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 <linux/compiler.h>
  23 #include <net/netlink.h>
  24
  25 #include <crypto/scatterwalk.h>
  26
  27 #include "internal.h"
  28
  29 struct ablkcipher_buffer {
  30         struct list_head        entry;
  31         struct scatter_walk     dst;
  32         unsigned int            len;
  33         void                    *data;
  34 };
  35
  36 enum {
  37         ABLKCIPHER_WALK_SLOW = 1 << 0,
  38 };
  39
  40 static inline void ablkcipher_buffer_write(struct ablkcipher_buffer *p)
  41 {
  42         scatterwalk_copychunks(p->data, &p->dst, p->len, 1);
  43 }
  44
  45 void __ablkcipher_walk_complete(struct ablkcipher_walk *walk)
  46 {
  47         struct ablkcipher_buffer *p, *tmp;
  48
  49         list_for_each_entry_safe(p, tmp, &walk->buffers, entry) {
  50                 ablkcipher_buffer_write(p);
  51                 list_del(&p->entry);
  52                 kfree(p);
  53         }
  54 }
  55 EXPORT_SYMBOL_GPL(__ablkcipher_walk_complete);
  56
  57 static inline void ablkcipher_queue_write(struct ablkcipher_walk *walk,
  58                                           struct ablkcipher_buffer *p)
  59 {
  60         p->dst = walk->out;
  61         list_add_tail(&p->entry, &walk->buffers);
  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 *ablkcipher_get_spot(u8 *start, unsigned int len)
  68 {
  69         u8 *end_page = (u8 *)(((unsigned long)(start + len - 1)) & PAGE_MASK);
  70
  71         return max(start, end_page);
  72 }
  73
  74 static inline void ablkcipher_done_slow(struct ablkcipher_walk *walk,
  75                                         unsigned int n)
  76 {
  77         for (;;) {
  78                 unsigned int len_this_page = scatterwalk_pagelen(&walk->out);
  79
  80                 if (len_this_page > n)
  81                         len_this_page = n;
  82                 scatterwalk_advance(&walk->out, n);
  83                 if (n == len_this_page)
  84                         break;
  85                 n -= len_this_page;
  86                 scatterwalk_start(&walk->out, sg_next(walk->out.sg));
  87         }
  88 }
  89
  90 static inline void ablkcipher_done_fast(struct ablkcipher_walk *walk,
  91                                         unsigned int n)
  92 {
  93         scatterwalk_advance(&walk->in, n);
  94         scatterwalk_advance(&walk->out, n);
  95 }
  96
  97 static int ablkcipher_walk_next(struct ablkcipher_request *req,
  98                                 struct ablkcipher_walk *walk);
  99
 100 int ablkcipher_walk_done(struct ablkcipher_request *req,
 101                          struct ablkcipher_walk *walk, int err)
 102 {
 103         struct crypto_tfm *tfm = req->base.tfm;
 104         unsigned int n; /* bytes processed */
 105         bool more;
 106
 107         if (unlikely(err < 0))
 108                 goto finish;
 109
 110         n = walk->nbytes - err;
 111         walk->total -= n;
 112         more = (walk->total != 0);
 113
 114         if (likely(!(walk->flags & ABLKCIPHER_WALK_SLOW))) {
 115                 ablkcipher_done_fast(walk, n);
 116         } else {
 117                 if (WARN_ON(err)) {
 118                         /* unexpected case; didn't process all bytes */
 119                         err = -EINVAL;
 120                         goto finish;
 121                 }
 122                 ablkcipher_done_slow(walk, n);
 123         }
 124
 125         scatterwalk_done(&walk->in, 0, more);
 126         scatterwalk_done(&walk->out, 1, more);
 127
 128         if (more) {
 129                 crypto_yield(req->base.flags);
 130                 return ablkcipher_walk_next(req, walk);
 131         }
 132         err = 0;
 133 finish:
 134         walk->nbytes = 0;
 135         if (walk->iv != req->info)
 136                 memcpy(req->info, walk->iv, tfm->crt_ablkcipher.ivsize);
 137         kfree(walk->iv_buffer);
 138         return err;
 139 }
 140 EXPORT_SYMBOL_GPL(ablkcipher_walk_done);
 141
 142 static inline int ablkcipher_next_slow(struct ablkcipher_request *req,
 143                                        struct ablkcipher_walk *walk,
 144                                        unsigned int bsize,
 145                                        unsigned int alignmask,
 146                                        void **src_p, void **dst_p)
 147 {
 148         unsigned aligned_bsize = ALIGN(bsize, alignmask + 1);
 149         struct ablkcipher_buffer *p;
 150         void *src, *dst, *base;
 151         unsigned int n;
 152
 153         n = ALIGN(sizeof(struct ablkcipher_buffer), alignmask + 1);
 154         n += (aligned_bsize * 3 - (alignmask + 1) +
 155               (alignmask & ~(crypto_tfm_ctx_alignment() - 1)));
 156
