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 <linux/kthread.h>
53 #include <cryptodev.h>
55 #ifdef CONFIG_OCF_FIPS
59 #ifndef HAS_RANDOM_INPUT_WAIT
60 #error "Please do not enable OCF_RANDOMHARVEST unless you have applied patches"
64 * a hack to access the debug levels from the crypto driver
66 extern int crypto_debug;
67 #define debug crypto_debug
70 * a list of all registered random providers
72 static LIST_HEAD(random_ops);
73 static int started = 0;
74 static int initted = 0;
77 struct list_head random_list;
79 int (*read_random)(void *arg, u_int32_t *buf, int len);
83 static struct task_struct *random_thread;
84 static int random_proc(void *arg);
86 static spinlock_t random_lock;
89 * just init the spin locks
92 crypto_random_init(void)
94 spin_lock_init(&random_lock);
100 * Add the given random reader to our list (if not present)
101 * and start the thread (if not already started)
103 * we have to assume that driver id is ok for now
108 int (*read_random)(void *arg, u_int32_t *buf, int len),
113 struct random_op *rops, *tmp;
115 dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__, __LINE__,
116 __FUNCTION__, driverid, read_random, arg);
119 crypto_random_init();
122 struct cryptocap *cap;
124 cap = crypto_checkdriver(driverid);
129 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
130 if (rops->driverid == driverid && rops->read_random == read_random)
134 rops = (struct random_op *) kmalloc(sizeof(*rops), GFP_KERNEL);
138 rops->driverid = driverid;
139 rops->read_random = read_random;
142 spin_lock_irqsave(&random_lock, flags);
143 list_add_tail(&rops->random_list, &random_ops);
145 random_thread = kthread_run(random_proc, NULL, "ocf-random");
146 if (IS_ERR(random_thread))
147 ret = PTR_ERR(random_thread);
151 spin_unlock_irqrestore(&random_lock, flags);
155 EXPORT_SYMBOL(crypto_rregister);
158 crypto_runregister_all(u_int32_t driverid)
160 struct random_op *rops, *tmp;
163 dprintk("%s,%d: %s(0x%x)\n", __FILE__, __LINE__, __FUNCTION__, driverid);
165 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
166 if (rops->driverid == driverid) {
167 list_del(&rops->random_list);
172 spin_lock_irqsave(&random_lock, flags);
173 if (list_empty(&random_ops) && started)
174 kthread_stop(random_thread);
175 spin_unlock_irqrestore(&random_lock, flags);
178 EXPORT_SYMBOL(crypto_runregister_all);
181 * while we can add entropy to random.c continue to read random data from
182 * the drivers and push it to random.
185 random_proc(void *arg)
193 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
195 spin_lock_irq(¤t->sigmask_lock);
196 sigemptyset(¤t->blocked);
197 recalc_sigpending(current);
198 spin_unlock_irq(¤t->sigmask_lock);
199 sprintf(current->comm, "ocf-random");
200 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(3,8,0)
202 sprintf(current->comm, "ocf-random");
204 daemonize("ocf-random");
210 #ifdef CONFIG_OCF_FIPS
211 #define NUM_INT (RNDTEST_NBYTES/sizeof(int))
217 * some devices can transferr their RNG data direct into memory,
218 * so make sure it is device friendly
220 buf = kmalloc(NUM_INT * sizeof(int), GFP_DMA);
222 printk("crypto: RNG could not allocate memory\n");
227 wantcnt = NUM_INT; /* start by adding some entropy */
230 * its possible due to errors or driver removal that we no longer
231 * have anything to do, if so exit or we will consume all the CPU
234 while (!list_empty(&random_ops)) {
235 struct random_op *rops, *tmp;
237 #ifdef CONFIG_OCF_FIPS
239 wantcnt = NUM_INT; /* FIPs mode can do 20000 bits or none */
242 /* see if we can get enough entropy to make the world
245 while (bufcnt < wantcnt && bufcnt < NUM_INT) {
246 list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
248 n = (*rops->read_random)(rops->arg, &buf[bufcnt],
251 /* on failure remove the random number generator */
253 list_del(&rops->random_list);
254 printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
260 /* give up CPU for a bit, just in case as this is a loop */
265 #ifdef CONFIG_OCF_FIPS
266 if (bufcnt > 0 && rndtest_buf((unsigned char *) &buf[0])) {
267 dprintk("crypto: buffer had fips errors, discarding\n");
273 * if we have a certified buffer, we can send some data
274 * to /dev/random and move along
277 /* add what we have */
278 random_input_words(buf, bufcnt, bufcnt*sizeof(int)*8);
282 /* give up CPU for a bit so we don't hog while filling */
285 /* wait for needing more */
286 wantcnt = random_input_wait();
289 wantcnt = 0; /* try to get some info again */
291 /* round up to one word or we can loop forever */
292 wantcnt = (wantcnt + (sizeof(int)*8)) / (sizeof(int)*8);
293 if (wantcnt > NUM_INT) {
297 if (signal_pending(current)) {
298 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
299 spin_lock_irq(¤t->sigmask_lock);
301 flush_signals(current);
302 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
303 spin_unlock_irq(¤t->sigmask_lock);
311 spin_lock_irq(&random_lock);
313 spin_unlock_irq(&random_lock);