crypto/blkcipher.c

   1 /*
   2  * Block chaining cipher operations.
   3  *
   4  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
   5  * multiple page boundaries by using temporary blocks.  In user context,
   6  * the kernel is given a chance to schedule us once per page.
   7  *
   8  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the Free
  12  * Software Foundation; either version 2 of the License, or (at your option)
  13  * any later version.
  14  *
  15  */
  16
  17 #include <crypto/aead.h>
  18 #include <crypto/internal/skcipher.h>
  19 #include <crypto/scatterwalk.h>
  20 #include <linux/errno.h>
  21 #include <linux/hardirq.h>
  22 #include <linux/kernel.h>
  23 #include <linux/module.h>
  24 #include <linux/scatterlist.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/slab.h>
  27 #include <linux/string.h>
  28 #include <linux/cryptouser.h>
  29 #include <net/netlink.h>
  30
  31 #include "internal.h"
  32
  33 enum {
  34         BLKCIPHER_WALK_PHYS = 1 << 0,
  35         BLKCIPHER_WALK_SLOW = 1 << 1,
  36         BLKCIPHER_WALK_COPY = 1 << 2,
  37         BLKCIPHER_WALK_DIFF = 1 << 3,
  38 };
  39
  40 static int blkcipher_walk_next(struct blkcipher_desc *desc,
  41                                struct blkcipher_walk *walk);
  42 static int blkcipher_walk_first(struct blkcipher_desc *desc,
  43                                 struct blkcipher_walk *walk);
  44
  45 static inline void blkcipher_map_src(struct blkcipher_walk *walk)
  46 {
  47         walk->src.virt.addr = scatterwalk_map(&walk->in);
  48 }
  49
  50 static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
  51 {
  52         walk->dst.virt.addr = scatterwalk_map(&walk->out);
  53 }
  54
  55 static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
  56 {
  57         scatterwalk_unmap(walk->src.virt.addr);
  58 }
  59
  60 static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
  61 {
  62         scatterwalk_unmap(walk->dst.virt.addr);
  63 }
  64
  65 /* Get a spot of the specified length that does not straddle a page.
  66  * The caller needs to ensure that there is enough space for this operation.
  67  */
  68 static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
  69 {
  70         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  71         return max(start, end_page);
  72 }
  73
  74 static inline unsigned int blkcipher_done_slow(struct blkcipher_walk *walk,
  75                                                unsigned int bsize)
  76 {
  77         u8 *addr;
  78
  79         addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
  80         addr = blkcipher_get_spot(addr, bsize);
  81         scatterwalk_copychunks(addr, &walk->out, bsize, 1);
  82         return bsize;
  83 }
  84
  85 static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
  86                                                unsigned int n)
  87 {
  88         if (walk->flags & BLKCIPHER_WALK_COPY) {
  89                 blkcipher_map_dst(walk);
  90                 memcpy(walk->dst.virt.addr, walk->page, n);
  91                 blkcipher_unmap_dst(walk);
  92         } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
  93                 if (walk->flags & BLKCIPHER_WALK_DIFF)
  94                         blkcipher_unmap_dst(walk);
  95                 blkcipher_unmap_src(walk);
  96         }
  97
  98         scatterwalk_advance(&walk->in, n);
  99         scatterwalk_advance(&walk->out, n);
 100
 101         return n;
 102 }
 103
 104 int blkcipher_walk_done(struct blkcipher_desc *desc,
 105                         struct blkcipher_walk *walk, int err)
 106 {
 107         unsigned int nbytes = 0;
 108
 109         if (likely(err >= 0)) {
 110                 unsigned int n = walk->nbytes - err;
 111
 112                 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
 113                         n = blkcipher_done_fast(walk, n);
 114                 else if (WARN_ON(err)) {
 115                         err = -EINVAL;
 116                         goto err;
 117                 } else
 118                         n = blkcipher_done_slow(walk, n);
 119
 120                 nbytes = walk->total - n;
 121                 err = 0;
 122         }
 123
 124         scatterwalk_done(&walk->in, 0, nbytes);
 125         scatterwalk_done(&walk->out, 1, nbytes);
 126
 127 err:
 128         walk->total = nbytes;
 129         walk->nbytes = nbytes;
 130
 131         if (nbytes) {
 132                 crypto_yield(desc->flags);
 133                 return blkcipher_walk_next(desc, walk);
 134         }
 135
 136         if (walk->iv != desc->info)
 137                 memcpy(desc->info, walk->iv, walk->ivsize);
 138         if (walk->buffer != walk->page)
 139                 kfree(walk->buffer);
 140         if (walk->page)
 141                 free_page((unsigned long)walk->page);
 142
 143         return err;
 144 }
 145 EXPORT_SYMBOL_GPL(blkcipher_walk_done);
 146
