target/linux/generic-2.6/files/crypto/ocf/random.c

   1 /*
   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.
   5  *
   6  * This should be fast and callable from timers/interrupts
   7  *
   8  * Written by David McCullough <david_mccullough@mcafee.com>
   9  * Copyright (C) 2006-2010 David McCullough
  10  * Copyright (C) 2004-2005 Intel Corporation.
  11  *
  12  * LICENSE TERMS
  13  *
  14  * The free distribution and use of this software in both source and binary
  15  * form is allowed (with or without changes) provided that:
  16  *
  17  *   1. distributions of this source code include the above copyright
  18  *      notice, this list of conditions and the following disclaimer;
  19  *
  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;
  23  *
  24  *   3. the copyright holder's name is not used to endorse products
  25  *      built using this software without specific written permission.
  26  *
  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.
  30  *
  31  * DISCLAIMER
  32  *
  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.
  36  */
  37
  38 #ifndef AUTOCONF_INCLUDED
  39 #include <linux/config.h>
  40 #endif
  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>
  53
  54 #ifdef CONFIG_OCF_FIPS
  55 #include "rndtest.h"
  56 #endif
  57
  58 #ifndef HAS_RANDOM_INPUT_WAIT
  59 #error "Please do not enable OCF_RANDOMHARVEST unless you have applied patches"
  60 #endif
  61
  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)
  65 #endif
  66
  67 /*
  68  * a hack to access the debug levels from the crypto driver
  69  */
  70 extern int crypto_debug;
  71 #define debug crypto_debug
  72
  73 /*
  74  * a list of all registered random providers
  75  */
  76 static LIST_HEAD(random_ops);
  77 static int started = 0;
  78 static int initted = 0;
  79
  80 struct random_op {
  81         struct list_head random_list;
  82         u_int32_t driverid;
  83         int (*read_random)(void *arg, u_int32_t *buf, int len);
  84         void *arg;
  85 };
  86
  87 static int random_proc(void *arg);
  88
  89 static pid_t            randomproc = (pid_t) -1;
  90 static spinlock_t       random_lock;
  91
  92 /*
  93  * just init the spin locks
  94  */
  95 static int
  96 crypto_random_init(void)
  97 {
  98         spin_lock_init(&random_lock);
  99         initted = 1;
 100         return(0);
 101 }
 102
 103 /*
 104  * Add the given random reader to our list (if not present)
 105  * and start the thread (if not already started)
 106  *
 107  * we have to assume that driver id is ok for now
 108  */
 109 int
 110 crypto_rregister(
 111         u_int32_t driverid,
 112         int (*read_random)(void *arg, u_int32_t *buf, int len),
 113         void *arg)
 114 {
 115         unsigned long flags;
 116         int ret = 0;
 117         struct random_op        *rops, *tmp;
 118
 119         dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__, __LINE__,
 120                         __FUNCTION__, driverid, read_random, arg);
 121
 122         if (!initted)
 123                 crypto_random_init();
 124
 125 #if 0
 126         struct cryptocap        *cap;
 127
 128         cap = crypto_checkdriver(driverid);
 129         if (!cap)
 130                 return EINVAL;
 131 #endif
 132
 133         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 134                 if (rops->driverid == driverid && rops->read_random == read_random)
 135                         return EEXIST;
 136         }
 137
 138         rops = (struct random_op *) kmalloc(sizeof(*rops), GFP_KERNEL);
 139         if (!rops)
 140                 return ENOMEM;
 141
 142         rops->driverid    = driverid;
 143         rops->read_random = read_random;
 144         rops->arg = arg;
 145
 146         spin_lock_irqsave(&random_lock, flags);
 147         list_add_tail(&rops->random_list, &random_ops);
 148         if (!started) {
 149                 randomproc = kernel_thread(random_proc, NULL, CLONE_FS|CLONE_FILES);
 150                 if (randomproc < 0) {
 151                         ret = randomproc;
 152                         printk("crypto: crypto_rregister cannot start random thread; "
 153                                         "error %d", ret);
 154                 } else
 155                         started = 1;
 156         }
 157         spin_unlock_irqrestore(&random_lock, flags);
 158
 159         return ret;
 160 }
 161 EXPORT_SYMBOL(crypto_rregister);
 162
 163 int
 164 crypto_runregister_all(u_int32_t driverid)
 165 {
 166         struct random_op *rops, *tmp;
 167         unsigned long flags;
 168
 169         dprintk("%s,%d: %s(0x%x)\n", __FILE__, __LINE__, __FUNCTION__, driverid);
 170
 171         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 172                 if (rops->driverid == driverid) {
 173                         list_del(&rops->random_list);
 174                         kfree(rops);
 175                 }
 176         }
 177
 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);
 182         return(0);
 183 }
 184 EXPORT_SYMBOL(crypto_runregister_all);
 185
 186 /*
 187  * while we can add entropy to random.c continue to read random data from
 188  * the drivers and push it to random.
