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665 lines
21 KiB
665 lines
21 KiB
/*
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* cipher.c
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*
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* cipher meta-functions
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*
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* David A. McGrew
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* Cisco Systems, Inc.
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*
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*/
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/*
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*
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* Copyright (c) 2001-2017 Cisco Systems, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include "cipher.h"
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#include "cipher_priv.h"
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#include "crypto_types.h"
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#include "err.h" /* for srtp_debug */
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#include "alloc.h" /* for crypto_alloc(), crypto_free() */
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srtp_debug_module_t srtp_mod_cipher = {
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0, /* debugging is off by default */
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"cipher" /* printable module name */
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};
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srtp_err_status_t srtp_cipher_type_alloc(const srtp_cipher_type_t *ct,
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srtp_cipher_t **c,
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int key_len,
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int tlen)
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{
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if (!ct || !ct->alloc) {
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return (srtp_err_status_bad_param);
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}
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return ((ct)->alloc((c), (key_len), (tlen)));
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}
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srtp_err_status_t srtp_cipher_dealloc(srtp_cipher_t *c)
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{
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if (!c || !c->type) {
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return (srtp_err_status_bad_param);
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}
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return (((c)->type)->dealloc(c));
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}
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srtp_err_status_t srtp_cipher_init(srtp_cipher_t *c, const uint8_t *key)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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return (((c)->type)->init(((c)->state), (key)));
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}
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srtp_err_status_t srtp_cipher_set_iv(srtp_cipher_t *c,
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uint8_t *iv,
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int direction)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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return (((c)->type)->set_iv(((c)->state), iv, direction));
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}
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srtp_err_status_t srtp_cipher_output(srtp_cipher_t *c,
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uint8_t *buffer,
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uint32_t *num_octets_to_output)
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{
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/* zeroize the buffer */
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octet_string_set_to_zero(buffer, *num_octets_to_output);
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/* exor keystream into buffer */
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return (((c)->type)->encrypt(((c)->state), buffer, num_octets_to_output));
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}
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srtp_err_status_t srtp_cipher_encrypt(srtp_cipher_t *c,
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uint8_t *buffer,
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uint32_t *num_octets_to_output)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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return (((c)->type)->encrypt(((c)->state), buffer, num_octets_to_output));
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}
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srtp_err_status_t srtp_cipher_decrypt(srtp_cipher_t *c,
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uint8_t *buffer,
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uint32_t *num_octets_to_output)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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return (((c)->type)->decrypt(((c)->state), buffer, num_octets_to_output));
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}
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srtp_err_status_t srtp_cipher_get_tag(srtp_cipher_t *c,
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uint8_t *buffer,
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uint32_t *tag_len)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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if (!((c)->type)->get_tag) {
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return (srtp_err_status_no_such_op);
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}
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return (((c)->type)->get_tag(((c)->state), buffer, tag_len));
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}
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srtp_err_status_t srtp_cipher_set_aad(srtp_cipher_t *c,
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const uint8_t *aad,
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uint32_t aad_len)
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{
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if (!c || !c->type || !c->state) {
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return (srtp_err_status_bad_param);
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}
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if (!((c)->type)->set_aad) {
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return (srtp_err_status_no_such_op);
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}
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return (((c)->type)->set_aad(((c)->state), aad, aad_len));
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}
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/* some bookkeeping functions */
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int srtp_cipher_get_key_length(const srtp_cipher_t *c)
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{
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return c->key_len;
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}
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/*
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* A trivial platform independent random source.
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* For use in test only.
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*/
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void srtp_cipher_rand_for_tests(void *dest, uint32_t len)
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{
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/* Generic C-library (rand()) version */
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/* This is a random source of last resort */
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uint8_t *dst = (uint8_t *)dest;
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while (len) {
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int val = rand();
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/* rand() returns 0-32767 (ugh) */
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/* Is this a good enough way to get random bytes?
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It is if it passes FIPS-140... */
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*dst++ = val & 0xff;
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len--;
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}
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}
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/*
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* A trivial platform independent 32 bit random number.
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* For use in test only.
