crypto/api.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Scatterlist Cryptographic API.
   4  *
   5  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   6  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
   7  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   8  *
   9  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
  10  * and Nettle, by Niels Möller.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/errno.h>
  15 #include <linux/kernel.h>
  16 #include <linux/kmod.h>
  17 #include <linux/module.h>
  18 #include <linux/param.h>
  19 #include <linux/sched/signal.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include <linux/completion.h>
  23 #include "internal.h"
  24
  25 LIST_HEAD(crypto_alg_list);
  26 EXPORT_SYMBOL_GPL(crypto_alg_list);
  27 DECLARE_RWSEM(crypto_alg_sem);
  28 EXPORT_SYMBOL_GPL(crypto_alg_sem);
  29
  30 BLOCKING_NOTIFIER_HEAD(crypto_chain);
  31 EXPORT_SYMBOL_GPL(crypto_chain);
  32
  33 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
  34
  35 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
  36 {
  37         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
  38 }
  39 EXPORT_SYMBOL_GPL(crypto_mod_get);
  40
  41 void crypto_mod_put(struct crypto_alg *alg)
  42 {
  43         struct module *module = alg->cra_module;
  44
  45         crypto_alg_put(alg);
  46         module_put(module);
  47 }
  48 EXPORT_SYMBOL_GPL(crypto_mod_put);
  49
  50 static inline int crypto_is_test_larval(struct crypto_larval *larval)
  51 {
  52         return larval->alg.cra_driver_name[0];
  53 }
  54
  55 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
  56                                               u32 mask)
  57 {
  58         struct crypto_alg *q, *alg = NULL;
  59         int best = -2;
  60
  61         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  62                 int exact, fuzzy;
  63
  64                 if (crypto_is_moribund(q))
  65                         continue;
  66
  67                 if ((q->cra_flags ^ type) & mask)
  68                         continue;
  69
  70                 if (crypto_is_larval(q) &&
  71                     !crypto_is_test_larval((struct crypto_larval *)q) &&
  72                     ((struct crypto_larval *)q)->mask != mask)
  73                         continue;
  74
  75                 exact = !strcmp(q->cra_driver_name, name);
  76                 fuzzy = !strcmp(q->cra_name, name);
  77                 if (!exact && !(fuzzy && q->cra_priority > best))
  78                         continue;
  79
  80                 if (unlikely(!crypto_mod_get(q)))
  81                         continue;
  82
  83                 best = q->cra_priority;
  84                 if (alg)
  85                         crypto_mod_put(alg);
  86                 alg = q;
  87
  88                 if (exact)
  89                         break;
  90         }
  91
  92         return alg;
  93 }
  94
  95 static void crypto_larval_destroy(struct crypto_alg *alg)
  96 {
  97         struct crypto_larval *larval = (void *)alg;
  98
  99         BUG_ON(!crypto_is_larval(alg));
 100         if (larval->adult)
 101                 crypto_mod_put(larval->adult);
 102         kfree(larval);
 103 }
 104
 105 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
 106 {
 107         struct crypto_larval *larval;
 108
 109         larval = kzalloc(sizeof(*larval), GFP_KERNEL);
 110         if (!larval)
 111                 return ERR_PTR(-ENOMEM);
 112
 113         larval->mask = mask;
 114         larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
 115         larval->alg.cra_priority = -1;
 116         larval->alg.cra_destroy = crypto_larval_destroy;
 117
 118         strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
 119         init_completion(&larval->completion);
 120
 121         return larval;
 122 }
 123 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
 124
 125 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
 126                                             u32 mask)
 127 {
 128         struct crypto_alg *alg;
 129         struct crypto_larval *larval;
 130
 131         larval = crypto_larval_alloc(name, type, mask);
 132         if (IS_ERR(larval))
 133                 return ERR_CAST(larval);
 134
 135         refcount_set(&larval->alg.cra_refcnt, 2);
 136
 137         down_write(&crypto_alg_sem);
 138         alg = __crypto_alg_lookup(name, type, mask);
 139         if (!alg) {
 140                 alg = &larval->alg;
