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         if (walk->iv_buffer)
 145                 kfree(walk->iv_buffer);
 146
 147         return err;
 148 }
 149 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 150
 151 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 152                                        struct ablkcipher_walk *walk,
 153                                        unsigned int bsize,
 154                                        unsigned int alignmask,
 155                                        void **src_p, void **dst_p)
 156 {
 157         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 158         struct ablkcipher_buffer *p;
 159         void *src, *dst, *base;
 160         unsigned int n;
 161
 162         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 163         n += (aligned_bsize * 3 - (alignmask + 1) +
 164               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 165
 166         p = kmalloc(n, GFP_ATOMIC);
 167         if (!p)
 168                 ablkcipher_walk_done(req, walk, -ENOMEM);
 169
 170         base = p + 1;
 171
 172         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 173         src = dst = ablkcipher_get_spot(dst, bsize);
 174
 175         p->len = bsize;
 176         p->data = dst;
 177
 178         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 179
 180         ablkcipher_queue_write(walk, p);
 181
 182         walk->nbytes = bsize;
 183         walk->flags |= ABLKCIPHER_WALK_SLOW;
 184
 185         *src_p = src;
 186         *dst_p = dst;
 187
 188         return 0;
 189 }
 190
 191 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 192                                      struct crypto_tfm *tfm,
 193                                      unsigned int alignmask)
 194 {
 195         unsigned bs = walk->blocksize;
 196         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 197         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 198         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 199                             (alignmask + 1);
 200         u8 *iv;
 201
 202         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 203         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 204         if (!walk->iv_buffer)
 205                 return -ENOMEM;
 206
 207         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 208         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 209         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 210         iv = ablkcipher_get_spot(iv, ivsize);
 211
 212         walk->iv = memcpy(iv, walk->iv, ivsize);
 213         return 0;
 214 }
 215
 216 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 217                                        struct ablkcipher_walk *walk)
 218 {
 219         walk->src.page = scatterwalk_page(&walk->in);
 220         walk->src.offset = offset_in_page(walk->in.offset);
 221         walk->dst.page = scatterwalk_page(&walk->out);
 222         walk->dst.offset = offset_in_page(walk->out.offset);
 223
 224         return 0;
 225 }
 226
 227 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 228                                 struct ablkcipher_walk *walk)
 229 {
 230         struct crypto_tfm *tfm = req->base.tfm;
 231         unsigned int alignmask, bsize, n;
 232         void *src, *dst;
 233         int err;
 234
 235         alignmask = crypto_tfm_alg_alignmask(tfm);
 236         n = walk->total;
 237         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 238                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 239                 return ablkcipher_walk_done(req, walk, -EINVAL);
 240         }
 241
 242         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 243         src = dst = NULL;
 244
 245         bsize = min(walk->blocksize, n);
 246         n = scatterwalk_clamp(&walk->in, n);
 247         n = scatterwalk_clamp(&walk->out, n);
 248
 249         if (n < bsize ||
 250             !scatterwalk_aligned(&walk->in, alignmask) ||
 251             !scatterwalk_aligned(&walk->out, alignmask)) {
 252                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 253                                            &src, &dst);
 254                 goto set_phys_lowmem;
 255         }
 256
 257         walk->nbytes = n;
 258
 259         return ablkcipher_next_fast(req, walk);
 260
 261 set_phys_lowmem:
 262         if (err >= 0) {
 263                 walk->src.page = virt_to_page(src);
 264                 walk->dst.page = virt_to_page(dst);
 265                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 266                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 267         }
 268
 269         return err;
 270 }
 271
 272 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 273                                  struct ablkcipher_walk *walk)
 274 {
 275         struct crypto_tfm *tfm = req->base.tfm;
 276         unsigned int alignmask;
 277
 278         alignmask = crypto_tfm_alg_alignmask(tfm);
 279         if (WARN_ON_ONCE(in_irq()))
 280                 return -EDEADLK;
 281
 282         walk->nbytes = walk->total;
 283         if (unlikely(!walk->total))
 284                 return 0;
 285
 286         walk->iv_buffer = NULL;
 287         walk->iv = req->info;
 288         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 289                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 290                 if (err)
 291                         return err;
 292         }
 293
 294         scatterwalk_start(&walk->in, walk->in.sg);
 295         scatterwalk_start(&walk->out, walk->out.sg);
 296
 297         return ablkcipher_walk_next(req, walk);
 298 }
 299
 300 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 301                          struct ablkcipher_walk *walk)
 302 {
 303         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 304         return ablkcipher_walk_first(req, walk);
 305 }
 306 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 307
