/*
* 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, 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_ossl.h"
#include "crypto_types.h"
#include "alloc.h"
#include "crypto_types.h"
debug_module_t mod_aes_icm = {
0, /* debugging is off by default */
"aes icm ossl" /* printable module name */
};
extern cipher_test_case_t aes_icm_test_case_0;
extern cipher_type_t aes_icm;
#ifndef SRTP_NO_AES192
extern cipher_type_t aes_icm_192;
#endif
extern cipher_type_t aes_icm_256;
/*
* 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.
*/
err_status_t aes_icm_openssl_alloc (cipher_t **c, int key_len, int tlen)
{
aes_icm_ctx_t *icm;
int tmp;
uint8_t *allptr;
debug_print(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 != AES_128_KEYSIZE_WSALT &&
#ifndef SRTP_NO_AES192
key_len != AES_192_KEYSIZE_WSALT &&
#endif
key_len != AES_256_KEYSIZE_WSALT) {
return err_status_bad_param;
}
/* allocate memory a cipher of type aes_icm */
tmp = sizeof(cipher_t) + sizeof(aes_icm_ctx_t);
allptr = (uint8_t*)crypto_alloc(tmp);
if (allptr == NULL) {
return err_status_alloc_fail;
}
/* set pointers */
*c = (cipher_t*)allptr;
(*c)->state = allptr + sizeof(cipher_t);
icm = (aes_icm_ctx_t*)(*c)->state;
icm->ctx = EVP_CIPHER_CTX_new();
if (icm->ctx == NULL) {
crypto_free(*c);
*c = NULL;
return err_status_alloc_fail;
}
/* increment ref_count */
switch (key_len) {
case AES_128_KEYSIZE_WSALT:
(*c)->algorithm = AES_128_ICM;
(*c)->type = &aes_icm;
aes_icm.ref_count++;
((aes_icm_ctx_t*)(*c)->state)->key_size = AES_128_KEYSIZE;
break;
#ifndef SRTP_NO_AES192
case AES_192_KEYSIZE_WSALT:
(*c)->algorithm = AES_192_ICM;
(*c)->type = &aes_icm_192;
aes_icm_192.ref_count++;
((aes_icm_ctx_t*)(*c)->state)->key_size = AES_192_KEYSIZE;
break;
#endif
case AES_256_KEYSIZE_WSALT:
(*c)->algorithm = AES_256_ICM;
(*c)->type = &aes_icm_256;
aes_icm_256.ref_count++;
((aes_icm_ctx_t*)(*c)->state)->key_size = AES_256_KEYSIZE;
break;
}
/* set key size */
(*c)->key_len = key_len;
return err_status_ok;
}
/*
* This function deallocates an instance of this engine
*/
err_status_t aes_icm_openssl_dealloc (cipher_t *c)
{
aes_icm_ctx_t *ctx;
if (c == NULL) {
return err_status_bad_param;
}
/*
* Free the EVP context
*/
ctx = (aes_icm_ctx_t*)c->state;
if (ctx != NULL) {
EVP_CIPHER_CTX_free(ctx->ctx);
/* decrement ref_count for the appropriate engine */
switch (ctx->key_size) {
case AES_256_KEYSIZE:
aes_icm_256.ref_count--;
break;
#ifndef SRTP_NO_AES192
case AES_192_KEYSIZE:
aes_icm_192.ref_count--;
break;
#endif
case AES_128_KEYSIZE:
aes_icm.ref_count--;
break;
default:
return err_status_dealloc_fail;
break;
}
}
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)c,
sizeof(cipher_t) + sizeof(aes_icm_ctx_t));
/* free memory */
crypto_free(c);
return 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
*/
err_status_t aes_icm_openssl_context_init (aes_icm_ctx_t *c, const uint8_t *key, int len)
{
/*
* set counter and initial values to 'offset' value, being careful not to
* go past the end of the key buffer
*/
if (c->key_size + SALT_SIZE != len)
return err_status_bad_param;
v128_set_to_zero(&c->counter);
v128_set_to_zero(&c->offset);
memcpy(&c->counter, key + c->key_size, SALT_SIZE);
memcpy(&c->offset, key + c->key_size, SALT_SIZE);
/* force last two octets of the offset to zero (for srtp compatibility) */
c->offset.v8[SALT_SIZE] = c->offset.v8[SALT_SIZE + 1] = 0;
c->counter.v8[SALT_SIZE] = c->counter.v8[SALT_SIZE + 1] = 0;
/* copy key to be used later when CiscoSSL crypto context is created */
v128_copy_octet_string((v128_t*)&c->key, key);
/* if the key is greater than 16 bytes, copy the second
* half. Note, we treat AES-192 and AES-256 the same here
* for simplicity. The storage location receiving the
* key is statically allocated to handle a full 32 byte key
* regardless of the cipher in use.
