crypto/ablkcipher.c

   1 /*
   2  * Asynchronous block chaining cipher operations.
   3  *
   4  * This is the asynchronous version of blkcipher.c indicating completion
   5  * via a callback.
   6  *
   7  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <crypto/internal/skcipher.h>
  17 #include <linux/cpumask.h>
  18 #include <linux/err.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/rtnetlink.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/seq_file.h>
  26
  27 #include <crypto/scatterwalk.h>
  28
  29 #include "internal.h"
  30
  31 static const char *skcipher_default_geniv __read_mostly;
  32
  33 struct ablkcipher_buffer {
  34         struct list_head        entry;
  35         struct scatter_walk     dst;
  36         unsigned int            len;
  37         void                    *data;
  38 };
  39
  40 enum {
  41         ABLKCIPHER_WALK_SLOW = 1 << 0,
  42 };
  43
  44 static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
  45 {
  46         scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
  47 }
  48
  49 void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
  50 {
  51         struct ablkcipher_buffer *p, *tmp;
  52
  53         list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  54                 ablkcipher_buffer_write(p);
  55                 list_del(&p->entry);
  56                 kfree(p);
  57         }
  58 }
  59 EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
  60
  61 static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
  62                                           struct ablkcipher_buffer *p)
  63 {
  64         p->dst = walk->out;
  65         list_add_tail(&p->entry, &walk->buffers);
  66 }
  67
  68 /* Get a spot of the specified length that does not straddle a page.
  69  * The caller needs to ensure that there is enough space for this operation.
  70  */
  71 static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
  72 {
  73         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  74         return max(start, end_page);
  75 }
  76
  77 static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
  78                                                 unsigned int bsize)
  79 {
  80         unsigned int n = bsize;
  81
  82         for (;;) {
  83                 unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  84
  85                 if (len_this_page > n)
  86                         len_this_page = n;
  87                 scatterwalk_advance(&walk->out, n);
  88                 if (n == len_this_page)
  89                         break;
  90                 n -= len_this_page;
  91                 scatterwalk_start(&walk->out, scatterwalk_sg_next(walk->out.sg));
  92         }
  93
  94         return bsize;
  95 }
  96
  97 static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
  98                                                 unsigned int n)
  99 {
 100         scatterwalk_advance(&walk->in, n);
 101         scatterwalk_advance(&walk->out, n);
 102
 103         return n;
 104 }
 105
 106 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 107                                 struct ablkcipher_walk *walk);
 108
 109 int ablkcipher_walk_done(struct ablkcipher_request *req,
 110                          struct ablkcipher_walk *walk, int err)
 111 {
 112         struct crypto_tfm *tfm = req->base.tfm;
 113         unsigned int nbytes = 0;
 114
 115         if (likely(err >= 0)) {
 116                 unsigned int n = walk->nbytes - err;
 117
 118                 if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW)))
 119                         n = ablkcipher_done_fast(walk, n);
 120                 else if (WARN_ON(err)) {
 121                         err = -EINVAL;
 122                         goto err;
 123                 } else
 124                         n = ablkcipher_done_slow(walk, n);
 125
 126                 nbytes = walk->total - n;
 127                 err = 0;
 128         }
 129
 130         scatterwalk_done(&walk->in, 0, nbytes);
 131         scatterwalk_done(&walk->out, 1, nbytes);
 132
 133 err:
 134         walk->total = nbytes;
 135         walk->nbytes = nbytes;
 136
 137         if (nbytes) {
 138                 crypto_yield(req->base.flags);
 139                 return ablkcipher_walk_next(req, walk);
 140         }
 141
 142         if (walk->iv != req->info)
 143                 memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 144         kfree(walk->iv_buffer);
 145
 146         return err;
 147 }
 148 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 149
 150 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 151                                        struct ablkcipher_walk *walk,
 152                                        unsigned int bsize,
 153                                        unsigned int alignmask,
 154                                        void **src_p, void **dst_p)
 155 {
 156         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 157         struct ablkcipher_buffer *p;
 158         void *src, *dst, *base;
 159         unsigned int n;
 160
 161         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 162         n += (aligned_bsize * 3 - (alignmask + 1) +
 163               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 164
 165         p = kmalloc(n, GFP_ATOMIC);
 166         if (!p)
 167                 return ablkcipher_walk_done(req, walk, -ENOMEM);
 168
 169         base = p + 1;
 170
 171         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 172         src = dst = ablkcipher_get_spot(dst, bsize);
 173
 174         p->len = bsize;
 175         p->data = dst;
 176
 177         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 178
 179         ablkcipher_queue_write(walk, p);
 180
 181         walk->nbytes = bsize;
