crypto/api.c

   1 /*
   2  * Scatterlist Cryptographic API.
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
   6  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   7  *
   8  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
   9  * and Nettle, by Niels Möller.
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/kernel.h>
  21 #include <linux/kmod.h>
  22 #include <linux/module.h>
  23 #include <linux/param.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include "internal.h"
  28
  29 LIST_HEAD(crypto_alg_list);
  30 EXPORT_SYMBOL_GPL(crypto_alg_list);
  31 DECLARE_RWSEM(crypto_alg_sem);
  32 EXPORT_SYMBOL_GPL(crypto_alg_sem);
  33
  34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
  35 EXPORT_SYMBOL_GPL(crypto_chain);
  36
  37 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
  38 {
  39         atomic_inc(&alg->cra_refcnt);
  40         return alg;
  41 }
  42
  43 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
  44 {
  45         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
  46 }
  47 EXPORT_SYMBOL_GPL(crypto_mod_get);
  48
  49 void crypto_mod_put(struct crypto_alg *alg)
  50 {
  51         struct module *module = alg->cra_module;
  52
  53         crypto_alg_put(alg);
  54         module_put(module);
  55 }
  56 EXPORT_SYMBOL_GPL(crypto_mod_put);
  57
  58 static inline int crypto_is_test_larval(struct crypto_larval *larval)
  59 {
  60         return larval->alg.cra_driver_name[0];
  61 }
  62
  63 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
  64                                               u32 mask)
  65 {
  66         struct crypto_alg *q, *alg = NULL;
  67         int best = -2;
  68
  69         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  70                 int exact, fuzzy;
  71
  72                 if (crypto_is_moribund(q))
  73                         continue;
  74
  75                 if ((q->cra_flags ^ type) & mask)
  76                         continue;
  77
  78                 if (crypto_is_larval(q) &&
  79                     !crypto_is_test_larval((struct crypto_larval *)q) &&
  80                     ((struct crypto_larval *)q)->mask != mask)
  81                         continue;
  82
  83                 exact = !strcmp(q->cra_driver_name, name);
  84                 fuzzy = !strcmp(q->cra_name, name);
  85                 if (!exact && !(fuzzy && q->cra_priority > best))
  86                         continue;
  87
  88                 if (unlikely(!crypto_mod_get(q)))
  89                         continue;
  90
  91                 best = q->cra_priority;
  92                 if (alg)
  93                         crypto_mod_put(alg);
  94                 alg = q;
  95
  96                 if (exact)
  97                         break;
  98         }
  99
 100         return alg;
 101 }
 102
 103 static void crypto_larval_destroy(struct crypto_alg *alg)
 104 {
 105         struct crypto_larval *larval = (void *)alg;
 106
 107         BUG_ON(!crypto_is_larval(alg));
 108         if (larval->adult)
 109                 crypto_mod_put(larval->adult);
 110         kfree(larval);
 111 }
 112
 113 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
 114 {
 115         struct crypto_larval *larval;
 116
 117         larval = kzalloc(sizeof(*larval), GFP_KERNEL);
 118         if (!larval)
 119                 return ERR_PTR(-ENOMEM);
 120
 121         larval->mask = mask;
 122         larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
 123         larval->alg.cra_priority = -1;
 124         larval->alg.cra_destroy = crypto_larval_destroy;
 125
 126         strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
 127         init_completion(&larval->completion);
 128
 129         return larval;
 130 }
 131 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
 132
 133 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
 134                                             u32 mask)
 135 {
 136         struct crypto_alg *alg;
 137         struct crypto_larval *larval;
 138
 139         larval = crypto_larval_alloc(name, type, mask);
 140         if (IS_ERR(larval))
 141                 return ERR_CAST(larval);
 142
 143         atomic_set(&larval->alg.cra_refcnt, 2);
 144
 145         down_write(&crypto_alg_sem);
 146         alg = __crypto_alg_lookup(name, type, mask);
 147         if (!alg) {
 148                 alg = &larval->alg;
 149                 list_add(&alg->cra_list, &crypto_alg_list);
 150         }
 151         up_write(&crypto_alg_sem);
 152
 153         if (alg != &larval->alg)
 154                 kfree(larval);
 155
 156         return alg;
 157 }
 158
 159 void crypto_larval_kill(struct crypto_alg *alg)
 160 {
 161         struct crypto_larval *larval = (void *)alg;
 162
 163         down_write(&crypto_alg_sem);
 164         list_del(&alg->cra_list);
