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/uio_internal.h>
44
45#include <dev/random/randomdev.h>
46
47#include <libkern/OSByteOrder.h>
48#include <libkern/OSAtomic.h>
49
50#include <mach/mach_time.h>
51
52#define RANDOM_MAJOR  -1 /* let the kernel pick the device number */
53#define RANDOM_MINOR   0
54#define URANDOM_MINOR  1
55
56d_ioctl_t       random_ioctl;
57
58/*
59 * A struct describing which functions will get invoked for certain
60 * actions.
61 */
62static struct cdevsw random_cdevsw =
63{
64	random_open,		/* open */
65	random_close,		/* close */
66	random_read,		/* read */
67	random_write,		/* write */
68	random_ioctl,		/* ioctl */
69	(stop_fcn_t *)nulldev, /* stop */
70	(reset_fcn_t *)nulldev, /* reset */
71	NULL,				/* tty's */
72	eno_select,			/* select */
73	eno_mmap,			/* mmap */
74	eno_strat,			/* strategy */
75	eno_getc,			/* getc */
76	eno_putc,			/* putc */
77	0					/* type */
78};
79
80
81/*
82 * Called to initialize our device,
83 * and to register ourselves with devfs
84 */
85void
86random_init(void)
87{
88	int ret;
89
90	ret = cdevsw_add(RANDOM_MAJOR, &random_cdevsw);
91	if (ret < 0) {
92		panic("random_init: failed to allocate a major number!");
93	}
94
95	devfs_make_node(makedev (ret, RANDOM_MINOR), DEVFS_CHAR,
96		UID_ROOT, GID_WHEEL, 0666, "random", 0);
97
98	/*
99	 * also make urandom
100	 * (which is exactly the same thing in our context)
101	 */
102	devfs_make_node(makedev (ret, URANDOM_MINOR), DEVFS_CHAR,
103		UID_ROOT, GID_WHEEL, 0666, "urandom", 0);
104
105}
106
107int
108random_ioctl(	__unused dev_t dev, u_long cmd, __unused caddr_t data,
109				__unused int flag, __unused struct proc *p  )
110{
111	switch (cmd) {
112	case FIONBIO:
113	case FIOASYNC:
114		break;
115	default:
116		return ENODEV;
117	}
118
119	return (0);
120}
121
122/*
123 * Open the device.  Make sure init happened, and make sure the caller is
124 * authorized.
125 */
126
127int
128random_open(__unused dev_t dev, int flags, __unused int devtype, __unused struct proc *p)
129{
130	/*
131	 * if we are being opened for write,
132	 * make sure that we have privledges do so
133	 */
134	if (flags & FWRITE) {
135		if (securelevel >= 2)
136			return (EPERM);
137#ifndef __APPLE__
138		if ((securelevel >= 1) && proc_suser(p))
139			return (EPERM);
140#endif	/* !__APPLE__ */
141	}
142
143	return (0);
144}
145
146
147/*
148 * close the device.
149 */
150
151int
152random_close(__unused dev_t dev, __unused int flags, __unused int mode, __unused struct proc *p)
153{
154	return (0);
155}
156
157
158/*
159 * Get entropic data from the Security Server, and use it to reseed the
160 * prng.
161 */
162int
163random_write (dev_t dev, struct uio *uio, __unused int ioflag)
164{
165    int retCode = 0;
166    char rdBuffer[256];
167
168    if (minor(dev) != RANDOM_MINOR)
169	return EPERM;
170
171    /* Security server is sending us entropy */
172
173    while (uio_resid(uio) > 0 && retCode == 0) {
174        /* get the user's data */
175        int bytesToInput = MIN(uio_resid(uio),
176			       (user_ssize_t) sizeof(rdBuffer));
177        retCode = uiomove(rdBuffer, bytesToInput, uio);
178        if (retCode != 0)
179	    break;
180	retCode = write_random(rdBuffer, bytesToInput);
181        if (retCode != 0)
182	    break;
183    }
184
185    return retCode;
186}
187
188/*
189 * return data to the caller.  Results unpredictable.
190 */
191int
192random_read(__unused dev_t dev, struct uio *uio, __unused int ioflag)
193{
194	int retCode = 0;
195	char buffer[512];
196
197	user_ssize_t bytes_remaining = uio_resid(uio);
198	while (bytes_remaining > 0 && retCode == 0) {
199		int bytesToRead = MIN(bytes_remaining,
200				      (user_ssize_t) sizeof(buffer));
201		read_random(buffer, bytesToRead);
202
203		retCode = uiomove(buffer, bytesToRead, uio);
204		if (retCode != 0)
205			break;
206
207		bytes_remaining = uio_resid(uio);
208	}
209
210	return retCode;
211}
212
213/*
214 * Return an u_int32_t pseudo-random number.
215 */
216u_int32_t
217RandomULong(void)
218{
219	u_int32_t buf;
220	read_random(&buf, sizeof (buf));
221	return (buf);
222}
223
224