 182         walk->flags |= ABLKCIPHER_WALK_SLOW;
 183
 184         *src_p = src;
 185         *dst_p = dst;
 186
 187         return 0;
 188 }
 189
 190 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 191                                      struct crypto_tfm *tfm,
 192                                      unsigned int alignmask)
 193 {
 194         unsigned bs = walk->blocksize;
 195         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 196         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 197         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 198                             (alignmask + 1);
 199         u8 *iv;
 200
 201         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 202         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 203         if (!walk->iv_buffer)
 204                 return -ENOMEM;
 205
 206         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 207         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 208         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 209         iv = ablkcipher_get_spot(iv, ivsize);
 210
 211         walk->iv = memcpy(iv, walk->iv, ivsize);
 212         return 0;
 213 }
 214
 215 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 216                                        struct ablkcipher_walk *walk)
 217 {
 218         walk->src.page = scatterwalk_page(&walk->in);
 219         walk->src.offset = offset_in_page(walk->in.offset);
 220         walk->dst.page = scatterwalk_page(&walk->out);
 221         walk->dst.offset = offset_in_page(walk->out.offset);
 222
 223         return 0;
 224 }
 225
 226 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 227                                 struct ablkcipher_walk *walk)
 228 {
 229         struct crypto_tfm *tfm = req->base.tfm;
 230         unsigned int alignmask, bsize, n;
 231         void *src, *dst;
 232         int err;
 233
 234         alignmask = crypto_tfm_alg_alignmask(tfm);
 235         n = walk->total;
 236         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 237                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 238                 return ablkcipher_walk_done(req, walk, -EINVAL);
 239         }
 240
 241         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 242         src = dst = NULL;
 243
 244         bsize = min(walk->blocksize, n);
 245         n = scatterwalk_clamp(&walk->in, n);
 246         n = scatterwalk_clamp(&walk->out, n);
 247
 248         if (n < bsize ||
 249             !scatterwalk_aligned(&walk->in, alignmask) ||
 250             !scatterwalk_aligned(&walk->out, alignmask)) {
 251                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 252                                            &src, &dst);
 253                 goto set_phys_lowmem;
 254         }
 255
 256         walk->nbytes = n;
 257
 258         return ablkcipher_next_fast(req, walk);
 259
 260 set_phys_lowmem:
 261         if (err >= 0) {
 262                 walk->src.page = virt_to_page(src);
 263                 walk->dst.page = virt_to_page(dst);
 264                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 265                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 266         }
 267
 268         return err;
 269 }
 270
 271 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 272                                  struct ablkcipher_walk *walk)
 273 {
 274         struct crypto_tfm *tfm = req->base.tfm;
 275         unsigned int alignmask;
 276
 277         alignmask = crypto_tfm_alg_alignmask(tfm);
 278         if (WARN_ON_ONCE(in_irq()))
 279                 return -EDEADLK;
 280
 281         walk->nbytes = walk->total;
 282         if (unlikely(!walk->total))
 283                 return 0;
 284
 285         walk->iv_buffer = NULL;
 286         walk->iv = req->info;
 287         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 288                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 289                 if (err)
 290                         return err;
 291         }
 292
 293         scatterwalk_start(&walk->in, walk->in.sg);
 294         scatterwalk_start(&walk->out, walk->out.sg);
 295
 296         return ablkcipher_walk_next(req, walk);
 297 }
 298
 299 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 300                          struct ablkcipher_walk *walk)
 301 {
 302         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 303         return ablkcipher_walk_first(req, walk);
 304 }
 305 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 306
 307 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 308                             unsigned int keylen)
 309 {
 310         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 311         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 312         int ret;
 313         u8 *buffer, *alignbuffer;
 314         unsigned long absize;
 315
 316         absize = keylen + alignmask;
 317         buffer = kmalloc(absize, GFP_ATOMIC);
 318         if (!buffer)
 319                 return -ENOMEM;
 320
 321         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 322         memcpy(alignbuffer, key, keylen);
 323         ret = cipher->setkey(tfm, alignbuffer, keylen);
 324         memset(alignbuffer, 0, keylen);
 325         kfree(buffer);
 326         return ret;
 327 }
 328
 329 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 330                   unsigned int keylen)
 331 {
 332         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 333         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 334
 335         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 336                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 337                 return -EINVAL;
 338         }
