| /* |
| * aes_icm_ossl.c |
| * |
| * AES Integer Counter Mode |
| * |
| * John A. Foley |
| * Cisco Systems, Inc. |
| * |
| * 2/24/2012: This module was modified to use CiscoSSL for AES counter |
| * mode. Eddy Lem contributed the code to allow this. |
| * |
| * 12/20/2012: Added support for AES-192 and AES-256. |
| */ |
| |
| /* |
| * |
| * Copyright (c) 2013-2017, Cisco Systems, Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * Neither the name of the Cisco Systems, Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif |
| |
| #include <openssl/evp.h> |
| #include "aes_icm_ext.h" |
| #include "crypto_types.h" |
| #include "err.h" /* for srtp_debug */ |
| #include "alloc.h" |
| #include "cipher_types.h" |
| #include "cipher_test_cases.h" |
| |
| srtp_debug_module_t srtp_mod_aes_icm = { |
| 0, /* debugging is off by default */ |
| "aes icm ossl" /* printable module name */ |
| }; |
| |
| /* |
| * integer counter mode works as follows: |
| * |
| * 16 bits |
| * <-----> |
| * +------+------+------+------+------+------+------+------+ |
| * | nonce | packet index | ctr |---+ |
| * +------+------+------+------+------+------+------+------+ | |
| * | |
| * +------+------+------+------+------+------+------+------+ v |
| * | salt |000000|->(+) |
| * +------+------+------+------+------+------+------+------+ | |
| * | |
| * +---------+ |
| * | encrypt | |
| * +---------+ |
| * | |
| * +------+------+------+------+------+------+------+------+ | |
| * | keystream block |<--+ |
| * +------+------+------+------+------+------+------+------+ |
| * |
| * All fields are big-endian |
| * |
| * ctr is the block counter, which increments from zero for |
| * each packet (16 bits wide) |
| * |
| * packet index is distinct for each packet (48 bits wide) |
| * |
| * nonce can be distinct across many uses of the same key, or |
| * can be a fixed value per key, or can be per-packet randomness |
| * (64 bits) |
| * |
| */ |
| |
| /* |
| * This function allocates a new instance of this crypto engine. |
| * The key_len parameter should be one of 30, 38, or 46 for |
| * AES-128, AES-192, and AES-256 respectively. Note, this key_len |
| * value is inflated, as it also accounts for the 112 bit salt |
| * value. The tlen argument is for the AEAD tag length, which |
| * isn't used in counter mode. |
| */ |
| static srtp_err_status_t srtp_aes_icm_openssl_alloc(srtp_cipher_t **c, |
| int key_len, |
| int tlen) |
| { |
| srtp_aes_icm_ctx_t *icm; |
| (void)tlen; |
| |
| debug_print(srtp_mod_aes_icm, "allocating cipher with key length %d", |
| key_len); |
| |
| /* |
| * Verify the key_len is valid for one of: AES-128/192/256 |
| */ |
| if (key_len != SRTP_AES_ICM_128_KEY_LEN_WSALT && |
| key_len != SRTP_AES_ICM_192_KEY_LEN_WSALT && |
| key_len != SRTP_AES_ICM_256_KEY_LEN_WSALT) { |
| return srtp_err_status_bad_param; |
| } |
| |
| /* allocate memory a cipher of type aes_icm */ |
| *c = (srtp_cipher_t *)srtp_crypto_alloc(sizeof(srtp_cipher_t)); |
| if (*c == NULL) { |
| return srtp_err_status_alloc_fail; |
| } |
| |
| icm = (srtp_aes_icm_ctx_t *)srtp_crypto_alloc(sizeof(srtp_aes_icm_ctx_t)); |
| if (icm == NULL) { |
| srtp_crypto_free(*c); |
| *c = NULL; |
| return srtp_err_status_alloc_fail; |
| } |
| |
| icm->ctx = EVP_CIPHER_CTX_new(); |
| if (icm->ctx == NULL) { |
| srtp_crypto_free(icm); |
| srtp_crypto_free(*c); |
