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_DIGEST:
 290                 if ((mask & CRYPTO_ALG_TYPE_HASH_MASK) !=
 291                     CRYPTO_ALG_TYPE_HASH_MASK)
 292                         return crypto_init_digest_ops_async(tfm);
 293                 else
 294                         return crypto_init_digest_ops(tfm);
 295
 296         case CRYPTO_ALG_TYPE_COMPRESS:
 297                 return crypto_init_compress_ops(tfm);
 298
 299         default:
 300                 break;
 301         }
 302
 303         BUG();
 304         return -EINVAL;
 305 }
 306
 307 static void crypto_exit_ops(struct crypto_tfm *tfm)
 308 {
 309         const struct crypto_type *type = tfm->__crt_alg->cra_type;
 310
 311         if (type) {
 312                 if (tfm->exit)
 313                         tfm->exit(tfm);
 314                 return;
 315         }
 316
 317         switch (crypto_tfm_alg_type(tfm)) {
 318         case CRYPTO_ALG_TYPE_CIPHER:
 319                 crypto_exit_cipher_ops(tfm);
 320                 break;
 321
 322         case CRYPTO_ALG_TYPE_DIGEST:
 323                 crypto_exit_digest_ops(tfm);
 324                 break;
 325
 326         case CRYPTO_ALG_TYPE_COMPRESS:
 327                 crypto_exit_compress_ops(tfm);
 328                 break;
 329
 330         default:
 331                 BUG();
 332
 333         }
 334 }
 335
 336 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
 337 {
 338         const struct crypto_type *type_obj = alg->cra_type;
 339         unsigned int len;
 340
 341         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 342         if (type_obj)
 343                 return len + type_obj->ctxsize(alg, type, mask);
 344
 345         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 346         default:
 347                 BUG();
 348
 349         case CRYPTO_ALG_TYPE_CIPHER:
 350                 len += crypto_cipher_ctxsize(alg);
 351                 break;
 352
 353         case CRYPTO_ALG_TYPE_DIGEST:
 354                 len += crypto_digest_ctxsize(alg);
 355                 break;
 356
 357         case CRYPTO_ALG_TYPE_COMPRESS:
 358                 len += crypto_compress_ctxsize(alg);
 359                 break;
 360         }
 361
 362         return len;
 363 }
 364
 365 void crypto_shoot_alg(struct crypto_alg *alg)
 366 {
 367         down_write(&crypto_alg_sem);
 368         alg->cra_flags |= CRYPTO_ALG_DYING;
 369         up_write(&crypto_alg_sem);
 370 }
 371 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
 372
 373 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 374                                       u32 mask)
 375 {
 376         struct crypto_tfm *tfm = NULL;
 377         unsigned int tfm_size;
 378         int err = -ENOMEM;
 379
 380         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
 381         tfm = kzalloc(tfm_size, GFP_KERNEL);
 382         if (tfm == NULL)
 383                 goto out_err;
 384
 385         tfm->__crt_alg = alg;
 386
 387         err = crypto_init_ops(tfm, type, mask);
 388         if (err)
 389                 goto out_free_tfm;
 390
 391         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 392                 goto cra_init_failed;
 393
 394         goto out;
 395
 396 cra_init_failed:
 397         crypto_exit_ops(tfm);
 398 out_free_tfm:
 399         if (err == -EAGAIN)
 400                 crypto_shoot_alg(alg);
 401         kfree(tfm);
 402 out_err:
 403         tfm = ERR_PTR(err);
 404 out:
 405         return tfm;
 406 }
 407 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
 408
 409 /*
 410  *      crypto_alloc_base - Locate algorithm and allocate transform
 411  *      @alg_name: Name of algorithm
 412  *      @type: Type of algorithm
 413  *      @mask: Mask for type comparison
 414  *
 415  *      This function should not be used by new algorithm types.
 416  *      Plesae use crypto_alloc_tfm instead.
 417  *
 418  *      crypto_alloc_base() will first attempt to locate an already loaded
 419  *      algorithm.  If that fails and the kernel supports dynamically loadable
 420  *      modules, it will then attempt to load a module of the same name or
 421  *      alias.  If that fails it will send a query to any loaded crypto manager
 422  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 423  *      algorithm which is then associated with the new transform.
 424  *
 425  *      The returned transform is of a non-determinate type.  Most people
 426  *      should use one of the more specific allocation functions such as
 427  *      crypto_alloc_blkcipher.
 428  *
 429  *      In case of error the return value is an error pointer.