 339
 340         if ((unsigned long)key & alignmask)
 341                 return setkey_unaligned(tfm, key, keylen);
 342
 343         return cipher->setkey(tfm, key, keylen);
 344 }
 345
 346 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 347                                               u32 mask)
 348 {
 349         return alg->cra_ctxsize;
 350 }
 351
 352 int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req)
 353 {
 354         return crypto_ablkcipher_encrypt(&req->creq);
 355 }
 356
 357 int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req)
 358 {
 359         return crypto_ablkcipher_decrypt(&req->creq);
 360 }
 361
 362 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 363                                       u32 mask)
 364 {
 365         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 366         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 367
 368         if (alg->ivsize > PAGE_SIZE / 8)
 369                 return -EINVAL;
 370
 371         crt->setkey = setkey;
 372         crt->encrypt = alg->encrypt;
 373         crt->decrypt = alg->decrypt;
 374         if (!alg->ivsize) {
 375                 crt->givencrypt = skcipher_null_givencrypt;
 376                 crt->givdecrypt = skcipher_null_givdecrypt;
 377         }
 378         crt->base = __crypto_ablkcipher_cast(tfm);
 379         crt->ivsize = alg->ivsize;
 380
 381         return 0;
 382 }
 383
 384 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 385         __attribute__ ((unused));
 386 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 387 {
 388         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 389
 390         seq_printf(m, "type         : ablkcipher\n");
 391         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 392                                              "yes" : "no");
 393         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 394         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 395         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 396         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 397         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 398 }
 399
 400 const struct crypto_type crypto_ablkcipher_type = {
 401         .ctxsize = crypto_ablkcipher_ctxsize,
 402         .init = crypto_init_ablkcipher_ops,
 403 #ifdef CONFIG_PROC_FS
 404         .show = crypto_ablkcipher_show,
 405 #endif
 406 };
 407 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 408
 409 static int no_givdecrypt(struct skcipher_givcrypt_request *req)
 410 {
 411         return -ENOSYS;
 412 }
 413
 414 static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 415                                       u32 mask)
 416 {
 417         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 418         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 419
 420         if (alg->ivsize > PAGE_SIZE / 8)
 421                 return -EINVAL;
 422
 423         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 424                       alg->setkey : setkey;
 425         crt->encrypt = alg->encrypt;
 426         crt->decrypt = alg->decrypt;
 427         crt->givencrypt = alg->givencrypt;
 428         crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
 429         crt->base = __crypto_ablkcipher_cast(tfm);
 430         crt->ivsize = alg->ivsize;
 431
 432         return 0;
 433 }
 434
 435 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 436         __attribute__ ((unused));
 437 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 438 {
 439         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 440
 441         seq_printf(m, "type         : givcipher\n");
 442         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 443                                              "yes" : "no");
 444         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 445         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 446         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 447         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 448         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 449 }
 450
 451 const struct crypto_type crypto_givcipher_type = {
 452         .ctxsize = crypto_ablkcipher_ctxsize,
 453         .init = crypto_init_givcipher_ops,
 454 #ifdef CONFIG_PROC_FS
 455         .show = crypto_givcipher_show,
 456 #endif
 457 };
 458 EXPORT_SYMBOL_GPL(crypto_givcipher_type);
 459
 460 const char *crypto_default_geniv(const struct crypto_alg *alg)
 461 {
 462         if (((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 463              CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 464                                          alg->cra_ablkcipher.ivsize) !=
 465             alg->cra_blocksize)
 466                 return "chainiv";
 467
 468         return alg->cra_flags & CRYPTO_ALG_ASYNC ?
 469                "eseqiv" : skcipher_default_geniv;
 470 }
 471
 472 static int crypto_givcipher_default(struct crypto_alg *alg, u32 type, u32 mask)
 473 {
 474         struct rtattr *tb[3];
 475         struct {
 476                 struct rtattr attr;
 477                 struct crypto_attr_type data;
 478         } ptype;
 479         struct {
 480                 struct rtattr attr;
 481                 struct crypto_attr_alg data;
 482         } palg;
 483         struct crypto_template *tmpl;
 484         struct crypto_instance *inst;
 485         struct crypto_alg *larval;
 486         const char *geniv;
 487         int err;
 488
 489         larval = crypto_larval_lookup(alg->cra_driver_name,
 490                                       (type & ~CRYPTO_ALG_TYPE_MASK) |
 491                                       CRYPTO_ALG_TYPE_GIVCIPHER,
 492                                       mask | CRYPTO_ALG_TYPE_MASK);