 147 static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
 148                                       struct blkcipher_walk *walk,
 149                                       unsigned int bsize,
 150                                       unsigned int alignmask)
 151 {
 152         unsigned int n;
 153         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 154
 155         if (walk->buffer)
 156                 goto ok;
 157
 158         walk->buffer = walk->page;
 159         if (walk->buffer)
 160                 goto ok;
 161
 162         n = aligned_bsize * 3 - (alignmask + 1) +
 163             (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
 164         walk->buffer = kmalloc(n, GFP_ATOMIC);
 165         if (!walk->buffer)
 166                 return blkcipher_walk_done(desc, walk, -ENOMEM);
 167
 168 ok:
 169         walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
 170                                           alignmask + 1);
 171         walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
 172         walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
 173                                                  aligned_bsize, bsize);
 174
 175         scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
 176
 177         walk->nbytes = bsize;
 178         walk->flags |= BLKCIPHER_WALK_SLOW;
 179
 180         return 0;
 181 }
 182
 183 static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
 184 {
 185         u8 *tmp = walk->page;
 186
 187         blkcipher_map_src(walk);
 188         memcpy(tmp, walk->src.virt.addr, walk->nbytes);
 189         blkcipher_unmap_src(walk);
 190
 191         walk->src.virt.addr = tmp;
 192         walk->dst.virt.addr = tmp;
 193
 194         return 0;
 195 }
 196
 197 static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
 198                                       struct blkcipher_walk *walk)
 199 {
 200         unsigned long diff;
 201
 202         walk->src.phys.page = scatterwalk_page(&walk->in);
 203         walk->src.phys.offset = offset_in_page(walk->in.offset);
 204         walk->dst.phys.page = scatterwalk_page(&walk->out);
 205         walk->dst.phys.offset = offset_in_page(walk->out.offset);
 206
 207         if (walk->flags & BLKCIPHER_WALK_PHYS)
 208                 return 0;
 209
 210         diff = walk->src.phys.offset - walk->dst.phys.offset;
 211         diff |= walk->src.virt.page - walk->dst.virt.page;
 212
 213         blkcipher_map_src(walk);
 214         walk->dst.virt.addr = walk->src.virt.addr;
 215
 216         if (diff) {
 217                 walk->flags |= BLKCIPHER_WALK_DIFF;
 218                 blkcipher_map_dst(walk);
 219         }
 220
 221         return 0;
 222 }
 223
 224 static int blkcipher_walk_next(struct blkcipher_desc *desc,
 225                                struct blkcipher_walk *walk)
 226 {
 227         unsigned int bsize;
 228         unsigned int n;
 229         int err;
 230
 231         n = walk->total;
 232         if (unlikely(n < walk->cipher_blocksize)) {
 233                 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 234                 return blkcipher_walk_done(desc, walk, -EINVAL);
 235         }
 236
 237         walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
 238                          BLKCIPHER_WALK_DIFF);
 239         if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
 240             !scatterwalk_aligned(&walk->out, walk->alignmask)) {
 241                 walk->flags |= BLKCIPHER_WALK_COPY;
 242                 if (!walk->page) {
 243                         walk->page = (void *)__get_free_page(GFP_ATOMIC);
 244                         if (!walk->page)
 245                                 n = 0;
 246                 }
 247         }
 248
 249         bsize = min(walk->walk_blocksize, n);
 250         n = scatterwalk_clamp(&walk->in, n);
 251         n = scatterwalk_clamp(&walk->out, n);
 252
 253         if (unlikely(n < bsize)) {
 254                 err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
 255                 goto set_phys_lowmem;
 256         }
 257
 258         walk->nbytes = n;
 259         if (walk->flags & BLKCIPHER_WALK_COPY) {
 260                 err = blkcipher_next_copy(walk);
 261                 goto set_phys_lowmem;
 262         }
 263
 264         return blkcipher_next_fast(desc, walk);
 265
 266 set_phys_lowmem:
 267         if (walk->flags & BLKCIPHER_WALK_PHYS) {
 268                 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
 269                 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
 270                 walk->src.phys.offset &= PAGE_SIZE - 1;
 271                 walk->dst.phys.offset &= PAGE_SIZE - 1;
 272         }
 273         return err;
 274 }
 275
 276 static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
 277 {
 278         unsigned bs = walk->walk_blocksize;
 279         unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
