2 * A system independant way of adding entropy to the kernels pool
3 * this way the drivers can focus on the real work and we can take
4 * care of pushing it to the appropriate place in the kernel.
6 * This should be fast and callable from timers/interrupts
8 * Written by David McCullough <david_mccullough@mcafee.com>
9 * Copyright (C) 2006-2010 David McCullough
10 * Copyright (C) 2004-2005 Intel Corporation.
14 * The free distribution and use of this software in both source and binary
15 * form is allowed (with or without changes) provided that:
17 * 1. distributions of this source code include the above copyright
18 * notice, this list of conditions and the following disclaimer;
20 * 2. distributions in binary form include the above copyright
21 * notice, this list of conditions and the following disclaimer
22 * in the documentation and/or other associated materials;
24 * 3. the copyright holder's name is not used to endorse products
25 * built using this software without specific written permission.
27 * ALTERNATIVELY, provided that this notice is retained in full, this product
28 * may be distributed under the terms of the GNU General Public License (GPL),
29 * in which case the provisions of the GPL apply INSTEAD OF those given above.
33 * This software is provided 'as is' with no explicit or implied warranties
34 * in respect of its properties, including, but not limited to, correctness
35 * and/or fitness for purpose.
38 #include <linux/version.h>
39 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,38) && !defined(AUTOCONF_INCLUDED)
40 #include <linux/config.h>
42 #include <linux/module.h>
43 #include <linux/init.h>
44 #include <linux/list.h>
45 #include <linux/slab.h>
46 #include <linux/wait.h>
47 #include <linux/sched.h>
48 #include <linux/spinlock.h>
49 #include <linux/unistd.h>
50 #include <linux/poll.h>
51 #include <linux/random.h>
52 #include <cryptodev.h>
54 #ifdef CONFIG_OCF_FIPS
58 #ifndef HAS_RANDOM_INPUT_WAIT
59 #error "Please do not enable OCF_RANDOMHARVEST unless you have applied patches"
63 * a hack to access the debug levels from the crypto driver
65 extern int crypto_debug
;
66 #define debug crypto_debug
69 * a list of all registered random providers
71 static LIST_HEAD(random_ops
);
72 static int started
= 0;
73 static int initted
= 0;
76 struct list_head random_list
;
78 int (*read_random
)(void *arg
, u_int32_t
*buf
, int len
);
82 static int random_proc(void *arg
);
84 static pid_t randomproc
= (pid_t
) -1;
85 static spinlock_t random_lock
;
88 * just init the spin locks
91 crypto_random_init(void)
93 spin_lock_init(&random_lock
);
99 * Add the given random reader to our list (if not present)
100 * and start the thread (if not already started)
102 * we have to assume that driver id is ok for now
107 int (*read_random
)(void *arg
, u_int32_t
*buf
, int len
),
112 struct random_op
*rops
, *tmp
;
114 dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__
, __LINE__
,
115 __FUNCTION__
, driverid
, read_random
, arg
);
118 crypto_random_init();
121 struct cryptocap
*cap
;
123 cap
= crypto_checkdriver(driverid
);
128 list_for_each_entry_safe(rops
, tmp
, &random_ops
, random_list
) {
129 if (rops
->driverid
== driverid
&& rops
->read_random
== read_random
)
133 rops
= (struct random_op
*) kmalloc(sizeof(*rops
), GFP_KERNEL
);
137 rops
->driverid
= driverid
;
138 rops
->read_random
= read_random
;
141 spin_lock_irqsave(&random_lock
, flags
);
142 list_add_tail(&rops
->random_list
, &random_ops
);
144 randomproc
= kernel_thread(random_proc
, NULL
, CLONE_FS
|CLONE_FILES
);
145 if (randomproc
< 0) {
147 printk("crypto: crypto_rregister cannot start random thread; "
152 spin_unlock_irqrestore(&random_lock
, flags
);
156 EXPORT_SYMBOL(crypto_rregister
);
159 crypto_runregister_all(u_int32_t driverid
)
161 struct random_op
*rops
, *tmp
;
164 dprintk("%s,%d: %s(0x%x)\n", __FILE__
, __LINE__
, __FUNCTION__
, driverid
);
166 list_for_each_entry_safe(rops
, tmp
, &random_ops
, random_list
) {
167 if (rops
->driverid
== driverid
) {
168 list_del(&rops
->random_list
);
173 spin_lock_irqsave(&random_lock
, flags
);
174 if (list_empty(&random_ops
) && started
)
175 kill_proc(randomproc
, SIGKILL
, 1);
176 spin_unlock_irqrestore(&random_lock
, flags
);
179 EXPORT_SYMBOL(crypto_runregister_all
);
182 * while we can add entropy to random.c continue to read random data from
183 * the drivers and push it to random.
186 random_proc(void *arg
)
194 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
196 spin_lock_irq(¤t
->sigmask_lock
);
197 sigemptyset(¤t
->blocked
);
198 recalc_sigpending(current
);
199 spin_unlock_irq(¤t
->sigmask_lock
);
200 sprintf(current
->comm
, "ocf-random");
202 daemonize("ocf-random");
203 allow_signal(SIGKILL
);
209 #ifdef CONFIG_OCF_FIPS
210 #define NUM_INT (RNDTEST_NBYTES/sizeof(int))
216 * some devices can transferr their RNG data direct into memory,
217 * so make sure it is device friendly
219 buf
= kmalloc(NUM_INT
* sizeof(int), GFP_DMA
);
221 printk("crypto: RNG could not allocate memory\n");
226 wantcnt
= NUM_INT
; /* start by adding some entropy */
229 * its possible due to errors or driver removal that we no longer
230 * have anything to do, if so exit or we will consume all the CPU
233 while (!list_empty(&random_ops
)) {
234 struct random_op
*rops
, *tmp
;
236 #ifdef CONFIG_OCF_FIPS
238 wantcnt
= NUM_INT
; /* FIPs mode can do 20000 bits or none */
241 /* see if we can get enough entropy to make the world
244 while (bufcnt
< wantcnt
&& bufcnt
< NUM_INT
) {
245 list_for_each_entry_safe(rops
, tmp
, &random_ops
, random_list
) {
247 n
= (*rops
->read_random
)(rops
->arg
, &buf
[bufcnt
],
250 /* on failure remove the random number generator */
252 list_del(&rops
->random_list
);
253 printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
259 /* give up CPU for a bit, just in case as this is a loop */
264 #ifdef CONFIG_OCF_FIPS
265 if (bufcnt
> 0 && rndtest_buf((unsigned char *) &buf
[0])) {
266 dprintk("crypto: buffer had fips errors, discarding\n");
272 * if we have a certified buffer, we can send some data
273 * to /dev/random and move along
276 /* add what we have */
277 random_input_words(buf
, bufcnt
, bufcnt
*sizeof(int)*8);
281 /* give up CPU for a bit so we don't hog while filling */
284 /* wait for needing more */
285 wantcnt
= random_input_wait();
288 wantcnt
= 0; /* try to get some info again */
290 /* round up to one word or we can loop forever */
291 wantcnt
= (wantcnt
+ (sizeof(int)*8)) / (sizeof(int)*8);
292 if (wantcnt
> NUM_INT
) {
296 if (signal_pending(current
)) {
297 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
298 spin_lock_irq(¤t
->sigmask_lock
);
300 flush_signals(current
);
301 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
302 spin_unlock_irq(¤t
->sigmask_lock
);
310 spin_lock_irq(&random_lock
);
311 randomproc
= (pid_t
) -1;
313 spin_unlock_irq(&random_lock
);
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