| *c = NULL; |
| return srtp_err_status_alloc_fail; |
| } |
| |
| /* set pointers */ |
| (*c)->state = icm; |
| |
| /* setup cipher parameters */ |
| switch (key_len) { |
| case SRTP_AES_ICM_128_KEY_LEN_WSALT: |
| (*c)->algorithm = SRTP_AES_ICM_128; |
| (*c)->type = &srtp_aes_icm_128; |
| icm->key_size = SRTP_AES_128_KEY_LEN; |
| break; |
| case SRTP_AES_ICM_192_KEY_LEN_WSALT: |
| (*c)->algorithm = SRTP_AES_ICM_192; |
| (*c)->type = &srtp_aes_icm_192; |
| icm->key_size = SRTP_AES_192_KEY_LEN; |
| break; |
| case SRTP_AES_ICM_256_KEY_LEN_WSALT: |
| (*c)->algorithm = SRTP_AES_ICM_256; |
| (*c)->type = &srtp_aes_icm_256; |
| icm->key_size = SRTP_AES_256_KEY_LEN; |
| break; |
| } |
| |
| /* set key size */ |
| (*c)->key_len = key_len; |
| |
| return srtp_err_status_ok; |
| } |
| |
| /* |
| * This function deallocates an instance of this engine |
| */ |
| static srtp_err_status_t srtp_aes_icm_openssl_dealloc(srtp_cipher_t *c) |
| { |
| srtp_aes_icm_ctx_t *ctx; |
| |
| if (c == NULL) { |
| return srtp_err_status_bad_param; |
| } |
| |
| /* |
| * Free the EVP context |
| */ |
| ctx = (srtp_aes_icm_ctx_t *)c->state; |
| if (ctx != NULL) { |
| EVP_CIPHER_CTX_free(ctx->ctx); |
| /* zeroize the key material */ |
| octet_string_set_to_zero(ctx, sizeof(srtp_aes_icm_ctx_t)); |
| srtp_crypto_free(ctx); |
| } |
| |
| /* free memory */ |
| srtp_crypto_free(c); |
| |
| return srtp_err_status_ok; |
| } |
| |
| /* |
| * aes_icm_openssl_context_init(...) initializes the aes_icm_context |
| * using the value in key[]. |
| * |
| * the key is the secret key |
| * |
| * the salt is unpredictable (but not necessarily secret) data which |
| * randomizes the starting point in the keystream |
| */ |
| static srtp_err_status_t srtp_aes_icm_openssl_context_init(void *cv, |
| const uint8_t *key) |
| { |
| srtp_aes_icm_ctx_t *c = (srtp_aes_icm_ctx_t *)cv; |
| const EVP_CIPHER *evp; |
| |
| /* |
| * set counter and initial values to 'offset' value, being careful not to |
| * go past the end of the key buffer |
| */ |
| v128_set_to_zero(&c->counter); |
| v128_set_to_zero(&c->offset); |
| memcpy(&c->counter, key + c->key_size, SRTP_SALT_LEN); |
| memcpy(&c->offset, key + c->key_size, SRTP_SALT_LEN); |
| |
| /* force last two octets of the offset to zero (for srtp compatibility) */ |
| c->offset.v8[SRTP_SALT_LEN] = c->offset.v8[SRTP_SALT_LEN + 1] = 0; |
| c->counter.v8[SRTP_SALT_LEN] = c->counter.v8[SRTP_SALT_LEN + 1] = 0; |
| |
| debug_print(srtp_mod_aes_icm, "key: %s", |
| srtp_octet_string_hex_string(key, c->key_size)); |
| debug_print(srtp_mod_aes_icm, "offset: %s", v128_hex_string(&c->offset)); |
| |
| switch (c->key_size) { |
| case SRTP_AES_256_KEY_LEN: |
| evp = EVP_aes_256_ctr(); |
| break; |
| case SRTP_AES_192_KEY_LEN: |
| evp = EVP_aes_192_ctr(); |
| break; |
| case SRTP_AES_128_KEY_LEN: |
| evp = EVP_aes_128_ctr(); |
| break; |
| default: |
| return srtp_err_status_bad_param; |
| break; |
| } |
| |
| EVP_CIPHER_CTX_reset(c->ctx); |
| |
| if (!EVP_EncryptInit_ex(c->ctx, evp, NULL, key, NULL)) { |
| return srtp_err_status_fail; |
| } |
| |
| return srtp_err_status_ok; |
| } |
| |
| /* |
| * aes_icm_set_iv(c, iv) sets the counter value to the exor of iv with |
| * the offset |
| */ |
| static srtp_err_status_t srtp_aes_icm_openssl_set_iv( |
| void *cv, |
| uint8_t *iv, |
| srtp_cipher_direction_t dir) |
| { |