 157         p = kmalloc(n, GFP_ATOMIC);
 158         if (!p)
 159                 return ablkcipher_walk_done(req, walk, -ENOMEM);
 160
 161         base = p + 1;
 162
 163         dst = (u8 *)ALIGN((unsigned long)base, alignmask + 1);
 164         src = dst = ablkcipher_get_spot(dst, bsize);
 165
 166         p->len = bsize;
 167         p->data = dst;
 168
 169         scatterwalk_copychunks(src, &walk->in, bsize, 0);
 170
 171         ablkcipher_queue_write(walk, p);
 172
 173         walk->nbytes = bsize;
 174         walk->flags |= ABLKCIPHER_WALK_SLOW;
 175
 176         *src_p = src;
 177         *dst_p = dst;
 178
 179         return 0;
 180 }
 181
 182 static inline int ablkcipher_copy_iv(struct ablkcipher_walk *walk,
 183                                      struct crypto_tfm *tfm,
 184                                      unsigned int alignmask)
 185 {
 186         unsigned bs = walk->blocksize;
 187         unsigned int ivsize = tfm->crt_ablkcipher.ivsize;
 188         unsigned aligned_bs = ALIGN(bs, alignmask + 1);
 189         unsigned int size = aligned_bs * 2 + ivsize + max(aligned_bs, ivsize) -
 190                             (alignmask + 1);
 191         u8 *iv;
 192
 193         size += alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 194         walk->iv_buffer = kmalloc(size, GFP_ATOMIC);
 195         if (!walk->iv_buffer)
 196                 return -ENOMEM;
 197
 198         iv = (u8 *)ALIGN((unsigned long)walk->iv_buffer, alignmask + 1);
 199         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 200         iv = ablkcipher_get_spot(iv, bs) + aligned_bs;
 201         iv = ablkcipher_get_spot(iv, ivsize);
 202
 203         walk->iv = memcpy(iv, walk->iv, ivsize);
 204         return 0;
 205 }
 206
 207 static inline int ablkcipher_next_fast(struct ablkcipher_request *req,
 208                                        struct ablkcipher_walk *walk)
 209 {
 210         walk->src.page = scatterwalk_page(&walk->in);
 211         walk->src.offset = offset_in_page(walk->in.offset);
 212         walk->dst.page = scatterwalk_page(&walk->out);
 213         walk->dst.offset = offset_in_page(walk->out.offset);
 214
 215         return 0;
 216 }
 217
 218 static int ablkcipher_walk_next(struct ablkcipher_request *req,
 219                                 struct ablkcipher_walk *walk)
 220 {
 221         struct crypto_tfm *tfm = req->base.tfm;
 222         unsigned int alignmask, bsize, n;
 223         void *src, *dst;
 224         int err;
 225
 226         alignmask = crypto_tfm_alg_alignmask(tfm);
 227         n = walk->total;
 228         if (unlikely(n < crypto_tfm_alg_blocksize(tfm))) {
 229                 req->base.flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
 230                 return ablkcipher_walk_done(req, walk, -EINVAL);
 231         }
 232
 233         walk->flags &= ~ABLKCIPHER_WALK_SLOW;
 234         src = dst = NULL;
 235
 236         bsize = min(walk->blocksize, n);
 237         n = scatterwalk_clamp(&walk->in, n);
 238         n = scatterwalk_clamp(&walk->out, n);
 239
 240         if (n < bsize ||
 241             !scatterwalk_aligned(&walk->in, alignmask) ||
 242             !scatterwalk_aligned(&walk->out, alignmask)) {
 243                 err = ablkcipher_next_slow(req, walk, bsize, alignmask,
 244                                            &src, &dst);
 245                 goto set_phys_lowmem;
 246         }
 247
 248         walk->nbytes = n;
 249
 250         return ablkcipher_next_fast(req, walk);
 251
 252 set_phys_lowmem:
 253         if (err >= 0) {
 254                 walk->src.page = virt_to_page(src);
 255                 walk->dst.page = virt_to_page(dst);
 256                 walk->src.offset = ((unsigned long)src & (PAGE_SIZE - 1));
 257                 walk->dst.offset = ((unsigned long)dst & (PAGE_SIZE - 1));
 258         }
 259
 260         return err;
 261 }
 262
 263 static int ablkcipher_walk_first(struct ablkcipher_request *req,
 264                                  struct ablkcipher_walk *walk)
 265 {
 266         struct crypto_tfm *tfm = req->base.tfm;
 267         unsigned int alignmask;
 268
 269         alignmask = crypto_tfm_alg_alignmask(tfm);
 270         if (WARN_ON_ONCE(in_irq()))
 271                 return -EDEADLK;
 272
 273         walk->iv = req->info;
 274         walk->nbytes = walk->total;
 275         if (unlikely(!walk->total))
 276                 return 0;
 277
 278         walk->iv_buffer = NULL;
 279         if (unlikely(((unsigned long)walk->iv & alignmask))) {
 280                 int err = ablkcipher_copy_iv(walk, tfm, alignmask);
 281
 282                 if (err)
 283                         return err;
 284         }
 285
 286         scatterwalk_start(&walk->in, walk->in.sg);
