1/*
2 * Copyright (c) 1999-2009 Apple, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/proc.h>
33#include <sys/errno.h>
34#include <sys/ioctl.h>
35#include <sys/conf.h>
36#include <sys/fcntl.h>
37#include <string.h>
38#include <miscfs/devfs/devfs.h>
39#include <kern/locks.h>
40#include <kern/clock.h>
41#include <sys/time.h>
42#include <sys/malloc.h>
43#include <sys/sysproto.h>
44#include <sys/uio_internal.h>
45
46#include <dev/random/randomdev.h>
47
48#include <libkern/OSByteOrder.h>
49#include <libkern/OSAtomic.h>
50
51#include <mach/mach_time.h>
52
53#define RANDOM_MAJOR -1 /* let the kernel pick the device number */
54#define RANDOM_MINOR 0
55#define URANDOM_MINOR 1
56
57d_ioctl_t random_ioctl;
58
59/*
60 * A struct describing which functions will get invoked for certain
61 * actions.
62 */
63static struct cdevsw random_cdevsw =
64{
65 random_open, /* open */
66 random_close, /* close */
67 random_read, /* read */
68 random_write, /* write */
69 random_ioctl, /* ioctl */
70 (stop_fcn_t *)nulldev, /* stop */
71 (reset_fcn_t *)nulldev, /* reset */
72 NULL, /* tty's */
73 eno_select, /* select */
74 eno_mmap, /* mmap */
75 eno_strat, /* strategy */
76 eno_getc, /* getc */
77 eno_putc, /* putc */
78 0 /* type */
79};
80
81
82/*
83 * Called to initialize our device,
84 * and to register ourselves with devfs
85 */
86void
87random_init(void)
88{
89 int ret;
90
91 ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
92 if (ret < 0) {
93 panic("random_init: failed to allocate a major number!");
94 }
95
96 devfs_make_node(makedev (ret, RANDOM_MINOR), DEVFS_CHAR,
97 UID_ROOT, GID_WHEEL, 0666, "random", 0);
98
99 /*
100 * also make urandom
101 * (which is exactly the same thing in our context)
102 */
103 devfs_make_node(makedev (ret, URANDOM_MINOR), DEVFS_CHAR,
104 UID_ROOT, GID_WHEEL, 0666, "urandom", 0);
105
106}
107
108int
109random_ioctl( __unused dev_t dev, u_long cmd, __unused caddr_t data,
110 __unused int flag, __unused struct proc *p )
111{
112 switch (cmd) {
113 case FIONBIO:
114 case FIOASYNC:
115 break;
116 default:
117 return ENODEV;
118 }
119
120 return (0);
121}
122
123/*
124 * Open the device. Make sure init happened, and make sure the caller is
125 * authorized.
126 */
127
128int
129random_open(__unused dev_t dev, int flags, __unused int devtype, __unused struct proc *p)
130{
131 /*
132 * if we are being opened for write,
133 * make sure that we have privledges do so
134 */
135 if (flags & FWRITE) {
136 if (securelevel >= 2)
137 return (EPERM);
138#ifndef __APPLE__
139 if ((securelevel >= 1) && proc_suser(p))
140 return (EPERM);
141#endif /* !__APPLE__ */
142 }
143
144 return (0);
145}
146
147
148/*
149 * close the device.
150 */
151
152int
153random_close(__unused dev_t dev, __unused int flags, __unused int mode, __unused struct proc *p)
154{
155 return (0);
156}
157
158
159/*
160 * Get entropic data from the Security Server, and use it to reseed the
161 * prng.
162 */
163int
164random_write (dev_t dev, struct uio *uio, __unused int ioflag)
165{
166 int retCode = 0;
167 char rdBuffer[256];
168
169 if (minor(dev) != RANDOM_MINOR)
170 return EPERM;
171
172 /* Security server is sending us entropy */
173
174 while (uio_resid(uio) > 0 && retCode == 0) {
175 /* get the user's data */
176 int bytesToInput = MIN(uio_resid(uio),
177 (user_ssize_t) sizeof(rdBuffer));
178 retCode = uiomove(rdBuffer, bytesToInput, uio);
179 if (retCode != 0)
180 break;
181 retCode = write_random(rdBuffer, bytesToInput);
182 if (retCode != 0)
183 break;
184 }
185
186 return retCode;
187}
188
189/*
190 * return data to the caller. Results unpredictable.
191 */
192int
193random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
194{
195 int retCode = 0;
196 char buffer[512];
197
198 user_ssize_t bytes_remaining = uio_resid(uio);
199 while (bytes_remaining > 0 && retCode == 0) {
200 int bytesToRead = MIN(bytes_remaining,
201 (user_ssize_t) sizeof(buffer));
202 read_random(buffer, bytesToRead);
203
204 retCode = uiomove(buffer, bytesToRead, uio);
205 if (retCode != 0)
206 break;
207
208 bytes_remaining = uio_resid(uio);
209 }
210
211 return retCode;
212}
213
214/*
215 * Return an u_int32_t pseudo-random number.
216 */
217u_int32_t
218RandomULong(void)
219{
220 u_int32_t buf;
221 read_random(&buf, sizeof (buf));
222 return (buf);
223}
224
225
226int
227getentropy(__unused struct proc * p, struct getentropy_args *gap, __unused int * ret) {
228 user_addr_t user_addr;
229 uint32_t user_size;
230 char buffer[256];
231
232 user_addr = (vm_map_offset_t)gap->buffer;
233 user_size = gap->size;
234 /* Can't request more than 256 random bytes
235 * at once. Complying with openbsd getentropy()
236 */
237 if (user_size > sizeof(buffer)) {
238 return EINVAL;
239 }
240 read_random(buffer, user_size);
241 return copyout(buffer, user_addr, user_size);
242}
243