randomdev.c revision 69174 
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 69174 2000-11-25 20:08:07Z markm $
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_close_t random_close;
55static d_read_t random_read;
56static d_write_t random_write;
57static d_ioctl_t random_ioctl;
58static d_poll_t random_poll;
59
60#define CDEV_MAJOR	2
61#define RANDOM_MINOR	3
62#define URANDOM_MINOR	4
63
64static struct cdevsw random_cdevsw = {
65	/* open */	random_open,
66	/* close */	random_close,
67	/* read */	random_read,
68	/* write */	random_write,
69	/* ioctl */	random_ioctl,
70	/* poll */	random_poll,
71	/* mmap */	nommap,
72	/* strategy */	nostrategy,
73	/* name */	"random",
74	/* maj */	CDEV_MAJOR,
75	/* dump */	nodump,
76	/* psize */	nopsize,
77	/* flags */	0,
78	/* bmaj */	-1
79};
80
81/* For use with make_dev(9)/destroy_dev(9). */
82static dev_t random_dev;
83static dev_t urandom_dev; /* XXX Temporary */
84
85SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Random Number Generator");
86SYSCTL_NODE(_kern_random, OID_AUTO, yarrow, CTLFLAG_RW, 0, "Yarrow Parameters");
87SYSCTL_INT(_kern_random_yarrow, OID_AUTO, gengateinterval, CTLFLAG_RW,
88	&random_state.gengateinterval, 10, "Generator Gate Interval");
89SYSCTL_INT(_kern_random_yarrow, OID_AUTO, bins, CTLFLAG_RW,
90	&random_state.bins, 10, "Execution time tuner");
91SYSCTL_INT(_kern_random_yarrow, OID_AUTO, fastthresh, CTLFLAG_RW,
92	&random_state.pool[0].thresh, 100, "Fast pool reseed threshhold");
93SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowthresh, CTLFLAG_RW,
94	&random_state.pool[1].thresh, 160, "Slow pool reseed threshhold");
95SYSCTL_INT(_kern_random_yarrow, OID_AUTO, slowoverthresh, CTLFLAG_RW,
96	&random_state.slowoverthresh, 2, "Slow pool over-threshhold reseed");
97
98static int
99random_open(dev_t dev, int flags, int fmt, struct proc *p)
100{
101	if ((flags & FWRITE) && (securelevel > 0 || suser(p)))
102		return EPERM;
103	else
104		return 0;
105}
106
107static int
108random_close(dev_t dev, int flags, int fmt, struct proc *p)
109{
110	if ((flags & FWRITE) && !(securelevel > 0 || suser(p)))
111		random_reseed();
112	return 0;
113}
114
115static int
116random_read(dev_t dev, struct uio *uio, int flag)
117{
118	u_int c, ret;
119	int error = 0;
120	void *random_buf;
121
122/* XXX Temporary ifndef to allow users to have a nonblocking device */
123#ifndef NOBLOCKRANDOM
124	while (!random_state.seeded) {
125		if (flag & IO_NDELAY)
126			error =  EWOULDBLOCK;
127		else
128			error = tsleep(&random_state, PUSER|PCATCH, "rndblk", 0);
129		if (error != 0)
130			return error;
131	}
132#endif
133	c = min(uio->uio_resid, PAGE_SIZE);
134	random_buf = (void *)malloc(c, M_TEMP, M_WAITOK);
135	while (uio->uio_resid > 0 && error == 0) {
136		ret = read_random_real(random_buf, c);
137		error = uiomove(random_buf, ret, uio);
138	}
139	free(random_buf, M_TEMP);
140	return error;
141}
142
143static int
144random_write(dev_t dev, struct uio *uio, int flag)
145{
146	u_int c;
147	int error = 0;
148	void *random_buf;
149
150	random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
151	while (uio->uio_resid > 0) {
152		c = min(uio->uio_resid, PAGE_SIZE);
153		error = uiomove(random_buf, c, uio);
154		if (error)
155			break;
156		write_random(random_buf, c);
157	}
158	free(random_buf, M_TEMP);
159	return error;
160}
161
162static int
163random_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
164{
165	return ENOTTY;
166}
167
168static int
169random_poll(dev_t dev, int events, struct proc *p)
170{
171	int revents;
172
173	revents = 0;
174	if (events & (POLLIN | POLLRDNORM)) {
175		if (random_state.seeded)
176			revents = events & (POLLIN | POLLRDNORM);
177		else
178			selrecord(p, &random_state.rsel);
179	}
180	return revents;
181}
182
183static int
184random_modevent(module_t mod, int type, void *data)
185{
186	int error;
187
188	switch(type) {
189	case MOD_LOAD:
190		error = random_init();
191		if (error != 0)
192			return error;
193		if (bootverbose)
194			printf("random: <entropy source>\n");
195		random_dev = make_dev(&random_cdevsw, RANDOM_MINOR, UID_ROOT,
196			GID_WHEEL, 0666, "random");
197		urandom_dev = make_dev(&random_cdevsw, URANDOM_MINOR, UID_ROOT,
198			GID_WHEEL, 0666, "urandom"); /* XXX Temporary */
199		return 0;
200
201	case MOD_UNLOAD:
202		random_deinit();
203		destroy_dev(random_dev);
204		destroy_dev(urandom_dev); /* XXX Temporary */
205		return 0;
206
207	case MOD_SHUTDOWN:
208		return 0;
209
210	default:
211		return EOPNOTSUPP;
212	}
213}
214
215DEV_MODULE(random, random_modevent, NULL);
216