~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/crypto/lrw.c

Version: ~ [ linux-5.9-rc6 ] ~ [ linux-5.8.10 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.66 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.146 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.198 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.236 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.236 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /* LRW: as defined by Cyril Guyot in
  2  *      http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
  3  *
  4  * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
  5  *
  6  * Based on ecb.c
  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 /* This implementation is checked against the test vectors in the above
 15  * document and by a test vector provided by Ken Buchanan at
 16  * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
 17  *
 18  * The test vectors are included in the testing module tcrypt.[ch] */
 19 
 20 #include <crypto/algapi.h>
 21 #include <linux/err.h>
 22 #include <linux/init.h>
 23 #include <linux/kernel.h>
 24 #include <linux/module.h>
 25 #include <linux/scatterlist.h>
 26 #include <linux/slab.h>
 27 
 28 #include <crypto/b128ops.h>
 29 #include <crypto/gf128mul.h>
 30 #include <crypto/lrw.h>
 31 
 32 struct priv {
 33         struct crypto_cipher *child;
 34         struct lrw_table_ctx table;
 35 };
 36 
 37 static inline void setbit128_bbe(void *b, int bit)
 38 {
 39         __set_bit(bit ^ (0x80 -
 40 #ifdef __BIG_ENDIAN
 41                          BITS_PER_LONG
 42 #else
 43                          BITS_PER_BYTE
 44 #endif
 45                         ), b);
 46 }
 47 
 48 int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
 49 {
 50         be128 tmp = { 0 };
 51         int i;
 52 
 53         if (ctx->table)
 54                 gf128mul_free_64k(ctx->table);
 55 
 56         /* initialize multiplication table for Key2 */
 57         ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
 58         if (!ctx->table)
 59                 return -ENOMEM;
 60 
 61         /* initialize optimization table */
 62         for (i = 0; i < 128; i++) {
 63                 setbit128_bbe(&tmp, i);
 64                 ctx->mulinc[i] = tmp;
 65                 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
 66         }
 67 
 68         return 0;
 69 }
 70 EXPORT_SYMBOL_GPL(lrw_init_table);
 71 
 72 void lrw_free_table(struct lrw_table_ctx *ctx)
 73 {
 74         if (ctx->table)
 75                 gf128mul_free_64k(ctx->table);
 76 }
 77 EXPORT_SYMBOL_GPL(lrw_free_table);
 78 
 79 static int setkey(struct crypto_tfm *parent, const u8 *key,
 80                   unsigned int keylen)
 81 {
 82         struct priv *ctx = crypto_tfm_ctx(parent);
 83         struct crypto_cipher *child = ctx->child;
 84         int err, bsize = LRW_BLOCK_SIZE;
 85         const u8 *tweak = key + keylen - bsize;
 86 
 87         crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 88         crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
 89                                        CRYPTO_TFM_REQ_MASK);
 90         err = crypto_cipher_setkey(child, key, keylen - bsize);
 91         if (err)
 92                 return err;
 93         crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
 94                                      CRYPTO_TFM_RES_MASK);
 95 
 96         return lrw_init_table(&ctx->table, tweak);
 97 }
 98 
 99 struct sinfo {
100         be128 t;
101         struct crypto_tfm *tfm;
102         void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
103 };
104 
105 static inline void inc(be128 *iv)
106 {
107         be64_add_cpu(&iv->b, 1);
108         if (!iv->b)
109                 be64_add_cpu(&iv->a, 1);
110 }
111 
112 static inline void lrw_round(struct sinfo *s, void *dst, const void *src)
113 {
114         be128_xor(dst, &s->t, src);             /* PP <- T xor P */
115         s->fn(s->tfm, dst, dst);                /* CC <- E(Key2,PP) */
116         be128_xor(dst, dst, &s->t);             /* C <- T xor CC */
117 }
118 
119 /* this returns the number of consequative 1 bits starting
120  * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
121 static inline int get_index128(be128 *block)
122 {
123         int x;
124         __be32 *p = (__be32 *) block;
125 
126         for (p += 3, x = 0; x < 128; p--, x += 32) {
127                 u32 val = be32_to_cpup(p);
128 
129                 if (!~val)
130                         continue;
131 
132                 return x + ffz(val);
133         }
134 
135         return x;
136 }
137 
138 static int crypt(struct blkcipher_desc *d,