*/
if (c->key_size == AES_256_KEYSIZE
#ifndef SRTP_NO_AES192
|| c->key_size == AES_192_KEYSIZE
#endif
) {
debug_print(mod_aes_icm, "Copying last 16 bytes of key: %s",
v128_hex_string((v128_t*)(key + AES_128_KEYSIZE)));
v128_copy_octet_string(((v128_t*)(&c->key.v8)) + 1, key + AES_128_KEYSIZE);
}
debug_print(mod_aes_icm, "key: %s", v128_hex_string((v128_t*)&c->key));
debug_print(mod_aes_icm, "offset: %s", v128_hex_string(&c->offset));
EVP_CIPHER_CTX_cleanup(c->ctx);
return err_status_ok;
}
/*
* aes_icm_set_iv(c, iv) sets the counter value to the exor of iv with
* the offset
*/
err_status_t aes_icm_openssl_set_iv (aes_icm_ctx_t *c, void *iv, int dir)
{
const EVP_CIPHER *evp;
v128_t nonce;
/* set nonce (for alignment) */
v128_copy_octet_string(&nonce, iv);
debug_print(mod_aes_icm, "setting iv: %s", v128_hex_string(&nonce));
v128_xor(&c->counter, &c->offset, &nonce);
debug_print(mod_aes_icm, "set_counter: %s", v128_hex_string(&c->counter));
switch (c->key_size) {
case AES_256_KEYSIZE:
evp = EVP_aes_256_ctr();
break;
#ifndef SRTP_NO_AES192
case AES_192_KEYSIZE:
evp = EVP_aes_192_ctr();
break;
#endif
case AES_128_KEYSIZE:
evp = EVP_aes_128_ctr();
break;
default:
return err_status_bad_param;
break;
}
if (!EVP_EncryptInit_ex(c->ctx, evp,
NULL, c->key.v8, c->counter.v8)) {
return err_status_fail;
} else {
return 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
*/
err_status_t aes_icm_openssl_encrypt (aes_icm_ctx_t *c, unsigned char *buf, unsigned int *enc_len)
{
int len = 0;
debug_print(mod_aes_icm, "rs0: %s", v128_hex_string(&c->counter));
if (!EVP_EncryptUpdate(c->ctx, buf, &len, buf, *enc_len)) {
return err_status_cipher_fail;
}
*enc_len = len;
if (!EVP_EncryptFinal_ex(c->ctx, buf, &len)) {
return err_status_cipher_fail;
}
*enc_len += len;
return err_status_ok;
}
uint16_t aes_icm_bytes_encrypted(aes_icm_ctx_t *c)
{
return htons(c->counter.v16[7]);
}
/*
* Name of this crypto engine
*/
char aes_icm_openssl_description[] = "AES-128 counter mode using openssl";
#ifndef SRTP_NO_AES192
char aes_icm_192_openssl_description[] = "AES-192 counter mode using openssl";
#endif
char aes_icm_256_openssl_description[] = "AES-256 counter mode using openssl";
/*
* KAT values for AES self-test. These
* values came from the legacy libsrtp code.