 280         unsigned int size = aligned_bs * 2 +
 281                             walk->ivsize + max(aligned_bs, walk->ivsize) -
 282                             (walk->alignmask + 1);
 283         u8 *iv;
 284
 285         size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 286         walk->buffer = kmalloc(size, GFP_ATOMIC);
 287         if (!walk->buffer)
 288                 return -ENOMEM;
 289
 290         iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
 291         iv = blkcipher_get_spot(iv, bs) + aligned_bs;
 292         iv = blkcipher_get_spot(iv, bs) + aligned_bs;
 293         iv = blkcipher_get_spot(iv, walk->ivsize);
 294
 295         walk->iv = memcpy(iv, walk->iv, walk->ivsize);
 296         return 0;
 297 }
 298
 299 int blkcipher_walk_virt(struct blkcipher_desc *desc,
 300                         struct blkcipher_walk *walk)
 301 {
 302         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 303         walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 304         walk->cipher_blocksize = walk->walk_blocksize;
 305         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 306         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 307         return blkcipher_walk_first(desc, walk);
 308 }
 309 EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
 310
 311 int blkcipher_walk_phys(struct blkcipher_desc *desc,
 312                         struct blkcipher_walk *walk)
 313 {
 314         walk->flags |= BLKCIPHER_WALK_PHYS;
 315         walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 316         walk->cipher_blocksize = walk->walk_blocksize;
 317         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 318         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 319         return blkcipher_walk_first(desc, walk);
 320 }
 321 EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
 322
 323 static int blkcipher_walk_first(struct blkcipher_desc *desc,
 324                                 struct blkcipher_walk *walk)
 325 {
 326         if (WARN_ON_ONCE(in_irq()))
 327                 return -EDEADLK;
 328
 329         walk->iv = desc->info;
 330         walk->nbytes = walk->total;
 331         if (unlikely(!walk->total))
 332                 return 0;
 333
 334         walk->buffer = NULL;
 335         if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
 336                 int err = blkcipher_copy_iv(walk);
 337                 if (err)
 338                         return err;
 339         }
 340
 341         scatterwalk_start(&walk->in, walk->in.sg);
 342         scatterwalk_start(&walk->out, walk->out.sg);
 343         walk->page = NULL;
 344
 345         return blkcipher_walk_next(desc, walk);
 346 }
 347
 348 int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
 349                               struct blkcipher_walk *walk,
 350                               unsigned int blocksize)
 351 {
 352         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 353         walk->walk_blocksize = blocksize;
 354         walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 355         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 356         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 357         return blkcipher_walk_first(desc, walk);
 358 }
 359 EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
 360
 361 int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
 362                                    struct blkcipher_walk *walk,
 363                                    struct crypto_aead *tfm,
 364                                    unsigned int blocksize)
 365 {
 366         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 367         walk->walk_blocksize = blocksize;
 368         walk->cipher_blocksize = crypto_aead_blocksize(tfm);
 369         walk->ivsize = crypto_aead_ivsize(tfm);
 370         walk->alignmask = crypto_aead_alignmask(tfm);
 371         return blkcipher_walk_first(desc, walk);
 372 }
 373 EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
 374
 375 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
 376                             unsigned int keylen)
 377 {
 378         struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
 379         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 380         int ret;
 381         u8 *buffer, *alignbuffer;
 382         unsigned long absize;
 383
 384         absize = keylen + alignmask;
 385         buffer = kmalloc(absize, GFP_ATOMIC);
 386         if (!buffer)
 387                 return -ENOMEM;
 388
 389         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 390         memcpy(alignbuffer, key, keylen);
 391         ret = cipher->setkey(tfm, alignbuffer, keylen);
 392         memset(alignbuffer, 0, keylen);
 393         kfree(buffer);
 394         return ret;
 395 }
 396
 397 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 398 {
 399         struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
