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/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 blkcipher_walk *walk,
  74                                                unsigned int bsize)
  75 {
  76         u8 *addr;
  77
  78         addr = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
  79         addr = blkcipher_get_spot(addr, bsize);
  80         scatterwalk_copychunks(addr, &walk->out, bsize, 1);
  81         return bsize;
  82 }
  83
  84 static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
  85                                                unsigned int n)
  86 {
  87         if (walk->flags & BLKCIPHER_WALK_COPY) {
  88                 blkcipher_map_dst(walk);
  89                 memcpy(walk->dst.virt.addr, walk->page, n);
  90                 blkcipher_unmap_dst(walk);
  91         } else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
  92                 if (walk->flags & BLKCIPHER_WALK_DIFF)
  93                         blkcipher_unmap_dst(walk);
  94                 blkcipher_unmap_src(walk);
  95         }
  96
  97         scatterwalk_advance(&walk->in, n);
  98         scatterwalk_advance(&walk->out, n);
  99
 100         return n;
 101 }
 102
 103 int blkcipher_walk_done(struct blkcipher_desc *desc,
 104                         struct blkcipher_walk *walk, int err)
 105 {
 106         unsigned int nbytes = 0;
 107
 108         if (likely(err >= 0)) {
 109                 unsigned int n = walk->nbytes - err;
 110
 111                 if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
 112                         n = blkcipher_done_fast(walk, n);
 113                 else if (WARN_ON(err)) {
 114                         err = -EINVAL;
 115                         goto err;
 116                 } else
 117                         n = blkcipher_done_slow(walk, n);
 118
 119                 nbytes = walk->total - n;
 120                 err = 0;
 121         }
 122
 123         scatterwalk_done(&walk->in, 0, nbytes);
 124         scatterwalk_done(&walk->out, 1, nbytes);
 125
 126 err:
 127         walk->total = nbytes;
 128         walk->nbytes = nbytes;
 129
 130         if (nbytes) {
 131                 crypto_yield(desc->flags);
 132                 return blkcipher_walk_next(desc, walk);
 133         }
 134
 135         if (walk->iv != desc->info)
 136                 memcpy(desc->info, walk->iv, walk->ivsize);
 137         if (walk->buffer != walk->page)
 138                 kfree(walk->buffer);
 139         if (walk->page)
 140                 free_page((unsigned long)walk->page);
 141
 142         return err;
 143 }
 144 EXPORT_SYMBOL_GPL(blkcipher_walk_done);
 145
 146 static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
 147                                       struct blkcipher_walk *walk,
 148                                       unsigned int bsize,
 149                                       unsigned int alignmask)
 150 {
 151         unsigned int n;
 152         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 153
 154         if (walk->buffer)
 155                 goto ok;
 156
 157         walk->buffer = walk->page;
 158         if (walk->buffer)
 159                 goto ok;
 160
 161         n = aligned_bsize * 3 - (alignmask + 1) +
 162             (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
 163         walk->buffer = kmalloc(n, GFP_ATOMIC);
 164         if (!walk->buffer)
 165                 return blkcipher_walk_done(desc, walk, -ENOMEM);
 166
 167 ok:
 168         walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
 169                                           alignmask + 1);
 170         walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
 171         walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr +
 172                                                  aligned_bsize, bsize);
 173
 174         scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
 175
 176         walk->nbytes = bsize;
 177         walk->flags |= BLKCIPHER_WALK_SLOW;
 178
 179         return 0;
 180 }
 181
 182 static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
 183 {
 184         u8 *tmp = walk->page;
 185
 186         blkcipher_map_src(walk);
 187         memcpy(tmp, walk->src.virt.addr, walk->nbytes);
 188         blkcipher_unmap_src(walk);
 189
 190         walk->src.virt.addr = tmp;
 191         walk->dst.virt.addr = tmp;
 192
 193         return 0;
 194 }
 195
 196 static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
 197                                       struct blkcipher_walk *walk)
 198 {
 199         unsigned long diff;
 200
 201         walk->src.phys.page = scatterwalk_page(&walk->in);