 287         scatterwalk_start(&walk->out, walk->out.sg);
 288
 289         return ablkcipher_walk_next(req, walk);
 290 }
 291
 292 int ablkcipher_walk_phys(struct ablkcipher_request *req,
 293                          struct ablkcipher_walk *walk)
 294 {
 295         walk->blocksize = crypto_tfm_alg_blocksize(req->base.tfm);
 296         return ablkcipher_walk_first(req, walk);
 297 }
 298 EXPORT_SYMBOL_GPL(ablkcipher_walk_phys);
 299
 300 static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
 301                             unsigned int keylen)
 302 {
 303         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 304         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 305         int ret;
 306         u8 *buffer, *alignbuffer;
 307         unsigned long absize;
 308
 309         absize = keylen + alignmask;
 310         buffer = kmalloc(absize, GFP_ATOMIC);
 311         if (!buffer)
 312                 return -ENOMEM;
 313
 314         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 315         memcpy(alignbuffer, key, keylen);
 316         ret = cipher->setkey(tfm, alignbuffer, keylen);
 317         memset(alignbuffer, 0, keylen);
 318         kfree(buffer);
 319         return ret;
 320 }
 321
 322 static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
 323                   unsigned int keylen)
 324 {
 325         struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
 326         unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
 327
 328         if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
 329                 crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 330                 return -EINVAL;
 331         }
 332
 333         if ((unsigned long)key & alignmask)
 334                 return setkey_unaligned(tfm, key, keylen);
 335
 336         return cipher->setkey(tfm, key, keylen);
 337 }
 338
 339 static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
 340                                               u32 mask)
 341 {
 342         return alg->cra_ctxsize;
 343 }
 344
 345 static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
 346                                       u32 mask)
 347 {
 348         struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
 349         struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
 350
 351         if (alg->ivsize > PAGE_SIZE / 8)
 352                 return -EINVAL;
 353
 354         crt->setkey = setkey;
 355         crt->encrypt = alg->encrypt;
 356         crt->decrypt = alg->decrypt;
 357         crt->base = __crypto_ablkcipher_cast(tfm);
 358         crt->ivsize = alg->ivsize;
 359
 360         return 0;
 361 }
 362
 363 #ifdef CONFIG_NET
 364 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 365 {
 366         struct crypto_report_blkcipher rblkcipher;
 367
 368         memset(&rblkcipher, 0, sizeof(rblkcipher));
 369
 370         strscpy(rblkcipher.type, "ablkcipher", sizeof(rblkcipher.type));
 371         strscpy(rblkcipher.geniv, "<default>", sizeof(rblkcipher.geniv));
 372
 373         rblkcipher.blocksize = alg->cra_blocksize;
 374         rblkcipher.min_keysize = alg->cra_ablkcipher.min_keysize;
 375         rblkcipher.max_keysize = alg->cra_ablkcipher.max_keysize;
 376         rblkcipher.ivsize = alg->cra_ablkcipher.ivsize;
 377
 378         return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
 379                        sizeof(rblkcipher), &rblkcipher);
 380 }
 381 #else
 382 static int crypto_ablkcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
 383 {
 384         return -ENOSYS;
 385 }
 386 #endif
 387
 388 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 389         __maybe_unused;
 390 static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
 391 {
 392         struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
 393
 394         seq_printf(m, "type         : ablkcipher\n");
 395         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 396                                              "yes" : "no");
 397         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 398         seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
 399         seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
 400         seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
 401         seq_printf(m, "geniv        : <default>\n");
 402 }
 403
 404 const struct crypto_type crypto_ablkcipher_type = {
 405         .ctxsize = crypto_ablkcipher_ctxsize,
 406         .init = crypto_init_ablkcipher_ops,
 407 #ifdef CONFIG_PROC_FS
 408         .show = crypto_ablkcipher_show,
 409 #endif
 410         .report = crypto_ablkcipher_report,
 411 };
 412 EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);