 400         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 401
 402         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 403                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 404                 return -EINVAL;
 405         }
 406
 407         if ((unsigned long)key & alignmask)
 408                 return setkey_unaligned(tfm, key, keylen);
 409
 410         return cipher->setkey(tfm, key, keylen);
 411 }
 412
 413 static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 414                         unsigned int keylen)
 415 {
 416         return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
 417 }
 418
 419 static int async_encrypt(struct ablkcipher_request *req)
 420 {
 421         struct crypto_tfm *tfm = req->base.tfm;
 422         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 423         struct blkcipher_desc desc = {
 424                 .tfm = __crypto_blkcipher_cast(tfm),
 425                 .info = req->info,
 426                 .flags = req->base.flags,
 427         };
 428
 429
 430         return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
 431 }
 432
 433 static int async_decrypt(struct ablkcipher_request *req)
 434 {
 435         struct crypto_tfm *tfm = req->base.tfm;
 436         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 437         struct blkcipher_desc desc = {
 438                 .tfm = __crypto_blkcipher_cast(tfm),
 439                 .info = req->info,
 440                 .flags = req->base.flags,
 441         };
 442
 443         return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
 444 }
 445
 446 static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 447                                              u32 mask)
 448 {
 449         struct blkcipher_alg *cipher = &alg->cra_blkcipher;
 450         unsigned int len = alg->cra_ctxsize;
 451
 452         if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
 453             cipher->ivsize) {
 454                 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
 455                 len += cipher->ivsize;
 456         }
 457
 458         return len;
 459 }
 460
 461 static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
 462 {
 463         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 464         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 465
 466         crt->setkey = async_setkey;
 467         crt->encrypt = async_encrypt;
 468         crt->decrypt = async_decrypt;
 469         if (!alg->ivsize) {
 470                 crt->givencrypt = skcipher_null_givencrypt;
 471                 crt->givdecrypt = skcipher_null_givdecrypt;
 472         }
 473         crt->base = __crypto_ablkcipher_cast(tfm);
 474         crt->ivsize = alg->ivsize;
 475
 476         return 0;
 477 }
 478
 479 static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
 480 {
 481         struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
 482         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 483         unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
 484         unsigned long addr;
 485
 486         crt->setkey = setkey;
 487         crt->encrypt = alg->encrypt;
 488         crt->decrypt = alg->decrypt;
 489
 490         addr = (unsigned long)crypto_tfm_ctx(tfm);
 491         addr = ALIGN(addr, align);
 492         addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 493         crt->iv = (void *)addr;
 494
 495         return 0;
 496 }
 497
 498 static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 499 {
 500         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 501
 502         if (alg->ivsize > PAGE_SIZE / 8)
 503                 return -EINVAL;
 504
 505         if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
 506                 return crypto_init_blkcipher_ops_sync(tfm);
 507         else
 508                 return crypto_init_blkcipher_ops_async(tfm);
 509 }
 510
 511 #ifdef CONFIG_NET
 512 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 513 {
 514         struct crypto_report_blkcipher rblkcipher;
 515
 516         strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
 517         strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
 518                 sizeof(rblkcipher.geniv));
 519
 520         rblkcipher.blocksize = alg->cra_blocksize;
 521         rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
 522         rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
 523         rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
 524
 525         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 526                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 527                 goto nla_put_failure;
 528         return 0;
 529
 530 nla_put_failure:
 531         return -EMSGSIZE;
 532 }
 533 #else
 534 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 535 {
 536         return -ENOSYS;
 537 }
 538 #endif
 539
