/*
* aes_gcm_ossl.c
*
* AES Galois Counter Mode
*
* John A. Foley
* Cisco Systems, Inc.
*
*/
/*
*
* 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_ossl.h"
#include "aes_gcm_ossl.h"
#include "alloc.h"
#include "err.h" /* for srtp_debug */
#include "crypto_types.h"
#include "cipher_types.h"
srtp_debug_module_t srtp_mod_aes_gcm = {
0, /* debugging is off by default */
"aes gcm" /* printable module name */
};
/*
* For now we only support 8 and 16 octet tags. The spec allows for
* optional 12 byte tag, which may be supported in the future.
*/
#define GCM_AUTH_TAG_LEN 16
#define GCM_AUTH_TAG_LEN_8 8
/*
* This function allocates a new instance of this crypto engine.
* The key_len parameter should be one of 28 or 44 for
* AES-128-GCM or AES-256-GCM respectively. Note that the
* key length includes the 14 byte salt value that is used when
* initializing the KDF.
*/
static srtp_err_status_t srtp_aes_gcm_openssl_alloc(srtp_cipher_t **c,
int key_len,
int tlen)
{
srtp_aes_gcm_ctx_t *gcm;
debug_print(srtp_mod_aes_gcm, "allocating cipher with key length %d",
key_len);
debug_print(srtp_mod_aes_gcm, "allocating cipher with tag length %d", tlen);
/*
* Verify the key_len is valid for one of: AES-128/256
*/
if (key_len != SRTP_AES_GCM_128_KEY_LEN_WSALT &&
key_len != SRTP_AES_GCM_256_KEY_LEN_WSALT) {
return (srtp_err_status_bad_param);
}
if (tlen != GCM_AUTH_TAG_LEN && tlen != GCM_AUTH_TAG_LEN_8) {
return (srtp_err_status_bad_param);
}
/* allocate memory a cipher of type aes_gcm */
*c = (srtp_cipher_t *)srtp_crypto_alloc(sizeof(srtp_cipher_t));
if (*c == NULL) {
return (srtp_err_status_alloc_fail);
}
gcm = (srtp_aes_gcm_ctx_t *)srtp_crypto_alloc(sizeof(srtp_aes_gcm_ctx_t));
if (gcm == NULL) {
srtp_crypto_free(*c);
*c = NULL;
return (srtp_err_status_alloc_fail);
}
gcm->ctx = EVP_CIPHER_CTX_new();
if (gcm->ctx == NULL) {
srtp_crypto_free(gcm);
srtp_crypto_free(*c);
*c = NULL;
return srtp_err_status_alloc_fail;
}
/* set pointers */
(*c)->state = gcm;
/* setup cipher attributes */
switch (key_len) {
case SRTP_AES_GCM_128_KEY_LEN_WSALT:
(*c)->type = &srtp_aes_gcm_128_openssl;
(*c)->algorithm = SRTP_AES_GCM_128;
gcm->key_size = SRTP_AES_128_KEY_LEN;
gcm->tag_len = tlen;
break;
case SRTP_AES_GCM_256_KEY_LEN_WSALT:
(*c)->type = &srtp_aes_gcm_256_openssl;
(*c)->algorithm = SRTP_AES_GCM_256;
gcm->key_size = SRTP_AES_256_KEY_LEN;
gcm->tag_len = tlen;
break;
}
/* set key size */
(*c)->key_len = key_len;
return (srtp_err_status_ok);
}
/*
* This function deallocates a GCM session
*/
static srtp_err_status_t srtp_aes_gcm_openssl_dealloc(srtp_cipher_t *c)
{
srtp_aes_gcm_ctx_t *ctx;
ctx = (srtp_aes_gcm_ctx_t *)c->state;
if (ctx) {
EVP_CIPHER_CTX_free(ctx->ctx);
/* zeroize the key material */
octet_string_set_to_zero(ctx, sizeof(srtp_aes_gcm_ctx_t));
srtp_crypto_free(ctx);
}
/* free memory */
srtp_crypto_free(c);
return (srtp_err_status_ok);
}
/*
* aes_gcm_openssl_context_init(...) initializes the aes_gcm_context
* using the value in key[].
