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 #ifndef AUTOCONF_INCLUDED
39 #include <linux/config.h>
41 #include <linux/module.h>
42 #include <linux/init.h>
43 #include <linux/list.h>
44 #include <linux/slab.h>
45 #include <linux/wait.h>
46 #include <linux/sched.h>
47 #include <linux/spinlock.h>
48 #include <linux/version.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"
62 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
63 #include <linux/sched.h>
64 #define kill_proc(p,s,v) send_sig(s,find_task_by_vpid(p),0)
68 * a hack to access the debug levels from the crypto driver
70 extern int crypto_debug;
71 #define debug crypto_debug
74 * a list of all registered random providers
76 static LIST_HEAD(random_ops);
77 static int started = 0;
78 static int initted = 0;
81 struct list_head random_list;
83 int (*read_random)(void *arg, u_int32_t *buf, int len);
87 static int random_proc(void *arg);
89 static pid_t randomproc = (pid_t) -1;
90 static spinlock_t random_lock;
93 * just init the spin locks
96 crypto_random_init(void)
98 spin_lock_init(&random_lock);
104 * Add the given random reader to our list (if not present)
105 * and start the thread (if not already started)
107 * we have to assume that driver id is ok for now
112 int (*read_random)(void *arg, u_int32_t *buf, int len),
117 struct random_op *rops, *tmp;
119 dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__, __LINE__,
120 __FUNCTION__, driverid, read_random, arg);
123 crypto_random_init();
126 struct cryptocap *cap;
128 cap = crypto_checkdriver(driverid);
133 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
134 if (rops->driverid == driverid && rops->read_random == read_random)
138 rops = (struct random_op *) kmalloc(sizeof(*rops), GFP_KERNEL);
142 rops->driverid = driverid;
143 rops->read_random = read_random;
146 spin_lock_irqsave(&random_lock, flags);
147 list_add_tail(&rops->random_list, &random_ops);
149 randomproc = kernel_thread(random_proc, NULL, CLONE_FS|CLONE_FILES);
150 if (randomproc < 0) {
152 printk("crypto: crypto_rregister cannot start random thread; "
157 spin_unlock_irqrestore(&random_lock, flags);
161 EXPORT_SYMBOL(crypto_rregister);
164 crypto_runregister_all(u_int32_t driverid)
166 struct random_op *rops, *tmp;
169 dprintk("%s,%d: %s(0x%x)\n", __FILE__, __LINE__, __FUNCTION__, driverid);
171 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
172 if (rops->driverid == driverid) {
173 list_del(&rops->random_list);
178 spin_lock_irqsave(&random_lock, flags);
179 if (list_empty(&random_ops) && started)
180 kill_proc(randomproc, SIGKILL, 1);
181 spin_unlock_irqrestore(&random_lock, flags);
184 EXPORT_SYMBOL(crypto_runregister_all);
187 * while we can add entropy to random.c continue to read random data from
188 * the drivers and push it to random.
191 random_proc(void *arg)
199 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
201 spin_lock_irq(¤t->sigmask_lock);
202 sigemptyset(¤t->blocked);
203 recalc_sigpending(current);
204 spin_unlock_irq(¤t->sigmask_lock);
205 sprintf(current->comm, "ocf-random");
207 daemonize("ocf-random");
208 allow_signal(SIGKILL);
214 #ifdef CONFIG_OCF_FIPS
215 #define NUM_INT (RNDTEST_NBYTES/sizeof(int))
221 * some devices can transferr their RNG data direct into memory,
222 * so make sure it is device friendly
224 buf = kmalloc(NUM_INT * sizeof(int), GFP_DMA);
226 printk("crypto: RNG could not allocate memory\n");
231 wantcnt = NUM_INT; /* start by adding some entropy */
234 * its possible due to errors or driver removal that we no longer
235 * have anything to do, if so exit or we will consume all the CPU
238 while (!list_empty(&random_ops)) {
239 struct random_op *rops, *tmp;
241 #ifdef CONFIG_OCF_FIPS
243 wantcnt = NUM_INT; /* FIPs mode can do 20000 bits or none */
246 /* see if we can get enough entropy to make the world
249 while (bufcnt < wantcnt && bufcnt < NUM_INT) {
250 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
252 n = (*rops->read_random)(rops->arg, &buf[bufcnt],
255 /* on failure remove the random number generator */
257 list_del(&rops->random_list);
258 printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
264 /* give up CPU for a bit, just in case as this is a loop */
269 #ifdef CONFIG_OCF_FIPS
270 if (bufcnt > 0 && rndtest_buf((unsigned char *) &buf[0])) {
271 dprintk("crypto: buffer had fips errors, discarding\n");
277 * if we have a certified buffer, we can send some data
278 * to /dev/random and move along
281 /* add what we have */
282 random_input_words(buf, bufcnt, bufcnt*sizeof(int)*8);
286 /* give up CPU for a bit so we don't hog while filling */
289 /* wait for needing more */
290 wantcnt = random_input_wait();
293 wantcnt = 0; /* try to get some info again */
295 /* round up to one word or we can loop forever */
296 wantcnt = (wantcnt + (sizeof(int)*8)) / (sizeof(int)*8);
297 if (wantcnt > NUM_INT) {
301 if (signal_pending(current)) {
302 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
303 spin_lock_irq(¤t->sigmask_lock);
305 flush_signals(current);
306 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
307 spin_unlock_irq(¤t->sigmask_lock);
315 spin_lock_irq(&random_lock);
316 randomproc = (pid_t) -1;
318 spin_unlock_irq(&random_lock);