crypto/ablkcipher.c

   1 /*
   2  * Asynchronous block chaining cipher operations.
   3  *
   4  * This is the asynchronous version of blkcipher.c indicating completion
   5  * via a callback.
   6  *
   7  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <crypto/internal/skcipher.h>
  17 #include <linux/err.h>
  18 #include <linux/kernel.h>
  19 #include <linux/slab.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/cryptouser.h>
  22 #include <net/netlink.h>
  23
  24 #include <crypto/scatterwalk.h>
  25
  26 #include "internal.h"
  27
  28 struct ablkcipher_buffer {
  29         struct list_head        entry;
  30         struct scatter_walk     dst;
  31         unsigned int            len;
  32         void                    *data;
  33 };
  34
  35 enum {
  36         ABLKCIPHER_WALK_SLOW = 1 << 0,
  37 };
  38
  39 static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
  40 {
  41         scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
  42 }
  43
  44 void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
  45 {
  46         struct ablkcipher_buffer *p, *tmp;
  47
  48         list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  49                 ablkcipher_buffer_write(p);
  50                 list_del(&p->entry);
  51                 kfree(p);
  52         }
  53 }
  54 EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
  55
  56 static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
  57                                           struct ablkcipher_buffer *p)
  58 {
  59         p->dst = walk->out;
  60         list_add_tail(&p->entry, &walk->buffers);
  61 }
  62
  63 /* Get a spot of the specified length that does not straddle a page.
  64  * The caller needs to ensure that there is enough space for this operation.
  65  */
  66 static inline u8 *ablkcipher_get_spot(u8 *start, unsigned int len)
  67 {
  68         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  69
  70         return max(start, end_page);
  71 }
  72
  73 static inline unsigned int ablkcipher_done_slow(struct ablkcipher_walk *walk,
  74                                                 unsigned int bsize)
  75 {
  76         unsigned int n = bsize;
  77
  78         for (;;) {
  79                 unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  80
  81                 if (len_this_page > n)
  82                         len_this_page = n;
  83                 scatterwalk_advance(&walk->out, n);
  84                 if (n == len_this_page)
  85                         break;
  86                 n -= len_this_page;
  87                 scatterwalk_start(&walk->out, sg_next(walk->out.sg));
  88         }
  89
  90         return bsize;
  91 }
  92
  93 static inline unsigned int ablkcipher_done_fast(struct ablkcipher_walk *walk,
  94                                                 unsigned int n)
  95 {
  96         scatterwalk_advance(&walk->in, n);
  97         scatterwalk_advance(&walk->out, n);
  98
  99         return n;
 100 }
 101
 102 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 103                                 struct ablkcipher_walk *walk);
 104
 105 int ablkcipher_walk_done(struct ablkcipher_request *req,
 106                          struct ablkcipher_walk *walk, int err)
 107 {
 108         struct crypto_tfm *tfm = req->base.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 & ABLKCIPHER_WALK_SLOW)))
 115                         n = ablkcipher_done_fast(walk, n);
 116                 else if (WARN_ON(err)) {
 117                         err = -EINVAL;
 118                         goto err;
 119                 } else
 120                         n = ablkcipher_done_slow(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(req->base.flags);
 135                 return ablkcipher_walk_next(req, walk);
 136         }
 137
 138         if (walk->iv != req->info)
 139                 memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 140         kfree(walk->iv_buffer);
 141
 142         return err;
 143 }
 144 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 145
 146 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 147                                        struct ablkcipher_walk *walk,
 148                                        unsigned int bsize,
 149                                        unsigned int alignmask,
 150                                        void **src_p, void **dst_p)
 151 {
 152         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 153         struct ablkcipher_buffer *p;
 154         void *src, *dst, *base;
 155         unsigned int n;
 156
 157         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 158         n += (aligned_bsize * 3 - (alignmask + 1) +
 159               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 160
 161         p = kmalloc(n, GFP_ATOMIC);
 162         if (!p)
 163                 return ablkcipher_walk_done(req, walk, -ENOMEM);
 164
 165         base = p + 1;
 166
 167         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 168         src = dst = ablkcipher_get_spot(dst, bsize);
 169
 170         p->len = bsize;
 171         p->data = dst;
 172
 173         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 174
 175         ablkcipher_queue_write(walk, p);
 176
 177         walk->nbytes = bsize;
 178         walk->flags |= ABLKCIPHER_WALK_SLOW;
 179
 180         *src_p = src;
 181         *dst_p = dst;
 182
 183         return 0;
 184 }
 185
 186 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 187                                      struct crypto_tfm *tfm,
 188                                      unsigned int alignmask)
 189 {