*
* the key is the secret key
*/
static srtp_err_status_t srtp_aes_gcm_openssl_context_init(void *cv,
const uint8_t *key)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
const EVP_CIPHER *evp;
c->dir = srtp_direction_any;
debug_print(srtp_mod_aes_gcm, "key: %s",
srtp_octet_string_hex_string(key, c->key_size));
switch (c->key_size) {
case SRTP_AES_256_KEY_LEN:
evp = EVP_aes_256_gcm();
break;
case SRTP_AES_128_KEY_LEN:
evp = EVP_aes_128_gcm();
break;
default:
return (srtp_err_status_bad_param);
break;
}
if (!EVP_CipherInit_ex(c->ctx, evp, NULL, key, NULL, 0)) {
return (srtp_err_status_init_fail);
}
return (srtp_err_status_ok);
}
/*
* aes_gcm_openssl_set_iv(c, iv) sets the counter value to the exor of iv with
* the offset
*/
static srtp_err_status_t srtp_aes_gcm_openssl_set_iv(
void *cv,
uint8_t *iv,
srtp_cipher_direction_t direction)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
if (direction != srtp_direction_encrypt &&
direction != srtp_direction_decrypt) {
return (srtp_err_status_bad_param);
}
c->dir = direction;
debug_print(srtp_mod_aes_gcm, "setting iv: %s",
v128_hex_string((v128_t *)iv));
if (!EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_IVLEN, 12, 0)) {
return (srtp_err_status_init_fail);
}
if (!EVP_CipherInit_ex(c->ctx, NULL, NULL, NULL, iv,
(c->dir == srtp_direction_encrypt ? 1 : 0))) {
return (srtp_err_status_init_fail);
}
return (srtp_err_status_ok);
}
/*
* This function processes the AAD
*
* Parameters:
* c Crypto context
* aad Additional data to process for AEAD cipher suites
* aad_len length of aad buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_set_aad(void *cv,
const uint8_t *aad,
uint32_t aad_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
int rv;
/*
* Set dummy tag, OpenSSL requires the Tag to be set before
* processing AAD
*/
/*
* OpenSSL never write to address pointed by the last parameter of
* EVP_CIPHER_CTX_ctrl while EVP_CTRL_GCM_SET_TAG (in reality,
* OpenSSL copy its content to the context), so we can make
* aad read-only in this function and all its wrappers.
*/
unsigned char dummy_tag[GCM_AUTH_TAG_LEN];
memset(dummy_tag, 0x0, GCM_AUTH_TAG_LEN);
EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len, &dummy_tag);
rv = EVP_Cipher(c->ctx, NULL, aad, aad_len);
if (rv != aad_len) {
return (srtp_err_status_algo_fail);
} else {
return (srtp_err_status_ok);
}
}
/*
* This function encrypts a buffer using AES GCM mode
*
* Parameters:
* c Crypto context
* buf data to encrypt
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_encrypt(void *cv,
unsigned char *buf,
unsigned int *enc_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
if (c->dir != srtp_direction_encrypt && c->dir != srtp_direction_decrypt) {
return (srtp_err_status_bad_param);
}
/*
* Encrypt the data
*/
EVP_Cipher(c->ctx, buf, buf, *enc_len);
return (srtp_err_status_ok);
}
/*
* This function calculates and returns the GCM tag for a given context.
* This should be called after encrypting the data. The *len value
* is increased by the tag size. The caller must ensure that *buf has
* enough room to accept the appended tag.
