1 /*-
2 * Copyright (c) 2015 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/malloc.h>
35 #include <sys/random.h>
36 #include <sys/sysctl.h>
37
38 #if defined(RANDOM_LOADABLE)
39 #include <sys/lock.h>
40 #include <sys/sx.h>
41 #endif
42
43 #include <dev/random/randomdev.h>
44
45 /* Set up the sysctl root node for the entropy device */
46 SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Cryptographically Secure Random Number Generator");
47
48 MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers and data structures");
49
50 struct sources_head source_list = LIST_HEAD_INITIALIZER(source_list);
51
52 #if defined(RANDOM_LOADABLE)
53 struct random_algorithm *p_random_alg_context = NULL;
54 #else /* !defined(RANDOM_LOADABLE) */
55 struct random_algorithm *p_random_alg_context = &random_alg_context;
56 #endif /* defined(RANDOM_LOADABLE) */
57
58 #if defined(RANDOM_LOADABLE)
59
60 struct random_readers {
61 int (*read_random_uio)(struct uio *, bool);
62 u_int (*read_random)(void *, u_int);
63 } random_reader_context = {
64 (int (*)(struct uio *, bool))nullop,
65 (u_int (*)(void *, u_int))nullop,
66 };
67
68 struct sx randomdev_config_lock;
69
70 static void
random_infra_sysinit(void * dummy __unused)71 random_infra_sysinit(void *dummy __unused)
72 {
73
74 RANDOM_CONFIG_INIT_LOCK();
75 }
76 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysinit, NULL);
77
78 void
random_infra_init(int (* p_random_read_uio)(struct uio *,bool),u_int (* p_random_read)(void *,u_int))79 random_infra_init(int (*p_random_read_uio)(struct uio *, bool), u_int (*p_random_read)(void *, u_int))
80 {
81
82 RANDOM_CONFIG_X_LOCK();
83 random_reader_context.read_random_uio = p_random_read_uio;
84 random_reader_context.read_random = p_random_read;
85 RANDOM_CONFIG_X_UNLOCK();
86 }
87
88 void
random_infra_uninit(void)89 random_infra_uninit(void)
90 {
91
92 RANDOM_CONFIG_X_LOCK();
93 random_reader_context.read_random_uio = (int (*)(struct uio *, bool))nullop;
94 random_reader_context.read_random = (u_int (*)(void *, u_int))nullop;
95 RANDOM_CONFIG_X_UNLOCK();
96 }
97
98 static void
random_infra_sysuninit(void * dummy __unused)99 random_infra_sysuninit(void *dummy __unused)
100 {
101
102 RANDOM_CONFIG_DEINIT_LOCK();
103 }
104 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysuninit, NULL);
105
106 int
read_random_uio(struct uio * uio,bool nonblock)107 read_random_uio(struct uio *uio, bool nonblock)
108 {
109 int retval;
110
111 RANDOM_CONFIG_S_LOCK();
112 retval = random_reader_context.read_random_uio(uio, nonblock);
113 RANDOM_CONFIG_S_UNLOCK();
114 return (retval);
115 }
116
117 u_int
read_random(void * buf,u_int len)118 read_random(void *buf, u_int len)
119 {
120 u_int retval;
121
122 RANDOM_CONFIG_S_LOCK();
123 retval = random_reader_context.read_random(buf, len);
124 RANDOM_CONFIG_S_UNLOCK();
125 return (retval);
126 }
127
128 #endif /* defined(RANDOM_LOADABLE) */
129