 141                 list_add(&alg->cra_list, &crypto_alg_list);
 142         }
 143         up_write(&crypto_alg_sem);
 144
 145         if (alg != &larval->alg) {
 146                 kfree(larval);
 147                 if (crypto_is_larval(alg))
 148                         alg = crypto_larval_wait(alg);
 149         }
 150
 151         return alg;
 152 }
 153
 154 void crypto_larval_kill(struct crypto_alg *alg)
 155 {
 156         struct crypto_larval *larval = (void *)alg;
 157
 158         down_write(&crypto_alg_sem);
 159         list_del(&alg->cra_list);
 160         up_write(&crypto_alg_sem);
 161         complete_all(&larval->completion);
 162         crypto_alg_put(alg);
 163 }
 164 EXPORT_SYMBOL_GPL(crypto_larval_kill);
 165
 166 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 167 {
 168         struct crypto_larval *larval = (void *)alg;
 169         long timeout;
 170
 171         timeout = wait_for_completion_killable_timeout(
 172                 &larval->completion, 60 * HZ);
 173
 174         alg = larval->adult;
 175         if (timeout < 0)
 176                 alg = ERR_PTR(-EINTR);
 177         else if (!timeout)
 178                 alg = ERR_PTR(-ETIMEDOUT);
 179         else if (!alg)
 180                 alg = ERR_PTR(-ENOENT);
 181         else if (crypto_is_test_larval(larval) &&
 182                  !(alg->cra_flags & CRYPTO_ALG_TESTED))
 183                 alg = ERR_PTR(-EAGAIN);
 184         else if (!crypto_mod_get(alg))
 185                 alg = ERR_PTR(-EAGAIN);
 186         crypto_mod_put(&larval->alg);
 187
 188         return alg;
 189 }
 190
 191 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
 192                                             u32 mask)
 193 {
 194         struct crypto_alg *alg;
 195         u32 test = 0;
 196
 197         if (!((type | mask) & CRYPTO_ALG_TESTED))
 198                 test |= CRYPTO_ALG_TESTED;
 199
 200         down_read(&crypto_alg_sem);
 201         alg = __crypto_alg_lookup(name, type | test, mask | test);
 202         if (!alg && test) {
 203                 alg = __crypto_alg_lookup(name, type, mask);
 204                 if (alg && !crypto_is_larval(alg)) {
 205                         /* Test failed */
 206                         crypto_mod_put(alg);
 207                         alg = ERR_PTR(-ELIBBAD);
 208                 }
 209         }
 210         up_read(&crypto_alg_sem);
 211
 212         return alg;
 213 }
 214
 215 static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
 216                                                u32 mask)
 217 {
 218         struct crypto_alg *alg;
 219
 220         if (!name)
 221                 return ERR_PTR(-ENOENT);
 222
 223         type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 224         mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 225
 226         alg = crypto_alg_lookup(name, type, mask);
 227         if (!alg && !(mask & CRYPTO_NOLOAD)) {
 228                 request_module("crypto-%s", name);
 229
 230                 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
 231                       CRYPTO_ALG_NEED_FALLBACK))
 232                         request_module("crypto-%s-all", name);
 233
 234                 alg = crypto_alg_lookup(name, type, mask);
 235         }
 236
 237         if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
 238                 alg = crypto_larval_wait(alg);
 239         else if (!alg)
 240                 alg = crypto_larval_add(name, type, mask);
 241
 242         return alg;
 243 }
 244
 245 int crypto_probing_notify(unsigned long val, void *v)
 246 {
 247         int ok;
 248
 249         ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 250         if (ok == NOTIFY_DONE) {
 251                 request_module("cryptomgr");
 252                 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 253         }
 254
 255         return ok;
 256 }
 257 EXPORT_SYMBOL_GPL(crypto_probing_notify);
 258
 259 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
 260 {
 261         struct crypto_alg *alg;
 262         struct crypto_alg *larval;
 263         int ok;
 264
 265         /*
 266          * If the internal flag is set for a cipher, require a caller to
 267          * to invoke the cipher with the internal flag to use that cipher.
 268          * Also, if a caller wants to allocate a cipher that may or may
 269          * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
 270          * !(mask & CRYPTO_ALG_INTERNAL).