 308 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 309                             unsigned int keylen)
 310 {
 311         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 312         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 313         int ret;
 314         u8 *buffer, *alignbuffer;
 315         unsigned long absize;
 316
 317         absize = keylen + alignmask;
 318         buffer = kmalloc(absize, GFP_ATOMIC);
 319         if (!buffer)
 320                 return -ENOMEM;
 321
 322         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 323         memcpy(alignbuffer, key, keylen);
 324         ret = cipher->setkey(tfm, alignbuffer, keylen);
 325         memset(alignbuffer, 0, keylen);
 326         kfree(buffer);
 327         return ret;
 328 }
 329
 330 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 331                   unsigned int keylen)
 332 {
 333         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 334         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 335
 336         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 337                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 338                 return -EINVAL;
 339         }
 340
 341         if ((unsigned long)key & alignmask)
 342                 return setkey_unaligned(tfm, key, keylen);
 343
 344         return cipher->setkey(tfm, key, keylen);
 345 }
 346
 347 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 348                                               u32 mask)
 349 {
 350         return alg->cra_ctxsize;
 351 }
 352
 353 int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req)
 354 {
 355         return crypto_ablkcipher_encrypt(&req->creq);
 356 }
 357
 358 int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req)
 359 {
 360         return crypto_ablkcipher_decrypt(&req->creq);
 361 }
 362
 363 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 364                                       u32 mask)
 365 {
 366         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 367         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 368
 369         if (alg->ivsize > PAGE_SIZE / 8)
 370                 return -EINVAL;
 371
 372         crt->setkey = setkey;
 373         crt->encrypt = alg->encrypt;
 374         crt->decrypt = alg->decrypt;
 375         if (!alg->ivsize) {
 376                 crt->givencrypt = skcipher_null_givencrypt;
 377                 crt->givdecrypt = skcipher_null_givdecrypt;
 378         }
 379         crt->base = __crypto_ablkcipher_cast(tfm);
 380         crt->ivsize = alg->ivsize;
 381
 382         return 0;
 383 }
 384
 385 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 386         __attribute__ ((unused));
 387 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 388 {
 389         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 390
 391         seq_printf(m, "type         : ablkcipher\n");
 392         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 393                                              "yes" : "no");
 394         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 395         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 396         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 397         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 398         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 399 }
 400
 401 const struct crypto_type crypto_ablkcipher_type = {
 402         .ctxsize = crypto_ablkcipher_ctxsize,
 403         .init = crypto_init_ablkcipher_ops,
 404 #ifdef CONFIG_PROC_FS
 405         .show = crypto_ablkcipher_show,
 406 #endif
 407 };
 408 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 409
 410 static int no_givdecrypt(struct skcipher_givcrypt_request *req)
 411 {
 412         return -ENOSYS;
 413 }
 414
 415 static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 416                                       u32 mask)
 417 {
 418         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 419         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 420
 421         if (alg->ivsize > PAGE_SIZE / 8)
 422                 return -EINVAL;
 423
 424         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 425                       alg->setkey : setkey;
 426         crt->encrypt = alg->encrypt;
 427         crt->decrypt = alg->decrypt;
 428         crt->givencrypt = alg->givencrypt;
 429         crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;
 430         crt->base = __crypto_ablkcipher_cast(tfm);
 431         crt->ivsize = alg->ivsize;
 432
 433         return 0;
 434 }
 435
 436 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 437         __attribute__ ((unused));
 438 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 439 {
 440         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 441
 442         seq_printf(m, "type         : givcipher\n");
 443         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 444                                              "yes" : "no");
 445         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 446         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 447         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 448         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 449         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 450 }
 451
 452 const struct crypto_type crypto_givcipher_type = {
 453         .ctxsize = crypto_ablkcipher_ctxsize,
 454         .init = crypto_init_givcipher_ops,
 455 #ifdef CONFIG_PROC_FS
 456         .show = crypto_givcipher_show,
 457 #endif
 458 };
 459 EXPORT_SYMBOL_GPL(crypto_givcipher_type);
 460
 461 const char *crypto_default_geniv(const struct crypto_alg *alg)
 462 {
 463         if (((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 464              CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 465                                          alg->cra_ablkcipher.ivsize) !=
 466             alg->cra_blocksize)
 467                 return "chainiv";
 468
 469         return alg->cra_flags & CRYPTO_ALG_ASYNC ?
