/*
* 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_128_GCM_KEYSIZE_WSALT &&
key_len != SRTP_AES_256_GCM_KEYSIZE_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);
}
memset(*c, 0x0, sizeof(srtp_cipher_t));
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);
}
memset(gcm, 0x0, sizeof(srtp_aes_gcm_ctx_t));
/* set pointers */
(*c)->state = gcm;
/* setup cipher attributes */
switch (key_len) {
case SRTP_AES_128_GCM_KEYSIZE_WSALT:
(*c)->type = &srtp_aes_gcm_128_openssl;
(*c)->algorithm = SRTP_AES_128_GCM;
gcm->key_size = SRTP_AES_128_KEYSIZE;
gcm->tag_len = tlen;
break;
case SRTP_AES_256_GCM_KEYSIZE_WSALT:
(*c)->type = &srtp_aes_gcm_256_openssl;
(*c)->algorithm = SRTP_AES_256_GCM;
gcm->key_size = SRTP_AES_256_KEYSIZE;
gcm->tag_len = tlen;
break;
}
/* set key size */
(*c)->key_len = key_len;
EVP_CIPHER_CTX_init(&gcm->ctx);
return (srtp_err_status_ok);
}
static srtp_err_status_t srtp_hmac_dealloc (srtp_auth_t *a)
{
HMAC_CTX *hmac_ctx;
hmac_ctx = (HMAC_CTX*)a->state;
#if OPENSSL_VERSION_NUMBER < 0x10100000L
HMAC_CTX_cleanup(hmac_ctx);
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)a,
sizeof(HMAC_CTX) + sizeof(srtp_auth_t));
#else
HMAC_CTX_free(hmac_ctx);
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)a, sizeof(srtp_auth_t));
#endif
/* free memory */
srtp_crypto_free(a);
return srtp_err_status_ok;
}
void
bitvector_dealloc(bitvector_t *v) {
if (v->word != NULL)
srtp_crypto_free(v->word);
v->word = NULL;
v->length = 0;
}
/*
* cipher_bits_per_second(c, l, t) computes (an estimate of) the
* number of bits that a cipher implementation can encrypt in a second
*
* c is a cipher (which MUST be allocated and initialized already), l
* is the length in octets of the test data to be encrypted, and t is
* the number of trials
*
* if an error is encountered, the value 0 is returned
*/
uint64_t srtp_cipher_bits_per_second (srtp_cipher_t *c, int octets_in_buffer, int num_trials)
{
int i;
v128_t nonce;
clock_t timer;
unsigned char *enc_buf;
unsigned int len = octets_in_buffer;
enc_buf = (unsigned char*)srtp_crypto_alloc(octets_in_buffer);
if (enc_buf == NULL) {
return 0; /* indicate bad parameters by returning null */
}
/* time repeated trials */
v128_set_to_zero(&nonce);
timer = clock();
for (i = 0; i < num_trials; i++, nonce.v32[3] = i) {
srtp_cipher_set_iv(c, (uint8_t*)&nonce, direction_encrypt);
srtp_cipher_encrypt(c, enc_buf, &len);
}
timer = clock() - timer;
srtp_crypto_free(enc_buf);
if (timer == 0) {
/* Too fast! */
return 0;
}
return (uint64_t)CLOCKS_PER_SEC * num_trials * 8 * octets_in_buffer / timer;
}
/*
* 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_cleanup(&ctx->ctx);
/* zeroize the key material */
octet_string_set_to_zero((uint8_t*)ctx, sizeof(srtp_aes_gcm_ctx_t));
srtp_crypto_free(ctx);
}
/* free memory */
srtp_crypto_free(c);
return (srtp_err_status_ok);
}
static srtp_err_status_t srtp_aes_icm_alloc_ismacryp (srtp_cipher_t **c, int key_len, int forIsmacryp)
{
extern const srtp_cipher_type_t srtp_aes_icm;
srtp_aes_icm_ctx_t *icm;
debug_print(srtp_mod_aes_icm,
"allocating cipher with key length %d", key_len);
/*
* Ismacryp, for example, uses 16 byte key + 8 byte
* salt so this function is called with key_len = 24.
* The check for key_len = 30/38/46 does not apply. Our usage
* of aes functions with key_len = values other than 30
* has not broken anything. Don't know what would be the
* effect of skipping this check for srtp in general.