 189  */
 190 static int
 191 random_proc(void *arg)
 192 {
 193         int n;
 194         int wantcnt;
 195         int bufcnt = 0;
 196         int retval = 0;
 197         int *buf = NULL;
 198
 199 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 200         daemonize();
 201         spin_lock_irq(&current->sigmask_lock);
 202         sigemptyset(&current->blocked);
 203         recalc_sigpending(current);
 204         spin_unlock_irq(&current->sigmask_lock);
 205         sprintf(current->comm, "ocf-random");
 206 #else
 207         daemonize("ocf-random");
 208         allow_signal(SIGKILL);
 209 #endif
 210
 211         (void) get_fs();
 212         set_fs(get_ds());
 213
 214 #ifdef CONFIG_OCF_FIPS
 215 #define NUM_INT (RNDTEST_NBYTES/sizeof(int))
 216 #else
 217 #define NUM_INT 32
 218 #endif
 219
 220         /*
 221          * some devices can transferr their RNG data direct into memory,
 222          * so make sure it is device friendly
 223          */
 224         buf = kmalloc(NUM_INT * sizeof(int), GFP_DMA);
 225         if (NULL == buf) {
 226                 printk("crypto: RNG could not allocate memory\n");
 227                 retval = -ENOMEM;
 228                 goto bad_alloc;
 229         }
 230
 231         wantcnt = NUM_INT;   /* start by adding some entropy */
 232
 233         /*
 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
 236          * doing nothing
 237          */
 238         while (!list_empty(&random_ops)) {
 239                 struct random_op        *rops, *tmp;
 240
 241 #ifdef CONFIG_OCF_FIPS
 242                 if (wantcnt)
 243                         wantcnt = NUM_INT; /* FIPs mode can do 20000 bits or none */
 244 #endif
 245
 246                 /* see if we can get enough entropy to make the world
 247                  * a better place.
 248                  */
 249                 while (bufcnt < wantcnt && bufcnt < NUM_INT) {
 250                         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 251
 252                                 n = (*rops->read_random)(rops->arg, &buf[bufcnt],
 253                                                          NUM_INT - bufcnt);
 254
 255                                 /* on failure remove the random number generator */
 256                                 if (n == -1) {
 257                                         list_del(&rops->random_list);
 258                                         printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
 259                                                         rops->driverid);
 260                                         kfree(rops);
 261                                 } else if (n > 0)
 262                                         bufcnt += n;
 263                         }
 264                         /* give up CPU for a bit, just in case as this is a loop */
 265                         schedule();
 266                 }
 267
 268
 269 #ifdef CONFIG_OCF_FIPS
 270                 if (bufcnt > 0 && rndtest_buf((unsigned char *) &buf[0])) {
 271                         dprintk("crypto: buffer had fips errors, discarding\n");
 272                         bufcnt = 0;
 273                 }
 274 #endif
 275
 276                 /*
 277                  * if we have a certified buffer,  we can send some data
 278                  * to /dev/random and move along
 279                  */
 280                 if (bufcnt > 0) {
 281                         /* add what we have */
 282                         random_input_words(buf, bufcnt, bufcnt*sizeof(int)*8);
 283                         bufcnt = 0;
 284                 }
 285
 286                 /* give up CPU for a bit so we don't hog while filling */
 287                 schedule();
 288
 289                 /* wait for needing more */
 290                 wantcnt = random_input_wait();
 291
 292                 if (wantcnt <= 0)
 293                         wantcnt = 0; /* try to get some info again */
 294                 else
 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) {
 298                         wantcnt = NUM_INT;
 299                 }
 300
 301                 if (signal_pending(current)) {
 302 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 303                         spin_lock_irq(&current->sigmask_lock);
 304 #endif
 305                         flush_signals(current);
 306 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 307                         spin_unlock_irq(&current->sigmask_lock);
 308 #endif
 309                 }
 310         }
 311
 312         kfree(buf);
 313
 314 bad_alloc:
 315         spin_lock_irq(&random_lock);
 316         randomproc = (pid_t) -1;
 317         started = 0;
 318         spin_unlock_irq(&random_lock);
 319
 320         return retval;
 321 }
 322