 430  */
 431 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
 432 {
 433         struct crypto_tfm *tfm;
 434         int err;
 435
 436         for (;;) {
 437                 struct crypto_alg *alg;
 438
 439                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
 440                 if (IS_ERR(alg)) {
 441                         err = PTR_ERR(alg);
 442                         goto err;
 443                 }
 444
 445                 tfm = __crypto_alloc_tfm(alg, type, mask);
 446                 if (!IS_ERR(tfm))
 447                         return tfm;
 448
 449                 crypto_mod_put(alg);
 450                 err = PTR_ERR(tfm);
 451
 452 err:
 453                 if (err != -EAGAIN)
 454                         break;
 455                 if (signal_pending(current)) {
 456                         err = -EINTR;
 457                         break;
 458                 }
 459         }
 460
 461         return ERR_PTR(err);
 462 }
 463 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 464
 465 void *crypto_create_tfm(struct crypto_alg *alg,
 466                         const struct crypto_type *frontend)
 467 {
 468         char *mem;
 469         struct crypto_tfm *tfm = NULL;
 470         unsigned int tfmsize;
 471         unsigned int total;
 472         int err = -ENOMEM;
 473
 474         tfmsize = frontend->tfmsize;
 475         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);
 476
 477         mem = kzalloc(total, GFP_KERNEL);
 478         if (mem == NULL)
 479                 goto out_err;
 480
 481         tfm = (struct crypto_tfm *)(mem + tfmsize);
 482         tfm->__crt_alg = alg;
 483
 484         err = frontend->init_tfm(tfm, frontend);
 485         if (err)
 486                 goto out_free_tfm;
 487
 488         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 489                 goto cra_init_failed;
 490
 491         goto out;
 492
 493 cra_init_failed:
 494         crypto_exit_ops(tfm);
 495 out_free_tfm:
 496         if (err == -EAGAIN)
 497                 crypto_shoot_alg(alg);
 498         kfree(mem);
 499 out_err:
 500         mem = ERR_PTR(err);
 501 out:
 502         return mem;
 503 }
 504 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 505
 506 /*
 507  *      crypto_alloc_tfm - Locate algorithm and allocate transform
 508  *      @alg_name: Name of algorithm
 509  *      @frontend: Frontend algorithm type
 510  *      @type: Type of algorithm
 511  *      @mask: Mask for type comparison
 512  *
 513  *      crypto_alloc_tfm() will first attempt to locate an already loaded
 514  *      algorithm.  If that fails and the kernel supports dynamically loadable
 515  *      modules, it will then attempt to load a module of the same name or
 516  *      alias.  If that fails it will send a query to any loaded crypto manager
 517  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 518  *      algorithm which is then associated with the new transform.
 519  *
 520  *      The returned transform is of a non-determinate type.  Most people
 521  *      should use one of the more specific allocation functions such as
 522  *      crypto_alloc_blkcipher.
 523  *
 524  *      In case of error the return value is an error pointer.
 525  */
 526 void *crypto_alloc_tfm(const char *alg_name,
 527                        const struct crypto_type *frontend, u32 type, u32 mask)
 528 {
 529         struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
 530         void *tfm;
 531         int err;
 532
 533         type &= frontend->maskclear;
 534         mask &= frontend->maskclear;
 535         type |= frontend->type;
 536         mask |= frontend->maskset;
 537
 538         lookup = frontend->lookup ?: crypto_alg_mod_lookup;
 539
 540         for (;;) {
 541                 struct crypto_alg *alg;
 542
 543                 alg = lookup(alg_name, type, mask);
 544                 if (IS_ERR(alg)) {
 545                         err = PTR_ERR(alg);
 546                         goto err;
 547                 }
 548
 549                 tfm = crypto_create_tfm(alg, frontend);
 550                 if (!IS_ERR(tfm))
 551                         return tfm;
 552
 553                 crypto_mod_put(alg);
 554                 err = PTR_ERR(tfm);
 555
 556 err:
 557                 if (err != -EAGAIN)
 558                         break;
 559                 if (signal_pending(current)) {
 560                         err = -EINTR;
 561                         break;
 562                 }
 563         }
 564
 565         return ERR_PTR(err);
 566 }
 567 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 568
 569 /*
 570  *      crypto_destroy_tfm - Free crypto transform
 571  *      @mem: Start of tfm slab
 572  *      @tfm: Transform to free
 573  *
 574  *      This function frees up the transform and any associated resources,
 575  *      then drops the refcount on the associated algorithm.
 576  */
 577 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 578 {
 579         struct crypto_alg *alg;
 580
 581         if (unlikely(!mem))
 582                 return;
 583
 584         alg = tfm->__crt_alg;
 585
 586         if (!tfm->exit && alg->cra_exit)
 587                 alg->cra_exit(tfm);
 588         crypto_exit_ops(tfm);
 589         crypto_mod_put(alg);
 590         kzfree(mem);
 591 }
 592 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 593
 594 int crypto_has_alg(const char *name, u32 type, u32 mask)
 595 {
 596         int ret = 0;
 597         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
 598
 599         if (!IS_ERR(alg)) {
 600                 crypto_mod_put(alg);
 601                 ret = 1;
 602         }
 603
 604         return ret;
 605 }
 606 EXPORT_SYMBOL_GPL(crypto_has_alg);
 607
 608 MODULE_DESCRIPTION("Cryptographic core API");
 609 MODULE_LICENSE("GPL");