *output, size_t output_len, |
| size_t data_len ) |
| { |
| size_t padding_len = output_len - data_len; |
| unsigned char i; |
| |
| for( i = 0; i < padding_len; i++ ) |
| output[data_len + i] = (unsigned char) padding_len; |
| } |
| |
| static int get_pkcs_padding( unsigned char *input, size_t input_len, |
| size_t *data_len ) |
| { |
| size_t i, pad_idx; |
| unsigned char padding_len, bad = 0; |
| |
| if( NULL == input || NULL == data_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| padding_len = input[input_len - 1]; |
| *data_len = input_len - padding_len; |
| |
| /* Avoid logical || since it results in a branch */ |
| bad |= padding_len > input_len; |
| bad |= padding_len == 0; |
| |
| /* The number of bytes checked must be independent of padding_len, |
| * so pick input_len, which is usually 8 or 16 (one block) */ |
| pad_idx = input_len - padding_len; |
| for( i = 0; i < input_len; i++ ) |
| bad |= ( input[i] ^ padding_len ) * ( i >= pad_idx ); |
| |
| return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); |
| } |
| #endif /* MBEDTLS_CIPHER_PADDING_PKCS7 */ |
| |
| #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) |
| /* |
| * One and zeros padding: fill with 80 00 ... 00 |
| */ |
| static void add_one_and_zeros_padding( unsigned char *output, |
| size_t output_len, size_t data_len ) |
| { |
| size_t padding_len = output_len - data_len; |
| unsigned char i = 0; |
| |
| output[data_len] = 0x80; |
| for( i = 1; i < padding_len; i++ ) |
| output[data_len + i] = 0x00; |
| } |
| |
| static int get_one_and_zeros_padding( unsigned char *input, size_t input_len, |
| size_t *data_len ) |
| { |
| size_t i; |
| unsigned char done = 0, prev_done, bad; |
| |
| if( NULL == input || NULL == data_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| bad = 0x80; |
| *data_len = 0; |
| for( i = input_len; i > 0; i-- ) |
| { |
| prev_done = done; |
| done |= ( input[i - 1] != 0 ); |
| *data_len |= ( i - 1 ) * ( done != prev_done ); |
| bad ^= input[i - 1] * ( done != prev_done ); |
| } |
| |
| return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); |
| |
| } |
| #endif /* MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS */ |
| |
| #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) |
| /* |
| * Zeros and len padding: fill with 00 ... 00 ll, where ll is padding length |
| */ |
| static void add_zeros_and_len_padding( unsigned char *output, |
| size_t output_len, size_t data_len ) |
| { |
| size_t padding_len = output_len - data_len; |
| unsigned char i = 0; |
| |
| for( i = 1; i < padding_len; i++ ) |
| output[data_len + i - 1] = 0x00; |
| output[output_len - 1] = (unsigned char) padding_len; |
| } |
| |
| static int get_zeros_and_len_padding( unsigned char *input, size_t input_len, |
| size_t *data_len ) |
| { |
| size_t i, pad_idx; |
| unsigned char padding_len, bad = 0; |
| |
| if( NULL == input || NULL == data_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| padding_len = input[input_len - 1]; |
| *data_len = input_len - padding_len; |
| |
| /* Avoid logical || since it results in a branch */ |
| bad |= padding_len > input_len; |
| bad |= padding_len == 0; |
| |
| /* The number of bytes checked must be independent of padding_len */ |
| pad_idx = input_len - padding_len; |
| for( i = 0; i < input_len - 1; i++ ) |
| bad |= input[i] * ( i >= pad_idx ); |
| |
| return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); |
| } |
| #endif /* MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN */ |
| |
| #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) |
| /* |
| * Zero padding: fill with 00 ... 00 |
| */ |
| static void add_zeros_padding( unsigned char *output, |
| size_t output_len, size_t data_len ) |
| { |
| size_t i; |
| |
| for( i = data_len; i < output_len; i++ ) |
| output[i] = 0x00; |
| } |
| |
| static int get_zeros_padding( unsigned char *input, size_t input_len, |
| size_t *data_len ) |
| { |
| size_t i; |
| unsigned char done = 0, prev_done; |
| |
| if( NULL == input || NULL == data_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| *data_len = 0; |
| for( i = input_len; i > 0; i-- ) |
| { |
| prev_done = done; |
| done |= ( input[i-1] != 0 ); |
| *data_len |= i * ( done != prev_done ); |
| } |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */ |
| |
| /* |
| * No padding: don't pad :) |
| * |
| * There is no add_padding function (check for NULL in mbedtls_cipher_finish) |
| * but a trivial get_padding function |
| */ |
| static int get_no_padding( unsigned char *input, size_t input_len, |
| size_t *data_len ) |
| { |
| if( NULL == input || NULL == data_len ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| *data_len = input_len; |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ |
| |
| int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx, |
| unsigned char *output, size_t *olen ) |
| { |
| if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| *olen = 0; |
