/* * 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 #endif #include #include "aes_gcm.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; (*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; (*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; } EVP_CIPHER_CTX_cleanup(c->ctx); 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", srtp_octet_string_hex_string(iv, 12)); 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; debug_print(srtp_mod_aes_gcm, "setting AAD: %s", srtp_octet_string_hex_string(aad, aad_len)); /* * 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 = { 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 = { 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 };