 202         walk->src.phys.offset = offset_in_page(walk->in.offset);
 203         walk->dst.phys.page = scatterwalk_page(&walk->out);
 204         walk->dst.phys.offset = offset_in_page(walk->out.offset);
 205
 206         if (walk->flags & BLKCIPHER_WALK_PHYS)
 207                 return 0;
 208
 209         diff = walk->src.phys.offset - walk->dst.phys.offset;
 210         diff |= walk->src.virt.page - walk->dst.virt.page;
 211
 212         blkcipher_map_src(walk);
 213         walk->dst.virt.addr = walk->src.virt.addr;
 214
 215         if (diff) {
 216                 walk->flags |= BLKCIPHER_WALK_DIFF;
 217                 blkcipher_map_dst(walk);
 218         }
 219
 220         return 0;
 221 }
 222
 223 static int blkcipher_walk_next(struct blkcipher_desc *desc,
 224                                struct blkcipher_walk *walk)
 225 {
 226         unsigned int bsize;
 227         unsigned int n;
 228         int err;
 229
 230         n = walk->total;
 231         if (unlikely(n < walk->cipher_blocksize)) {
 232                 desc->flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 233                 return blkcipher_walk_done(desc, walk, -EINVAL);
 234         }
 235
 236         walk->flags &= ~(BLKCIPHER_WALK_SLOW | BLKCIPHER_WALK_COPY |
 237                          BLKCIPHER_WALK_DIFF);
 238         if (!scatterwalk_aligned(&walk->in, walk->alignmask) ||
 239             !scatterwalk_aligned(&walk->out, walk->alignmask)) {
 240                 walk->flags |= BLKCIPHER_WALK_COPY;
 241                 if (!walk->page) {
 242                         walk->page = (void *)__get_free_page(GFP_ATOMIC);
 243                         if (!walk->page)
 244                                 n = 0;
 245                 }
 246         }
 247
 248         bsize = min(walk->walk_blocksize, n);
 249         n = scatterwalk_clamp(&walk->in, n);
 250         n = scatterwalk_clamp(&walk->out, n);
 251
 252         if (unlikely(n < bsize)) {
 253                 err = blkcipher_next_slow(desc, walk, bsize, walk->alignmask);
 254                 goto set_phys_lowmem;
 255         }
 256
 257         walk->nbytes = n;
 258         if (walk->flags & BLKCIPHER_WALK_COPY) {
 259                 err = blkcipher_next_copy(walk);
 260                 goto set_phys_lowmem;
 261         }
 262
 263         return blkcipher_next_fast(desc, walk);
 264
 265 set_phys_lowmem:
 266         if (walk->flags & BLKCIPHER_WALK_PHYS) {
 267                 walk->src.phys.page = virt_to_page(walk->src.virt.addr);
 268                 walk->dst.phys.page = virt_to_page(walk->dst.virt.addr);
 269                 walk->src.phys.offset &= PAGE_SIZE - 1;
 270                 walk->dst.phys.offset &= PAGE_SIZE - 1;
 271         }
 272         return err;
 273 }
 274
 275 static inline int blkcipher_copy_iv(struct blkcipher_walk *walk)
 276 {
 277         unsigned bs = walk->walk_blocksize;
 278         unsigned aligned_bs = ALIGN(bs, walk->alignmask + 1);
 279         unsigned int size = aligned_bs * 2 +
 280                             walk->ivsize + max(aligned_bs, walk->ivsize) -
 281                             (walk->alignmask + 1);
 282         u8 *iv;
 283
 284         size += walk->alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 285         walk->buffer = kmalloc(size, GFP_ATOMIC);
 286         if (!walk->buffer)
 287                 return -ENOMEM;
 288
 289         iv = (u8 *)ALIGN((unsigned long)walk->buffer, walk->alignmask + 1);
 290         iv = blkcipher_get_spot(iv, bs) + aligned_bs;
 291         iv = blkcipher_get_spot(iv, bs) + aligned_bs;
 292         iv = blkcipher_get_spot(iv, walk->ivsize);
 293
 294         walk->iv = memcpy(iv, walk->iv, walk->ivsize);
 295         return 0;
 296 }
 297
 298 int blkcipher_walk_virt(struct blkcipher_desc *desc,
 299                         struct blkcipher_walk *walk)
 300 {
 301         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 302         walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 303         walk->cipher_blocksize = walk->walk_blocksize;
 304         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 305         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 306         return blkcipher_walk_first(desc, walk);
 307 }
 308 EXPORT_SYMBOL_GPL(blkcipher_walk_virt);
 309
 310 int blkcipher_walk_phys(struct blkcipher_desc *desc,
 311                         struct blkcipher_walk *walk)
 312 {
 313         walk->flags |= BLKCIPHER_WALK_PHYS;
 314         walk->walk_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 315         walk->cipher_blocksize = walk->walk_blocksize;
