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