1 #include "tommath_private.h"
2 #ifdef BN_S_MP_RAND_PLATFORM_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis */
4 /* SPDX-License-Identifier: Unlicense */
5
6 /* First the OS-specific special cases
7 * - *BSD
8 * - Windows
9 */
10 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
11 #define BN_S_READ_ARC4RANDOM_C
s_read_arc4random(void * p,size_t n)12 static mp_err s_read_arc4random(void *p, size_t n)
13 {
14 arc4random_buf(p, n);
15 return MP_OKAY;
16 }
17 #endif
18
19 #if defined(_WIN32) || defined(_WIN32_WCE)
20 #define BN_S_READ_WINCSP_C
21
22 #ifndef _WIN32_WINNT
23 #define _WIN32_WINNT 0x0400
24 #endif
25 #ifdef _WIN32_WCE
26 #define UNDER_CE
27 #define ARM
28 #endif
29
30 #define WIN32_LEAN_AND_MEAN
31 #include <windows.h>
32 #include <wincrypt.h>
33
s_read_wincsp(void * p,size_t n)34 static mp_err s_read_wincsp(void *p, size_t n)
35 {
36 static HCRYPTPROV hProv = 0;
37 if (hProv == 0) {
38 HCRYPTPROV h = 0;
39 if (!CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
40 (CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET)) &&
41 !CryptAcquireContext(&h, NULL, MS_DEF_PROV, PROV_RSA_FULL,
42 CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET)) {
43 return MP_ERR;
44 }
45 hProv = h;
46 }
47 return CryptGenRandom(hProv, (DWORD)n, (BYTE *)p) == TRUE ? MP_OKAY : MP_ERR;
48 }
49 #endif /* WIN32 */
50
51 #if !defined(BN_S_READ_WINCSP_C) && defined(__linux__) && defined(__GLIBC_PREREQ)
52 #if __GLIBC_PREREQ(2, 25)
53 #define BN_S_READ_GETRANDOM_C
54 #include <sys/random.h>
55 #include <errno.h>
56
s_read_getrandom(void * p,size_t n)57 static mp_err s_read_getrandom(void *p, size_t n)
58 {
59 char *q = (char *)p;
60 while (n > 0u) {
61 ssize_t ret = getrandom(q, n, 0);
62 if (ret < 0) {
63 if (errno == EINTR) {
64 continue;
65 }
66 return MP_ERR;
67 }
68 q += ret;
69 n -= (size_t)ret;
70 }
71 return MP_OKAY;
72 }
73 #endif
74 #endif
75
76 /* We assume all platforms besides windows provide "/dev/urandom".
77 * In case yours doesn't, define MP_NO_DEV_URANDOM at compile-time.
78 */
79 #if !defined(BN_S_READ_WINCSP_C) && !defined(MP_NO_DEV_URANDOM)
80 #define BN_S_READ_URANDOM_C
81 #ifndef MP_DEV_URANDOM
82 #define MP_DEV_URANDOM "/dev/urandom"
83 #endif
84 #include <fcntl.h>
85 #include <errno.h>
86 #include <unistd.h>
87
s_read_urandom(void * p,size_t n)88 static mp_err s_read_urandom(void *p, size_t n)
89 {
90 int fd;
91 char *q = (char *)p;
92
93 do {
94 fd = open(MP_DEV_URANDOM, O_RDONLY);
95 } while ((fd == -1) && (errno == EINTR));
96 if (fd == -1) return MP_ERR;
97
98 while (n > 0u) {
99 ssize_t ret = read(fd, p, n);
100 if (ret < 0) {
101 if (errno == EINTR) {
102 continue;
103 }
104 close(fd);
105 return MP_ERR;
106 }
107 q += ret;
108 n -= (size_t)ret;
109 }
110
111 close(fd);
112 return MP_OKAY;
113 }
114 #endif
115
116 #if defined(MP_PRNG_ENABLE_LTM_RNG)
117 #define BN_S_READ_LTM_RNG
118 unsigned long (*ltm_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
119 void (*ltm_rng_callback)(void);
120
s_read_ltm_rng(void * p,size_t n)121 static mp_err s_read_ltm_rng(void *p, size_t n)
122 {
123 unsigned long res;
124 if (ltm_rng == NULL) return MP_ERR;
125 res = ltm_rng(p, n, ltm_rng_callback);
126 if (res != n) return MP_ERR;
127 return MP_OKAY;
128 }
129 #endif
130
131 mp_err s_read_arc4random(void *p, size_t n);
132 mp_err s_read_wincsp(void *p, size_t n);
133 mp_err s_read_getrandom(void *p, size_t n);
134 mp_err s_read_urandom(void *p, size_t n);
135 mp_err s_read_ltm_rng(void *p, size_t n);
136
s_mp_rand_platform(void * p,size_t n)137 mp_err s_mp_rand_platform(void *p, size_t n)
138 {
139 mp_err err = MP_ERR;
140 if ((err != MP_OKAY) && MP_HAS(S_READ_ARC4RANDOM)) err = s_read_arc4random(p, n);
141 if ((err != MP_OKAY) && MP_HAS(S_READ_WINCSP)) err = s_read_wincsp(p, n);
142 if ((err != MP_OKAY) && MP_HAS(S_READ_GETRANDOM)) err = s_read_getrandom(p, n);
143 if ((err != MP_OKAY) && MP_HAS(S_READ_URANDOM)) err = s_read_urandom(p, n);
144 if ((err != MP_OKAY) && MP_HAS(S_READ_LTM_RNG)) err = s_read_ltm_rng(p, n);
145 return err;
146 }
147
148 #endif
149