 190         unsigned bs = walk->blocksize;
 191         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 192         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 193         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 194                             (alignmask + 1);
 195         u8 *iv;
 196
 197         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 198         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 199         if (!walk->iv_buffer)
 200                 return -ENOMEM;
 201
 202         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 203         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 204         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 205         iv = ablkcipher_get_spot(iv, ivsize);
 206
 207         walk->iv = memcpy(iv, walk->iv, ivsize);
 208         return 0;
 209 }
 210
 211 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 212                                        struct ablkcipher_walk *walk)
 213 {
 214         walk->src.page = scatterwalk_page(&walk->in);
 215         walk->src.offset = offset_in_page(walk->in.offset);
 216         walk->dst.page = scatterwalk_page(&walk->out);
 217         walk->dst.offset = offset_in_page(walk->out.offset);
 218
 219         return 0;
 220 }
 221
 222 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 223                                 struct ablkcipher_walk *walk)
 224 {
 225         struct crypto_tfm *tfm = req->base.tfm;
 226         unsigned int alignmask, bsize, n;
 227         void *src, *dst;
 228         int err;
 229
 230         alignmask = crypto_tfm_alg_alignmask(tfm);
 231         n = walk->total;
 232         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 233                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 234                 return ablkcipher_walk_done(req, walk, -EINVAL);
 235         }
 236
 237         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 238         src = dst = NULL;
 239
 240         bsize = min(walk->blocksize, n);
 241         n = scatterwalk_clamp(&walk->in, n);
 242         n = scatterwalk_clamp(&walk->out, n);
 243
 244         if (n < bsize ||
 245             !scatterwalk_aligned(&walk->in, alignmask) ||
 246             !scatterwalk_aligned(&walk->out, alignmask)) {
 247                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 248                                            &src, &dst);
 249                 goto set_phys_lowmem;
 250         }
 251
 252         walk->nbytes = n;
 253
 254         return ablkcipher_next_fast(req, walk);
 255
 256 set_phys_lowmem:
 257         if (err >= 0) {
 258                 walk->src.page = virt_to_page(src);
 259                 walk->dst.page = virt_to_page(dst);
 260                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 261                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 262         }
 263
 264         return err;
 265 }
 266
 267 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 268                                  struct ablkcipher_walk *walk)
 269 {
 270         struct crypto_tfm *tfm = req->base.tfm;
 271         unsigned int alignmask;
 272
 273         alignmask = crypto_tfm_alg_alignmask(tfm);
 274         if (WARN_ON_ONCE(in_irq()))
 275                 return -EDEADLK;
 276
 277         walk->iv = req->info;
 278         walk->nbytes = walk->total;
 279         if (unlikely(!walk->total))
 280                 return 0;
 281
 282         walk->iv_buffer = NULL;
 283         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 284                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 285
 286                 if (err)
 287                         return err;
 288         }
 289
 290         scatterwalk_start(&walk->in, walk->in.sg);
 291         scatterwalk_start(&walk->out, walk->out.sg);
 292
 293         return ablkcipher_walk_next(req, walk);
 294 }
 295
 296 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 297                          struct ablkcipher_walk *walk)
 298 {
 299         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 300         return ablkcipher_walk_first(req, walk);
 301 }
 302 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 303
 304 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 305                             unsigned int keylen)
 306 {
 307         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 308         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 309         int ret;
 310         u8 *buffer, *alignbuffer;
 311         unsigned long absize;
 312
 313         absize = keylen + alignmask;
 314         buffer = kmalloc(absize, GFP_ATOMIC);
 315         if (!buffer)
 316                 return -ENOMEM;
 317
 318         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 319         memcpy(alignbuffer, key, keylen);
 320         ret = cipher->setkey(tfm, alignbuffer, keylen);
 321         memset(alignbuffer, 0, keylen);
 322         kfree(buffer);
 323         return ret;
 324 }
 325
 326 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 327                   unsigned int keylen)
 328 {
 329         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 330         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 331
 332         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 333                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 334                 return -EINVAL;
 335         }
 336
 337         if ((unsigned long)key & alignmask)
 338                 return setkey_unaligned(tfm, key, keylen);
 339
 340         return cipher->setkey(tfm, key, keylen);
 341 }
 342
