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