 316         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 317         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 318         return blkcipher_walk_first(desc, walk);
 319 }
 320 EXPORT_SYMBOL_GPL(blkcipher_walk_phys);
 321
 322 static int blkcipher_walk_first(struct blkcipher_desc *desc,
 323                                 struct blkcipher_walk *walk)
 324 {
 325         if (WARN_ON_ONCE(in_irq()))
 326                 return -EDEADLK;
 327
 328         walk->iv = desc->info;
 329         walk->nbytes = walk->total;
 330         if (unlikely(!walk->total))
 331                 return 0;
 332
 333         walk->buffer = NULL;
 334         if (unlikely(((unsigned long)walk->iv & walk->alignmask))) {
 335                 int err = blkcipher_copy_iv(walk);
 336                 if (err)
 337                         return err;
 338         }
 339
 340         scatterwalk_start(&walk->in, walk->in.sg);
 341         scatterwalk_start(&walk->out, walk->out.sg);
 342         walk->page = NULL;
 343
 344         return blkcipher_walk_next(desc, walk);
 345 }
 346
 347 int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
 348                               struct blkcipher_walk *walk,
 349                               unsigned int blocksize)
 350 {
 351         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 352         walk->walk_blocksize = blocksize;
 353         walk->cipher_blocksize = crypto_blkcipher_blocksize(desc->tfm);
 354         walk->ivsize = crypto_blkcipher_ivsize(desc->tfm);
 355         walk->alignmask = crypto_blkcipher_alignmask(desc->tfm);
 356         return blkcipher_walk_first(desc, walk);
 357 }
 358 EXPORT_SYMBOL_GPL(blkcipher_walk_virt_block);
 359
 360 int blkcipher_aead_walk_virt_block(struct blkcipher_desc *desc,
 361                                    struct blkcipher_walk *walk,
 362                                    struct crypto_aead *tfm,
 363                                    unsigned int blocksize)
 364 {
 365         walk->flags &= ~BLKCIPHER_WALK_PHYS;
 366         walk->walk_blocksize = blocksize;
 367         walk->cipher_blocksize = crypto_aead_blocksize(tfm);
 368         walk->ivsize = crypto_aead_ivsize(tfm);
 369         walk->alignmask = crypto_aead_alignmask(tfm);
 370         return blkcipher_walk_first(desc, walk);
 371 }
 372 EXPORT_SYMBOL_GPL(blkcipher_aead_walk_virt_block);
 373
 374 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
 375                             unsigned int keylen)
 376 {
 377         struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
 378         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 379         int ret;
 380         u8 *buffer, *alignbuffer;
 381         unsigned long absize;
 382
 383         absize = keylen + alignmask;
 384         buffer = kmalloc(absize, GFP_ATOMIC);
 385         if (!buffer)
 386                 return -ENOMEM;
 387
 388         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 389         memcpy(alignbuffer, key, keylen);
 390         ret = cipher->setkey(tfm, alignbuffer, keylen);
 391         memset(alignbuffer, 0, keylen);
 392         kfree(buffer);
 393         return ret;
 394 }
 395
 396 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
 397 {
 398         struct blkcipher_alg *cipher = &tfm->__crt_alg->cra_blkcipher;
 399         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 400
 401         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 402                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 403                 return -EINVAL;
 404         }
 405
 406         if ((unsigned long)key & alignmask)
 407                 return setkey_unaligned(tfm, key, keylen);
 408
 409         return cipher->setkey(tfm, key, keylen);
 410 }
 411
 412 static int async_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 413                         unsigned int keylen)
 414 {
 415         return setkey(crypto_ablkcipher_tfm(tfm), key, keylen);
 416 }
 417
 418 static int async_encrypt(struct ablkcipher_request *req)
 419 {
 420         struct crypto_tfm *tfm = req->base.tfm;
 421         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 422         struct blkcipher_desc desc = {
 423                 .tfm = __crypto_blkcipher_cast(tfm),
 424                 .info = req->info,
 425                 .flags = req->base.flags,
 426         };
 427
 428
 429         return alg->encrypt(&desc, req->dst, req->src, req->nbytes);
 430 }
 431
 432 static int async_decrypt(struct ablkcipher_request *req)
 433 {
 434         struct crypto_tfm *tfm = req->base.tfm;
 435         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 436         struct blkcipher_desc desc = {