*/
if (!(forIsmacryp && key_len > 16 && key_len < 30) &&
key_len != 30 && key_len != 38 && key_len != 46) {
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;
}
memset(*c, 0x0, sizeof(srtp_cipher_t));
icm = (srtp_aes_icm_ctx_t *)srtp_crypto_alloc(sizeof(srtp_aes_icm_ctx_t));
if (icm == NULL) {
srtp_crypto_free(*c);
return srtp_err_status_alloc_fail;
}
memset(icm, 0x0, sizeof(srtp_aes_icm_ctx_t));
/* set pointers */
(*c)->state = icm;
(*c)->type = &srtp_aes_icm;
switch (key_len) {
case 46:
(*c)->algorithm = SRTP_AES_256_ICM;
break;
case 38:
(*c)->algorithm = SRTP_AES_192_ICM;
break;
default:
(*c)->algorithm = SRTP_AES_128_ICM;
break;
}
/* set key size */
icm->key_size = key_len;
(*c)->key_len = key_len;
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_hmac_dealloc (srtp_auth_t *a)
{
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)a,
sizeof(srtp_hmac_ctx_t) + sizeof(srtp_auth_t));
/* free memory */
srtp_crypto_free(a);
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_aes_icm_dealloc (srtp_cipher_t *c)
{
srtp_aes_icm_ctx_t *ctx;
if (c == NULL) {
return srtp_err_status_bad_param;
}
ctx = (srtp_aes_icm_ctx_t *)c->state;
if (ctx) {
/* zeroize the key material */
octet_string_set_to_zero((uint8_t*)ctx, sizeof(srtp_aes_icm_ctx_t));
srtp_crypto_free(ctx);
}
/* free the cipher context */
srtp_crypto_free(c);
return srtp_err_status_ok;
}
srtp_err_status_t srtp_crypto_kernel_shutdown ()
{
/*
* free dynamic memory used in crypto_kernel at present
*/
/* walk down cipher type list, freeing memory */
while (crypto_kernel.cipher_type_list != NULL) {
srtp_kernel_cipher_type_t *ctype = crypto_kernel.cipher_type_list;
crypto_kernel.cipher_type_list = ctype->next;
debug_print(srtp_mod_crypto_kernel,
"freeing memory for cipher %s",
ctype->cipher_type->description);
srtp_crypto_free(ctype);
}
/* walk down authetication module list, freeing memory */
while (crypto_kernel.auth_type_list != NULL) {
srtp_kernel_auth_type_t *atype = crypto_kernel.auth_type_list;
crypto_kernel.auth_type_list = atype->next;
debug_print(srtp_mod_crypto_kernel,
"freeing memory for authentication %s",
atype->auth_type->description);
srtp_crypto_free(atype);
}
/* walk down debug module list, freeing memory */
while (crypto_kernel.debug_module_list != NULL) {
srtp_kernel_debug_module_t *kdm = crypto_kernel.debug_module_list;
crypto_kernel.debug_module_list = kdm->next;
debug_print(srtp_mod_crypto_kernel,
"freeing memory for debug module %s",
kdm->mod->name);
srtp_crypto_free(kdm);
}
/* return to insecure state */
crypto_kernel.state = srtp_crypto_kernel_state_insecure;
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_hmac_alloc (srtp_auth_t **a, int key_len, int out_len)
{
extern const srtp_auth_type_t srtp_hmac;
debug_print(srtp_mod_hmac, "allocating auth func with key length %d", key_len);
debug_print(srtp_mod_hmac, " tag length %d", out_len);
/* check output length - should be less than 20 bytes */
if (out_len > SHA1_DIGEST_SIZE) {
return srtp_err_status_bad_param;
}
/* OpenSSL 1.1.0 made HMAC_CTX an opaque structure, which must be allocated
using HMAC_CTX_new. But this function doesn't exist in OpenSSL 1.0.x. */
#if OPENSSL_VERSION_NUMBER < 0x10100000L
{
/* allocate memory for auth and HMAC_CTX structures */
uint8_t* pointer;
HMAC_CTX *new_hmac_ctx;
pointer = (uint8_t*)srtp_crypto_alloc(sizeof(HMAC_CTX) + sizeof(srtp_auth_t));
if (pointer == NULL) {
return srtp_err_status_alloc_fail;
}
*a = (srtp_auth_t*)pointer;
(*a)->state = pointer + sizeof(srtp_auth_t);
new_hmac_ctx = (HMAC_CTX*)((*a)->state);
HMAC_CTX_init(new_hmac_ctx);
}
#else
*a = (srtp_auth_t*)srtp_crypto_alloc(sizeof(srtp_auth_t));
if (*a == NULL) {
return srtp_err_status_alloc_fail;
}
(*a)->state = HMAC_CTX_new();
if ((*a)->state == NULL) {
srtp_crypto_free(*a);
*a = NULL;
return srtp_err_status_alloc_fail;
}
#endif
/* set pointers */
(*a)->type = &srtp_hmac;
(*a)->out_len = out_len;
(*a)->key_len = key_len;
(*a)->prefix_len = 0;
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_null_cipher_dealloc (srtp_cipher_t *c)
{
extern const srtp_cipher_type_t srtp_null_cipher;
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)c, sizeof(srtp_cipher_t));
/* free memory of type null_cipher */
srtp_crypto_free(c);
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_aes_icm_alloc (srtp_cipher_t **c, int key_len, int tlen)
{
srtp_aes_icm_ctx_t *icm;
debug_print(srtp_mod_aes_icm,
"allocating cipher with key length %d", key_len);
/*
* The check for key_len = 30/46 does not apply. Our usage
* of aes functions with key_len = values other than 30
* has not broken anything. Don't know what would be the
* effect of skipping this check for srtp in general.