*
* Parameters:
* c Crypto context
* buf data to encrypt
* len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_get_tag(void *cv,
uint8_t *buf,
uint32_t *len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
/*
* Calculate the tag
*/
EVP_Cipher(c->ctx, NULL, NULL, 0);
/*
* Retreive the tag
*/
EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_GET_TAG, c->tag_len, buf);
/*
* Increase encryption length by desired tag size
*/
*len = c->tag_len;
return (srtp_err_status_ok);
}
/*
* This function decrypts a buffer using AES GCM mode
*
* Parameters:
* c Crypto context
* buf data to encrypt
* enc_len length of encrypt buffer
*/
static srtp_err_status_t srtp_aes_gcm_openssl_decrypt(void *cv,
unsigned char *buf,
unsigned int *enc_len)
{
srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv;
if (c->dir != srtp_direction_encrypt && c->dir != srtp_direction_decrypt) {
return (srtp_err_status_bad_param);
}
/*
* Set the tag before decrypting
*/
EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len,
buf + (*enc_len - c->tag_len));
EVP_Cipher(c->ctx, buf, buf, *enc_len - c->tag_len);
/*
* Check the tag
*/
if (EVP_Cipher(c->ctx, NULL, NULL, 0)) {
return (srtp_err_status_auth_fail);
}
/*
* Reduce the buffer size by the tag length since the tag
* is not part of the original payload
*/
*enc_len -= c->tag_len;
return (srtp_err_status_ok);
}
/*
* Name of this crypto engine
*/
static const char srtp_aes_gcm_128_openssl_description[] =
"AES-128 GCM using openssl";
static const char srtp_aes_gcm_256_openssl_description[] =
"AES-256 GCM using openssl";
/*
* KAT values for AES self-test. These
* values we're derived from independent test code
* using OpenSSL.
*/
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_0_key[SRTP_AES_GCM_128_KEY_LEN_WSALT] = {
0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08,
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c,
};
/* clang-format on */
/* clang-format off */
static uint8_t srtp_aes_gcm_test_case_0_iv[12] = {
0xca, 0xfe, 0xba, 0xbe, 0xfa, 0xce, 0xdb, 0xad,
0xde, 0xca, 0xf8, 0x88
};
/* clang-format on */
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_0_plaintext[60] = {
0xd9, 0x31, 0x32, 0x25, 0xf8, 0x84, 0x06, 0xe5,
0xa5, 0x59, 0x09, 0xc5, 0xaf, 0xf5, 0x26, 0x9a,
0x86, 0xa7, 0xa9, 0x53, 0x15, 0x34, 0xf7, 0xda,
0x2e, 0x4c, 0x30, 0x3d, 0x8a, 0x31, 0x8a, 0x72,
0x1c, 0x3c, 0x0c, 0x95, 0x95, 0x68, 0x09, 0x53,
0x2f, 0xcf, 0x0e, 0x24, 0x49, 0xa6, 0xb5, 0x25,
0xb1, 0x6a, 0xed, 0xf5, 0xaa, 0x0d, 0xe6, 0x57,
0xba, 0x63, 0x7b, 0x39
};
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_0_aad[20] = {
0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
0xab, 0xad, 0xda, 0xd2
};