 165         up_write(&crypto_alg_sem);
 166         complete_all(&larval->completion);
 167         crypto_alg_put(alg);
 168 }
 169 EXPORT_SYMBOL_GPL(crypto_larval_kill);
 170
 171 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 172 {
 173         struct crypto_larval *larval = (void *)alg;
 174         long timeout;
 175
 176         timeout = wait_for_completion_interruptible_timeout(
 177                 &larval->completion, 60 * HZ);
 178
 179         alg = larval->adult;
 180         if (timeout < 0)
 181                 alg = ERR_PTR(-EINTR);
 182         else if (!timeout)
 183                 alg = ERR_PTR(-ETIMEDOUT);
 184         else if (!alg)
 185                 alg = ERR_PTR(-ENOENT);
 186         else if (crypto_is_test_larval(larval) &&
 187                  !(alg->cra_flags & CRYPTO_ALG_TESTED))
 188                 alg = ERR_PTR(-EAGAIN);
 189         else if (!crypto_mod_get(alg))
 190                 alg = ERR_PTR(-EAGAIN);
 191         crypto_mod_put(&larval->alg);
 192
 193         return alg;
 194 }
 195
 196 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
 197 {
 198         struct crypto_alg *alg;
 199
 200         down_read(&crypto_alg_sem);
 201         alg = __crypto_alg_lookup(name, type, mask);
 202         up_read(&crypto_alg_sem);
 203
 204         return alg;
 205 }
 206 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
 207
 208 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
 209 {
 210         struct crypto_alg *alg;
 211
 212         if (!name)
 213                 return ERR_PTR(-ENOENT);
 214
 215         mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 216         type &= mask;
 217
 218         alg = crypto_alg_lookup(name, type, mask);
 219         if (!alg) {
 220                 request_module("%s", name);
 221
 222                 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
 223                       CRYPTO_ALG_NEED_FALLBACK))
 224                         request_module("%s-all", name);
 225
 226                 alg = crypto_alg_lookup(name, type, mask);
 227         }
 228
 229         if (alg)
 230                 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
 231
 232         return crypto_larval_add(name, type, mask);
 233 }
 234 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
 235
 236 int crypto_probing_notify(unsigned long val, void *v)
 237 {
 238         int ok;
 239
 240         ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 241         if (ok == NOTIFY_DONE) {
 242                 request_module("cryptomgr");
 243                 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 244         }
 245
 246         return ok;
 247 }
 248 EXPORT_SYMBOL_GPL(crypto_probing_notify);
 249
 250 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
 251 {
 252         struct crypto_alg *alg;
 253         struct crypto_alg *larval;
 254         int ok;
 255
 256         if (!((type | mask) & CRYPTO_ALG_TESTED)) {
 257                 type |= CRYPTO_ALG_TESTED;
 258                 mask |= CRYPTO_ALG_TESTED;
 259         }
 260
 261         larval = crypto_larval_lookup(name, type, mask);
 262         if (IS_ERR(larval) || !crypto_is_larval(larval))
 263                 return larval;
 264
 265         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
 266
 267         if (ok == NOTIFY_STOP)
 268                 alg = crypto_larval_wait(larval);
 269         else {
 270                 crypto_mod_put(larval);
 271                 alg = ERR_PTR(-ENOENT);
 272         }
 273         crypto_larval_kill(larval);
 274         return alg;
 275 }
 276 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
 277
 278 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 279 {
 280         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
 281
 282         if (type_obj)
 283                 return type_obj->init(tfm, type, mask);
 284
 285         switch (crypto_tfm_alg_type(tfm)) {
 286         case CRYPTO_ALG_TYPE_CIPHER:
 287                 return crypto_init_cipher_ops(tfm);
 288
 289         case CRYPTO_ALG_TYPE_COMPRESS:
 290                 return crypto_init_compress_ops(tfm);
 291
 292         default:
 293                 break;
 294         }
 295
 296         BUG();
 297         return -EINVAL;
 298 }
 299
 300 static void crypto_exit_ops(struct crypto_tfm *tfm)
 301 {
 302         const struct crypto_type *type = tfm->__crt_alg->cra_type;
 303
 304         if (type) {
 305                 if (tfm->exit)
 306                         tfm->exit(tfm);
 307                 return;
 308         }
 309
 310         switch (crypto_tfm_alg_type(tfm)) {
 311         case CRYPTO_ALG_TYPE_CIPHER:
 312                 crypto_exit_cipher_ops(tfm);
 313                 break;
 314
 315         case CRYPTO_ALG_TYPE_COMPRESS:
 316                 crypto_exit_compress_ops(tfm);
 317                 break;
 318
 319         default:
 320                 BUG();
 321
 322         }
 323 }
 324
 325 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
 326 {
 327         const struct crypto_type *type_obj = alg->cra_type;
 328         unsigned int len;
 329
 330         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 331         if (type_obj)
 332                 return len + type_obj->ctxsize(alg, type, mask);
 333
 334         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 335         default:
 336                 BUG();
 337
 338         case CRYPTO_ALG_TYPE_CIPHER:
 339                 len += crypto_cipher_ctxsize(alg);
 340                 break;
 341
 342         case CRYPTO_ALG_TYPE_COMPRESS:
 343                 len += crypto_compress_ctxsize(alg);
 344                 break;
 345         }
 346
 347         return len;
 348 }
 349
 350 void crypto_shoot_alg(struct crypto_alg *alg)
 351 {
 352         down_write(&crypto_alg_sem);
 353         alg->cra_flags |= CRYPTO_ALG_DYING;
 354         up_write(&crypto_alg_sem);
 355 }
 356 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
 357
 358 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 359                                       u32 mask)
 360 {
 361         struct crypto_tfm *tfm = NULL;
 362         unsigned int tfm_size;
 363         int err = -ENOMEM;
 364
 365         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
 366         tfm = kzalloc(tfm_size, GFP_KERNEL);
 367         if (tfm == NULL)
 368                 goto out_err;
 369
 370         tfm->__crt_alg = alg;
 371
 372         err = crypto_init_ops(tfm, type, mask);
 373         if (err)
 374                 goto out_free_tfm;
 375
 376         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 377                 goto cra_init_failed;
 378
 379         goto out;
 380
 381 cra_init_failed:
 382         crypto_exit_ops(tfm);
 383 out_free_tfm:
 384         if (err == -EAGAIN)
 385                 crypto_shoot_alg(alg);
 386         kfree(tfm);
 387 out_err:
 388         tfm = ERR_PTR(err);
 389 out:
 390         return tfm;
 391 }
 392 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
 393
 394 /*
 395  *      crypto_alloc_base - Locate algorithm and allocate transform
 396  *      @alg_name: Name of algorithm
 397  *      @type: Type of algorithm
 398  *      @mask: Mask for type comparison
 399  *
 400  *      This function should not be used by new algorithm types.
 401  *      Plesae use crypto_alloc_tfm instead.
 402  *
 403  *      crypto_alloc_base() will first attempt to locate an already loaded
 404  *      algorithm.  If that fails and the kernel supports dynamically loadable
 405  *      modules, it will then attempt to load a module of the same name or
 406  *      alias.  If that fails it will send a query to any loaded crypto manager
 407  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 408  *      algorithm which is then associated with the new transform.
 409  *
 410  *      The returned transform is of a non-determinate type.  Most people
 411  *      should use one of the more specific allocation functions such as
 412  *      crypto_alloc_blkcipher.
 413  *
 414  *      In case of error the return value is an error pointer.
 415  */
 416 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
 417 {
 418         struct crypto_tfm *tfm;
 419         int err;
 420
 421         for (;;) {
 422                 struct crypto_alg *alg;
 423
 424                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
 425                 if (IS_ERR(alg)) {
 426                         err = PTR_ERR(alg);
 427                         goto err;
 428                 }
 429
 430                 tfm = __crypto_alloc_tfm(alg, type, mask);
 431                 if (!IS_ERR(tfm))
 432                         return tfm;
 433
 434                 crypto_mod_put(alg);
 435                 err = PTR_ERR(tfm);
 436
 437 err:
 438                 if (err != -EAGAIN)
 439                         break;
 440                 if (signal_pending(current)) {
 441                         err = -EINTR;
 442                         break;
 443                 }
 444         }
 445
 446         return ERR_PTR(err);
 447 }
 448 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 449
 450 void *crypto_create_tfm(struct crypto_alg *alg,
 451                         const struct crypto_type *frontend)
 452 {
 453         char *mem;
 454         struct crypto_tfm *tfm = NULL;
 455         unsigned int tfmsize;
 456         unsigned int total;
 457         int err = -ENOMEM;
 458
 459         tfmsize = frontend->tfmsize;
 460         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
 461
 462         mem = kzalloc(total, GFP_KERNEL);
