Update libsrtp to version 2.0

crypto/cipher/cipher.c

+/*
+ * cipher.c
+ *
+ * cipher meta-functions
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ *
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2006,2013 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 "cipher.h"
+#include "crypto_types.h"
+#include "err.h"                /* for srtp_debug */
+#include "alloc.h"              /* for crypto_alloc(), crypto_free()  */
+
+srtp_debug_module_t srtp_mod_cipher = {
+    0,               /* debugging is off by default */
+    "cipher"         /* printable module name       */
+};
+
+srtp_err_status_t srtp_cipher_type_alloc (const srtp_cipher_type_t *ct, srtp_cipher_t **c, int key_len, int tlen)
+{
+    if (!ct || !ct->alloc) {
+        return (srtp_err_status_bad_param);
+    }
+    return ((ct)->alloc((c), (key_len), (tlen)));
+}
+
+srtp_err_status_t srtp_cipher_dealloc (srtp_cipher_t *c)
+{
+    if (!c || !c->type) {
+        return (srtp_err_status_bad_param);
+    }
+    return (((c)->type)->dealloc(c));
+}
+
+srtp_err_status_t srtp_cipher_init (srtp_cipher_t *c, const uint8_t *key)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+    return (((c)->type)->init(((c)->state), (key)));
+}
+
+
+srtp_err_status_t srtp_cipher_set_iv (srtp_cipher_t *c, uint8_t *iv, int direction)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+
+    return (((c)->type)->set_iv(((c)->state), iv, direction)); 
+}
+
+srtp_err_status_t srtp_cipher_output (srtp_cipher_t *c, uint8_t *buffer, uint32_t *num_octets_to_output)
+{
+
+    /* zeroize the buffer */
+    octet_string_set_to_zero(buffer, *num_octets_to_output);
+
+    /* exor keystream into buffer */
+    return (((c)->type)->encrypt(((c)->state), buffer, num_octets_to_output));
+}
+
+srtp_err_status_t srtp_cipher_encrypt (srtp_cipher_t *c, uint8_t *buffer, uint32_t *num_octets_to_output)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+
+    return (((c)->type)->encrypt(((c)->state), buffer, num_octets_to_output));
+}
+
+srtp_err_status_t srtp_cipher_decrypt (srtp_cipher_t *c, uint8_t *buffer, uint32_t *num_octets_to_output)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+
+    return (((c)->type)->decrypt(((c)->state), buffer, num_octets_to_output));
+}
+
+srtp_err_status_t srtp_cipher_get_tag (srtp_cipher_t *c, uint8_t *buffer, uint32_t *tag_len)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+    if (!((c)->type)->get_tag) {
+        return (srtp_err_status_no_such_op);
+    }
+
+    return (((c)->type)->get_tag(((c)->state), buffer, tag_len));
+}
+
+srtp_err_status_t srtp_cipher_set_aad (srtp_cipher_t *c, const uint8_t *aad, uint32_t aad_len)
+{
+    if (!c || !c->type || !c->state) {
+        return (srtp_err_status_bad_param);
+    }
+    if (!((c)->type)->set_aad) {
+        return (srtp_err_status_no_such_op);
+    }
+
+    return (((c)->type)->set_aad(((c)->state), aad, aad_len));
+}
+
+/* some bookkeeping functions */
+
+int srtp_cipher_get_key_length (const srtp_cipher_t *c)
+{
+    return c->key_len;
+}
+
+
+/*
+ * A trivial platform independent random source.  The random
+ * data is used for some of the cipher self-tests.
+ */
+static srtp_err_status_t srtp_cipher_rand (void *dest, uint32_t len) 
+{
+#if defined(HAVE_RAND_S)
+  uint8_t *dst = (uint8_t *)dest;
+  while (len)
+  {
+    unsigned int val;
+    errno_t err = rand_s(&val);
+
+    if (err != 0)
+      return srtp_err_status_fail;
+  
+    *dst++ = val & 0xff;
+    len--;
+  }
+#else
+  /* Generic C-library (rand()) version */
+  /* This is a random source of last resort */
+  uint8_t *dst = (uint8_t *)dest;
+  while (len)
+  {
+          int val = rand();
+          /* rand() returns 0-32767 (ugh) */
+          /* Is this a good enough way to get random bytes?
