Refactor code structure for improved readability and maintainability
This commit is contained in:
391
libsrtp/crypto/cipher/aes_icm_ossl.c
Normal file
391
libsrtp/crypto/cipher/aes_icm_ossl.c
Normal file
@@ -0,0 +1,391 @@
|
||||
/*
|
||||
* 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 = {
|
||||
false, /* 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,
|
||||
size_t key_len,
|
||||
size_t tlen)
|
||||
{
|
||||
srtp_aes_icm_ctx_t *icm;
|
||||
(void)tlen;
|
||||
|
||||
debug_print(srtp_mod_aes_icm, "allocating cipher with key length %zu",
|
||||
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,
|
||||
const uint8_t *src,
|
||||
size_t src_len,
|
||||
uint8_t *dst,
|
||||
size_t *dst_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 (dst_len == NULL) {
|
||||
return srtp_err_status_bad_param;
|
||||
}
|
||||
|
||||
if (*dst_len < src_len) {
|
||||
return srtp_err_status_buffer_small;
|
||||
}
|
||||
|
||||
if (!EVP_EncryptUpdate(c->ctx, dst, &len, src, src_len)) {
|
||||
return srtp_err_status_cipher_fail;
|
||||
}
|
||||
*dst_len = len;
|
||||
|
||||
if (!EVP_EncryptFinal_ex(c->ctx, dst + len, &len)) {
|
||||
return srtp_err_status_cipher_fail;
|
||||
}
|
||||
*dst_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, /* */
|
||||
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, /* */
|
||||
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, /* */
|
||||
srtp_aes_icm_256_openssl_description, /* */
|
||||
&srtp_aes_icm_256_test_case_0, /* */
|
||||
SRTP_AES_ICM_256 /* */
|
||||
};
|
||||
Reference in New Issue
Block a user