| |
| if( MBEDTLS_MODE_CFB == ctx->cipher_info->mode || |
| MBEDTLS_MODE_OFB == ctx->cipher_info->mode || |
| MBEDTLS_MODE_CTR == ctx->cipher_info->mode || |
| MBEDTLS_MODE_GCM == ctx->cipher_info->mode || |
| MBEDTLS_MODE_XTS == ctx->cipher_info->mode || |
| MBEDTLS_MODE_STREAM == ctx->cipher_info->mode ) |
| { |
| return( 0 ); |
| } |
| |
| if ( ( MBEDTLS_CIPHER_CHACHA20 == ctx->cipher_info->type ) || |
| ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) ) |
| { |
| return( 0 ); |
| } |
| |
| if( MBEDTLS_MODE_ECB == ctx->cipher_info->mode ) |
| { |
| if( ctx->unprocessed_len != 0 ) |
| return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_CIPHER_MODE_CBC) |
| if( MBEDTLS_MODE_CBC == ctx->cipher_info->mode ) |
| { |
| int ret = 0; |
| |
| if( MBEDTLS_ENCRYPT == ctx->operation ) |
| { |
| /* check for 'no padding' mode */ |
| if( NULL == ctx->add_padding ) |
| { |
| if( 0 != ctx->unprocessed_len ) |
| return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); |
| |
| return( 0 ); |
| } |
| |
| ctx->add_padding( ctx->unprocessed_data, mbedtls_cipher_get_iv_size( ctx ), |
| ctx->unprocessed_len ); |
| } |
| else if( mbedtls_cipher_get_block_size( ctx ) != ctx->unprocessed_len ) |
| { |
| /* |
| * For decrypt operations, expect a full block, |
| * or an empty block if no padding |
| */ |
| if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len ) |
| return( 0 ); |
| |
| return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); |
| } |
| |
| /* cipher block */ |
| if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, |
| ctx->operation, mbedtls_cipher_get_block_size( ctx ), ctx->iv, |
| ctx->unprocessed_data, output ) ) ) |
| { |
| return( ret ); |
| } |
| |
| /* Set output size for decryption */ |
| if( MBEDTLS_DECRYPT == ctx->operation ) |
| return ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ), |
| olen ); |
| |
| /* Set output size for encryption */ |
| *olen = mbedtls_cipher_get_block_size( ctx ); |
| return( 0 ); |
| } |
| #else |
| ((void) output); |
| #endif /* MBEDTLS_CIPHER_MODE_CBC */ |
| |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| |
| #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) |
| int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode ) |
| { |
| if( NULL == ctx || |
| MBEDTLS_MODE_CBC != ctx->cipher_info->mode ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| switch( mode ) |
| { |
| #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) |
| case MBEDTLS_PADDING_PKCS7: |
| ctx->add_padding = add_pkcs_padding; |
| ctx->get_padding = get_pkcs_padding; |
| break; |
| #endif |
| #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) |
| case MBEDTLS_PADDING_ONE_AND_ZEROS: |
| ctx->add_padding = add_one_and_zeros_padding; |
| ctx->get_padding = get_one_and_zeros_padding; |
| break; |
| #endif |
| #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) |
| case MBEDTLS_PADDING_ZEROS_AND_LEN: |
| ctx->add_padding = add_zeros_and_len_padding; |
| ctx->get_padding = get_zeros_and_len_padding; |
| break; |
| #endif |
| #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) |
| case MBEDTLS_PADDING_ZEROS: |
| ctx->add_padding = add_zeros_padding; |
| ctx->get_padding = get_zeros_padding; |
| break; |
| #endif |
| case MBEDTLS_PADDING_NONE: |
| ctx->add_padding = NULL; |
| ctx->get_padding = get_no_padding; |
| break; |
| |
| default: |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ |
| |
| #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) |
| int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx, |
| unsigned char *tag, size_t tag_len ) |
| { |
| if( NULL == ctx || NULL == ctx->cipher_info || NULL == tag ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| if( MBEDTLS_ENCRYPT != ctx->operation ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_GCM_C) |
| if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) |
| return mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, tag, tag_len ); |
| #endif |
| |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) |
| { |
| /* Don't allow truncated MAC for Poly1305 */ |
| if ( tag_len != 16U ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| return mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, |
| tag ); |
| } |
| #endif |
| |
| return( 0 ); |
| } |
| |
| int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx, |
| const unsigned char *tag, size_t tag_len ) |
| { |
| unsigned char check_tag[16]; |
| int ret; |
| |
| if( NULL == ctx || NULL == ctx->cipher_info || |
| MBEDTLS_DECRYPT != ctx->operation ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| #if defined(MBEDTLS_GCM_C) |
| if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) |
| { |
| if( tag_len > sizeof( check_tag ) ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| if( 0 != ( ret = mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, |
| check_tag, tag_len ) ) ) |
| { |
| return( ret ); |
| } |
| |