+             It is if it passes FIPS-140... */
+          *dst++ = val & 0xff;
+          len--;
+  }
+#endif
+  return srtp_err_status_ok;
+}
+ 
+#define SELF_TEST_BUF_OCTETS 128
+#define NUM_RAND_TESTS       128
+#define MAX_KEY_LEN          64
+/*
+ * srtp_cipher_type_test(ct, test_data) tests a cipher of type ct against
+ * test cases provided in a list test_data of values of key, salt, iv,
+ * plaintext, and ciphertext that is known to be good
+ */
+srtp_err_status_t srtp_cipher_type_test (const srtp_cipher_type_t *ct, const srtp_cipher_test_case_t *test_data)
+{
+    const srtp_cipher_test_case_t *test_case = test_data;
+    srtp_cipher_t *c;
+    srtp_err_status_t status;
+    uint8_t buffer[SELF_TEST_BUF_OCTETS];
+    uint8_t buffer2[SELF_TEST_BUF_OCTETS];
+    uint32_t tag_len;
+    unsigned int len;
+    int i, j, case_num = 0;
+
+    debug_print(srtp_mod_cipher, "running self-test for cipher %s",
+                ct->description);
+
+    /*
+     * check to make sure that we have at least one test case, and
+     * return an error if we don't - we need to be paranoid here
+     */
+    if (test_case == NULL) {
+        return srtp_err_status_cant_check;
+    }
+
+    /*
+     * loop over all test cases, perform known-answer tests of both the
+     * encryption and decryption functions
+     */
+    while (test_case != NULL) {
+        /* allocate cipher */
+        status = srtp_cipher_type_alloc(ct, &c, test_case->key_length_octets, test_case->tag_length_octets);
+        if (status) {
+            return status;
+        }
+
+        /*
+         * test the encrypt function
+         */
+        debug_print(srtp_mod_cipher, "testing encryption", NULL);
+
+        /* initialize cipher */
+        status = srtp_cipher_init(c, test_case->key);
+        if (status) {
+            srtp_cipher_dealloc(c);
+            return status;
+        }
+
+        /* copy plaintext into test buffer */
+        if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
+            srtp_cipher_dealloc(c);
+            return srtp_err_status_bad_param;
+        }
+        for (i = 0; i < test_case->plaintext_length_octets; i++) {
+            buffer[i] = test_case->plaintext[i];
+        }
+
+        debug_print(srtp_mod_cipher, "plaintext:    %s",
+                    srtp_octet_string_hex_string(buffer,
+                                                 test_case->plaintext_length_octets));
+
+        /* set the 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_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            debug_print(srtp_mod_cipher, "IV:    %s",
+                        srtp_octet_string_hex_string(test_case->idx, 12));
+
+            /*
+             * 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 */
+        len = test_case->plaintext_length_octets;
+        status = srtp_cipher_encrypt(c, buffer, &len);
+        if (status) {
+            srtp_cipher_dealloc(c);
+            return status;
+        }
+
+        if (c->algorithm == SRTP_AES_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            /*
+             * Get the GCM tag
+             */
+            status = srtp_cipher_get_tag(c, buffer + len, &tag_len);
+            if (status) {
+                srtp_cipher_dealloc(c);
+                return status;
+            }
+            len += tag_len;
+        }
+
+        debug_print(srtp_mod_cipher, "ciphertext:   %s",
+                    srtp_octet_string_hex_string(buffer,
+                                                 test_case->ciphertext_length_octets));
+
+        /* compare the resulting ciphertext with that in the test case */
+        if (len != test_case->ciphertext_length_octets) {
+            return srtp_err_status_algo_fail;
+        }
+        status = srtp_err_status_ok;
+        for (i = 0; i < test_case->ciphertext_length_octets; i++) {
+            if (buffer[i] != test_case->ciphertext[i]) {
+                status = srtp_err_status_algo_fail;
+                debug_print(srtp_mod_cipher, "test case %d failed", case_num);
+                debug_print(srtp_mod_cipher, "(failure at byte %d)", i);
+                break;
+            }
+        }
+        if (status) {
+
+            debug_print(srtp_mod_cipher, "c computed: %s",
+                        srtp_octet_string_hex_string(buffer,
+                                                     2 * test_case->plaintext_length_octets));
+            debug_print(srtp_mod_cipher, "c expected: %s",
+                        srtp_octet_string_hex_string(test_case->ciphertext,
+                                                     2 * test_case->plaintext_length_octets));
+
+            srtp_cipher_dealloc(c);
+            return srtp_err_status_algo_fail;
+        }
+
+        /*
+         * test the decrypt function
+         */
+        debug_print(srtp_mod_cipher, "testing decryption", NULL);
+
+        /* re-initialize cipher for decryption */
+        status = srtp_cipher_init(c, test_case->key);
+        if (status) {
+            srtp_cipher_dealloc(c);
+            return status;
+        }
+
+        /* copy ciphertext into test buffer */
+        if (test_case->ciphertext_length_octets > SELF_TEST_BUF_OCTETS) {
+            srtp_cipher_dealloc(c);
+            return srtp_err_status_bad_param;
+        }
