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@securecomputing.com>
   9  * Copyright (C) 2006-2007 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 /*
  63  * a hack to access the debug levels from the crypto driver
  64  */
  65 extern int crypto_debug;
  66 #define debug crypto_debug
  67
  68 /*
  69  * a list of all registered random providers
  70  */
  71 static LIST_HEAD(random_ops);
  72 static int started = 0;
  73 static int initted = 0;
  74
  75 struct random_op {
  76         struct list_head random_list;
  77         u_int32_t driverid;
  78         int (*read_random)(void *arg, u_int32_t *buf, int len);
  79         void *arg;
  80 };
  81
  82 static int random_proc(void *arg);
  83
  84 static pid_t            randomproc = (pid_t) -1;
  85 static spinlock_t       random_lock;
  86
  87 /*
  88  * just init the spin locks
  89  */
  90 static int
  91 crypto_random_init(void)
  92 {
  93         spin_lock_init(&random_lock);
  94         initted = 1;
  95         return(0);
  96 }
  97
  98 /*
  99  * Add the given random reader to our list (if not present)
 100  * and start the thread (if not already started)
 101  *
 102  * we have to assume that driver id is ok for now
 103  */
 104 int
 105 crypto_rregister(
 106         u_int32_t driverid,
 107         int (*read_random)(void *arg, u_int32_t *buf, int len),
 108         void *arg)
 109 {
 110         unsigned long flags;
 111         int ret = 0;
 112         struct random_op        *rops, *tmp;
 113
 114         dprintk("%s,%d: %s(0x%x, %p, %p)\n", __FILE__, __LINE__,
 115                         __FUNCTION__, driverid, read_random, arg);
 116
 117         if (!initted)
 118                 crypto_random_init();
 119
 120 #if 0
 121         struct cryptocap        *cap;
 122
 123         cap = crypto_checkdriver(driverid);
 124         if (!cap)
 125                 return EINVAL;
 126 #endif
 127
 128         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 129                 if (rops->driverid == driverid && rops->read_random == read_random)
 130                         return EEXIST;
 131         }
 132
 133         rops = (struct random_op *) kmalloc(sizeof(*rops), GFP_KERNEL);
 134         if (!rops)
 135                 return ENOMEM;
 136
 137         rops->driverid    = driverid;
 138         rops->read_random = read_random;
 139         rops->arg = arg;
 140
 141         spin_lock_irqsave(&random_lock, flags);
 142         list_add_tail(&rops->random_list, &random_ops);
 143         if (!started) {
 144                 randomproc = kernel_thread(random_proc, NULL, CLONE_FS|CLONE_FILES);
 145                 if (randomproc < 0) {
 146                         ret = randomproc;
 147                         printk("crypto: crypto_rregister cannot start random thread; "
 148                                         "error %d", ret);
 149                 } else
 150                         started = 1;
 151         }
 152         spin_unlock_irqrestore(&random_lock, flags);
 153
 154         return ret;
 155 }
 156 EXPORT_SYMBOL(crypto_rregister);
 157
 158 int
 159 crypto_runregister_all(u_int32_t driverid)
 160 {
 161         struct random_op *rops, *tmp;
 162         unsigned long flags;
 163
 164         dprintk("%s,%d: %s(0x%x)\n", __FILE__, __LINE__, __FUNCTION__, driverid);
 165
 166         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 167                 if (rops->driverid == driverid) {
 168                         list_del(&rops->random_list);
 169                         kfree(rops);
 170                 }
 171         }
 172
 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);
 177         return(0);
 178 }
 179 EXPORT_SYMBOL(crypto_runregister_all);
 180
 181 /*
 182  * while we can add entropy to random.c continue to read random data from
 183  * the drivers and push it to random.