| srtp_aes_icm_ctx_t *c = (srtp_aes_icm_ctx_t *)cv; |
| v128_t nonce; |
| (void)dir; |
| |
| /* set nonce (for alignment) */ |
| v128_copy_octet_string(&nonce, iv); |
| |
| debug_print(srtp_mod_aes_icm, "setting iv: %s", v128_hex_string(&nonce)); |
| |
| v128_xor(&c->counter, &c->offset, &nonce); |
| |
| debug_print(srtp_mod_aes_icm, "set_counter: %s", |
| v128_hex_string(&c->counter)); |
| |
| if (!EVP_EncryptInit_ex(c->ctx, NULL, NULL, NULL, c->counter.v8)) { |
| return srtp_err_status_fail; |
| } |
| |
| return srtp_err_status_ok; |
| } |
| |
| /* |
| * This function encrypts a buffer using AES CTR mode |
| * |
| * Parameters: |
| * c Crypto context |
| * buf data to encrypt |
| * enc_len length of encrypt buffer |
| */ |
| static srtp_err_status_t srtp_aes_icm_openssl_encrypt(void *cv, |
| unsigned char *buf, |
| unsigned int *enc_len) |
| { |
| srtp_aes_icm_ctx_t *c = (srtp_aes_icm_ctx_t *)cv; |
| int len = 0; |
| |
| debug_print(srtp_mod_aes_icm, "rs0: %s", v128_hex_string(&c->counter)); |
| |
| if (!EVP_EncryptUpdate(c->ctx, buf, &len, buf, *enc_len)) { |
| return srtp_err_status_cipher_fail; |
| } |
| *enc_len = len; |
| |
| if (!EVP_EncryptFinal_ex(c->ctx, buf + len, &len)) { |
| return srtp_err_status_cipher_fail; |
| } |
| *enc_len += len; |
| |
| return srtp_err_status_ok; |
| } |
| |
| /* |
| * Name of this crypto engine |
| */ |
| static const char srtp_aes_icm_128_openssl_description[] = |
| "AES-128 counter mode using openssl"; |
| static const char srtp_aes_icm_192_openssl_description[] = |
| "AES-192 counter mode using openssl"; |
| static const char srtp_aes_icm_256_openssl_description[] = |
| "AES-256 counter mode using openssl"; |
| |
| /* |
| * This is the function table for this crypto engine. |
| * note: the encrypt function is identical to the decrypt function |
| */ |
| const srtp_cipher_type_t srtp_aes_icm_128 = { |
| srtp_aes_icm_openssl_alloc, /* */ |
| srtp_aes_icm_openssl_dealloc, /* */ |
| srtp_aes_icm_openssl_context_init, /* */ |
| 0, /* set_aad */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_set_iv, /* */ |
| 0, /* get_tag */ |
| srtp_aes_icm_128_openssl_description, /* */ |
| &srtp_aes_icm_128_test_case_0, /* */ |
| SRTP_AES_ICM_128 /* */ |
| }; |
| |
| /* |
| * This is the function table for this crypto engine. |
| * note: the encrypt function is identical to the decrypt function |
| */ |
| const srtp_cipher_type_t srtp_aes_icm_192 = { |
| srtp_aes_icm_openssl_alloc, /* */ |
| srtp_aes_icm_openssl_dealloc, /* */ |
| srtp_aes_icm_openssl_context_init, /* */ |
| 0, /* set_aad */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_set_iv, /* */ |
| 0, /* get_tag */ |
| srtp_aes_icm_192_openssl_description, /* */ |
| &srtp_aes_icm_192_test_case_0, /* */ |
| SRTP_AES_ICM_192 /* */ |
| }; |
| |
| /* |
| * This is the function table for this crypto engine. |
| * note: the encrypt function is identical to the decrypt function |
| */ |
| const srtp_cipher_type_t srtp_aes_icm_256 = { |
| srtp_aes_icm_openssl_alloc, /* */ |
| srtp_aes_icm_openssl_dealloc, /* */ |
| srtp_aes_icm_openssl_context_init, /* */ |
| 0, /* set_aad */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_encrypt, /* */ |
| srtp_aes_icm_openssl_set_iv, /* */ |
| 0, /* get_tag */ |
| srtp_aes_icm_256_openssl_description, /* */ |
| &srtp_aes_icm_256_test_case_0, /* */ |
| SRTP_AES_ICM_256 /* */ |
| }; |