/* clang-format on */
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_0_ciphertext[76] = {
0x42, 0x83, 0x1e, 0xc2, 0x21, 0x77, 0x74, 0x24,
0x4b, 0x72, 0x21, 0xb7, 0x84, 0xd0, 0xd4, 0x9c,
0xe3, 0xaa, 0x21, 0x2f, 0x2c, 0x02, 0xa4, 0xe0,
0x35, 0xc1, 0x7e, 0x23, 0x29, 0xac, 0xa1, 0x2e,
0x21, 0xd5, 0x14, 0xb2, 0x54, 0x66, 0x93, 0x1c,
0x7d, 0x8f, 0x6a, 0x5a, 0xac, 0x84, 0xaa, 0x05,
0x1b, 0xa3, 0x0b, 0x39, 0x6a, 0x0a, 0xac, 0x97,
0x3d, 0x58, 0xe0, 0x91,
/* the last 16 bytes are the tag */
0x5b, 0xc9, 0x4f, 0xbc, 0x32, 0x21, 0xa5, 0xdb,
0x94, 0xfa, 0xe9, 0x5a, 0xe7, 0x12, 0x1a, 0x47,
};
/* clang-format on */
static const srtp_cipher_test_case_t srtp_aes_gcm_test_case_0a = {
SRTP_AES_GCM_128_KEY_LEN_WSALT, /* octets in key */
srtp_aes_gcm_test_case_0_key, /* key */
srtp_aes_gcm_test_case_0_iv, /* packet index */
60, /* octets in plaintext */
srtp_aes_gcm_test_case_0_plaintext, /* plaintext */
68, /* octets in ciphertext */
srtp_aes_gcm_test_case_0_ciphertext, /* ciphertext + tag */
20, /* octets in AAD */
srtp_aes_gcm_test_case_0_aad, /* AAD */
GCM_AUTH_TAG_LEN_8, /* */
NULL /* pointer to next testcase */
};
static const srtp_cipher_test_case_t srtp_aes_gcm_test_case_0 = {
SRTP_AES_GCM_128_KEY_LEN_WSALT, /* octets in key */
srtp_aes_gcm_test_case_0_key, /* key */
srtp_aes_gcm_test_case_0_iv, /* packet index */
60, /* octets in plaintext */
srtp_aes_gcm_test_case_0_plaintext, /* plaintext */
76, /* octets in ciphertext */
srtp_aes_gcm_test_case_0_ciphertext, /* ciphertext + tag */
20, /* octets in AAD */
srtp_aes_gcm_test_case_0_aad, /* AAD */
GCM_AUTH_TAG_LEN, /* */
&srtp_aes_gcm_test_case_0a /* pointer to next testcase */
};
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_1_key[SRTP_AES_GCM_256_KEY_LEN_WSALT] = {
0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
0xa5, 0x59, 0x09, 0xc5, 0x54, 0x66, 0x93, 0x1c,
0xaf, 0xf5, 0x26, 0x9a, 0x21, 0xd5, 0x14, 0xb2,
0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08,
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c,
};
/* clang-format on */
/* clang-format off */
static uint8_t srtp_aes_gcm_test_case_1_iv[12] = {
0xca, 0xfe, 0xba, 0xbe, 0xfa, 0xce, 0xdb, 0xad,
0xde, 0xca, 0xf8, 0x88
};
/* clang-format on */
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_1_plaintext[60] = {
0xd9, 0x31, 0x32, 0x25, 0xf8, 0x84, 0x06, 0xe5,
0xa5, 0x59, 0x09, 0xc5, 0xaf, 0xf5, 0x26, 0x9a,
0x86, 0xa7, 0xa9, 0x53, 0x15, 0x34, 0xf7, 0xda,
0x2e, 0x4c, 0x30, 0x3d, 0x8a, 0x31, 0x8a, 0x72,
0x1c, 0x3c, 0x0c, 0x95, 0x95, 0x68, 0x09, 0x53,
0x2f, 0xcf, 0x0e, 0x24, 0x49, 0xa6, 0xb5, 0x25,
0xb1, 0x6a, 0xed, 0xf5, 0xaa, 0x0d, 0xe6, 0x57,
0xba, 0x63, 0x7b, 0x39
};
/* clang-format on */