 540 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 541         __attribute__ ((unused));
 542 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 543 {
 544         seq_printf(m, "type         : blkcipher\n");
 545         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 546         seq_printf(m, "min keysize  : %u\n", alg->cra_blkcipher.min_keysize);
 547         seq_printf(m, "max keysize  : %u\n", alg->cra_blkcipher.max_keysize);
 548         seq_printf(m, "ivsize       : %u\n", alg->cra_blkcipher.ivsize);
 549         seq_printf(m, "geniv        : %s\n", alg->cra_blkcipher.geniv ?:
 550                                              "<default>");
 551 }
 552
 553 const struct crypto_type crypto_blkcipher_type = {
 554         .ctxsize = crypto_blkcipher_ctxsize,
 555         .init = crypto_init_blkcipher_ops,
 556 #ifdef CONFIG_PROC_FS
 557         .show = crypto_blkcipher_show,
 558 #endif
 559         .report = crypto_blkcipher_report,
 560 };
 561 EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
 562
 563 static int crypto_grab_nivcipher(struct crypto_skcipher_spawn *spawn,
 564                                 const char *name, u32 type, u32 mask)
 565 {
 566         struct crypto_alg *alg;
 567         int err;
 568
 569         type = crypto_skcipher_type(type);
 570         mask = crypto_skcipher_mask(mask)| CRYPTO_ALG_GENIV;
 571
 572         alg = crypto_alg_mod_lookup(name, type, mask);
 573         if (IS_ERR(alg))
 574                 return PTR_ERR(alg);
 575
 576         err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
 577         crypto_mod_put(alg);
 578         return err;
 579 }
 580
 581 struct crypto_instance *skcipher_geniv_alloc(struct crypto_template *tmpl,
 582                                              struct rtattr **tb, u32 type,
 583                                              u32 mask)
 584 {
 585         struct {
 586                 int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
 587                               unsigned int keylen);
 588                 int (*encrypt)(struct ablkcipher_request *req);
 589                 int (*decrypt)(struct ablkcipher_request *req);
 590
 591                 unsigned int min_keysize;
 592                 unsigned int max_keysize;
 593                 unsigned int ivsize;
 594
 595                 const char *geniv;
 596         } balg;
 597         const char *name;
 598         struct crypto_skcipher_spawn *spawn;
 599         struct crypto_attr_type *algt;
 600         struct crypto_instance *inst;
 601         struct crypto_alg *alg;
 602         int err;
 603
 604         algt = crypto_get_attr_type(tb);
 605         if (IS_ERR(algt))
 606                 return ERR_CAST(algt);
 607
 608         if ((algt->type ^ (CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV)) &
 609             algt->mask)
 610                 return ERR_PTR(-EINVAL);
 611
 612         name = crypto_attr_alg_name(tb[1]);
 613         if (IS_ERR(name))
 614                 return ERR_CAST(name);
 615
 616         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 617         if (!inst)
 618                 return ERR_PTR(-ENOMEM);
 619
 620         spawn = crypto_instance_ctx(inst);
 621
 622         /* Ignore async algorithms if necessary. */
 623         mask |= crypto_requires_sync(algt->type, algt->mask);
 624
 625         crypto_set_skcipher_spawn(spawn, inst);
 626         err = crypto_grab_nivcipher(spawn, name, type, mask);
 627         if (err)
 628                 goto err_free_inst;
 629
 630         alg = crypto_skcipher_spawn_alg(spawn);
 631
 632         if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 633             CRYPTO_ALG_TYPE_BLKCIPHER) {
 634                 balg.ivsize = alg->cra_blkcipher.ivsize;
 635                 balg.min_keysize = alg->cra_blkcipher.min_keysize;
 636                 balg.max_keysize = alg->cra_blkcipher.max_keysize;
 637
 638                 balg.setkey = async_setkey;
 639                 balg.encrypt = async_encrypt;
 640                 balg.decrypt = async_decrypt;
 641
 642                 balg.geniv = alg->cra_blkcipher.geniv;
 643         } else {
 644                 balg.ivsize = alg->cra_ablkcipher.ivsize;
 645                 balg.min_keysize = alg->cra_ablkcipher.min_keysize;
 646                 balg.max_keysize = alg->cra_ablkcipher.max_keysize;
 647
 648                 balg.setkey = alg->cra_ablkcipher.setkey;
 649                 balg.encrypt = alg->cra_ablkcipher.encrypt;
 650                 balg.decrypt = alg->cra_ablkcipher.decrypt;
 651
 652                 balg.geniv = alg->cra_ablkcipher.geniv;
 653         }
 654
 655         err = -EINVAL;
 656         if (!balg.ivsize)
 657                 goto err_drop_alg;
 658
 659         /*
 660          * This is only true if we're constructing an algorithm with its
 661          * default IV generator.  For the default generator we elide the
 662          * template name and double-check the IV generator.