 271          */
 272         if (!((type | mask) & CRYPTO_ALG_INTERNAL))
 273                 mask |= CRYPTO_ALG_INTERNAL;
 274
 275         larval = crypto_larval_lookup(name, type, mask);
 276         if (IS_ERR(larval) || !crypto_is_larval(larval))
 277                 return larval;
 278
 279         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
 280
 281         if (ok == NOTIFY_STOP)
 282                 alg = crypto_larval_wait(larval);
 283         else {
 284                 crypto_mod_put(larval);
 285                 alg = ERR_PTR(-ENOENT);
 286         }
 287         crypto_larval_kill(larval);
 288         return alg;
 289 }
 290 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
 291
 292 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 293 {
 294         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
 295
 296         if (type_obj)
 297                 return type_obj->init(tfm, type, mask);
 298
 299         switch (crypto_tfm_alg_type(tfm)) {
 300         case CRYPTO_ALG_TYPE_CIPHER:
 301                 return crypto_init_cipher_ops(tfm);
 302
 303         case CRYPTO_ALG_TYPE_COMPRESS:
 304                 return crypto_init_compress_ops(tfm);
 305
 306         default:
 307                 break;
 308         }
 309
 310         BUG();
 311         return -EINVAL;
 312 }
 313
 314 static void crypto_exit_ops(struct crypto_tfm *tfm)
 315 {
 316         const struct crypto_type *type = tfm->__crt_alg->cra_type;
 317
 318         if (type && tfm->exit)
 319                 tfm->exit(tfm);
 320 }
 321
 322 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
 323 {
 324         const struct crypto_type *type_obj = alg->cra_type;
 325         unsigned int len;
 326
 327         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 328         if (type_obj)
 329                 return len + type_obj->ctxsize(alg, type, mask);
 330
 331         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 332         default:
 333                 BUG();
 334
 335         case CRYPTO_ALG_TYPE_CIPHER:
 336                 len += crypto_cipher_ctxsize(alg);
 337                 break;
 338
 339         case CRYPTO_ALG_TYPE_COMPRESS:
 340                 len += crypto_compress_ctxsize(alg);
 341                 break;
 342         }
 343
 344         return len;
 345 }
 346
 347 void crypto_shoot_alg(struct crypto_alg *alg)
 348 {
 349         down_write(&crypto_alg_sem);
 350         alg->cra_flags |= CRYPTO_ALG_DYING;
 351         up_write(&crypto_alg_sem);
 352 }
 353 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
 354
 355 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 356                                       u32 mask)
 357 {
 358         struct crypto_tfm *tfm = NULL;
 359         unsigned int tfm_size;
 360         int err = -ENOMEM;
 361
 362         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
 363         tfm = kzalloc(tfm_size, GFP_KERNEL);
 364         if (tfm == NULL)
 365                 goto out_err;
 366
 367         tfm->__crt_alg = alg;
 368
 369         err = crypto_init_ops(tfm, type, mask);
 370         if (err)
 371                 goto out_free_tfm;
 372
 373         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 374                 goto cra_init_failed;
 375
 376         goto out;
 377
 378 cra_init_failed:
 379         crypto_exit_ops(tfm);
 380 out_free_tfm:
 381         if (err == -EAGAIN)
 382                 crypto_shoot_alg(alg);
 383         kfree(tfm);
 384 out_err:
 385         tfm = ERR_PTR(err);
 386 out:
 387         return tfm;
 388 }
 389 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
 390
 391 /*
 392  *      crypto_alloc_base - Locate algorithm and allocate transform
 393  *      @alg_name: Name of algorithm
 394  *      @type: Type of algorithm
 395  *      @mask: Mask for type comparison
 396  *
 397  *      This function should not be used by new algorithm types.
 398  *      Please use crypto_alloc_tfm instead.
 399  *
 400  *      crypto_alloc_base() will first attempt to locate an already loaded
 401  *      algorithm.  If that fails and the kernel supports dynamically loadable
 402  *      modules, it will then attempt to load a module of the same name or
 403  *      alias.  If that fails it will send a query to any loaded crypto manager
 404  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 405  *      algorithm which is then associated with the new transform.
 406  *
 407  *      The returned transform is of a non-determinate type.  Most people
 408  *      should use one of the more specific allocation functions such as
 409  *      crypto_alloc_skcipher().
 410  *
 411  *      In case of error the return value is an error pointer.
 412  */
 413 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
 414 {
 415         struct crypto_tfm *tfm;
 416         int err;
 417
 418         for (;;) {
 419                 struct crypto_alg *alg;
 420
 421                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
 422                 if (IS_ERR(alg)) {
 423                         err = PTR_ERR(alg);
 424                         goto err;
 425                 }
 426
 427                 tfm = __crypto_alloc_tfm(alg, type, mask);
 428                 if (!IS_ERR(tfm))
 429                         return tfm;
 430
 431                 crypto_mod_put(alg);
 432                 err = PTR_ERR(tfm);
 433
 434 err:
 435                 if (err != -EAGAIN)
 436                         break;
 437                 if (fatal_signal_pending(current)) {
 438                         err = -EINTR;
 439                         break;