*/
uint8_t aes_icm_test_case_0_key[AES_128_KEYSIZE_WSALT] = {
0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd
};
uint8_t aes_icm_test_case_0_nonce[16] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
uint8_t aes_icm_test_case_0_plaintext[32] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
uint8_t aes_icm_test_case_0_ciphertext[32] = {
0xe0, 0x3e, 0xad, 0x09, 0x35, 0xc9, 0x5e, 0x80,
0xe1, 0x66, 0xb1, 0x6d, 0xd9, 0x2b, 0x4e, 0xb4,
0xd2, 0x35, 0x13, 0x16, 0x2b, 0x02, 0xd0, 0xf7,
0x2a, 0x43, 0xa2, 0xfe, 0x4a, 0x5f, 0x97, 0xab
};
cipher_test_case_t aes_icm_test_case_0 = {
AES_128_KEYSIZE_WSALT, /* octets in key */
aes_icm_test_case_0_key, /* key */
aes_icm_test_case_0_nonce, /* packet index */
32, /* octets in plaintext */
aes_icm_test_case_0_plaintext, /* plaintext */
32, /* octets in ciphertext */
aes_icm_test_case_0_ciphertext, /* ciphertext */
0,
NULL,
0,
NULL /* pointer to next testcase */
};
#ifndef SRTP_NO_AES192
/*
* KAT values for AES-192-CTR self-test. These
* values came from section 7 of RFC 6188.
*/
uint8_t aes_icm_192_test_case_1_key[AES_192_KEYSIZE_WSALT] = {
0xea, 0xb2, 0x34, 0x76, 0x4e, 0x51, 0x7b, 0x2d,
0x3d, 0x16, 0x0d, 0x58, 0x7d, 0x8c, 0x86, 0x21,
0x97, 0x40, 0xf6, 0x5f, 0x99, 0xb6, 0xbc, 0xf7,
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd
};
uint8_t aes_icm_192_test_case_1_nonce[16] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
uint8_t aes_icm_192_test_case_1_plaintext[32] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
uint8_t aes_icm_192_test_case_1_ciphertext[32] = {
0x35, 0x09, 0x6c, 0xba, 0x46, 0x10, 0x02, 0x8d,
0xc1, 0xb5, 0x75, 0x03, 0x80, 0x4c, 0xe3, 0x7c,
0x5d, 0xe9, 0x86, 0x29, 0x1d, 0xcc, 0xe1, 0x61,
0xd5, 0x16, 0x5e, 0xc4, 0x56, 0x8f, 0x5c, 0x9a
};
cipher_test_case_t aes_icm_192_test_case_1 = {
AES_192_KEYSIZE_WSALT, /* octets in key */
aes_icm_192_test_case_1_key, /* key */
aes_icm_192_test_case_1_nonce, /* packet index */
32, /* octets in plaintext */
aes_icm_192_test_case_1_plaintext, /* plaintext */
32, /* octets in ciphertext */
aes_icm_192_test_case_1_ciphertext, /* ciphertext */
0,
NULL,
0,
NULL /* pointer to next testcase */
};
#endif
/*
* KAT values for AES-256-CTR self-test. These
* values came from section 7 of RFC 6188.
