2 * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
3 * Copyright (c) 2013 David E. O'Brien <obrien@NUXI.org>
4 * Copyright (c) 2013 Mark R V Murray
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #include <sys/param.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/kthread.h>
35 #include <sys/libkern.h>
37 #include <sys/malloc.h>
38 #include <sys/queue.h>
39 #include <sys/random.h>
40 #include <sys/selinfo.h>
42 #include <sys/sysctl.h>
43 #include <sys/unistd.h>
45 #include <dev/random/randomdev.h>
46 #include <dev/random/randomdev_soft.h>
47 #include <dev/random/random_adaptors.h>
49 LIST_HEAD(adaptors_head, random_adaptors);
50 static struct adaptors_head adaptors = LIST_HEAD_INITIALIZER(adaptors);
51 static struct sx adaptors_lock; /* need a sleepable lock */
53 /* List for the dynamic sysctls */
54 static struct sysctl_ctx_list random_clist;
56 struct random_adaptor *random_adaptor;
58 MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers and data structures");
61 random_adaptor_register(const char *name, struct random_adaptor *rsp)
63 struct random_adaptors *rpp;
65 KASSERT(name != NULL && rsp != NULL, ("invalid input to %s", __func__));
67 rpp = malloc(sizeof(struct random_adaptors), M_ENTROPY, M_WAITOK);
71 sx_xlock(&adaptors_lock);
72 LIST_INSERT_HEAD(&adaptors, rpp, entries);
73 sx_xunlock(&adaptors_lock);
78 struct random_adaptor *
79 random_adaptor_get(const char *name)
81 struct random_adaptors *rpp;
82 struct random_adaptor *rsp;
86 sx_slock(&adaptors_lock);
88 LIST_FOREACH(rpp, &adaptors, entries)
89 if (strcmp(rpp->name, name) == 0)
92 sx_sunlock(&adaptors_lock);
98 * Walk a list of registered random(4) adaptors and pick the last non-selected
101 * If none are selected, use yarrow if available.
104 random_adaptor_choose(struct random_adaptor **adaptor)
106 char rngs[128], *token, *cp;
107 struct random_adaptors *rppi, *ramax;
110 KASSERT(adaptor != NULL, ("pre-conditions failed"));
113 if (TUNABLE_STR_FETCH("kern.random.active_adaptor", rngs, sizeof(rngs))) {
116 while ((token = strsep(&cp, ",")) != NULL)
117 if ((*adaptor = random_adaptor_get(token)) != NULL)
119 else if (bootverbose)
120 printf("%s random adaptor is not available,"
121 " skipping\n", token);
125 if (*adaptor == NULL) {
127 * Fall back to the highest priority item on the available
130 sx_slock(&adaptors_lock);
133 LIST_FOREACH(rppi, &adaptors, entries) {
134 if (rppi->rsp->priority >= primax) {
136 primax = rppi->rsp->priority;
140 *adaptor = ramax->rsp;
142 sx_sunlock(&adaptors_lock);
144 if (bootverbose && *adaptor)
145 printf("Falling back to <%s> random adaptor\n",
151 random_adaptors_deinit(void *unused)
154 sx_destroy(&adaptors_lock);
155 sysctl_ctx_free(&random_clist);
159 random_sysctl_adaptors_handler(SYSCTL_HANDLER_ARGS)
161 struct random_adaptors *rpp;
166 sx_slock(&adaptors_lock);
168 if (LIST_EMPTY(&adaptors))
169 error = SYSCTL_OUT(req, "", 0);
171 LIST_FOREACH(rpp, &adaptors, entries) {
173 error = SYSCTL_OUT(req, ",", count++ ? 1 : 0);
177 error = SYSCTL_OUT(req, rpp->name, strlen(rpp->name));
183 sx_sunlock(&adaptors_lock);
189 random_sysctl_active_adaptor_handler(SYSCTL_HANDLER_ARGS)
191 struct random_adaptor *rsp;
192 struct random_adaptors *rpp;
197 rsp = random_adaptor;
200 sx_slock(&adaptors_lock);
202 LIST_FOREACH(rpp, &adaptors, entries)
206 sx_sunlock(&adaptors_lock);
209 if (rsp == NULL || name == NULL)
210 error = SYSCTL_OUT(req, "", 0);
212 error = SYSCTL_OUT(req, name, strlen(name));
218 random_adaptors_init(void *unused)
221 SYSCTL_PROC(_kern_random, OID_AUTO, adaptors,
222 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
223 NULL, 0, random_sysctl_adaptors_handler, "A",
224 "Random Number Generator adaptors");
226 SYSCTL_PROC(_kern_random, OID_AUTO, active_adaptor,
227 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
228 NULL, 0, random_sysctl_active_adaptor_handler, "A",
229 "Active Random Number Generator Adaptor");
231 sx_init(&adaptors_lock, "random_adaptors");
234 SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
236 SYSINIT(random_adaptors, SI_SUB_DRIVERS, SI_ORDER_FIRST, random_adaptors_init,
238 SYSUNINIT(random_adaptors, SI_SUB_DRIVERS, SI_ORDER_FIRST,
239 random_adaptors_deinit, NULL);
242 random_adaptors_reseed(void *unused)
246 if (random_adaptor != NULL)
247 (*random_adaptor->reseed)();
248 arc4rand(NULL, 0, 1);
250 SYSINIT(random_reseed, SI_SUB_INTRINSIC_POST, SI_ORDER_SECOND,
251 random_adaptors_reseed, NULL);