| /* Check the tag in "constant-time" */ |
| if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) |
| return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_GCM_C */ |
| |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) |
| { |
| /* Don't allow truncated MAC for Poly1305 */ |
| if ( tag_len != sizeof( check_tag ) ) |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| |
| ret = mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, |
| check_tag ); |
| if ( ret != 0 ) |
| { |
| return( ret ); |
| } |
| |
| /* Check the tag in "constant-time" */ |
| if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) |
| return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_CHACHAPOLY_C */ |
| |
| return( 0 ); |
| } |
| #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ |
| |
| /* |
| * Packet-oriented wrapper for non-AEAD modes |
| */ |
| int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx, |
| const unsigned char *iv, size_t iv_len, |
| const unsigned char *input, size_t ilen, |
| unsigned char *output, size_t *olen ) |
| { |
| int ret; |
| size_t finish_olen; |
| |
| if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 ) |
| return( ret ); |
| |
| if( ( ret = mbedtls_cipher_reset( ctx ) ) != 0 ) |
| return( ret ); |
| |
| if( ( ret = mbedtls_cipher_update( ctx, input, ilen, output, olen ) ) != 0 ) |
| return( ret ); |
| |
| if( ( ret = mbedtls_cipher_finish( ctx, output + *olen, &finish_olen ) ) != 0 ) |
| return( ret ); |
| |
| *olen += finish_olen; |
| |
| return( 0 ); |
| } |
| |
| #if defined(MBEDTLS_CIPHER_MODE_AEAD) |
| /* |
| * Packet-oriented encryption for AEAD modes |
| */ |
| int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx, |
| const unsigned char *iv, size_t iv_len, |
| const unsigned char *ad, size_t ad_len, |
| const unsigned char *input, size_t ilen, |
| unsigned char *output, size_t *olen, |
| unsigned char *tag, size_t tag_len ) |
| { |
| #if defined(MBEDTLS_GCM_C) |
| if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) |
| { |
| *olen = ilen; |
| return( mbedtls_gcm_crypt_and_tag( ctx->cipher_ctx, MBEDTLS_GCM_ENCRYPT, ilen, |
| iv, iv_len, ad, ad_len, input, output, |
| tag_len, tag ) ); |
| } |
| #endif /* MBEDTLS_GCM_C */ |
| #if defined(MBEDTLS_CCM_C) |
| if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) |
| { |
| *olen = ilen; |
| return( mbedtls_ccm_encrypt_and_tag( ctx->cipher_ctx, ilen, |
| iv, iv_len, ad, ad_len, input, output, |
| tag, tag_len ) ); |
| } |
| #endif /* MBEDTLS_CCM_C */ |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) |
| { |
| /* ChachaPoly has fixed length nonce and MAC (tag) */ |
| if ( ( iv_len != ctx->cipher_info->iv_size ) || |
| ( tag_len != 16U ) ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| *olen = ilen; |
| return( mbedtls_chachapoly_encrypt_and_tag( ctx->cipher_ctx, |
| ilen, iv, ad, ad_len, input, output, tag ) ); |
| } |
| #endif /* MBEDTLS_CHACHAPOLY_C */ |
| |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| |
| /* |
| * Packet-oriented decryption for AEAD modes |
| */ |
| int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx, |
| const unsigned char *iv, size_t iv_len, |
| const unsigned char *ad, size_t ad_len, |
| const unsigned char *input, size_t ilen, |
| unsigned char *output, size_t *olen, |
| const unsigned char *tag, size_t tag_len ) |
| { |
| #if defined(MBEDTLS_GCM_C) |
| if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) |
| { |
| int ret; |
| |
| *olen = ilen; |
| ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen, |
| iv, iv_len, ad, ad_len, |
| tag, tag_len, input, output ); |
| |
| if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED ) |
| ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_GCM_C */ |
| #if defined(MBEDTLS_CCM_C) |
| if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) |
| { |
| int ret; |
| |
| *olen = ilen; |
| ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen, |
| iv, iv_len, ad, ad_len, |
| input, output, tag, tag_len ); |
| |
| if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED ) |
| ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_CCM_C */ |
| #if defined(MBEDTLS_CHACHAPOLY_C) |
| if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) |
| { |
| int ret; |
| |
| /* ChachaPoly has fixed length nonce and MAC (tag) */ |
| if ( ( iv_len != ctx->cipher_info->iv_size ) || |
| ( tag_len != 16U ) ) |
| { |
| return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); |
| } |
| |
| *olen = ilen; |
| ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen, |
| iv, ad, ad_len, tag, input, output ); |
| |
| if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED ) |
| ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; |
| |
| return( ret ); |
| } |
| #endif /* MBEDTLS_CHACHAPOLY_C */ |
| |
| return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); |
| } |
| #endif /* MBEDTLS_CIPHER_MODE_AEAD */ |
| |
| #endif /* MBEDTLS_CIPHER_C */ |