*/
if (key_len != SRTP_AES_ICM_128_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;
}
memset(*c, 0x0, sizeof(srtp_cipher_t));
icm = (srtp_aes_icm_ctx_t *)srtp_crypto_alloc(sizeof(srtp_aes_icm_ctx_t));
if (icm == NULL) {
srtp_crypto_free(*c);
return srtp_err_status_alloc_fail;
}
memset(icm, 0x0, sizeof(srtp_aes_icm_ctx_t));
/* set pointers */
(*c)->state = icm;
switch (key_len) {
case SRTP_AES_ICM_256_KEY_LEN_WSALT:
(*c)->algorithm = SRTP_AES_ICM_256;
(*c)->type = &srtp_aes_icm_256;
break;
default:
(*c)->algorithm = SRTP_AES_ICM_128;
(*c)->type = &srtp_aes_icm_128;
break;
}
/* set key size */
icm->key_size = key_len;
(*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_cleanup(&ctx->ctx);
/* zeroize the key material */
octet_string_set_to_zero((uint8_t*)ctx, sizeof(srtp_aes_icm_ctx_t));
srtp_crypto_free(ctx);
}
/* free memory */
srtp_crypto_free(c);
return srtp_err_status_ok;
}
static srtp_err_status_t srtp_hmac_dealloc (srtp_auth_t *a)
{
srtp_hmac_ctx_t *hmac_ctx;
hmac_ctx = (srtp_hmac_ctx_t*)a->state;
if (hmac_ctx->ctx_initialized) {
EVP_MD_CTX_cleanup(&hmac_ctx->ctx);
}
if (hmac_ctx->init_ctx_initialized) {
EVP_MD_CTX_cleanup(&hmac_ctx->init_ctx);
}
/* zeroize entire state*/
octet_string_set_to_zero((uint8_t*)a,
sizeof(srtp_hmac_ctx_t) + sizeof(srtp_auth_t));
/* free memory */
srtp_crypto_free(a);
return srtp_err_status_ok;
}
/*
* 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;
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_128_KEYSIZE_WSALT && key_len != SRTP_AES_192_KEYSIZE_WSALT &&
key_len != SRTP_AES_256_KEYSIZE_WSALT) {
return srtp_err_status_bad_param;
}
if (key_len != SRTP_AES_128_KEYSIZE_WSALT &&
#ifndef SRTP_NO_AES192
key_len != SRTP_AES_192_KEYSIZE_WSALT &&
#endif
key_len != SRTP_AES_256_KEYSIZE_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;
}
memset(*c, 0x0, sizeof(srtp_cipher_t));
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;
}
memset(icm, 0x0, sizeof(srtp_aes_icm_ctx_t));
/* set pointers */
(*c)->state = icm;
/* setup cipher parameters */
switch (key_len) {
case SRTP_AES_128_KEYSIZE_WSALT:
(*c)->algorithm = SRTP_AES_128_ICM;
(*c)->type = &srtp_aes_icm;
icm->key_size = SRTP_AES_128_KEYSIZE;
break;
#ifndef SRTP_NO_AES192
case SRTP_AES_192_KEYSIZE_WSALT:
(*c)->algorithm = SRTP_AES_192_ICM;
(*c)->type = &srtp_aes_icm_192;
icm->key_size = SRTP_AES_192_KEYSIZE;
break;
#endif
case SRTP_AES_256_KEYSIZE_WSALT:
(*c)->algorithm = SRTP_AES_256_ICM;
(*c)->type = &srtp_aes_icm_256;
icm->key_size = SRTP_AES_256_KEYSIZE;
break;
}
/* set key size */
(*c)->key_len = key_len;
EVP_CIPHER_CTX_init(&icm->ctx);
return srtp_err_status_ok;
}