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*/
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uint32_t srtp_cipher_rand_u32_for_tests(void)
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{
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uint32_t r;
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srtp_cipher_rand_for_tests(&r, sizeof(r));
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return r;
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}
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#define SELF_TEST_BUF_OCTETS 128
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#define NUM_RAND_TESTS 128
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#define MAX_KEY_LEN 64
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/*
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* srtp_cipher_type_test(ct, test_data) tests a cipher of type ct against
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* test cases provided in a list test_data of values of key, salt, iv,
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* plaintext, and ciphertext that is known to be good
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*/
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srtp_err_status_t srtp_cipher_type_test(
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const srtp_cipher_type_t *ct,
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const srtp_cipher_test_case_t *test_data)
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{
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const srtp_cipher_test_case_t *test_case = test_data;
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srtp_cipher_t *c;
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srtp_err_status_t status;
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uint8_t buffer[SELF_TEST_BUF_OCTETS];
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uint8_t buffer2[SELF_TEST_BUF_OCTETS];
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uint32_t tag_len;
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unsigned int len;
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int i, j, case_num = 0;
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unsigned k = 0;
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debug_print(srtp_mod_cipher, "running self-test for cipher %s",
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ct->description);
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/*
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* check to make sure that we have at least one test case, and
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* return an error if we don't - we need to be paranoid here
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*/
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if (test_case == NULL) {
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return srtp_err_status_cant_check;
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}
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/*
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* loop over all test cases, perform known-answer tests of both the
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* encryption and decryption functions
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*/
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while (test_case != NULL) {
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/* allocate cipher */
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status = srtp_cipher_type_alloc(ct, &c, test_case->key_length_octets,
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test_case->tag_length_octets);
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if (status) {
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return status;
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}
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/*
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* test the encrypt function
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*/
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debug_print(srtp_mod_cipher, "testing encryption", NULL);
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/* initialize cipher */
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status = srtp_cipher_init(c, test_case->key);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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/* copy plaintext into test buffer */
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if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
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srtp_cipher_dealloc(c);
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return srtp_err_status_bad_param;
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}
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for (k = 0; k < test_case->plaintext_length_octets; k++) {
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buffer[k] = test_case->plaintext[k];
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}
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debug_print(srtp_mod_cipher, "plaintext: %s",
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srtp_octet_string_hex_string(
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buffer, test_case->plaintext_length_octets));
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/* set the initialization vector */
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status = srtp_cipher_set_iv(c, (uint8_t *)test_case->idx,
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srtp_direction_encrypt);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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if (c->algorithm == SRTP_AES_GCM_128 ||
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c->algorithm == SRTP_AES_GCM_256) {
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debug_print(srtp_mod_cipher, "IV: %s",
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srtp_octet_string_hex_string(test_case->idx, 12));
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/*
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* Set the AAD
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*/
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status = srtp_cipher_set_aad(c, test_case->aad,
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test_case->aad_length_octets);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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debug_print(srtp_mod_cipher, "AAD: %s",
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srtp_octet_string_hex_string(
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test_case->aad, test_case->aad_length_octets));
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}
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/* encrypt */
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len = test_case->plaintext_length_octets;
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status = srtp_cipher_encrypt(c, buffer, &len);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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if (c->algorithm == SRTP_AES_GCM_128 ||
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c->algorithm == SRTP_AES_GCM_256) {
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/*
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* Get the GCM tag
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*/
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status = srtp_cipher_get_tag(c, buffer + len, &tag_len);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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len += tag_len;
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}