 343 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 344                                               u32 mask)
 345 {
 346         return alg->cra_ctxsize;
 347 }
 348
 349 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 350                                       u32 mask)
 351 {
 352         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 353         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 354
 355         if (alg->ivsize > PAGE_SIZE / 8)
 356                 return -EINVAL;
 357
 358         crt->setkey = setkey;
 359         crt->encrypt = alg->encrypt;
 360         crt->decrypt = alg->decrypt;
 361         crt->base = __crypto_ablkcipher_cast(tfm);
 362         crt->ivsize = alg->ivsize;
 363
 364         return 0;
 365 }
 366
 367 #ifdef CONFIG_NET
 368 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 369 {
 370         struct crypto_report_blkcipher rblkcipher;
 371
 372         strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 373         strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
 374                 sizeof(rblkcipher.geniv));
 375
 376         rblkcipher.blocksize = alg->cra_blocksize;
 377         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 378         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 379         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 380
 381         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 382                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 383                 goto nla_put_failure;
 384         return 0;
 385
 386 nla_put_failure:
 387         return -EMSGSIZE;
 388 }
 389 #else
 390 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 391 {
 392         return -ENOSYS;
 393 }
 394 #endif
 395
 396 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 397         __attribute__ ((unused));
 398 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 399 {
 400         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 401
 402         seq_printf(m, "type         : ablkcipher\n");
 403         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 404                                              "yes" : "no");
 405         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 406         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 407         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 408         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 409         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 410 }
 411
 412 const struct crypto_type crypto_ablkcipher_type = {
 413         .ctxsize = crypto_ablkcipher_ctxsize,
 414         .init = crypto_init_ablkcipher_ops,
 415 #ifdef CONFIG_PROC_FS
 416         .show = crypto_ablkcipher_show,
 417 #endif
 418         .report = crypto_ablkcipher_report,
 419 };
 420 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 421
 422 static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 423                                       u32 mask)
 424 {
 425         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 426         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 427
 428         if (alg->ivsize > PAGE_SIZE / 8)
 429                 return -EINVAL;
 430
 431         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 432                       alg->setkey : setkey;
 433         crt->encrypt = alg->encrypt;
 434         crt->decrypt = alg->decrypt;
 435         crt->base = __crypto_ablkcipher_cast(tfm);
 436         crt->ivsize = alg->ivsize;
 437
 438         return 0;
 439 }
 440
 441 #ifdef CONFIG_NET
 442 static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 443 {
 444         struct crypto_report_blkcipher rblkcipher;
 445
 446         strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
 447         strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
 448                 sizeof(rblkcipher.geniv));
 449
 450         rblkcipher.blocksize = alg->cra_blocksize;
 451         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 452         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 453         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 454
 455         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 456                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 457                 goto nla_put_failure;
 458         return 0;
 459
 460 nla_put_failure:
 461         return -EMSGSIZE;
 462 }
 463 #else
 464 static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 465 {
 466         return -ENOSYS;
 467 }
 468 #endif
 469
 470 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 471         __attribute__ ((unused));
 472 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 473 {
 474         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 475
 476         seq_printf(m, "type         : givcipher\n");
 477         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 478                                              "yes" : "no");
 479         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 480         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 481         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 482         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 483         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 484 }
 485
 486 const struct crypto_type crypto_givcipher_type = {
 487         .ctxsize = crypto_ablkcipher_ctxsize,
 488         .init = crypto_init_givcipher_ops,
 489 #ifdef CONFIG_PROC_FS
 490         .show = crypto_givcipher_show,
 491 #endif
 492         .report = crypto_givcipher_report,
 493 };
 494 EXPORT_SYMBOL_GPL(crypto_givcipher_type);