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 void ablkcipher_done_slow(struct ablkcipher_walk *walk,
  74                                         unsigned int n)
  75 {
  76         for (;;) {
  77                 unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  78
  79                 if (len_this_page > n)
  80                         len_this_page = n;
  81                 scatterwalk_advance(&walk->out, n);
  82                 if (n == len_this_page)
  83                         break;
  84                 n -= len_this_page;
  85                 scatterwalk_start(&walk->out, sg_next(walk->out.sg));
  86         }
  87 }
  88
  89 static inline void ablkcipher_done_fast(struct ablkcipher_walk *walk,
  90                                         unsigned int n)
  91 {
  92         scatterwalk_advance(&walk->in, n);
  93         scatterwalk_advance(&walk->out, n);
  94 }
  95
  96 static int ablkcipher_walk_next(struct ablkcipher_request *req,
  97                                 struct ablkcipher_walk *walk);
  98
  99 int ablkcipher_walk_done(struct ablkcipher_request *req,
 100                          struct ablkcipher_walk *walk, int err)
 101 {
 102         struct crypto_tfm *tfm = req->base.tfm;
 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 & ABLKCIPHER_WALK_SLOW))) {
 114                 ablkcipher_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                 ablkcipher_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(req->base.flags);
 129                 return ablkcipher_walk_next(req, walk);
 130         }
 131         err = 0;
 132 finish:
 133         walk->nbytes = 0;
 134         if (walk->iv != req->info)
 135                 memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 136         kfree(walk->iv_buffer);
 137         return err;
 138 }
 139 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 140
 141 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 142                                        struct ablkcipher_walk *walk,
 143                                        unsigned int bsize,
 144                                        unsigned int alignmask,
 145                                        void **src_p, void **dst_p)
 146 {
 147         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 148         struct ablkcipher_buffer *p;
 149         void *src, *dst, *base;
 150         unsigned int n;
 151
 152         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 153         n += (aligned_bsize * 3 - (alignmask + 1) +
 154               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 155
 156         p = kmalloc(n, GFP_ATOMIC);
 157         if (!p)
 158                 return ablkcipher_walk_done(req, walk, -ENOMEM);
 159
 160         base = p + 1;
 161
 162         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 163         src = dst = ablkcipher_get_spot(dst, bsize);
 164
 165         p->len = bsize;
 166         p->data = dst;
 167
 168         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 169
 170         ablkcipher_queue_write(walk, p);
 171
 172         walk->nbytes = bsize;
 173         walk->flags |= ABLKCIPHER_WALK_SLOW;
 174
 175         *src_p = src;
 176         *dst_p = dst;
 177
 178         return 0;
 179 }
 180
 181 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 182                                      struct crypto_tfm *tfm,
 183                                      unsigned int alignmask)
 184 {
 185         unsigned bs = walk->blocksize;
 186         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 187         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 188         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 189                             (alignmask + 1);
 190         u8 *iv;
 191
 192         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 193         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 194         if (!walk->iv_buffer)
 195                 return -ENOMEM;
 196
 197         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 198         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 199         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 200         iv = ablkcipher_get_spot(iv, ivsize);
 201
 202         walk->iv = memcpy(iv, walk->iv, ivsize);
 203         return 0;
 204 }
 205
 206 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 207                                        struct ablkcipher_walk *walk)
 208 {
 209         walk->src.page = scatterwalk_page(&walk->in);
 210         walk->src.offset = offset_in_page(walk->in.offset);
 211         walk->dst.page = scatterwalk_page(&walk->out);
 212         walk->dst.offset = offset_in_page(walk->out.offset);
 213
 214         return 0;
 215 }
 216
 217 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 218                                 struct ablkcipher_walk *walk)
 219 {
 220         struct crypto_tfm *tfm = req->base.tfm;
 221         unsigned int alignmask, bsize, n;
 222         void *src, *dst;
 223         int err;
 224
 225         alignmask = crypto_tfm_alg_alignmask(tfm);
 226         n = walk->total;
 227         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 228                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 229                 return ablkcipher_walk_done(req, walk, -EINVAL);
 230         }
 231
 232         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 233         src = dst = NULL;
 234
 235         bsize = min(walk->blocksize, n);
 236         n = scatterwalk_clamp(&walk->in, n);
 237         n = scatterwalk_clamp(&walk->out, n);
 238
 239         if (n < bsize ||
 240             !scatterwalk_aligned(&walk->in, alignmask) ||
 241             !scatterwalk_aligned(&walk->out, alignmask)) {
 242                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 243                                            &src, &dst);
 244                 goto set_phys_lowmem;
 245         }
 246
 247         walk->nbytes = n;
 248
 249         return ablkcipher_next_fast(req, walk);
 250
 251 set_phys_lowmem:
 252         if (err >= 0) {
 253                 walk->src.page = virt_to_page(src);
 254                 walk->dst.page = virt_to_page(dst);
 255                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 256                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 257         }
 258
 259         return err;
 260 }
 261
 262 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 263                                  struct ablkcipher_walk *walk)
 264 {
 265         struct crypto_tfm *tfm = req->base.tfm;
 266         unsigned int alignmask;
 267
 268         alignmask = crypto_tfm_alg_alignmask(tfm);
 269         if (WARN_ON_ONCE(in_irq()))
 270                 return -EDEADLK;
 271
 272         walk->iv = req->info;
 273         walk->nbytes = walk->total;
 274         if (unlikely(!walk->total))
 275                 return 0;
 276
 277         walk->iv_buffer = NULL;
 278         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 279                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 280
 281                 if (err)
 282                         return err;
 283         }
 284
 285         scatterwalk_start(&walk->in, walk->in.sg);
 286         scatterwalk_start(&walk->out, walk->out.sg);
 287
 288         return ablkcipher_walk_next(req, walk);
 289 }
 290
 291 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 292                          struct ablkcipher_walk *walk)
