xref: /php-src/ext/random/zend_utils.c (revision d1048a08)
1 /*
2    +----------------------------------------------------------------------+
3    | Copyright (c) The PHP Group                                          |
4    +----------------------------------------------------------------------+
5    | This source file is subject to version 3.01 of the PHP license,      |
6    | that is bundled with this package in the file LICENSE, and is        |
7    | available through the world-wide-web at the following url:           |
8    | https://www.php.net/license/3_01.txt                                 |
9    | If you did not receive a copy of the PHP license and are unable to   |
10    | obtain it through the world-wide-web, please send a note to          |
11    | license@php.net so we can mail you a copy immediately.               |
12    +----------------------------------------------------------------------+
13    | Authors: Arnaud Le Blanc <arnaud.lb@gmail.com>                       |
14    |          Tim Düsterhus <timwolla@php.net>                            |
15    +----------------------------------------------------------------------+
16 */
17 
18 #ifdef HAVE_CONFIG_H
19 # include "config.h"
20 #endif
21 
22 #include "php_random_zend_utils.h"
23 
php_random_bytes_insecure_for_zend(zend_random_bytes_insecure_state * opaque_state,void * bytes,size_t size)24 ZEND_ATTRIBUTE_NONNULL PHPAPI void php_random_bytes_insecure_for_zend(
25 		zend_random_bytes_insecure_state *opaque_state, void *bytes, size_t size)
26 {
27 	php_random_bytes_insecure_state_for_zend *state = (php_random_bytes_insecure_state_for_zend*) opaque_state;
28 
29 	if (UNEXPECTED(!state->initialized)) {
30 		uint64_t t[4];
31 		php_random_fallback_seed_state fallback_state;
32 		fallback_state.initialized = false;
33 
34 		do {
35 			/* Skip the CSPRNG if it has already failed */
36 			if (!fallback_state.initialized) {
37 				char errstr[128];
38 				if (php_random_bytes_ex(&t, sizeof(t), errstr, sizeof(errstr)) == FAILURE) {
39 #if ZEND_DEBUG
40 					fprintf(stderr, "php_random_bytes_ex: Failed to generate a random seed: %s\n", errstr);
41 #endif
42 					goto fallback;
43 				}
44 			} else {
45 fallback:
46 				t[0] = php_random_generate_fallback_seed_ex(&fallback_state);
47 				t[1] = php_random_generate_fallback_seed_ex(&fallback_state);
48 				t[2] = php_random_generate_fallback_seed_ex(&fallback_state);
49 				t[3] = php_random_generate_fallback_seed_ex(&fallback_state);
50 			}
51 		} while (UNEXPECTED(t[0] == 0 && t[1] == 0 && t[2] == 0 && t[3] == 0));
52 
53 		php_random_xoshiro256starstar_seed256(&state->xoshiro256starstar_state, t[0], t[1], t[2], t[3]);
54 		state->initialized = true;
55 	}
56 
57 	while (size > 0) {
58 		php_random_result result = php_random_algo_xoshiro256starstar.generate(&state->xoshiro256starstar_state);
59 		ZEND_ASSERT(result.size == 8 && sizeof(result.result) == 8);
60 		size_t chunk_size = MIN(size, 8);
61 		bytes = zend_mempcpy(bytes, &result.result, chunk_size);
62 		size -= chunk_size;
63 	}
64 }
65