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debug_print(srtp_mod_cipher, "ciphertext: %s",
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srtp_octet_string_hex_string(
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buffer, test_case->ciphertext_length_octets));
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/* compare the resulting ciphertext with that in the test case */
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if (len != test_case->ciphertext_length_octets) {
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srtp_cipher_dealloc(c);
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return srtp_err_status_algo_fail;
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}
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status = srtp_err_status_ok;
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for (k = 0; k < test_case->ciphertext_length_octets; k++) {
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if (buffer[k] != test_case->ciphertext[k]) {
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status = srtp_err_status_algo_fail;
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debug_print(srtp_mod_cipher, "test case %d failed", case_num);
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debug_print(srtp_mod_cipher, "(failure at byte %u)", k);
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break;
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}
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}
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if (status) {
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debug_print(srtp_mod_cipher, "c computed: %s",
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srtp_octet_string_hex_string(
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buffer, 2 * test_case->plaintext_length_octets));
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debug_print(srtp_mod_cipher, "c expected: %s",
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srtp_octet_string_hex_string(
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test_case->ciphertext,
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2 * test_case->plaintext_length_octets));
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srtp_cipher_dealloc(c);
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return srtp_err_status_algo_fail;
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}
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/*
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* test the decrypt function
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*/
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debug_print(srtp_mod_cipher, "testing decryption", NULL);
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/* re-initialize cipher for decryption */
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status = srtp_cipher_init(c, test_case->key);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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/* copy ciphertext into test buffer */
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if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
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srtp_cipher_dealloc(c);
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return srtp_err_status_bad_param;
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}
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for (k = 0; k < test_case->ciphertext_length_octets; k++) {
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buffer[k] = test_case->ciphertext[k];
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}
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debug_print(srtp_mod_cipher, "ciphertext: %s",
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srtp_octet_string_hex_string(
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buffer, test_case->plaintext_length_octets));
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/* set the initialization vector */
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status = srtp_cipher_set_iv(c, (uint8_t *)test_case->idx,
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srtp_direction_decrypt);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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if (c->algorithm == SRTP_AES_GCM_128 ||
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c->algorithm == SRTP_AES_GCM_256) {
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/*
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* Set the AAD
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*/
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status = srtp_cipher_set_aad(c, test_case->aad,
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test_case->aad_length_octets);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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debug_print(srtp_mod_cipher, "AAD: %s",
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srtp_octet_string_hex_string(
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test_case->aad, test_case->aad_length_octets));
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}
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/* decrypt */
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len = test_case->ciphertext_length_octets;
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status = srtp_cipher_decrypt(c, buffer, &len);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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debug_print(srtp_mod_cipher, "plaintext: %s",
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srtp_octet_string_hex_string(
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buffer, test_case->plaintext_length_octets));
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/* compare the resulting plaintext with that in the test case */
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if (len != test_case->plaintext_length_octets) {
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srtp_cipher_dealloc(c);
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return srtp_err_status_algo_fail;
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}
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status = srtp_err_status_ok;
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for (k = 0; k < test_case->plaintext_length_octets; k++) {
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if (buffer[k] != test_case->plaintext[k]) {
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status = srtp_err_status_algo_fail;
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debug_print(srtp_mod_cipher, "test case %d failed", case_num);
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debug_print(srtp_mod_cipher, "(failure at byte %u)", k);
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}
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}
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if (status) {
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debug_print(srtp_mod_cipher, "p computed: %s",
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srtp_octet_string_hex_string(
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buffer, 2 * test_case->plaintext_length_octets));
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debug_print(srtp_mod_cipher, "p expected: %s",
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srtp_octet_string_hex_string(
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test_case->plaintext,
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2 * test_case->plaintext_length_octets));
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srtp_cipher_dealloc(c);
