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