netwerk/srtp/src/crypto/rng/ctr_prng.c@6474c204b198 (annotated)
netwerk/srtp/src/crypto/rng/ctr_prng.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /* |
| michael@0 | 2 | * ctr_prng.c |
| michael@0 | 3 | * |
| michael@0 | 4 | * counter mode based pseudorandom source |
| michael@0 | 5 | * |
| michael@0 | 6 | * David A. McGrew |
| michael@0 | 7 | * Cisco Systems, Inc. |
| michael@0 | 8 | */ |
| michael@0 | 9 | /* |
| michael@0 | 10 | * |
| michael@0 | 11 | * Copyright(c) 2001-2006 Cisco Systems, Inc. |
| michael@0 | 12 | * All rights reserved. |
| michael@0 | 13 | * |
| michael@0 | 14 | * Redistribution and use in source and binary forms, with or without |
| michael@0 | 15 | * modification, are permitted provided that the following conditions |
| michael@0 | 16 | * are met: |
| michael@0 | 17 | * |
| michael@0 | 18 | * Redistributions of source code must retain the above copyright |
| michael@0 | 19 | * notice, this list of conditions and the following disclaimer. |
| michael@0 | 20 | * |
| michael@0 | 21 | * Redistributions in binary form must reproduce the above |
| michael@0 | 22 | * copyright notice, this list of conditions and the following |
| michael@0 | 23 | * disclaimer in the documentation and/or other materials provided |
| michael@0 | 24 | * with the distribution. |
| michael@0 | 25 | * |
| michael@0 | 26 | * Neither the name of the Cisco Systems, Inc. nor the names of its |
| michael@0 | 27 | * contributors may be used to endorse or promote products derived |
| michael@0 | 28 | * from this software without specific prior written permission. |
| michael@0 | 29 | * |
| michael@0 | 30 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| michael@0 | 31 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| michael@0 | 32 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| michael@0 | 33 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| michael@0 | 34 | * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| michael@0 | 35 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| michael@0 | 36 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| michael@0 | 37 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| michael@0 | 38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| michael@0 | 39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 40 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| michael@0 | 41 | * OF THE POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 42 | * |
| michael@0 | 43 | */ |
| michael@0 | 44 | |
| michael@0 | 45 | |
| michael@0 | 46 | #include "prng.h" |
| michael@0 | 47 | |
| michael@0 | 48 | /* single, global prng structure */ |
| michael@0 | 49 | |
| michael@0 | 50 | ctr_prng_t ctr_prng; |
| michael@0 | 51 | |
| michael@0 | 52 | err_status_t |
| michael@0 | 53 | ctr_prng_init(rand_source_func_t random_source) { |
| michael@0 | 54 | uint8_t tmp_key[32]; |
| michael@0 | 55 | err_status_t status; |
| michael@0 | 56 | |
| michael@0 | 57 | /* initialize output count to zero */ |
| michael@0 | 58 | ctr_prng.octet_count = 0; |
| michael@0 | 59 | |
| michael@0 | 60 | /* set random source */ |
| michael@0 | 61 | ctr_prng.rand = random_source; |
| michael@0 | 62 | |
| michael@0 | 63 | /* initialize secret key from random source */ |
| michael@0 | 64 | status = random_source(tmp_key, 32); |
| michael@0 | 65 | if (status) |
| michael@0 | 66 | return status; |
| michael@0 | 67 | |
| michael@0 | 68 | /* initialize aes ctr context with random key */ |
| michael@0 | 69 | status = aes_icm_context_init(&ctr_prng.state, tmp_key, 30); |
| michael@0 | 70 | if (status) |
| michael@0 | 71 | return status; |
| michael@0 | 72 | |
| michael@0 | 73 | return err_status_ok; |
| michael@0 | 74 | } |
| michael@0 | 75 | |
| michael@0 | 76 | err_status_t |
| michael@0 | 77 | ctr_prng_get_octet_string(void *dest, uint32_t len) { |
| michael@0 | 78 | err_status_t status; |
| michael@0 | 79 | |
| michael@0 | 80 | /* |
| michael@0 | 81 | * if we need to re-initialize the prng, do so now |
| michael@0 | 82 | * |
| michael@0 | 83 | * avoid 32-bit overflows by subtracting instead of adding |
| michael@0 | 84 | */ |
| michael@0 | 85 | if (ctr_prng.octet_count > MAX_PRNG_OUT_LEN - len) { |
| michael@0 | 86 | status = ctr_prng_init(ctr_prng.rand); |
| michael@0 | 87 | if (status) |
| michael@0 | 88 | return status; |
| michael@0 | 89 | } |
| michael@0 | 90 | ctr_prng.octet_count += len; |
| michael@0 | 91 | |
| michael@0 | 92 | /* |
| michael@0 | 93 | * write prng output |
| michael@0 | 94 | */ |
| michael@0 | 95 | status = aes_icm_output(&ctr_prng.state, (uint8_t*)dest, len); |
| michael@0 | 96 | if (status) |
| michael@0 | 97 | return status; |
| michael@0 | 98 | |
| michael@0 | 99 | return err_status_ok; |
| michael@0 | 100 | } |
| michael@0 | 101 | |
| michael@0 | 102 | err_status_t |
| michael@0 | 103 | ctr_prng_deinit(void) { |
| michael@0 | 104 | |
| michael@0 | 105 | /* nothing */ |
| michael@0 | 106 | |
| michael@0 | 107 | return err_status_ok; |
| michael@0 | 108 | } |