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_1_aad[20] = {
0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
0xab, 0xad, 0xda, 0xd2
};
/* clang-format on */
/* clang-format off */
static const uint8_t srtp_aes_gcm_test_case_1_ciphertext[76] = {
0x0b, 0x11, 0xcf, 0xaf, 0x68, 0x4d, 0xae, 0x46,
0xc7, 0x90, 0xb8, 0x8e, 0xb7, 0x6a, 0x76, 0x2a,
0x94, 0x82, 0xca, 0xab, 0x3e, 0x39, 0xd7, 0x86,
0x1b, 0xc7, 0x93, 0xed, 0x75, 0x7f, 0x23, 0x5a,
0xda, 0xfd, 0xd3, 0xe2, 0x0e, 0x80, 0x87, 0xa9,
0x6d, 0xd7, 0xe2, 0x6a, 0x7d, 0x5f, 0xb4, 0x80,
0xef, 0xef, 0xc5, 0x29, 0x12, 0xd1, 0xaa, 0x10,
0x09, 0xc9, 0x86, 0xc1,
/* the last 16 bytes are the tag */
0x45, 0xbc, 0x03, 0xe6, 0xe1, 0xac, 0x0a, 0x9f,
0x81, 0xcb, 0x8e, 0x5b, 0x46, 0x65, 0x63, 0x1d,
};
/* clang-format on */
static const srtp_cipher_test_case_t srtp_aes_gcm_test_case_1a = {
SRTP_AES_GCM_256_KEY_LEN_WSALT, /* octets in key */
srtp_aes_gcm_test_case_1_key, /* key */
srtp_aes_gcm_test_case_1_iv, /* packet index */
60, /* octets in plaintext */
srtp_aes_gcm_test_case_1_plaintext, /* plaintext */
68, /* octets in ciphertext */
srtp_aes_gcm_test_case_1_ciphertext, /* ciphertext + tag */
20, /* octets in AAD */
srtp_aes_gcm_test_case_1_aad, /* AAD */
GCM_AUTH_TAG_LEN_8, /* */
NULL /* pointer to next testcase */
};
static const srtp_cipher_test_case_t srtp_aes_gcm_test_case_1 = {
SRTP_AES_GCM_256_KEY_LEN_WSALT, /* octets in key */
srtp_aes_gcm_test_case_1_key, /* key */
srtp_aes_gcm_test_case_1_iv, /* packet index */
60, /* octets in plaintext */
srtp_aes_gcm_test_case_1_plaintext, /* plaintext */
76, /* octets in ciphertext */
srtp_aes_gcm_test_case_1_ciphertext, /* ciphertext + tag */
20, /* octets in AAD */
srtp_aes_gcm_test_case_1_aad, /* AAD */
GCM_AUTH_TAG_LEN, /* */
&srtp_aes_gcm_test_case_1a /* pointer to next testcase */
};
/*
* This is the vector function table for this crypto engine.
*/
const srtp_cipher_type_t srtp_aes_gcm_128_openssl = {
srtp_aes_gcm_openssl_alloc,
srtp_aes_gcm_openssl_dealloc,
srtp_aes_gcm_openssl_context_init,
srtp_aes_gcm_openssl_set_aad,
srtp_aes_gcm_openssl_encrypt,
srtp_aes_gcm_openssl_decrypt,
srtp_aes_gcm_openssl_set_iv,
srtp_aes_gcm_openssl_get_tag,
srtp_aes_gcm_128_openssl_description,
&srtp_aes_gcm_test_case_0,
SRTP_AES_GCM_128
};
/*
* This is the vector function table for this crypto engine.
*/
const srtp_cipher_type_t srtp_aes_gcm_256_openssl = {
srtp_aes_gcm_openssl_alloc,
srtp_aes_gcm_openssl_dealloc,
srtp_aes_gcm_openssl_context_init,
srtp_aes_gcm_openssl_set_aad,
srtp_aes_gcm_openssl_encrypt,
srtp_aes_gcm_openssl_decrypt,
srtp_aes_gcm_openssl_set_iv,
srtp_aes_gcm_openssl_get_tag,
srtp_aes_gcm_256_openssl_description,
&srtp_aes_gcm_test_case_1,
SRTP_AES_GCM_256
};