 184  */
 185 static int
 186 random_proc(void *arg)
 187 {
 188         int n;
 189         int wantcnt;
 190         int bufcnt = 0;
 191         int retval = 0;
 192         int *buf = NULL;
 193
 194 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 195         daemonize();
 196         spin_lock_irq(&current->sigmask_lock);
 197         sigemptyset(&current->blocked);
 198         recalc_sigpending(current);
 199         spin_unlock_irq(&current->sigmask_lock);
 200         sprintf(current->comm, "ocf-random");
 201 #else
 202         daemonize("ocf-random");
 203         allow_signal(SIGKILL);
 204 #endif
 205
 206         (void) get_fs();
 207         set_fs(get_ds());
 208
 209 #ifdef CONFIG_OCF_FIPS
 210 #define NUM_INT (RNDTEST_NBYTES/sizeof(int))
 211 #else
 212 #define NUM_INT 32
 213 #endif
 214
 215         /*
 216          * some devices can transferr their RNG data direct into memory,
 217          * so make sure it is device friendly
 218          */
 219         buf = kmalloc(NUM_INT * sizeof(int), GFP_DMA);
 220         if (NULL == buf) {
 221                 printk("crypto: RNG could not allocate memory\n");
 222                 retval = -ENOMEM;
 223                 goto bad_alloc;
 224         }
 225
 226         wantcnt = NUM_INT;   /* start by adding some entropy */
 227
 228         /*
 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
 231          * doing nothing
 232          */
 233         while (!list_empty(&random_ops)) {
 234                 struct random_op        *rops, *tmp;
 235
 236 #ifdef CONFIG_OCF_FIPS
 237                 if (wantcnt)
 238                         wantcnt = NUM_INT; /* FIPs mode can do 20000 bits or none */
 239 #endif
 240
 241                 /* see if we can get enough entropy to make the world
 242                  * a better place.
 243                  */
 244                 while (bufcnt < wantcnt && bufcnt < NUM_INT) {
 245                         list_for_each_entry_safe(rops, tmp, &random_ops, random_list) {
 246
 247                                 n = (*rops->read_random)(rops->arg, &buf[bufcnt],
 248                                                          NUM_INT - bufcnt);
 249
 250                                 /* on failure remove the random number generator */
 251                                 if (n == -1) {
 252                                         list_del(&rops->random_list);
 253                                         printk("crypto: RNG (driverid=0x%x) failed, disabling\n",
 254                                                         rops->driverid);
 255                                         kfree(rops);
 256                                 } else if (n > 0)
 257                                         bufcnt += n;
 258                         }
 259                         /* give up CPU for a bit, just in case as this is a loop */
 260                         schedule();
 261                 }
 262
 263
 264 #ifdef CONFIG_OCF_FIPS
 265                 if (bufcnt > 0 && rndtest_buf((unsigned char *) &buf[0])) {
 266                         dprintk("crypto: buffer had fips errors, discarding\n");
 267                         bufcnt = 0;
 268                 }
 269 #endif
 270
 271                 /*
 272                  * if we have a certified buffer,  we can send some data
 273                  * to /dev/random and move along
 274                  */
 275                 if (bufcnt > 0) {
 276                         /* add what we have */
 277                         random_input_words(buf, bufcnt, bufcnt*sizeof(int)*8);
 278                         bufcnt = 0;
 279                 }
 280
 281                 /* give up CPU for a bit so we don't hog while filling */
 282                 schedule();
 283
 284                 /* wait for needing more */
 285                 wantcnt = random_input_wait();
 286
 287                 if (wantcnt <= 0)
 288                         wantcnt = 0; /* try to get some info again */
 289                 else
 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) {
 293                         wantcnt = NUM_INT;
 294                 }
 295
 296                 if (signal_pending(current)) {
 297 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 298                         spin_lock_irq(&current->sigmask_lock);
 299 #endif
 300                         flush_signals(current);
 301 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
 302                         spin_unlock_irq(&current->sigmask_lock);
 303 #endif
 304                 }
 305         }
 306
 307         kfree(buf);
 308
 309 bad_alloc:
 310         spin_lock_irq(&random_lock);
 311         randomproc = (pid_t) -1;
 312         started = 0;
 313         spin_unlock_irq(&random_lock);
 314
 315         return retval;
 316 }
 317