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