/* * aes_gcm_nss.c * * AES Galois Counter Mode * * Richard L. Barnes * 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 "aes_gcm.h" #include "alloc.h" #include "err.h" /* for srtp_debug */ #include "crypto_types.h" #include "cipher_types.h" #include #include srtp_debug_module_t srtp_mod_aes_gcm = { 0, /* debugging is off by default */ "aes gcm nss" /* 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_IV_LEN 12 #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_nss_alloc(srtp_cipher_t **c, int key_len, int tlen) { srtp_aes_gcm_ctx_t *gcm; NSSInitContext *nss; 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); } /* Initialize NSS equiv of NSS_NoDB_Init(NULL) */ nss = NSS_InitContext("", "", "", "", NULL, NSS_INIT_READONLY | NSS_INIT_NOCERTDB | NSS_INIT_NOMODDB | NSS_INIT_FORCEOPEN | NSS_INIT_OPTIMIZESPACE); if (!nss) { return (srtp_err_status_cipher_fail); } /* allocate memory a cipher of type aes_gcm */ *c = (srtp_cipher_t *)srtp_crypto_alloc(sizeof(srtp_cipher_t)); if (*c == NULL) { NSS_ShutdownContext(nss); return (srtp_err_status_alloc_fail); } gcm = (srtp_aes_gcm_ctx_t *)srtp_crypto_alloc(sizeof(srtp_aes_gcm_ctx_t)); if (gcm == NULL) { NSS_ShutdownContext(nss); srtp_crypto_free(*c); *c = NULL; return (srtp_err_status_alloc_fail); } gcm->nss = nss; /* 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_size = tlen; gcm->params.ulTagBits = 8 * 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_size = tlen; gcm->params.ulTagBits = 8 * tlen; break; default: /* this should never hit, but to be sure... */ return (srtp_err_status_bad_param); } /* set key size and tag 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_nss_dealloc(srtp_cipher_t *c) { srtp_aes_gcm_ctx_t *ctx; ctx = (srtp_aes_gcm_ctx_t *)c->state; if (ctx) { /* release NSS resources */ if (ctx->key) { PK11_FreeSymKey(ctx->key); } if (ctx->nss) { NSS_ShutdownContext(ctx->nss); ctx->nss = NULL; } /* 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_nss_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_nss_context_init(void *cv, const uint8_t *key) { srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv; c->dir = srtp_direction_any; debug_print(srtp_mod_aes_gcm, "key: %s", srtp_octet_string_hex_string(key, c->key_size)); if (c->key) { PK11_FreeSymKey(c->key); c->key = NULL; } PK11SlotInfo *slot = PK11_GetBestSlot(CKM_AES_GCM, NULL); if (!slot) { return (srtp_err_status_cipher_fail); } SECItem key_item = { siBuffer, (unsigned char *)key, c->key_size }; c->key = PK11_ImportSymKey(slot, CKM_AES_GCM, PK11_OriginUnwrap, CKA_ENCRYPT, &key_item, NULL); PK11_FreeSlot(slot); if (!c->key) { return (srtp_err_status_cipher_fail); } return (srtp_err_status_ok); } /* * aes_gcm_nss_set_iv(c, iv) sets the counter value to the exor of iv with * the offset */ static srtp_err_status_t srtp_aes_gcm_nss_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, GCM_IV_LEN)); memcpy(c->iv, iv, GCM_IV_LEN); 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_nss_set_aad(void *cv, const uint8_t *aad, uint32_t aad_len) { srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv; debug_print(srtp_mod_aes_gcm, "setting AAD: %s", srtp_octet_string_hex_string(aad, aad_len)); if (aad_len + c->aad_size > MAX_AD_SIZE) { return srtp_err_status_bad_param; } memcpy(c->aad + c->aad_size, aad, aad_len); c->aad_size += aad_len; return (srtp_err_status_ok); } static srtp_err_status_t srtp_aes_gcm_nss_do_crypto(void *cv, int encrypt, unsigned char *buf, unsigned int *enc_len) { srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv; c->params.pIv = c->iv; c->params.ulIvLen = GCM_IV_LEN; c->params.pAAD = c->aad; c->params.ulAADLen = c->aad_size; // Reset AAD c->aad_size = 0; int rv; SECItem param = { siBuffer, (unsigned char *)&c->params, sizeof(CK_GCM_PARAMS) }; if (encrypt) { rv = PK11_Encrypt(c->key, CKM_AES_GCM, ¶m, buf, enc_len, *enc_len + 16, buf, *enc_len); } else { rv = PK11_Decrypt(c->key, CKM_AES_GCM, ¶m, buf, enc_len, *enc_len, buf, *enc_len); } srtp_err_status_t status = (srtp_err_status_ok); if (rv != SECSuccess) { status = (srtp_err_status_cipher_fail); } return status; } /* * This function encrypts a buffer using AES GCM mode * * XXX(rlb@ipv.sx): We're required to break off and cache the tag * here, because the get_tag() method is separate and the tests expect * encrypt() not to change the size of the plaintext. It might be * good to update the calling API so that this is cleaner. * * Parameters: * c Crypto context * buf data to encrypt * enc_len length of encrypt buffer */ static srtp_err_status_t srtp_aes_gcm_nss_encrypt(void *cv, unsigned char *buf, unsigned int *enc_len) { srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv; // When we get a non-NULL buffer, we know that the caller is // prepared to also take the tag. When we get a NULL buffer, // even though there's no data, we need to give NSS a buffer // where it can write the tag. We can't just use c->tag because // memcpy has undefined behavior on overlapping ranges. unsigned char tagbuf[16]; unsigned char *non_null_buf = buf; if (!non_null_buf && (*enc_len == 0)) { non_null_buf = tagbuf; } else if (!non_null_buf) { return srtp_err_status_bad_param; } srtp_err_status_t status = srtp_aes_gcm_nss_do_crypto(cv, 1, non_null_buf, enc_len); if (status != srtp_err_status_ok) { return status; } memcpy(c->tag, non_null_buf + (*enc_len - c->tag_size), c->tag_size); *enc_len -= c->tag_size; 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_nss_get_tag(void *cv, uint8_t *buf, uint32_t *len) { srtp_aes_gcm_ctx_t *c = (srtp_aes_gcm_ctx_t *)cv; *len = c->tag_size; memcpy(buf, c->tag, c->tag_size); 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_nss_decrypt(void *cv, unsigned char *buf, unsigned int *enc_len) { srtp_err_status_t status = srtp_aes_gcm_nss_do_crypto(cv, 0, buf, enc_len); if (status != srtp_err_status_ok) { int err = PR_GetError(); if (err == SEC_ERROR_BAD_DATA) { status = srtp_err_status_auth_fail; } } return status; } /* * Name of this crypto engine */ static const char srtp_aes_gcm_128_nss_description[] = "AES-128 GCM using NSS"; static const char srtp_aes_gcm_256_nss_description[] = "AES-256 GCM using NSS"; /* * 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. */ /* clang-format off */ const srtp_cipher_type_t srtp_aes_gcm_128 = { srtp_aes_gcm_nss_alloc, srtp_aes_gcm_nss_dealloc, srtp_aes_gcm_nss_context_init, srtp_aes_gcm_nss_set_aad, srtp_aes_gcm_nss_encrypt, srtp_aes_gcm_nss_decrypt, srtp_aes_gcm_nss_set_iv, srtp_aes_gcm_nss_get_tag, srtp_aes_gcm_128_nss_description, &srtp_aes_gcm_test_case_0, SRTP_AES_GCM_128 }; /* clang-format on */ /* * This is the vector function table for this crypto engine. */ /* clang-format off */ const srtp_cipher_type_t srtp_aes_gcm_256 = { srtp_aes_gcm_nss_alloc, srtp_aes_gcm_nss_dealloc, srtp_aes_gcm_nss_context_init, srtp_aes_gcm_nss_set_aad, srtp_aes_gcm_nss_encrypt, srtp_aes_gcm_nss_decrypt, srtp_aes_gcm_nss_set_iv, srtp_aes_gcm_nss_get_tag, srtp_aes_gcm_256_nss_description, &srtp_aes_gcm_test_case_1, SRTP_AES_GCM_256 }; /* clang-format on */