 663          */
 664         if (algt->mask & CRYPTO_ALG_GENIV) {
 665                 if (!balg.geniv)
 666                         balg.geniv = crypto_default_geniv(alg);
 667                 err = -EAGAIN;
 668                 if (strcmp(tmpl->name, balg.geniv))
 669                         goto err_drop_alg;
 670
 671                 memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
 672                 memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
 673                        CRYPTO_MAX_ALG_NAME);
 674         } else {
 675                 err = -ENAMETOOLONG;
 676                 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 677                              "%s(%s)", tmpl->name, alg->cra_name) >=
 678                     CRYPTO_MAX_ALG_NAME)
 679                         goto err_drop_alg;
 680                 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 681                              "%s(%s)", tmpl->name, alg->cra_driver_name) >=
 682                     CRYPTO_MAX_ALG_NAME)
 683                         goto err_drop_alg;
 684         }
 685
 686         inst->alg.cra_flags = CRYPTO_ALG_TYPE_GIVCIPHER | CRYPTO_ALG_GENIV;
 687         inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 688         inst->alg.cra_priority = alg->cra_priority;
 689         inst->alg.cra_blocksize = alg->cra_blocksize;
 690         inst->alg.cra_alignmask = alg->cra_alignmask;
 691         inst->alg.cra_type = &crypto_givcipher_type;
 692
 693         inst->alg.cra_ablkcipher.ivsize = balg.ivsize;
 694         inst->alg.cra_ablkcipher.min_keysize = balg.min_keysize;
 695         inst->alg.cra_ablkcipher.max_keysize = balg.max_keysize;
 696         inst->alg.cra_ablkcipher.geniv = balg.geniv;
 697
 698         inst->alg.cra_ablkcipher.setkey = balg.setkey;
 699         inst->alg.cra_ablkcipher.encrypt = balg.encrypt;
 700         inst->alg.cra_ablkcipher.decrypt = balg.decrypt;
 701
 702 out:
 703         return inst;
 704
 705 err_drop_alg:
 706         crypto_drop_skcipher(spawn);
 707 err_free_inst:
 708         kfree(inst);
 709         inst = ERR_PTR(err);
 710         goto out;
 711 }
 712 EXPORT_SYMBOL_GPL(skcipher_geniv_alloc);
 713
 714 void skcipher_geniv_free(struct crypto_instance *inst)
 715 {
 716         crypto_drop_skcipher(crypto_instance_ctx(inst));
 717         kfree(inst);
 718 }
 719 EXPORT_SYMBOL_GPL(skcipher_geniv_free);
 720
 721 int skcipher_geniv_init(struct crypto_tfm *tfm)
 722 {
 723         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 724         struct crypto_ablkcipher *cipher;
 725
 726         cipher = crypto_spawn_skcipher(crypto_instance_ctx(inst));
 727         if (IS_ERR(cipher))
 728                 return PTR_ERR(cipher);
 729
 730         tfm->crt_ablkcipher.base = cipher;
 731         tfm->crt_ablkcipher.reqsize += crypto_ablkcipher_reqsize(cipher);
 732
 733         return 0;
 734 }
 735 EXPORT_SYMBOL_GPL(skcipher_geniv_init);
 736
 737 void skcipher_geniv_exit(struct crypto_tfm *tfm)
 738 {
 739         crypto_free_ablkcipher(tfm->crt_ablkcipher.base);
 740 }
 741 EXPORT_SYMBOL_GPL(skcipher_geniv_exit);
 742
 743 MODULE_LICENSE("GPL");
 744 MODULE_DESCRIPTION("Generic block chaining cipher type");