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return srtp_err_status_algo_fail;
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}
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/* deallocate the cipher */
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status = srtp_cipher_dealloc(c);
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if (status) {
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return status;
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}
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/*
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* the cipher passed the test case, so move on to the next test
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* case in the list; if NULL, we'l proceed to the next test
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*/
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test_case = test_case->next_test_case;
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++case_num;
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}
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/* now run some random invertibility tests */
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/* allocate cipher, using paramaters from the first test case */
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test_case = test_data;
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status = srtp_cipher_type_alloc(ct, &c, test_case->key_length_octets,
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test_case->tag_length_octets);
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if (status) {
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return status;
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}
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for (j = 0; j < NUM_RAND_TESTS; j++) {
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unsigned int length;
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unsigned int plaintext_len;
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uint8_t key[MAX_KEY_LEN];
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uint8_t iv[MAX_KEY_LEN];
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/* choose a length at random (leaving room for IV and padding) */
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length = srtp_cipher_rand_u32_for_tests() % (SELF_TEST_BUF_OCTETS - 64);
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debug_print(srtp_mod_cipher, "random plaintext length %d\n", length);
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srtp_cipher_rand_for_tests(buffer, length);
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debug_print(srtp_mod_cipher, "plaintext: %s",
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srtp_octet_string_hex_string(buffer, length));
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/* copy plaintext into second buffer */
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for (i = 0; (unsigned int)i < length; i++) {
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buffer2[i] = buffer[i];
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}
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/* choose a key at random */
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if (test_case->key_length_octets > MAX_KEY_LEN) {
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srtp_cipher_dealloc(c);
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return srtp_err_status_cant_check;
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}
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srtp_cipher_rand_for_tests(key, test_case->key_length_octets);
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/* chose a random initialization vector */
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srtp_cipher_rand_for_tests(iv, MAX_KEY_LEN);
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/* initialize cipher */
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status = srtp_cipher_init(c, key);
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if (status) {
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srtp_cipher_dealloc(c);
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return status;
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}
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/* set initialization vector */
|
|
status = srtp_cipher_set_iv(c, (uint8_t *)test_case->idx,
|
|
srtp_direction_encrypt);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
|
|
if (c->algorithm == SRTP_AES_GCM_128 ||
|
|
c->algorithm == SRTP_AES_GCM_256) {
|
|
/*
|
|
* Set the AAD
|
|
*/
|
|
status = srtp_cipher_set_aad(c, test_case->aad,
|
|
test_case->aad_length_octets);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
debug_print(srtp_mod_cipher, "AAD: %s",
|
|
srtp_octet_string_hex_string(
|
|
test_case->aad, test_case->aad_length_octets));
|
|
}
|
|
|
|
/* encrypt buffer with cipher */
|
|
plaintext_len = length;
|
|
status = srtp_cipher_encrypt(c, buffer, &length);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
if (c->algorithm == SRTP_AES_GCM_128 ||
|
|
c->algorithm == SRTP_AES_GCM_256) {
|
|
/*
|
|
* Get the GCM tag
|
|
*/
|
|
status = srtp_cipher_get_tag(c, buffer + length, &tag_len);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
length += tag_len;
|
|
}
|
|
debug_print(srtp_mod_cipher, "ciphertext: %s",
|
|
srtp_octet_string_hex_string(buffer, length));
|
|
|
|
/*
|
|
* re-initialize cipher for decryption, re-set the iv, then
|
|
* decrypt the ciphertext
|
|
*/
|
|
status = srtp_cipher_init(c, key);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
status = srtp_cipher_set_iv(c, (uint8_t *)test_case->idx,
|
|
srtp_direction_decrypt);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
if (c->algorithm == SRTP_AES_GCM_128 ||
|
|
c->algorithm == SRTP_AES_GCM_256) {
|
|
/*
|
|
* Set the AAD
|
|
*/
|
|
status = srtp_cipher_set_aad(c, test_case->aad,
|
|
test_case->aad_length_octets);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
debug_print(srtp_mod_cipher, "AAD: %s",
|
|
srtp_octet_string_hex_string(
|
|
test_case->aad, test_case->aad_length_octets));
|
|
}
|
|
status = srtp_cipher_decrypt(c, buffer, &length);
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return status;
|
|
}
|
|
|
|
debug_print(srtp_mod_cipher, "plaintext[2]: %s",
|
|
srtp_octet_string_hex_string(buffer, length));
|
|
|
|
/* compare the resulting plaintext with the original one */
|
|
if (length != plaintext_len) {
|
|
srtp_cipher_dealloc(c);
|
|
return srtp_err_status_algo_fail;
|
|
}
|
|
status = srtp_err_status_ok;
|
|
for (k = 0; k < plaintext_len; k++) {
|
|
if (buffer[k] != buffer2[k]) {
|
|
status = srtp_err_status_algo_fail;
|
|
debug_print(srtp_mod_cipher, "random test case %d failed",
|
|
case_num);
|
|
debug_print(srtp_mod_cipher, "(failure at byte %u)", k);
|
|
}
|
|
}
|
|
if (status) {
|
|
srtp_cipher_dealloc(c);
|
|
return srtp_err_status_algo_fail;
|
|
}
|
|
}
|
|
|
|
status = srtp_cipher_dealloc(c);
|
|
if (status) {
|
|
return status;
|
|
}
|
|
|
|
return srtp_err_status_ok;
|
|
}
|
|
|
|
/*
|
|
* srtp_cipher_type_self_test(ct) performs srtp_cipher_type_test on ct's
|
|
* internal list of test data.
|
|
*/
|
|
srtp_err_status_t srtp_cipher_type_self_test(const srtp_cipher_type_t *ct)
|
|
{
|
|
return srtp_cipher_type_test(ct, ct->test_data);
|
|
}
|
|
|
|
/*
|
|
* 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) {
|
|
if (srtp_cipher_set_iv(c, (uint8_t *)&nonce, srtp_direction_encrypt) !=
|
|
srtp_err_status_ok) {
|
|
srtp_crypto_free(enc_buf);
|
|
return 0;
|
|
}
|
|
if (srtp_cipher_encrypt(c, enc_buf, &len) != srtp_err_status_ok) {
|
|
srtp_crypto_free(enc_buf);
|
|
return 0;
|
|
}
|
|
}
|
|
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;
|
|
}
|