cryptodev_main.c

   1 /*
   2  * Driver for /dev/crypto device (aka CryptoDev)
   3  *
   4  * Copyright (c) 2004 Michal Ludvig <mludvig@logix.net.nz>, SuSE Labs
   5  * Copyright (c) 2009,2010 Nikos Mavrogiannopoulos <nmav@gnutls.org>
   6  *
   7  * This file is part of linux cryptodev.
   8  *
   9  * cryptodev is free software: you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation, either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * cryptodev is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23 /*
  24  * Device /dev/crypto provides an interface for
  25  * accessing kernel CryptoAPI algorithms (ciphers,
  26  * hashes) from userspace programs.
  27  *
  28  * /dev/crypto interface was originally introduced in
  29  * OpenBSD and this module attempts to keep the API,
  30  * although a bit extended.
  31  *
  32  */
  33
  34 #include <linux/crypto.h>
  35 #include <linux/mm.h>
  36 #include <linux/highmem.h>
  37 #include <linux/random.h>
  38 #include "cryptodev.h"
  39 #include <asm/uaccess.h>
  40 #include <asm/ioctl.h>
  41 #include <linux/scatterlist.h>
  42 #include "cryptodev_int.h"
  43
  44 MODULE_AUTHOR("Nikos Mavrogiannopoulos <nmav@gnutls.org>");
  45 MODULE_DESCRIPTION("CryptoDev driver");
  46 MODULE_LICENSE("GPL");
  47
  48 /* ====== Compile-time config ====== */
  49
  50 #define CRYPTODEV_STATS
  51
  52 /* ====== Module parameters ====== */
  53
  54 int cryptodev_verbosity = 0;
  55 module_param(cryptodev_verbosity, int, 0644);
  56 MODULE_PARM_DESC(cryptodev_verbosity, "0: normal, 1: verbose, 2: debug");
  57
  58 #ifdef CRYPTODEV_STATS
  59 static int enable_stats = 0;
  60 module_param(enable_stats, int, 0644);
  61 MODULE_PARM_DESC(enable_stats, "collect statictics about cryptodev usage");
  62 #endif
  63
  64 /* ====== CryptoAPI ====== */
  65
  66 #define FILL_SG(sg,ptr,len)                                     \
  67         do {                                                    \
  68                 (sg)->page = virt_to_page(ptr);                 \
  69                 (sg)->offset = offset_in_page(ptr);             \
  70                 (sg)->length = len;                             \
  71                 (sg)->dma_address = 0;                          \
  72         } while (0)
  73
  74 struct csession {
  75         struct list_head entry;
  76         struct semaphore sem;
  77         struct cipher_data cdata;
  78         struct hash_data hdata;
  79         uint32_t sid;
  80 #ifdef CRYPTODEV_STATS
  81 #if ! ((COP_ENCRYPT < 2) && (COP_DECRYPT < 2))
  82 #error Struct csession.stat uses COP_{ENCRYPT,DECRYPT} as indices. Do something!
  83 #endif
  84         unsigned long long stat[2];
  85         size_t stat_max_size, stat_count;
  86 #endif
  87 };
  88
  89 struct fcrypt {
  90         struct list_head list;
  91         struct semaphore sem;
  92 };
  93
  94 /* Prepare session for future use. */
  95 static int
  96 crypto_create_session(struct fcrypt *fcr, struct session_op *sop)
  97 {
  98         struct csession *ses_new, *ses_ptr;
  99         int ret = 0;
 100         const char *alg_name=NULL;
 101         const char *hash_name=NULL;
 102         int hmac_mode = 1;
 103
 104         /* Does the request make sense? */
 105         if (!sop->cipher && !sop->mac) {
 106                 dprintk(1,KERN_DEBUG,"Both 'cipher' and 'mac' unset.\n");
 107                 return -EINVAL;
 108         }
 109
 110         switch (sop->cipher) {
 111                 case 0:
 112                         break;
 113                 case CRYPTO_DES_CBC:
 114                         alg_name = "cbc(des)";
 115                         break;
 116                 case CRYPTO_3DES_CBC:
 117                         alg_name = "cbc(des3_ede)";
 118                         break;
 119                 case CRYPTO_BLF_CBC:
 120                         alg_name = "cbc(blowfish)";
 121                         break;
 122                 case CRYPTO_AES_CBC:
 123                         alg_name = "cbc(aes)";
 124                         break;
 125                 case CRYPTO_CAMELLIA_CBC:
 126                         alg_name = "cbc(camelia)";
 127                         break;
 128                 default:
 129                         dprintk(1,KERN_DEBUG,"%s: bad cipher: %d\n", __func__, sop->cipher);
 130                         return -EINVAL;
 131         }
 132
 133         switch (sop->mac) {
 134                 case 0:
 135                         break;
 136                 case CRYPTO_MD5_HMAC:
 137                         hash_name = "hmac(md5)";
 138                         break;
 139                 case CRYPTO_RIPEMD160_HMAC:
 140                         hash_name = "hmac(rmd160)";
 141                         break;
 142                 case CRYPTO_SHA1_HMAC:
 143                         hash_name = "hmac(sha1)";
 144                         break;
 145                 case CRYPTO_SHA2_256_HMAC:
 146                         hash_name = "hmac(sha256)";
 147                         break;
 148                 case CRYPTO_SHA2_384_HMAC:
 149                         hash_name = "hmac(sha384)";
 150                         break;
 151                 case CRYPTO_SHA2_512_HMAC:
 152                         hash_name = "hmac(sha512)";
 153                         break;
 154
 155                 /* non-hmac cases */
 156                 case CRYPTO_MD5:
 157                         hash_name = "md5";
 158                         hmac_mode = 0;
 159                         break;
 160                 case CRYPTO_RIPEMD160:
 161                         hash_name = "rmd160";
 162                         hmac_mode = 0;
 163                         break;
 164                 case CRYPTO_SHA1:
 165                         hash_name = "sha1";
 166                         hmac_mode = 0;
 167                         break;
 168                 case CRYPTO_SHA2_256:
 169                         hash_name = "sha256";
 170                         hmac_mode = 0;
 171                         break;
 172                 case CRYPTO_SHA2_384:
 173                         hash_name = "sha384";
 174                         hmac_mode = 0;
 175                         break;
 176                 case CRYPTO_SHA2_512:
 177                         hash_name = "sha512";
 178                         hmac_mode = 0;
 179                         break;
 180
 181                 default:
 182                         dprintk(1,KERN_DEBUG,"%s: bad mac: %d\n", __func__, sop->mac);
 183                         return -EINVAL;
 184         }
 185
 186         /* Create a session and put it to the list. */
 187         ses_new = kmalloc(sizeof(*ses_new), GFP_KERNEL);
 188         if(!ses_new) {
 189                 ret = -ENOMEM;
 190                 goto error;
 191         }
 192
 193         memset(ses_new, 0, sizeof(*ses_new));
 194
 195         /* Set-up crypto transform. */
 196         if (alg_name) {
 197
 198                 ret = cryptodev_cipher_init(&ses_new->cdata, alg_name, sop->key, sop->keylen);
 199                 if (ret < 0) {
 200                         return ret;
 201                 }
 202         }
 203
 204         if (hash_name) {
 205                 ret = cryptodev_hash_init(&ses_new->hdata, hash_name, hmac_mode, sop->mackey, sop->mackeylen);
 206                 if (ret != 0) {
 207                         dprintk(1,KERN_DEBUG,"%s: Failed to load transform for %s\n", __func__,
 208                                    hash_name);
 209                         return -EINVAL;
 210                 }
 211         }
 212
 213         /* put the new session to the list */
 214         get_random_bytes(&ses_new->sid, sizeof(ses_new->sid));
 215         init_MUTEX(&ses_new->sem);
 216
 217         down(&fcr->sem);
 218 restart:
 219         list_for_each_entry(ses_ptr, &fcr->list, entry) {
 220                 /* Check for duplicate SID */
 221                 if (unlikely(ses_new->sid == ses_ptr->sid)) {
 222                         get_random_bytes(&ses_new->sid, sizeof(ses_new->sid));
 223                         /* Unless we have a broken RNG this
 224                            shouldn't loop forever... ;-) */
 225                         goto restart;
 226                 }
 227         }
 228
 229         list_add(&ses_new->entry, &fcr->list);
 230         up(&fcr->sem);
 231
 232         /* Fill in some values for the user. */
 233         sop->ses = ses_new->sid;
 234
 235         return 0;
 236
 237 error:
 238         cryptodev_cipher_deinit( &ses_new->cdata);
 239         cryptodev_hash_deinit( &ses_new->hdata);
 240
 241         return ret;
 242
 243 }
 244
 245 /* Everything that needs to be done when remowing a session. */
 246 static inline void
 247 crypto_destroy_session(struct csession *ses_ptr)
 248 {
 249         if(down_trylock(&ses_ptr->sem)) {
 250                 dprintk(2, KERN_DEBUG, "Waiting for semaphore of sid=0x%08X\n",
