1 /* $NetBSD: rand-unix.c,v 1.2 2017/01/28 21:31:47 christos Exp $ */
2
3 /*
4 * Copyright (c) 2006 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <config.h>
37 #include <krb5/roken.h>
38
39 #include <rand.h>
40 #include <heim_threads.h>
41
42 #include "randi.h"
43
44 /*
45 * Unix /dev/random
46 */
47
48 int
_hc_unix_device_fd(int flags,const char ** fn)49 _hc_unix_device_fd(int flags, const char **fn)
50 {
51 static const char *rnd_devices[] = {
52 "/dev/urandom",
53 "/dev/random",
54 "/dev/srandom",
55 "/dev/arandom",
56 NULL
57 };
58 const char **p;
59
60 for(p = rnd_devices; *p; p++) {
61 int fd = open(*p, flags | O_NDELAY);
62 if(fd >= 0) {
63 if (fn)
64 *fn = *p;
65 rk_cloexec(fd);
66 return fd;
67 }
68 }
69 return -1;
70 }
71
72 static void
unix_seed(const void * p,int size)73 unix_seed(const void *p, int size)
74 {
75 const unsigned char *indata = p;
76 ssize_t count;
77 int fd;
78
79 if (size < 0)
80 return;
81 else if (size == 0)
82 return;
83
84 fd = _hc_unix_device_fd(O_RDONLY, NULL);
85 if (fd < 0)
86 return;
87
88 while (size > 0) {
89 count = write(fd, indata, size);
90 if (count < 0 && errno == EINTR)
91 continue;
92 else if (count <= 0) {
93 close(fd);
94 return;
95 }
96 indata += count;
97 size -= count;
98 }
99 close(fd);
100 }
101
102
103 static int
unix_bytes(unsigned char * outdata,int size)104 unix_bytes(unsigned char *outdata, int size)
105 {
106 ssize_t count;
107 int fd;
108
109 if (size < 0)
110 return 0;
111 else if (size == 0)
112 return 1;
113
114 fd = _hc_unix_device_fd(O_RDONLY, NULL);
115 if (fd < 0)
116 return 0;
117
118 while (size > 0) {
119 count = read(fd, outdata, size);
120 if (count < 0 && errno == EINTR)
121 continue;
122 else if (count <= 0) {
123 close(fd);
124 return 0;
125 }
126 outdata += count;
127 size -= count;
128 }
129 close(fd);
130
131 return 1;
132 }
133
134 static void
unix_cleanup(void)135 unix_cleanup(void)
136 {
137 }
138
139 static void
unix_add(const void * indata,int size,double entropi)140 unix_add(const void *indata, int size, double entropi)
141 {
142 unix_seed(indata, size);
143 }
144
145 static int
unix_pseudorand(unsigned char * outdata,int size)146 unix_pseudorand(unsigned char *outdata, int size)
147 {
148 return unix_bytes(outdata, size);
149 }
150
151 static int
unix_status(void)152 unix_status(void)
153 {
154 int fd;
155
156 fd = _hc_unix_device_fd(O_RDONLY, NULL);
157 if (fd < 0)
158 return 0;
159 close(fd);
160
161 return 1;
162 }
163
164 const RAND_METHOD hc_rand_unix_method = {
165 unix_seed,
166 unix_bytes,
167 unix_cleanup,
168 unix_add,
169 unix_pseudorand,
170 unix_status
171 };
172
173 const RAND_METHOD *
RAND_unix_method(void)174 RAND_unix_method(void)
175 {
176 return &hc_rand_unix_method;
177 }
178