*/
uint8_t aes_icm_256_test_case_2_key[AES_256_KEYSIZE_WSALT] = {
0x57, 0xf8, 0x2f, 0xe3, 0x61, 0x3f, 0xd1, 0x70,
0xa8, 0x5e, 0xc9, 0x3c, 0x40, 0xb1, 0xf0, 0x92,
0x2e, 0xc4, 0xcb, 0x0d, 0xc0, 0x25, 0xb5, 0x82,
0x72, 0x14, 0x7c, 0xc4, 0x38, 0x94, 0x4a, 0x98,
0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd
};
uint8_t aes_icm_256_test_case_2_nonce[16] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
uint8_t aes_icm_256_test_case_2_plaintext[32] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
};
uint8_t aes_icm_256_test_case_2_ciphertext[32] = {
0x92, 0xbd, 0xd2, 0x8a, 0x93, 0xc3, 0xf5, 0x25,
0x11, 0xc6, 0x77, 0xd0, 0x8b, 0x55, 0x15, 0xa4,
0x9d, 0xa7, 0x1b, 0x23, 0x78, 0xa8, 0x54, 0xf6,
0x70, 0x50, 0x75, 0x6d, 0xed, 0x16, 0x5b, 0xac
};
cipher_test_case_t aes_icm_256_test_case_2 = {
AES_256_KEYSIZE_WSALT, /* octets in key */
aes_icm_256_test_case_2_key, /* key */
aes_icm_256_test_case_2_nonce, /* packet index */
32, /* octets in plaintext */
aes_icm_256_test_case_2_plaintext, /* plaintext */
32, /* octets in ciphertext */
aes_icm_256_test_case_2_ciphertext, /* ciphertext */
0,
NULL,
0,
NULL /* pointer to next testcase */
};
/*
* This is the function table for this crypto engine.
* note: the encrypt function is identical to the decrypt function
*/
cipher_type_t aes_icm = {
(cipher_alloc_func_t) aes_icm_openssl_alloc,
(cipher_dealloc_func_t) aes_icm_openssl_dealloc,
(cipher_init_func_t) aes_icm_openssl_context_init,
(cipher_set_aad_func_t) 0,
(cipher_encrypt_func_t) aes_icm_openssl_encrypt,
(cipher_decrypt_func_t) aes_icm_openssl_encrypt,
(cipher_set_iv_func_t) aes_icm_openssl_set_iv,
(cipher_get_tag_func_t) 0,
(char*) aes_icm_openssl_description,
(int) 0, /* instance count */
(cipher_test_case_t*) &aes_icm_test_case_0,
(debug_module_t*) &mod_aes_icm,
(cipher_type_id_t) AES_ICM
};
#ifndef SRTP_NO_AES192
/*
* This is the function table for this crypto engine.
* note: the encrypt function is identical to the decrypt function
*/
cipher_type_t aes_icm_192 = {
(cipher_alloc_func_t) aes_icm_openssl_alloc,
(cipher_dealloc_func_t) aes_icm_openssl_dealloc,
(cipher_init_func_t) aes_icm_openssl_context_init,
(cipher_set_aad_func_t) 0,
(cipher_encrypt_func_t) aes_icm_openssl_encrypt,
(cipher_decrypt_func_t) aes_icm_openssl_encrypt,
(cipher_set_iv_func_t) aes_icm_openssl_set_iv,
(cipher_get_tag_func_t) 0,
(char*) aes_icm_192_openssl_description,
(int) 0, /* instance count */
(cipher_test_case_t*) &aes_icm_192_test_case_1,
(debug_module_t*) &mod_aes_icm,
(cipher_type_id_t) AES_192_ICM
};
#endif
/*
* This is the function table for this crypto engine.
* note: the encrypt function is identical to the decrypt function
*/
cipher_type_t aes_icm_256 = {
(cipher_alloc_func_t) aes_icm_openssl_alloc,
(cipher_dealloc_func_t) aes_icm_openssl_dealloc,
(cipher_init_func_t) aes_icm_openssl_context_init,
(cipher_set_aad_func_t) 0,
(cipher_encrypt_func_t) aes_icm_openssl_encrypt,
(cipher_decrypt_func_t) aes_icm_openssl_encrypt,
(cipher_set_iv_func_t) aes_icm_openssl_set_iv,
(cipher_get_tag_func_t) 0,
(char*) aes_icm_256_openssl_description,
(int) 0, /* instance count */
(cipher_test_case_t*) &aes_icm_256_test_case_2,
(debug_module_t*) &mod_aes_icm,
(cipher_type_id_t) AES_256_ICM
};