 463         if (mem == NULL)
 464                 goto out_err;
 465
 466         tfm = (struct crypto_tfm *)(mem + tfmsize);
 467         tfm->__crt_alg = alg;
 468
 469         err = frontend->init_tfm(tfm);
 470         if (err)
 471                 goto out_free_tfm;
 472
 473         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 474                 goto cra_init_failed;
 475
 476         goto out;
 477
 478 cra_init_failed:
 479         crypto_exit_ops(tfm);
 480 out_free_tfm:
 481         if (err == -EAGAIN)
 482                 crypto_shoot_alg(alg);
 483         kfree(mem);
 484 out_err:
 485         mem = ERR_PTR(err);
 486 out:
 487         return mem;
 488 }
 489 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 490
 491 struct crypto_alg *crypto_find_alg(const char *alg_name,
 492                                    const struct crypto_type *frontend,
 493                                    u32 type, u32 mask)
 494 {
 495         struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
 496                 crypto_alg_mod_lookup;
 497
 498         if (frontend) {
 499                 type &= frontend->maskclear;
 500                 mask &= frontend->maskclear;
 501                 type |= frontend->type;
 502                 mask |= frontend->maskset;
 503
 504                 if (frontend->lookup)
 505                         lookup = frontend->lookup;
 506         }
 507
 508         return lookup(alg_name, type, mask);
 509 }
 510 EXPORT_SYMBOL_GPL(crypto_find_alg);
 511
 512 /*
 513  *      crypto_alloc_tfm - Locate algorithm and allocate transform
 514  *      @alg_name: Name of algorithm
 515  *      @frontend: Frontend algorithm type
 516  *      @type: Type of algorithm
 517  *      @mask: Mask for type comparison
 518  *
 519  *      crypto_alloc_tfm() will first attempt to locate an already loaded
 520  *      algorithm.  If that fails and the kernel supports dynamically loadable
 521  *      modules, it will then attempt to load a module of the same name or
 522  *      alias.  If that fails it will send a query to any loaded crypto manager
 523  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 524  *      algorithm which is then associated with the new transform.
 525  *
 526  *      The returned transform is of a non-determinate type.  Most people
 527  *      should use one of the more specific allocation functions such as
 528  *      crypto_alloc_blkcipher.
 529  *
 530  *      In case of error the return value is an error pointer.
 531  */
 532 void *crypto_alloc_tfm(const char *alg_name,
 533                        const struct crypto_type *frontend, u32 type, u32 mask)
 534 {
 535         void *tfm;
 536         int err;
 537
 538         for (;;) {
 539                 struct crypto_alg *alg;
 540
 541                 alg = crypto_find_alg(alg_name, frontend, type, mask);
 542                 if (IS_ERR(alg)) {
 543                         err = PTR_ERR(alg);
 544                         goto err;
 545                 }
 546
 547                 tfm = crypto_create_tfm(alg, frontend);
 548                 if (!IS_ERR(tfm))
 549                         return tfm;
 550
 551                 crypto_mod_put(alg);
 552                 err = PTR_ERR(tfm);
 553
 554 err:
 555                 if (err != -EAGAIN)
 556                         break;
 557                 if (signal_pending(current)) {
 558                         err = -EINTR;
 559                         break;
 560                 }
 561         }
 562
 563         return ERR_PTR(err);
 564 }
 565 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 566
 567 /*
 568  *      crypto_destroy_tfm - Free crypto transform
 569  *      @mem: Start of tfm slab
 570  *      @tfm: Transform to free
 571  *
 572  *      This function frees up the transform and any associated resources,
 573  *      then drops the refcount on the associated algorithm.
 574  */
 575 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 576 {
 577         struct crypto_alg *alg;
 578
 579         if (unlikely(!mem))
 580                 return;
 581
 582         alg = tfm->__crt_alg;
 583
 584         if (!tfm->exit && alg->cra_exit)
 585                 alg->cra_exit(tfm);
 586         crypto_exit_ops(tfm);
 587         crypto_mod_put(alg);
 588         kzfree(mem);
 589 }
 590 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 591
 592 int crypto_has_alg(const char *name, u32 type, u32 mask)
 593 {
 594         int ret = 0;
 595         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
 596
 597         if (!IS_ERR(alg)) {
 598                 crypto_mod_put(alg);
 599                 ret = 1;
 600         }
 601
 602         return ret;
 603 }
 604 EXPORT_SYMBOL_GPL(crypto_has_alg);
 605
 606 MODULE_DESCRIPTION("Cryptographic core API");
 607 MODULE_LICENSE("GPL");