 251                         ses_ptr->sid);
 252                 down(&ses_ptr->sem);
 253         }
 254         dprintk(2, KERN_DEBUG, "Removed session 0x%08X\n", ses_ptr->sid);
 255 #if defined(CRYPTODEV_STATS)
 256         if(enable_stats)
 257                 dprintk(2, KERN_DEBUG,
 258                         "Usage in Bytes: enc=%llu, dec=%llu, max=%zu, avg=%lu, cnt=%zu\n",
 259                         ses_ptr->stat[COP_ENCRYPT], ses_ptr->stat[COP_DECRYPT],
 260                         ses_ptr->stat_max_size, ses_ptr->stat_count > 0
 261                                 ? ((unsigned long)(ses_ptr->stat[COP_ENCRYPT]+
 262                                                    ses_ptr->stat[COP_DECRYPT]) /
 263                                    ses_ptr->stat_count) : 0,
 264                         ses_ptr->stat_count);
 265 #endif
 266         cryptodev_cipher_deinit(&ses_ptr->cdata);
 267         cryptodev_hash_deinit(&ses_ptr->hdata);
 268         up(&ses_ptr->sem);
 269         kfree(ses_ptr);
 270 }
 271
 272 /* Look up a session by ID and remove. */
 273 static int
 274 crypto_finish_session(struct fcrypt *fcr, uint32_t sid)
 275 {
 276         struct csession *tmp, *ses_ptr;
 277         struct list_head *head;
 278         int ret = 0;
 279
 280         down(&fcr->sem);
 281         head = &fcr->list;
 282         list_for_each_entry_safe(ses_ptr, tmp, head, entry) {
 283                 if(ses_ptr->sid == sid) {
 284                         list_del(&ses_ptr->entry);
 285                         crypto_destroy_session(ses_ptr);
 286                         break;
 287                 }
 288         }
 289
 290         if (!ses_ptr) {
 291                 dprintk(1, KERN_ERR, "Session with sid=0x%08X not found!\n", sid);
 292                 ret = -ENOENT;
 293         }
 294         up(&fcr->sem);
 295
 296         return ret;
 297 }
 298
 299 /* Remove all sessions when closing the file */
 300 static int
 301 crypto_finish_all_sessions(struct fcrypt *fcr)
 302 {
 303         struct csession *tmp, *ses_ptr;
 304         struct list_head *head;
 305
 306         down(&fcr->sem);
 307
 308         head = &fcr->list;
 309         list_for_each_entry_safe(ses_ptr, tmp, head, entry) {
 310                 list_del(&ses_ptr->entry);
 311                 crypto_destroy_session(ses_ptr);
 312         }
 313         up(&fcr->sem);
 314
 315         return 0;
 316 }
 317
 318 /* Look up session by session ID. The returned session is locked. */
 319 static struct csession *
 320 crypto_get_session_by_sid(struct fcrypt *fcr, uint32_t sid)
 321 {
 322         struct csession *ses_ptr;
 323
 324         down(&fcr->sem);
 325         list_for_each_entry(ses_ptr, &fcr->list, entry) {
 326                 if(ses_ptr->sid == sid) {
 327                         down(&ses_ptr->sem);
 328                         break;
 329                 }
 330         }
 331         up(&fcr->sem);
 332
 333         return ses_ptr;
 334 }
 335
 336 /* This is the main crypto function - feed it with plaintext
 337    and get a ciphertext (or vice versa :-) */
 338 static int
 339 crypto_run(struct fcrypt *fcr, struct crypt_op *cop)
 340 {
 341         char *data;
 342         char __user *src, __user *dst;
 343         struct scatterlist sg;
 344         struct csession *ses_ptr;
 345         unsigned int ivsize=0;
 346         size_t nbytes, bufsize;
 347         int ret = 0;
 348         uint8_t hash_output[AALG_MAX_RESULT_LEN];
 349
 350         if (unlikely(cop->op != COP_ENCRYPT && cop->op != COP_DECRYPT)) {
 351                 dprintk(1, KERN_DEBUG, "invalid operation op=%u\n", cop->op);
 352                 return -EINVAL;
 353         }
 354
 355         ses_ptr = crypto_get_session_by_sid(fcr, cop->ses);
 356         if (!ses_ptr) {
 357                 dprintk(1, KERN_ERR, "invalid session ID=0x%08X\n", cop->ses);
 358                 return -EINVAL;
 359         }
 360
 361         nbytes = cop->len;
 362         data = (char*)__get_free_page(GFP_KERNEL);
 363
 364         if (unlikely(!data)) {
 365                 ret = -ENOMEM;
 366                 goto out_unlock;
 367         }
 368         bufsize = PAGE_SIZE < nbytes ? PAGE_SIZE : nbytes;
 369
 370         nbytes = cop->len;
 371
 372         if (ses_ptr->hdata.init != 0) {
 373                 ret = cryptodev_hash_reset(&ses_ptr->hdata);
 374                 if (unlikely(ret)) {
 375                         dprintk(1, KERN_ERR,
