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Diffstat (limited to 'third_party/libsrtp/src/crypto/cipher/aes_icm_mbedtls.c')
-rw-r--r--third_party/libsrtp/src/crypto/cipher/aes_icm_mbedtls.c371
1 files changed, 371 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/cipher/aes_icm_mbedtls.c b/third_party/libsrtp/src/crypto/cipher/aes_icm_mbedtls.c
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index 0000000000..9893ded702
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+++ b/third_party/libsrtp/src/crypto/cipher/aes_icm_mbedtls.c
@@ -0,0 +1,371 @@
+/*
+ * aes_icm_mbedtls.c
+ *
+ * AES Integer Counter Mode
+ *
+ * YongCheng Yang
+ */
+
+/*
+ *
+ * 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 <mbedtls/aes.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 mbedtls" /* printable module name */
+};
+
+/*
+ * integer counter mode works as follows:
+ *
+ * https://tools.ietf.org/html/rfc3711#section-4.1.1
+ *
+ * E(k, IV) || E(k, IV + 1 mod 2^128) || E(k, IV + 2 mod 2^128) ...
+ * IV = (k_s * 2^16) XOR (SSRC * 2^64) XOR (i * 2^16)
+ *
+ * IV SHALL be defined by the SSRC, the SRTP packet index i,
+ * and the SRTP session salting key k_s.
+ *
+ * SSRC: 32bits.
+ * Sequence number: 16bits.
+ * nonce is 64bits. .
+ * packet index = ROC || SEQ. (ROC: Rollover counter)
+ *
+ * 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_mbedtls_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_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 =
+ (mbedtls_aes_context *)srtp_crypto_alloc(sizeof(mbedtls_aes_context));
+ if (icm->ctx == NULL) {
+ srtp_crypto_free(icm);
+ srtp_crypto_free(*c);
+ *c = NULL;
+ return srtp_err_status_alloc_fail;
+ }
+
+ mbedtls_aes_init(icm->ctx);
+
+ /* 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_mbedtls_dealloc(srtp_cipher_t *c)
+{
+ srtp_aes_icm_ctx_t *ctx;
+
+ if (c == NULL) {
+ return srtp_err_status_bad_param;
+ }
+
+ /*
+ * Free the aes context
+ */
+ ctx = (srtp_aes_icm_ctx_t *)c->state;
+ if (ctx != NULL) {
+ mbedtls_aes_free(ctx->ctx);
+ srtp_crypto_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;
+}
+
+static srtp_err_status_t srtp_aes_icm_mbedtls_context_init(void *cv,
+ const uint8_t *key)
+{
+ srtp_aes_icm_ctx_t *c = (srtp_aes_icm_ctx_t *)cv;
+ uint32_t key_size_in_bits = (c->key_size << 3);
+ int errcode = 0;
+
+ /*
+ * 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:
+ case SRTP_AES_192_KEY_LEN:
+ case SRTP_AES_128_KEY_LEN:
+ break;
+ default:
+ return srtp_err_status_bad_param;
+ break;
+ }
+
+ errcode = mbedtls_aes_setkey_enc(c->ctx, key, key_size_in_bits);
+ if (errcode != 0) {
+ debug_print(srtp_mod_aes_icm, "errCode: %d", errcode);
+ }
+
+ 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_mbedtls_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;
+ c->nc_off = 0;
+ /* 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));
+
+ 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_mbedtls_encrypt(void *cv,
+ unsigned char *buf,
+ unsigned int *enc_len)
+{
+ srtp_aes_icm_ctx_t *c = (srtp_aes_icm_ctx_t *)cv;
+
+ int errCode = 0;
+ debug_print(srtp_mod_aes_icm, "rs0: %s", v128_hex_string(&c->counter));
+
+ errCode =
+ mbedtls_aes_crypt_ctr(c->ctx, *enc_len, &(c->nc_off), c->counter.v8,
+ c->stream_block.v8, buf, buf);
+ if (errCode != 0) {
+ debug_print(srtp_mod_aes_icm, "encrypt error: %d", errCode);
+ return srtp_err_status_cipher_fail;
+ }
+
+ return srtp_err_status_ok;
+}
+
+/*
+ * Name of this crypto engine
+ */
+static const char srtp_aes_icm_128_mbedtls_description[] =
+ "AES-128 counter mode using mbedtls";
+static const char srtp_aes_icm_192_mbedtls_description[] =
+ "AES-192 counter mode using mbedtls";
+static const char srtp_aes_icm_256_mbedtls_description[] =
+ "AES-256 counter mode using mbedtls";
+
+/*
+ * 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_mbedtls_alloc, /* */
+ srtp_aes_icm_mbedtls_dealloc, /* */
+ srtp_aes_icm_mbedtls_context_init, /* */
+ 0, /* set_aad */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_set_iv, /* */
+ 0, /* get_tag */
+ srtp_aes_icm_128_mbedtls_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_mbedtls_alloc, /* */
+ srtp_aes_icm_mbedtls_dealloc, /* */
+ srtp_aes_icm_mbedtls_context_init, /* */
+ 0, /* set_aad */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_set_iv, /* */
+ 0, /* get_tag */
+ srtp_aes_icm_192_mbedtls_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_mbedtls_alloc, /* */
+ srtp_aes_icm_mbedtls_dealloc, /* */
+ srtp_aes_icm_mbedtls_context_init, /* */
+ 0, /* set_aad */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_encrypt, /* */
+ srtp_aes_icm_mbedtls_set_iv, /* */
+ 0, /* get_tag */
+ srtp_aes_icm_256_mbedtls_description, /* */
+ &srtp_aes_icm_256_test_case_0, /* */
+ SRTP_AES_ICM_256 /* */
+};
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