 440                 }
 441         }
 442
 443         return ERR_PTR(err);
 444 }
 445 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 446
 447 void *crypto_create_tfm(struct crypto_alg *alg,
 448                         const struct crypto_type *frontend)
 449 {
 450         char *mem;
 451         struct crypto_tfm *tfm = NULL;
 452         unsigned int tfmsize;
 453         unsigned int total;
 454         int err = -ENOMEM;
 455
 456         tfmsize = frontend->tfmsize;
 457         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
 458
 459         mem = kzalloc(total, GFP_KERNEL);
 460         if (mem == NULL)
 461                 goto out_err;
 462
 463         tfm = (struct crypto_tfm *)(mem + tfmsize);
 464         tfm->__crt_alg = alg;
 465
 466         err = frontend->init_tfm(tfm);
 467         if (err)
 468                 goto out_free_tfm;
 469
 470         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 471                 goto cra_init_failed;
 472
 473         goto out;
 474
 475 cra_init_failed:
 476         crypto_exit_ops(tfm);
 477 out_free_tfm:
 478         if (err == -EAGAIN)
 479                 crypto_shoot_alg(alg);
 480         kfree(mem);
 481 out_err:
 482         mem = ERR_PTR(err);
 483 out:
 484         return mem;
 485 }
 486 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 487
 488 struct crypto_alg *crypto_find_alg(const char *alg_name,
 489                                    const struct crypto_type *frontend,
 490                                    u32 type, u32 mask)
 491 {
 492         if (frontend) {
 493                 type &= frontend->maskclear;
 494                 mask &= frontend->maskclear;
 495                 type |= frontend->type;
 496                 mask |= frontend->maskset;
 497         }
 498
 499         return crypto_alg_mod_lookup(alg_name, type, mask);
 500 }
 501 EXPORT_SYMBOL_GPL(crypto_find_alg);
 502
 503 /*
 504  *      crypto_alloc_tfm - Locate algorithm and allocate transform
 505  *      @alg_name: Name of algorithm
 506  *      @frontend: Frontend algorithm type
 507  *      @type: Type of algorithm
 508  *      @mask: Mask for type comparison
 509  *
 510  *      crypto_alloc_tfm() will first attempt to locate an already loaded
 511  *      algorithm.  If that fails and the kernel supports dynamically loadable
 512  *      modules, it will then attempt to load a module of the same name or
 513  *      alias.  If that fails it will send a query to any loaded crypto manager
 514  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 515  *      algorithm which is then associated with the new transform.
 516  *
 517  *      The returned transform is of a non-determinate type.  Most people
 518  *      should use one of the more specific allocation functions such as
 519  *      crypto_alloc_blkcipher.
 520  *
 521  *      In case of error the return value is an error pointer.
 522  */
 523 void *crypto_alloc_tfm(const char *alg_name,
 524                        const struct crypto_type *frontend, u32 type, u32 mask)
 525 {
 526         void *tfm;
 527         int err;
 528
 529         for (;;) {
 530                 struct crypto_alg *alg;
 531
 532                 alg = crypto_find_alg(alg_name, frontend, type, mask);
 533                 if (IS_ERR(alg)) {
 534                         err = PTR_ERR(alg);
 535                         goto err;
 536                 }
 537
 538                 tfm = crypto_create_tfm(alg, frontend);
 539                 if (!IS_ERR(tfm))
 540                         return tfm;
 541
 542                 crypto_mod_put(alg);
 543                 err = PTR_ERR(tfm);
 544
 545 err:
 546                 if (err != -EAGAIN)
 547                         break;
 548                 if (fatal_signal_pending(current)) {
 549                         err = -EINTR;
 550                         break;
 551                 }
 552         }
 553
 554         return ERR_PTR(err);
 555 }
 556 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 557
 558 /*
 559  *      crypto_destroy_tfm - Free crypto transform
 560  *      @mem: Start of tfm slab
 561  *      @tfm: Transform to free
 562  *
 563  *      This function frees up the transform and any associated resources,
 564  *      then drops the refcount on the associated algorithm.
 565  */
 566 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 567 {
 568         struct crypto_alg *alg;
 569
 570         if (unlikely(!mem))
 571                 return;
 572
 573         alg = tfm->__crt_alg;
 574
 575         if (!tfm->exit && alg->cra_exit)
 576                 alg->cra_exit(tfm);
 577         crypto_exit_ops(tfm);
 578         crypto_mod_put(alg);
 579         kzfree(mem);
 580 }
 581 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 582
 583 int crypto_has_alg(const char *name, u32 type, u32 mask)
 584 {
 585         int ret = 0;
 586         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
 587
 588         if (!IS_ERR(alg)) {
 589                 crypto_mod_put(alg);
 590                 ret = 1;
 591         }
 592
 593         return ret;
 594 }
 595 EXPORT_SYMBOL_GPL(crypto_has_alg);
 596
 597 void crypto_req_done(struct crypto_async_request *req, int err)
 598 {
 599         struct crypto_wait *wait = req->data;
 600
 601         if (err == -EINPROGRESS)
 602                 return;
 603
 604         wait->err = err;
 605         complete(&wait->completion);
 606 }
 607 EXPORT_SYMBOL_GPL(crypto_req_done);
 608
 609 MODULE_DESCRIPTION("Cryptographic core API");
 610 MODULE_LICENSE("GPL");
 611 MODULE_SOFTDEP("pre: cryptomgr");