 376                                 "error in cryptodev_hash_reset()\n");
 377                         goto out_unlock;
 378                 }
 379         }
 380
 381         if (ses_ptr->cdata.init != 0) {
 382                 int blocksize = ses_ptr->cdata.blocksize;
 383
 384                 if (unlikely(nbytes % blocksize)) {
 385                         dprintk(1, KERN_ERR,
 386                                 "data size (%zu) isn't a multiple of block size (%u)\n",
 387                                 nbytes, blocksize);
 388                         ret = -EINVAL;
 389                         goto out_unlock;
 390                 }
 391
 392                 ivsize = ses_ptr->cdata.ivsize;
 393
 394                 if (cop->iv) {
 395                         cryptodev_cipher_set_iv(&ses_ptr->cdata, cop->iv, ivsize);
 396                 }
 397         }
 398
 399         src = cop->src;
 400         dst = cop->dst;
 401
 402
 403         while(nbytes > 0) {
 404                 size_t current_len = nbytes > bufsize ? bufsize : nbytes;
 405
 406                 copy_from_user(data, src, current_len);
 407
 408                 sg_init_one(&sg, data, current_len);
 409
 410                 /* Always hash before encryption and after decryption. Maybe
 411                  * we should introduce a flag to switch... TBD later on.
 412                  */
 413                 if (cop->op == COP_ENCRYPT) {
 414                         if (ses_ptr->hdata.init != 0) {
 415                                 ret = cryptodev_hash_update(&ses_ptr->hdata, &sg, current_len);
 416                                 if (unlikely(ret)) {
 417                                         dprintk(0, KERN_ERR, "CryptoAPI failure: %d\n",ret);
 418                                         goto out;
 419                                 }
 420                         }
 421                         if (ses_ptr->cdata.init != 0) {
 422                                 ret = cryptodev_cipher_encrypt( &ses_ptr->cdata, &sg, &sg, current_len);
 423
 424                                 if (unlikely(ret)) {
 425                                         dprintk(0, KERN_ERR, "CryptoAPI failure: %d\n",ret);
 426                                         goto out;
 427                                 }
 428                                 copy_to_user(dst, data, current_len);
 429                                 dst += current_len;
 430                         }
 431                 } else {
 432                         if (ses_ptr->cdata.init != 0) {
 433                                 ret = cryptodev_cipher_decrypt( &ses_ptr->cdata, &sg, &sg, current_len);
 434
 435                                 if (unlikely(ret)) {
 436                                         dprintk(0, KERN_ERR, "CryptoAPI failure: %d\n",ret);
 437                                         goto out;
 438                                 }
 439                                 copy_to_user(dst, data, current_len);
 440                                 dst += current_len;
 441
 442                         }
 443
 444                         if (ses_ptr->hdata.init != 0) {
 445                                 ret = cryptodev_hash_update(&ses_ptr->hdata, &sg, current_len);
 446                                 if (unlikely(ret)) {
 447                                         dprintk(0, KERN_ERR, "CryptoAPI failure: %d\n",ret);
 448                                         goto out;
 449                                 }
 450                         }
 451                 }
 452
 453                 nbytes -= current_len;
 454                 src += current_len;
 455         }
 456
 457         if (ses_ptr->hdata.init != 0) {
 458                 ret = cryptodev_hash_final(&ses_ptr->hdata, hash_output);
 459                 if (unlikely(ret)) {
 460                         dprintk(0, KERN_ERR, "CryptoAPI failure: %d\n",ret);
 461                         goto out;
 462                 }
 463
 464                 copy_to_user(cop->mac, hash_output, ses_ptr->hdata.digestsize);
 465         }
 466
 467 #if defined(CRYPTODEV_STATS)
 468         if (enable_stats) {
 469                 /* this is safe - we check cop->op at the function entry */
 470                 ses_ptr->stat[cop->op] += cop->len;
 471                 if (ses_ptr->stat_max_size < cop->len)
 472                         ses_ptr->stat_max_size = cop->len;
 473                 ses_ptr->stat_count++;
 474         }
 475 #endif
 476
 477 out:
 478         free_page((unsigned long)data);
 479
 480 out_unlock:
 481         up(&ses_ptr->sem);
 482
 483         return ret;
 484 }
 485
 486 /* ====== /dev/crypto ====== */
 487
 488 static int
 489 cryptodev_open(struct inode *inode, struct file *filp)
 490 {
 491         struct fcrypt *fcr;
 492
 493         fcr = kmalloc(sizeof(*fcr), GFP_KERNEL);
 494         if(!fcr)
 495                 return -ENOMEM;
 496
 497         memset(fcr, 0, sizeof(*fcr));
 498         init_MUTEX(&fcr->sem);
 499         INIT_LIST_HEAD(&fcr->list);
 500         filp->private_data = fcr;
 501
 502         return 0;
 503 }
 504
 505 static int
 506 cryptodev_release(struct inode *inode, struct file *filp)
 507 {
 508         struct fcrypt *fcr = filp->private_data;
 509
 510         if(fcr) {
 511                 crypto_finish_all_sessions(fcr);
 512                 kfree(fcr);
 513                 filp->private_data = NULL;
 514         }
 515
 516         return 0;
 517 }
 518
 519 static int
 520 clonefd(struct file *filp)
 521 {
 522         struct fdtable *fdt = files_fdtable(current->files);
 523         int ret;
 524         ret = get_unused_fd();
 525         if (ret >= 0) {
 526                         get_file(filp);
 527                         FD_SET(ret, fdt->open_fds);
 528                         fd_install(ret, filp);
 529         }
 530
 531         return ret;
 532 }
 533
 534 static int
 535 cryptodev_ioctl(struct inode *inode, struct file *filp,
 536                 unsigned int cmd, unsigned long arg)
 537 {
 538         int __user *p = (void __user *)arg;
 539         struct session_op sop;
 540         struct crypt_op cop;
 541         struct fcrypt *fcr = filp->private_data;
 542         uint32_t ses;
 543         int ret, fd;
 544
 545         if (!fcr)
 546                 BUG();
 547
 548         switch (cmd) {
 549                 case CIOCASYMFEAT:
 550                         put_user(0, p);
 551                         return 0;
 552                 case CRIOGET:
 553                         fd = clonefd(filp);
 554                         put_user(fd, p);
 555                         return 0;
 556
 557                 case CIOCGSESSION:
 558                         copy_from_user(&sop, (void*)arg, sizeof(sop));
 559                         ret = crypto_create_session(fcr, &sop);
 560                         if (ret)
 561                                 return ret;
 562                         copy_to_user((void*)arg, &sop, sizeof(sop));
 563                         return 0;
 564
 565                 case CIOCFSESSION:
 566                         get_user(ses, (uint32_t*)arg);
 567                         ret = crypto_finish_session(fcr, ses);
 568                         return ret;
 569
 570                 case CIOCCRYPT:
 571                         copy_from_user(&cop, (void*)arg, sizeof(cop));
 572                         ret = crypto_run(fcr, &cop);
 573                         copy_to_user((void*)arg, &cop, sizeof(cop));
 574                         return ret;
 575
 576                 default:
 577                         return -EINVAL;
 578         }
 579 }
 580
 581 struct file_operations cryptodev_fops = {
 582         .owner = THIS_MODULE,
 583         .open = cryptodev_open,
 584         .release = cryptodev_release,
 585         .ioctl = cryptodev_ioctl,
 586 };
 587
 588 struct miscdevice cryptodev = {
 589         .minor = MISC_DYNAMIC_MINOR,
 590         .name = "crypto",
 591         .fops = &cryptodev_fops,
 592 };
 593
 594 static int
 595 cryptodev_register(void)
 596 {
 597         int rc;
 598
 599         rc = misc_register (&cryptodev);
 600         if (rc) {
 601                 printk(KERN_ERR PFX "registeration of /dev/crypto failed\n");
 602                 return rc;
 603         }
 604
 605         return 0;
 606 }
 607
 608 static void
 609 cryptodev_deregister(void)
 610 {
 611         misc_deregister(&cryptodev);
 612 }
 613
 614 /* ====== Module init/exit ====== */
 615
 616 int __init init_cryptodev(void)
 617 {
 618         int rc;
 619
 620         rc = cryptodev_register();
 621         if (rc)
 622                 return rc;
 623
 624         printk(KERN_INFO PFX "driver loaded.\n");
 625
 626         return 0;
 627 }
 628
 629 void __exit exit_cryptodev(void)
 630 {
 631         cryptodev_deregister();
 632         printk(KERN_INFO PFX "driver unloaded.\n");
 633 }
 634
 635 module_init(init_cryptodev);
 636 module_exit(exit_cryptodev);