 437                 .tfm = __crypto_blkcipher_cast(tfm),
 438                 .info = req->info,
 439                 .flags = req->base.flags,
 440         };
 441
 442         return alg->decrypt(&desc, req->dst, req->src, req->nbytes);
 443 }
 444
 445 static unsigned int crypto_blkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 446                                              u32 mask)
 447 {
 448         struct blkcipher_alg *cipher = &alg->cra_blkcipher;
 449         unsigned int len = alg->cra_ctxsize;
 450
 451         if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK &&
 452             cipher->ivsize) {
 453                 len = ALIGN(len, (unsigned long)alg->cra_alignmask + 1);
 454                 len += cipher->ivsize;
 455         }
 456
 457         return len;
 458 }
 459
 460 static int crypto_init_blkcipher_ops_async(struct crypto_tfm *tfm)
 461 {
 462         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 463         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 464
 465         crt->setkey = async_setkey;
 466         crt->encrypt = async_encrypt;
 467         crt->decrypt = async_decrypt;
 468         crt->base = __crypto_ablkcipher_cast(tfm);
 469         crt->ivsize = alg->ivsize;
 470
 471         return 0;
 472 }
 473
 474 static int crypto_init_blkcipher_ops_sync(struct crypto_tfm *tfm)
 475 {
 476         struct blkcipher_tfm *crt = &tfm->crt_blkcipher;
 477         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 478         unsigned long align = crypto_tfm_alg_alignmask(tfm) + 1;
 479         unsigned long addr;
 480
 481         crt->setkey = setkey;
 482         crt->encrypt = alg->encrypt;
 483         crt->decrypt = alg->decrypt;
 484
 485         addr = (unsigned long)crypto_tfm_ctx(tfm);
 486         addr = ALIGN(addr, align);
 487         addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 488         crt->iv = (void *)addr;
 489
 490         return 0;
 491 }
 492
 493 static int crypto_init_blkcipher_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 494 {
 495         struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
 496
 497         if (alg->ivsize > PAGE_SIZE / 8)
 498                 return -EINVAL;
 499
 500         if ((mask & CRYPTO_ALG_TYPE_MASK) == CRYPTO_ALG_TYPE_MASK)
 501                 return crypto_init_blkcipher_ops_sync(tfm);
 502         else
 503                 return crypto_init_blkcipher_ops_async(tfm);
 504 }
 505
 506 #ifdef CONFIG_NET
 507 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 508 {
 509         struct crypto_report_blkcipher rblkcipher;
 510
 511         strncpy(rblkcipher.type, "blkcipher", sizeof(rblkcipher.type));
 512         strncpy(rblkcipher.geniv, alg->cra_blkcipher.geniv ?: "<default>",
 513                 sizeof(rblkcipher.geniv));
 514
 515         rblkcipher.blocksize = alg->cra_blocksize;
 516         rblkcipher.min_keysize = alg->cra_blkcipher.min_keysize;
 517         rblkcipher.max_keysize = alg->cra_blkcipher.max_keysize;
 518         rblkcipher.ivsize = alg->cra_blkcipher.ivsize;
 519
 520         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 521                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 522                 goto nla_put_failure;
 523         return 0;
 524
 525 nla_put_failure:
 526         return -EMSGSIZE;
 527 }
 528 #else
 529 static int crypto_blkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 530 {
 531         return -ENOSYS;
 532 }
 533 #endif
 534
 535 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 536         __attribute__ ((unused));
 537 static void crypto_blkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 538 {
 539         seq_printf(m, "type         : blkcipher\n");
 540         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 541         seq_printf(m, "min keysize  : %u\n", alg->cra_blkcipher.min_keysize);
 542         seq_printf(m, "max keysize  : %u\n", alg->cra_blkcipher.max_keysize);
 543         seq_printf(m, "ivsize       : %u\n", alg->cra_blkcipher.ivsize);
 544         seq_printf(m, "geniv        : %s\n", alg->cra_blkcipher.geniv ?:
 545                                              "<default>");
 546 }
 547
 548 const struct crypto_type crypto_blkcipher_type = {
 549         .ctxsize = crypto_blkcipher_ctxsize,
 550         .init = crypto_init_blkcipher_ops,
 551 #ifdef CONFIG_PROC_FS
 552         .show = crypto_blkcipher_show,
 553 #endif
 554         .report = crypto_blkcipher_report,
 555 };
 556 EXPORT_SYMBOL_GPL(crypto_blkcipher_type);
 557
 558 MODULE_LICENSE("GPL");
 559 MODULE_DESCRIPTION("Generic block chaining cipher type");