diff options
Diffstat (limited to 'third_party/libsrtp/src/crypto/cipher/aes_icm_ossl.c')
-rw-r--r-- | third_party/libsrtp/src/crypto/cipher/aes_icm_ossl.c | 383 |
1 files changed, 383 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/cipher/aes_icm_ossl.c b/third_party/libsrtp/src/crypto/cipher/aes_icm_ossl.c new file mode 100644 index 0000000000..f960a33ecf --- /dev/null +++ b/third_party/libsrtp/src/crypto/cipher/aes_icm_ossl.c @@ -0,0 +1,383 @@ +/* + * 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 = { + 0, /* 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, + 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 = 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_cleanup(c->ctx); + if (!EVP_EncryptInit_ex(c->ctx, evp, NULL, key, NULL)) { + return srtp_err_status_fail; + } else { + return srtp_err_status_ok; + } + + 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; + + /* 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; + } else { + 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, + unsigned char *buf, + unsigned int *enc_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 (!EVP_EncryptUpdate(c->ctx, buf, &len, buf, *enc_len)) { + return srtp_err_status_cipher_fail; + } + *enc_len = len; + + if (!EVP_EncryptFinal_ex(c->ctx, buf + len, &len)) { + return srtp_err_status_cipher_fail; + } + *enc_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, /* */ + 0, /* get_tag */ + 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, /* */ + 0, /* get_tag */ + 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, /* */ + 0, /* get_tag */ + srtp_aes_icm_256_openssl_description, /* */ + &srtp_aes_icm_256_test_case_0, /* */ + SRTP_AES_ICM_256 /* */ +}; 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