randomdev.c revision 67893 
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 67893 2000-10-29 16:06:56Z phk $
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/select.h>
41#include <sys/random.h>
42#include <sys/vnode.h>
43#include <machine/bus.h>
44#include <machine/resource.h>
45#include <sys/sysctl.h>
46#include <crypto/blowfish/blowfish.h>
47
48#include <dev/random/hash.h>
49#include <dev/random/yarrow.h>
50
51#include "opt_noblockrandom.h"
52
53static d_open_t random_open;
54static d_read_t random_read;
55static d_write_t random_write;
56static d_ioctl_t random_ioctl;
57static d_poll_t random_poll;
58
59#define CDEV_MAJOR	2
60#define RANDOM_MINOR	3
61#define URANDOM_MINOR	4
62
63static struct cdevsw random_cdevsw = {
64	/* open */	random_open,
65	/* close */	(d_close_t *)nullop,
66	/* read */	random_read,
67	/* write */	random_write,
68	/* ioctl */	random_ioctl,
69	/* poll */	random_poll,
70	/* mmap */	nommap,
71	/* strategy */	nostrategy,
72	/* name */	"random",
73	/* maj */	CDEV_MAJOR,
74	/* dump */	nodump,
75	/* psize */	nopsize,
76	/* flags */	0,
77	/* bmaj */	-1
78};
79
80/* For use with make_dev(9)/destroy_dev(9). */
81static dev_t random_dev;
82static dev_t urandom_dev; /* XXX Temporary */
83
84SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
85SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters");
86SYSCTL_INT(_kern_random_yarrow, OID_AUTO, gengateinterval, CTLFLAG_RW,
87	&random_state.gengateinterval, 10, "Generator Gate Interval");
88SYSCTL_INT(_kern_random_yarrow, OID_AUTO, bins, CTLFLAG_RW,
89	&random_state.bins, 10, "Execution time tuner");
90SYSCTL_INT(_kern_random_yarrow, OID_AUTO, fastthresh, CTLFLAG_RW,
91	&random_state.pool[0].thresh, 100, "Fast pool reseed threshhold");
92SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowthresh, CTLFLAG_RW,
93	&random_state.pool[1].thresh, 160, "Slow pool reseed threshhold");
94SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowoverthresh, CTLFLAG_RW,
95	&random_state.slowoverthresh, 2, "Slow pool over-threshhold reseed");
96
97static int
98random_open(dev_t dev, int flags, int fmt, struct proc *p)
99{
100	if ((flags & FWRITE) && (securelevel > 0 || suser(p)))
101		return EPERM;
102	else
103		return 0;
104}
105
106static int
107random_read(dev_t dev, struct uio *uio, int flag)
108{
109	u_int c, ret;
110	int error = 0;
111	void *random_buf;
112
113/* XXX Temporary ifndef to allow users to have a nonblocking device */
114#ifndef NOBLOCKRANDOM
115	while (!random_state.seeded) {
116		if (flag & IO_NDELAY)
117			error =  EWOULDBLOCK;
118		else
119			error = tsleep(&random_state, PUSER|PCATCH, "rndblk", 0);
120		if (error != 0)
121			return error;
122	}
123#endif
124	c = min(uio->uio_resid, PAGE_SIZE);
125	random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
126	while (uio->uio_resid > 0 && error == 0) {
127		ret = read_random_real(random_buf, c);
128		error = uiomove(random_buf, ret, uio);
129	}
130	free(random_buf, M_TEMP);
131	return error;
132}
133
134static int
135random_write(dev_t dev, struct uio *uio, int flag)
136{
137	u_int c;
138	int error = 0;
139	void *random_buf;
140
141	random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
142	while (uio->uio_resid > 0) {
143		c = min(uio->uio_resid, PAGE_SIZE);
144		error = uiomove(random_buf, c, uio);
145		if (error)
146			break;
147		write_random(random_buf, c);
148	}
149	free(random_buf, M_TEMP);
150	return error;
151}
152
153static int
154random_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
155{
156	return ENOTTY;
157}
158
159static int
160random_poll(dev_t dev, int events, struct proc *p)
161{
162	int revents;
163
164	revents = 0;
165	if (events & (POLLIN | POLLRDNORM)) {
166		if (random_state.seeded)
167			revents = events & (POLLIN | POLLRDNORM);
168		else
169			selrecord(p, &random_state.rsel);
170	}
171	return revents;
172}
173
174static int
175random_modevent(module_t mod, int type, void *data)
176{
177	int error;
178
179	switch(type) {
180	case MOD_LOAD:
181		error = random_init();
182		if (error != 0)
183			return error;
184		if (bootverbose)
185			printf("random: <entropy source>\n");
186		random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
187			GID_WHEEL, 0666, "random");
188		urandom_dev = make_dev(&random_cdevsw, URANDOM_MINOR, UID_ROOT,
189			GID_WHEEL, 0666, "urandom"); /* XXX Temporary */
190		return 0;
191
192	case MOD_UNLOAD:
193		random_deinit();
194		destroy_dev(random_dev);
195		destroy_dev(urandom_dev); /* XXX Temporary */
196		return 0;
197
198	case MOD_SHUTDOWN:
199		return 0;
200
201	default:
202		return EOPNOTSUPP;
203	}
204}
205
206DEV_MODULE(random, random_modevent, NULL);
207