 293 {
 294         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 295         return ablkcipher_walk_first(req, walk);
 296 }
 297 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 298
 299 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 300                             unsigned int keylen)
 301 {
 302         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 303         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 304         int ret;
 305         u8 *buffer, *alignbuffer;
 306         unsigned long absize;
 307
 308         absize = keylen + alignmask;
 309         buffer = kmalloc(absize, GFP_ATOMIC);
 310         if (!buffer)
 311                 return -ENOMEM;
 312
 313         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 314         memcpy(alignbuffer, key, keylen);
 315         ret = cipher->setkey(tfm, alignbuffer, keylen);
 316         memset(alignbuffer, 0, keylen);
 317         kfree(buffer);
 318         return ret;
 319 }
 320
 321 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 322                   unsigned int keylen)
 323 {
 324         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 325         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 326
 327         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 328                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 329                 return -EINVAL;
 330         }
 331
 332         if ((unsigned long)key & alignmask)
 333                 return setkey_unaligned(tfm, key, keylen);
 334
 335         return cipher->setkey(tfm, key, keylen);
 336 }
 337
 338 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 339                                               u32 mask)
 340 {
 341         return alg->cra_ctxsize;
 342 }
 343
 344 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 345                                       u32 mask)
 346 {
 347         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 348         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 349
 350         if (alg->ivsize > PAGE_SIZE / 8)
 351                 return -EINVAL;
 352
 353         crt->setkey = setkey;
 354         crt->encrypt = alg->encrypt;
 355         crt->decrypt = alg->decrypt;
 356         crt->base = __crypto_ablkcipher_cast(tfm);
 357         crt->ivsize = alg->ivsize;
 358
 359         return 0;
 360 }
 361
 362 #ifdef CONFIG_NET
 363 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 364 {
 365         struct crypto_report_blkcipher rblkcipher;
 366
 367         strncpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 368         strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<default>",
 369                 sizeof(rblkcipher.geniv));
 370         rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
 371
 372         rblkcipher.blocksize = alg->cra_blocksize;
 373         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 374         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 375         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 376
 377         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 378                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 379                 goto nla_put_failure;
 380         return 0;
 381
 382 nla_put_failure:
 383         return -EMSGSIZE;
 384 }
 385 #else
 386 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 387 {
 388         return -ENOSYS;
 389 }
 390 #endif
 391
 392 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 393         __attribute__ ((unused));
 394 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 395 {
 396         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 397
 398         seq_printf(m, "type         : ablkcipher\n");
 399         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 400                                              "yes" : "no");
 401         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 402         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 403         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 404         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 405         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<default>");
 406 }
 407
 408 const struct crypto_type crypto_ablkcipher_type = {
 409         .ctxsize = crypto_ablkcipher_ctxsize,
 410         .init = crypto_init_ablkcipher_ops,
 411 #ifdef CONFIG_PROC_FS
 412         .show = crypto_ablkcipher_show,
 413 #endif
 414         .report = crypto_ablkcipher_report,
 415 };
 416 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);
 417
 418 static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
 419                                       u32 mask)
 420 {
 421         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 422         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 423
 424         if (alg->ivsize > PAGE_SIZE / 8)
 425                 return -EINVAL;
 426
 427         crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
 428                       alg->setkey : setkey;
 429         crt->encrypt = alg->encrypt;
 430         crt->decrypt = alg->decrypt;
 431         crt->base = __crypto_ablkcipher_cast(tfm);
 432         crt->ivsize = alg->ivsize;
 433
 434         return 0;
 435 }
 436
 437 #ifdef CONFIG_NET
 438 static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 439 {
 440         struct crypto_report_blkcipher rblkcipher;
 441
 442         strncpy(rblkcipher.type, "givcipher", sizeof(rblkcipher.type));
 443         strncpy(rblkcipher.geniv, alg->cra_ablkcipher.geniv ?: "<built-in>",
 444                 sizeof(rblkcipher.geniv));
 445         rblkcipher.geniv[sizeof(rblkcipher.geniv) - 1] = '\0';
 446
 447         rblkcipher.blocksize = alg->cra_blocksize;
 448         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 449         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 450         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 451
 452         if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 453                     sizeof(struct crypto_report_blkcipher), &rblkcipher))
 454                 goto nla_put_failure;
 455         return 0;
 456
 457 nla_put_failure:
 458         return -EMSGSIZE;
 459 }
 460 #else
 461 static int crypto_givcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 462 {
 463         return -ENOSYS;
 464 }
 465 #endif
 466
 467 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 468         __attribute__ ((unused));
 469 static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
 470 {
 471         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 472
 473         seq_printf(m, "type         : givcipher\n");
 474         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 475                                              "yes" : "no");
 476         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 477         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 478         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 479         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 480         seq_printf(m, "geniv        : %s\n", ablkcipher->geniv ?: "<built-in>");
 481 }
 482
 483 const struct crypto_type crypto_givcipher_type = {
 484         .ctxsize = crypto_ablkcipher_ctxsize,
 485         .init = crypto_init_givcipher_ops,
 486 #ifdef CONFIG_PROC_FS
 487         .show = crypto_givcipher_show,
 488 #endif
 489         .report = crypto_givcipher_report,
 490 };
 491 EXPORT_SYMBOL_GPL(crypto_givcipher_type);