1 /* uECC_platform_specific.c - Implementation of platform specific functions */
2
3 /* Copyright (c) 2014, Kenneth MacKay
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 * * Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
15 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
18 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
20 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
21 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
22 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
23 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE. */
25
26 /*
27 * Copyright (C) 2017 by Intel Corporation, All Rights Reserved.
28 *
29 * Redistribution and use in source and binary forms, with or without
30 * modification, are permitted provided that the following conditions are met:
31 *
32 * - Redistributions of source code must retain the above copyright notice,
33 * this list of conditions and the following disclaimer.
34 *
35 * - Redistributions in binary form must reproduce the above copyright
36 * notice, this list of conditions and the following disclaimer in the
37 * documentation and/or other materials provided with the distribution.
38 *
39 * - Neither the name of Intel Corporation nor the names of its contributors
40 * may be used to endorse or promote products derived from this software
41 * without specific prior written permission.
42 *
43 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
44 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
47 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
48 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
49 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
50 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
51 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
52 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
53 * POSSIBILITY OF SUCH DAMAGE.
54 *
55 * uECC_platform_specific.c -- Implementation of platform specific functions
56 */
57
58 #if defined(unix) || defined(__linux__) || defined(__unix__) || \
59 defined(__unix) | (defined(__APPLE__) && defined(__MACH__)) || \
60 defined(uECC_POSIX)
61
62 /* Some POSIX-like system with /dev/urandom or /dev/random. */
63 #include <sys/types.h>
64 #include <fcntl.h>
65 #include <unistd.h>
66
67 #include <stdint.h>
68
69 #ifndef O_CLOEXEC
70 #define O_CLOEXEC 0
71 #endif
72
default_CSPRNG(uint8_t * dest,unsigned int size)73 int default_CSPRNG(uint8_t *dest, unsigned int size)
74 {
75 /* input sanity check: */
76 if (dest == (uint8_t *) 0 || (size == 0)) {
77 return 0;
78 }
79
80 int fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
81 if (fd == -1) {
82 fd = open("/dev/random", O_RDONLY | O_CLOEXEC);
83 if (fd == -1) {
84 return 0;
85 }
86 }
87
88 char *ptr = (char *)dest;
89 size_t left = (size_t) size;
90
91 while (left > 0) {
92 ssize_t bytes_read = read(fd, ptr, left);
93 if (bytes_read <= 0) { // read failed
94 close(fd);
95 return 0;
96 }
97
98 left -= bytes_read;
99 ptr += bytes_read;
100 }
101
102 close(fd);
103 return 1;
104 }
105
106 #endif /* platform */