xref: /freebsd/sys/dev/random/randomdev.c (revision cf1fec423af7716ba778ed1ca9f94211cccec534)
1 /*-
2  * Copyright (c) 2000 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  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/queue.h>
31 #include <sys/systm.h>
32 #include <sys/conf.h>
33 #include <sys/fcntl.h>
34 #include <sys/uio.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/bus.h>
39 #include <sys/random.h>
40 #include <machine/bus.h>
41 #include <machine/resource.h>
42 #include <sys/rman.h>
43 #include <sys/signalvar.h>
44 #include <sys/sysctl.h>
45 #include <crypto/blowfish/blowfish.h>
46 
47 #include <dev/randomdev/hash.h>
48 #include <dev/randomdev/yarrow.h>
49 
50 static d_open_t random_open;
51 static d_read_t random_read;
52 static d_write_t random_write;
53 static d_ioctl_t random_ioctl;
54 
55 #define CDEV_MAJOR	2
56 #define RANDOM_MINOR	3
57 #define URANDOM_MINOR	4
58 
59 static struct cdevsw random_cdevsw = {
60 	/* open */	random_open,
61 	/* close */	(d_close_t *)nullop,
62 	/* read */	random_read,
63 	/* write */	random_write,
64 	/* ioctl */	random_ioctl,
65 	/* poll */	nopoll,
66 	/* mmap */	nommap,
67 	/* strategy */	nostrategy,
68 	/* name */	"random",
69 	/* maj */	CDEV_MAJOR,
70 	/* dump */	nodump,
71 	/* psize */	nopsize,
72 	/* flags */	0,
73 	/* bmaj */	-1
74 };
75 
76 /* For use with make_dev(9)/destroy_dev(9). */
77 static dev_t random_dev;
78 static dev_t urandom_dev; /* XXX Temporary */
79 
80 SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
81 SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters");
82 SYSCTL_INT(_kern_random_yarrow, OID_AUTO, gengateinterval, CTLFLAG_RW,
83 	&random_state.gengateinterval, 10, "Generator Gate Interval");
84 SYSCTL_INT(_kern_random_yarrow, OID_AUTO, bins, CTLFLAG_RW,
85 	&random_state.bins, 10, "Execution time tuner");
86 SYSCTL_INT(_kern_random_yarrow, OID_AUTO, fastthresh, CTLFLAG_RW,
87 	&random_state.pool[0].thresh, 100, "Fast pool reseed threshhold");
88 SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowthresh, CTLFLAG_RW,
89 	&random_state.pool[1].thresh, 160, "Slow pool reseed threshhold");
90 SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowoverthresh, CTLFLAG_RW,
91 	&random_state.slowoverthresh, 2, "Slow pool over-threshhold reseed");
92 
93 static int
94 random_open(dev_t dev, int flags, int fmt, struct proc *p)
95 {
96 	if ((flags & FWRITE) && (securelevel > 0 || suser(p)))
97 		return EPERM;
98 	else
99 		return 0;
100 }
101 
102 static int
103 random_read(dev_t dev, struct uio *uio, int flag)
104 {
105 	u_int c, ret;
106 	int error = 0;
107 	void *random_buf;
108 
109 	c = min(uio->uio_resid, PAGE_SIZE);
110 	random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
111 	while (uio->uio_resid > 0 && error == 0) {
112 		ret = read_random(random_buf, c);
113 		error = uiomove(random_buf, ret, uio);
114 	}
115 	free(random_buf, M_TEMP);
116 	return error;
117 }
118 
119 static int
120 random_write(dev_t dev, struct uio *uio, int flag)
121 {
122 	u_int c;
123 	int error = 0;
124 	void *random_buf;
125 
126 	random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
127 	while (uio->uio_resid > 0) {
128 		c = min(uio->uio_resid, PAGE_SIZE);
129 		error = uiomove(random_buf, c, uio);
130 		if (error)
131 			break;
132 		write_random(random_buf, c);
133 	}
134 	free(random_buf, M_TEMP);
135 	return error;
136 }
137 
138 static int
139 random_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
140 {
141 	return ENOTTY;
142 }
143 
144 static int
145 random_modevent(module_t mod, int type, void *data)
146 {
147 	int error;
148 
149 	switch(type) {
150 	case MOD_LOAD:
151 		error = random_init();
152 		if (error != 0)
153 			return error;
154 		if (bootverbose)
155 			printf("random: <entropy source>\n");
156 		random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
157 			GID_WHEEL, 0666, "random");
158 		urandom_dev = make_dev(&random_cdevsw, URANDOM_MINOR, UID_ROOT,
159 			GID_WHEEL, 0666, "urandom"); /* XXX Temporary */
160 		return 0;
161 
162 	case MOD_UNLOAD:
163 		random_deinit();
164 		destroy_dev(random_dev);
165 		destroy_dev(urandom_dev); /* XXX Temporary */
166 		return 0;
167 
168 	case MOD_SHUTDOWN:
169 		return 0;
170 
171 	default:
172 		return EOPNOTSUPP;
173 	}
174 }
175 
176 DEV_MODULE(random, random_modevent, NULL);
177