+        for (i = 0; i < test_case->ciphertext_length_octets; i++) {
+            buffer[i] = test_case->ciphertext[i];
+        }
+
+        debug_print(srtp_mod_cipher, "ciphertext:    %s",
+                    srtp_octet_string_hex_string(buffer,
+                                                 test_case->plaintext_length_octets));
+
+        /* set the initialization vector */
+        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_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            /*
+             * 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));
+        }
+
+        /* decrypt */
+        len = test_case->ciphertext_length_octets;
+        status = srtp_cipher_decrypt(c, buffer, &len);
+        if (status) {
+            srtp_cipher_dealloc(c);
+            return status;
+        }
+
+        debug_print(srtp_mod_cipher, "plaintext:   %s",
+                    srtp_octet_string_hex_string(buffer,
+                                                 test_case->plaintext_length_octets));
+
+        /* compare the resulting plaintext with that in the test case */
+        if (len != test_case->plaintext_length_octets) {
+            return srtp_err_status_algo_fail;
+        }
+        status = srtp_err_status_ok;
+        for (i = 0; i < test_case->plaintext_length_octets; i++) {
+            if (buffer[i] != test_case->plaintext[i]) {
+                status = srtp_err_status_algo_fail;
+                debug_print(srtp_mod_cipher, "test case %d failed", case_num);
+                debug_print(srtp_mod_cipher, "(failure at byte %d)", i);
+            }
+        }
+        if (status) {
+
+            debug_print(srtp_mod_cipher, "p computed: %s",
+                        srtp_octet_string_hex_string(buffer,
+                                                     2 * test_case->plaintext_length_octets));
+            debug_print(srtp_mod_cipher, "p expected: %s",
+                        srtp_octet_string_hex_string(test_case->plaintext,
+                                                     2 * test_case->plaintext_length_octets));
+
+            srtp_cipher_dealloc(c);
+            return srtp_err_status_algo_fail;
+        }
+
+        /* deallocate the cipher */
+        status = srtp_cipher_dealloc(c);
+        if (status) {
+            return status;
+        }
+
+        /*
+         * the cipher passed the test case, so move on to the next test
+         * case in the list; if NULL, we'l proceed to the next test
+         */
+        test_case = test_case->next_test_case;
+        ++case_num;
+    }
+
+    /* now run some random invertibility tests */
+
+    /* allocate cipher, using paramaters from the first test case */
+    test_case = test_data;
+    status = srtp_cipher_type_alloc(ct, &c, test_case->key_length_octets, test_case->tag_length_octets);
+    if (status) {
+        return status;
+    }
+
+    for (j = 0; j < NUM_RAND_TESTS; j++) {
+        unsigned length;
+        int plaintext_len;
+        uint8_t key[MAX_KEY_LEN];
+        uint8_t iv[MAX_KEY_LEN];
+
+        /* choose a length at random (leaving room for IV and padding) */
+        length = rand() % (SELF_TEST_BUF_OCTETS - 64);
+        debug_print(srtp_mod_cipher, "random plaintext length %d\n", length);
+        status = srtp_cipher_rand(buffer, length);
+        if (status) {
+            return status;
+        }
+
+        debug_print(srtp_mod_cipher, "plaintext:    %s",
+                    srtp_octet_string_hex_string(buffer, length));
+
+        /* copy plaintext into second buffer */
+        for (i = 0; (unsigned int)i < length; i++) {
+            buffer2[i] = buffer[i];
+        }
+
+        /* choose a key at random */
+        if (test_case->key_length_octets > MAX_KEY_LEN) {
+            return srtp_err_status_cant_check;
+        }
+        status = srtp_cipher_rand(key, test_case->key_length_octets);
+        if (status) {
+            return status;
+        }
+
+        /* chose a random initialization vector */
+        status = srtp_cipher_rand(iv, MAX_KEY_LEN);
+        if (status) {
+            return status;
+        }
+
+        /* initialize cipher */
+        status = srtp_cipher_init(c, key);
+        if (status) {
+            srtp_cipher_dealloc(c);
+            return status;
+        }
+
+        /* 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_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            /*
+             * 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_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            /*
+             * 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_128_GCM || c->algorithm == SRTP_AES_256_GCM) {
+            /*
+             * 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) {
+            return srtp_err_status_algo_fail;
+        }
+        status = srtp_err_status_ok;
+        for (i = 0; i < plaintext_len; i++) {
+            if (buffer[i] != buffer2[i]) {
+                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 %d)", i);
+            }
+        }
+        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) {
+        srtp_cipher_set_iv(c, (uint8_t*)&nonce, srtp_direction_encrypt);
+        srtp_cipher_encrypt(c, enc_buf, &len);
+    }
+    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;
+}