 470                "eseqiv" : skcipher_default_geniv;
 471 }
 472
 473 static int crypto_givcipher_default(struct crypto_alg *alg, u32 type, u32 mask)
 474 {
 475         struct rtattr *tb[3];
 476         struct {
 477                 struct rtattr attr;
 478                 struct crypto_attr_type data;
 479         } ptype;
 480         struct {
 481                 struct rtattr attr;
 482                 struct crypto_attr_alg data;
 483         } palg;
 484         struct crypto_template *tmpl;
 485         struct crypto_instance *inst;
 486         struct crypto_alg *larval;
 487         const char *geniv;
 488         int err;
 489
 490         larval = crypto_larval_lookup(alg->cra_driver_name,
 491                                       (type & ~CRYPTO_ALG_TYPE_MASK) |
 492                                       CRYPTO_ALG_TYPE_GIVCIPHER,
 493                                       mask | CRYPTO_ALG_TYPE_MASK);
 494         err = PTR_ERR(larval);
 495         if (IS_ERR(larval))
 496                 goto out;
 497
 498         err = -EAGAIN;
 499         if (!crypto_is_larval(larval))
 500                 goto drop_larval;
 501
 502         ptype.attr.rta_len = sizeof(ptype);
 503         ptype.attr.rta_type = CRYPTOA_TYPE;
 504         ptype.data.type = type | CRYPTO_ALG_GENIV;
 505         /* GENIV tells the template that we're making a default geniv. */
 506         ptype.data.mask = mask | CRYPTO_ALG_GENIV;
 507         tb[0] = &ptype.attr;
 508
 509         palg.attr.rta_len = sizeof(palg);
 510         palg.attr.rta_type = CRYPTOA_ALG;
 511         /* Must use the exact name to locate ourselves. */
 512         memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
 513         tb[1] = &palg.attr;
 514
 515         tb[2] = NULL;
 516
 517         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 518             CRYPTO_ALG_TYPE_BLKCIPHER)
 519                 geniv = alg->cra_blkcipher.geniv;
 520         else
 521                 geniv = alg->cra_ablkcipher.geniv;
 522
 523         if (!geniv)
 524                 geniv = crypto_default_geniv(alg);
 525
 526         tmpl = crypto_lookup_template(geniv);
 527         err = -ENOENT;
 528         if (!tmpl)
 529                 goto kill_larval;
 530
 531         inst = tmpl->alloc(tb);
 532         err = PTR_ERR(inst);
 533         if (IS_ERR(inst))
 534                 goto put_tmpl;
 535
 536         if ((err = crypto_register_instance(tmpl, inst))) {
 537                 tmpl->free(inst);
 538                 goto put_tmpl;
 539         }
 540
 541         /* Redo the lookup to use the instance we just registered. */
 542         err = -EAGAIN;
 543
 544 put_tmpl:
 545         crypto_tmpl_put(tmpl);
 546 kill_larval:
 547         crypto_larval_kill(larval);
 548 drop_larval:
 549         crypto_mod_put(larval);
 550 out:
 551         crypto_mod_put(alg);
 552         return err;
 553 }
 554
 555 static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
 556                                                  u32 mask)
 557 {
 558         struct crypto_alg *alg;
 559
 560         alg = crypto_alg_mod_lookup(name, type, mask);
 561         if (IS_ERR(alg))
 562                 return alg;
 563
 564         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 565             CRYPTO_ALG_TYPE_GIVCIPHER)
 566                 return alg;
 567
 568         if (!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 569               CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 570                                           alg->cra_ablkcipher.ivsize))
 571                 return alg;
 572
 573         crypto_mod_put(alg);
 574         alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
 575                                     mask & ~CRYPTO_ALG_TESTED);
 576         if (IS_ERR(alg))
 577                 return alg;
 578
 579         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 580             CRYPTO_ALG_TYPE_GIVCIPHER) {
 581                 if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
 582                         crypto_mod_put(alg);
 583                         alg = ERR_PTR(-ENOENT);
 584                 }
 585                 return alg;
 586         }
 587
 588         BUG_ON(!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 589                  CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
 590                                              alg->cra_ablkcipher.ivsize));
 591
 592         return ERR_PTR(crypto_givcipher_default(alg, type, mask));
 593 }
 594
 595 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
 596                          u32 type, u32 mask)
 597 {
 598         struct crypto_alg *alg;
 599         int err;
 600
 601         type = crypto_skcipher_type(type);
 602         mask = crypto_skcipher_mask(mask);
 603
 604         alg = crypto_lookup_skcipher(name, type, mask);
 605         if (IS_ERR(alg))
 606                 return PTR_ERR(alg);
 607
 608         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 609         crypto_mod_put(alg);
 610         return err;
 611 }
 612 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
 613
 614 struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
 615                                                   u32 type, u32 mask)
 616 {
 617         struct crypto_tfm *tfm;
 618         int err;
 619
 620         type = crypto_skcipher_type(type);
 621         mask = crypto_skcipher_mask(mask);
 622
 623         for (;;) {
 624                 struct crypto_alg *alg;
 625
 626                 alg = crypto_lookup_skcipher(alg_name, type, mask);
 627                 if (IS_ERR(alg)) {
 628                         err = PTR_ERR(alg);
 629                         goto err;
 630                 }
 631
 632                 tfm = __crypto_alloc_tfm(alg, type, mask);
 633                 if (!IS_ERR(tfm))
 634                         return __crypto_ablkcipher_cast(tfm);
 635
 636                 crypto_mod_put(alg);
 637                 err = PTR_ERR(tfm);
 638
 639 err:
 640                 if (err != -EAGAIN)
 641                         break;
 642                 if (signal_pending(current)) {
 643                         err = -EINTR;
 644                         break;
 645                 }
 646         }
 647
 648         return ERR_PTR(err);
 649 }
 650 EXPORT_SYMBOL_GPL(crypto_alloc_ablkcipher);
 651
 652 static int __init skcipher_module_init(void)
 653 {
 654         skcipher_default_geniv = num_possible_cpus() > 1 ?
 655                                  "eseqiv" : "chainiv";
 656         return 0;
 657 }
 658
 659 static void skcipher_module_exit(void)
 660 {
 661 }
 662
 663 module_init(skcipher_module_init);
 664 module_exit(skcipher_module_exit);