randomdev.c revision 67286 
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: head/sys/dev/random/randomdev.c 67286 2000-10-18 10:39:18Z peter $
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/poll.h>
40#include <sys/proc.h>
41#include <sys/select.h>
42#include <sys/random.h>
43#include <sys/vnode.h>
44#include <machine/bus.h>
45#include <machine/resource.h>
46#include <sys/sysctl.h>
47#include <crypto/blowfish/blowfish.h>
48
49#include <dev/random/hash.h>
50#include <dev/random/yarrow.h>
51
52static d_open_t random_open;
53static d_read_t random_read;
54static d_write_t random_write;
55static d_ioctl_t random_ioctl;
56static d_poll_t random_poll;
57
58#define CDEV_MAJOR	2
59#define RANDOM_MINOR	3
60#define URANDOM_MINOR	4
61
62static struct cdevsw random_cdevsw = {
63	/* open */	random_open,
64	/* close */	(d_close_t *)nullop,
65	/* read */	random_read,
66	/* write */	random_write,
67	/* ioctl */	random_ioctl,
68	/* poll */	random_poll,
69	/* mmap */	nommap,
70	/* strategy */	nostrategy,
71	/* name */	"random",
72	/* maj */	CDEV_MAJOR,
73	/* dump */	nodump,
74	/* psize */	nopsize,
75	/* flags */	0,
76	/* bmaj */	-1
77};
78
79/* For use with make_dev(9)/destroy_dev(9). */
80static dev_t random_dev;
81static dev_t urandom_dev; /* XXX Temporary */
82
83SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
84SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters");
85SYSCTL_INT(_kern_random_yarrow, OID_AUTO, gengateinterval, CTLFLAG_RW,
86	&random_state.gengateinterval, 10, "Generator Gate Interval");
87SYSCTL_INT(_kern_random_yarrow, OID_AUTO, bins, CTLFLAG_RW,
88	&random_state.bins, 10, "Execution time tuner");
89SYSCTL_INT(_kern_random_yarrow, OID_AUTO, fastthresh, CTLFLAG_RW,
90	&random_state.pool[0].thresh, 100, "Fast pool reseed threshhold");
91SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowthresh, CTLFLAG_RW,
92	&random_state.pool[1].thresh, 160, "Slow pool reseed threshhold");
93SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowoverthresh, CTLFLAG_RW,
94	&random_state.slowoverthresh, 2, "Slow pool over-threshhold reseed");
95
96static int
97random_open(dev_t dev, int flags, int fmt, struct proc *p)
98{
99	if ((flags & FWRITE) && (securelevel > 0 || suser(p)))
100		return EPERM;
101	else
102		return 0;
103}
104
105static int
106random_read(dev_t dev, struct uio *uio, int flag)
107{
108	u_int c, ret;
109	int error = 0;
110	void *random_buf;
111
112	while (!random_state.seeded) {
113		if (flag & IO_NDELAY)
114			error =  EWOULDBLOCK;
115		else
116			error = tsleep(&random_state, PUSER|PCATCH, "rndblk", 0);
117		if (error != 0)
118			return error;
119	}
120	c = min(uio->uio_resid, PAGE_SIZE);
121	random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
122	while (uio->uio_resid > 0 && error == 0) {
123		ret = read_random_real(random_buf, c);
124		error = uiomove(random_buf, ret, uio);
125	}
126	free(random_buf, M_TEMP);
127	return error;
128}
129
130static int
131random_write(dev_t dev, struct uio *uio, int flag)
132{
133	u_int c;
134	int error = 0;
135	void *random_buf;
136
137	random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
138	while (uio->uio_resid > 0) {
139		c = min(uio->uio_resid, PAGE_SIZE);
140		error = uiomove(random_buf, c, uio);
141		if (error)
142			break;
143		write_random(random_buf, c);
144	}
145	free(random_buf, M_TEMP);
146	return error;
147}
148
149static int
150random_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
151{
152	return ENOTTY;
153}
154
155static int
156random_poll(dev_t dev, int events, struct proc *p)
157{
158	int revents;
159
160	revents = 0;
161	if (events & (POLLIN | POLLRDNORM)) {
162		if (random_state.seeded)
163			revents = events & (POLLIN | POLLRDNORM);
164		else
165			selrecord(p, &random_state.rsel);
166	}
167	return revents;
168}
169
170static int
171random_modevent(module_t mod, int type, void *data)
172{
173	int error;
174
175	switch(type) {
176	case MOD_LOAD:
177		error = random_init();
178		if (error != 0)
179			return error;
180		if (bootverbose)
181			printf("random: <entropy source>\n");
182		random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
183			GID_WHEEL, 0666, "random");
184		urandom_dev = make_dev(&random_cdevsw, URANDOM_MINOR, UID_ROOT,
185			GID_WHEEL, 0666, "urandom"); /* XXX Temporary */
186		return 0;
187
188	case MOD_UNLOAD:
189		random_deinit();
190		destroy_dev(random_dev);
191		destroy_dev(urandom_dev); /* XXX Temporary */
192		return 0;
193
194	case MOD_SHUTDOWN:
195		return 0;
196
197	default:
198		return EOPNOTSUPP;
199	}
200}
201
202DEV_MODULE(random, random_modevent, NULL);
203