 493         err = PTR_ERR(larval);
 494         if (IS_ERR(larval))
 495                 goto out;
 496
 497         err = -EAGAIN;
 498         if (!crypto_is_larval(larval))
 499                 goto drop_larval;
 500
 501         ptype.attr.rta_len = sizeof(ptype);
 502         ptype.attr.rta_type = CRYPTOA_TYPE;
 503         ptype.data.type = type | CRYPTO_ALG_GENIV;
 504         /* GENIV tells the template that we're making a default geniv. */
 505         ptype.data.mask = mask | CRYPTO_ALG_GENIV;
 506         tb[0] = &ptype.attr;
 507
 508         palg.attr.rta_len = sizeof(palg);
 509         palg.attr.rta_type = CRYPTOA_ALG;
 510         /* Must use the exact name to locate ourselves. */
 511         memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
 512         tb[1] = &palg.attr;
 513
 514         tb[2] = NULL;
 515
 516         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 517             CRYPTO_ALG_TYPE_BLKCIPHER)
 518                 geniv = alg->cra_blkcipher.geniv;
 519         else
 520                 geniv = alg->cra_ablkcipher.geniv;
 521
 522         if (!geniv)
 523                 geniv = crypto_default_geniv(alg);
 524
 525         tmpl = crypto_lookup_template(geniv);
 526         err = -ENOENT;
 527         if (!tmpl)
 528                 goto kill_larval;
 529
 530         inst = tmpl->alloc(tb);
 531         err = PTR_ERR(inst);
 532         if (IS_ERR(inst))
 533                 goto put_tmpl;
 534
 535         if ((err = crypto_register_instance(tmpl, inst))) {
 536                 tmpl->free(inst);
 537                 goto put_tmpl;
 538         }
 539
 540         /* Redo the lookup to use the instance we just registered. */
 541         err = -EAGAIN;
 542
 543 put_tmpl:
 544         crypto_tmpl_put(tmpl);
 545 kill_larval:
 546         crypto_larval_kill(larval);
 547 drop_larval:
 548         crypto_mod_put(larval);
 549 out:
 550         crypto_mod_put(alg);
 551         return err;
 552 }
 553
 554 static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
 555                                                  u32 mask)
 556 {
 557         struct crypto_alg *alg;
 558
 559         alg = crypto_alg_mod_lookup(name, type, mask);
 560         if (IS_ERR(alg))
 561                 return alg;
 562
 563         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 564             CRYPTO_ALG_TYPE_GIVCIPHER)
 565                 return alg;
 566
 567         if (!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 568               CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 569                                           alg->cra_ablkcipher.ivsize))
 570                 return alg;
 571
 572         crypto_mod_put(alg);
 573         alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
 574                                     mask & ~CRYPTO_ALG_TESTED);
 575         if (IS_ERR(alg))
 576                 return alg;
 577
 578         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 579             CRYPTO_ALG_TYPE_GIVCIPHER) {
 580                 if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
 581                         crypto_mod_put(alg);
 582                         alg = ERR_PTR(-ENOENT);
 583                 }
 584                 return alg;
 585         }
 586
 587         BUG_ON(!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 588                  CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 589                                              alg->cra_ablkcipher.ivsize));
 590
 591         return ERR_PTR(crypto_givcipher_default(alg, type, mask));
 592 }
 593
 594 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
 595                          u32 type, u32 mask)
 596 {
 597         struct crypto_alg *alg;
 598         int err;
 599
 600         type = crypto_skcipher_type(type);
 601         mask = crypto_skcipher_mask(mask);
 602
 603         alg = crypto_lookup_skcipher(name, type, mask);
 604         if (IS_ERR(alg))
 605                 return PTR_ERR(alg);
 606
 607         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 608         crypto_mod_put(alg);
 609         return err;
 610 }
 611 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
 612
 613 struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
 614                                                   u32 type, u32 mask)
 615 {
 616         struct crypto_tfm *tfm;
 617         int err;
 618
 619         type = crypto_skcipher_type(type);
 620         mask = crypto_skcipher_mask(mask);
 621
 622         for (;;) {
 623                 struct crypto_alg *alg;
 624
 625                 alg = crypto_lookup_skcipher(alg_name, type, mask);
 626                 if (IS_ERR(alg)) {
 627                         err = PTR_ERR(alg);
 628                         goto err;
 629                 }
 630
 631                 tfm = __crypto_alloc_tfm(alg, type, mask);
 632                 if (!IS_ERR(tfm))
 633                         return __crypto_ablkcipher_cast(tfm);
 634
 635                 crypto_mod_put(alg);
 636                 err = PTR_ERR(tfm);
 637
 638 err:
 639                 if (err != -EAGAIN)
 640                         break;
 641                 if (signal_pending(current)) {
 642                         err = -EINTR;
 643                         break;
 644                 }
 645         }
 646
 647         return ERR_PTR(err);
 648 }
 649 EXPORT_SYMBOL_GPL(crypto_alloc_ablkcipher);
 650
 651 static int __init skcipher_module_init(void)
 652 {
 653         skcipher_default_geniv = num_possible_cpus() > 1 ?
 654                                  "eseqiv" : "chainiv";
 655         return 0;
 656 }
 657
 658 static void skcipher_module_exit(void)
 659 {
 660 }
 661
 662 module_init(skcipher_module_init);
 663 module_exit(skcipher_module_exit);