139                  struct blkcipher_walk *w, struct priv *ctx,
140                  void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
141 {
142         int err;
143         unsigned int avail;
144         const int bs = LRW_BLOCK_SIZE;
145         struct sinfo s = {
146                 .tfm = crypto_cipher_tfm(ctx->child),
147                 .fn = fn
148         };
149         be128 *iv;
150         u8 *wsrc;
151         u8 *wdst;
152 
153         err = blkcipher_walk_virt(d, w);
154         if (!(avail = w->nbytes))
155                 return err;
156 
157         wsrc = w->src.virt.addr;
158         wdst = w->dst.virt.addr;
159 
160         /* calculate first value of T */
161         iv = (be128 *)w->iv;
162         s.t = *iv;
163 
164         /* T <- I*Key2 */
165         gf128mul_64k_bbe(&s.t, ctx->table.table);
166 
167         goto first;
168 
169         for (;;) {
170                 do {
171                         /* T <- I*Key2, using the optimization
172                          * discussed in the specification */
173                         be128_xor(&s.t, &s.t,
174                                   &ctx->table.mulinc[get_index128(iv)]);
175                         inc(iv);
176 
177 first:
178                         lrw_round(&s, wdst, wsrc);
179 
180                         wsrc += bs;
181                         wdst += bs;
182                 } while ((avail -= bs) >= bs);
183 
184                 err = blkcipher_walk_done(d, w, avail);
185                 if (!(avail = w->nbytes))
186                         break;
187 
188                 wsrc = w->src.virt.addr;
189                 wdst = w->dst.virt.addr;
190         }
191 
192         return err;
193 }
194 
195 static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
196                    struct scatterlist *src, unsigned int nbytes)
197 {
198         struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
199         struct blkcipher_walk w;
200 
201         blkcipher_walk_init(&w, dst, src, nbytes);
202         return crypt(desc, &w, ctx,
203                      crypto_cipher_alg(ctx->child)->cia_encrypt);
204 }
205 
206 static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
207                    struct scatterlist *src, unsigned int nbytes)
208 {
209         struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
210         struct blkcipher_walk w;
211 
212         blkcipher_walk_init(&w, dst, src, nbytes);
213         return crypt(desc, &w, ctx,
214                      crypto_cipher_alg(ctx->child)->cia_decrypt);
215 }
216 
217 int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
218               struct scatterlist *ssrc, unsigned int nbytes,
219               struct lrw_crypt_req *req)
220 {
221         const unsigned int bsize = LRW_BLOCK_SIZE;
222         const unsigned int max_blks = req->tbuflen / bsize;
223         struct lrw_table_ctx *ctx = req->table_ctx;
224         struct blkcipher_walk walk;
225         unsigned int nblocks;
226         be128 *iv, *src, *dst, *t;
227         be128 *t_buf = req->tbuf;
228         int err, i;
229 
230         BUG_ON(max_blks < 1);
231 
232         blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
233 
234         err = blkcipher_walk_virt(desc, &walk);
235         nbytes = walk.nbytes;
236         if (!nbytes)
237                 return err;
238 
239         nblocks = min(walk.nbytes / bsize, max_blks);
240         src = (be128 *)walk.src.virt.addr;
241         dst = (be128 *)walk.dst.virt.addr;
242 
243         /* calculate first value of T */
244         iv = (be128 *)walk.iv;
245         t_buf[0] = *iv;
246 
247         /* T <- I*Key2 */
248         gf128mul_64k_bbe(&t_buf[0], ctx->table);
249 
250         i = 0;
251         goto first;
252 
253         for (;;) {
254                 do {
255                         for (i = 0; i < nblocks; i++) {
256                                 /* T <- I*Key2, using the optimization
257                                  * discussed in the specification */
258                                 be128_xor(&t_buf[i], t,
259                                                 &ctx->mulinc[get_index128(iv)]);
260                                 inc(iv);
261 first:
262                                 t = &t_buf[i];
263 
264                                 /* PP <- T xor P */
265                                 be128_xor(dst + i, t, src + i);
266                         }
267 
268                         /* CC <- E(Key2,PP) */
269                         req->crypt_fn(req->crypt_ctx, (u8 *)dst,
270                                       nblocks * bsize);
271 
272                         /* C <- T xor CC */
273                         for (i = 0; i < nblocks; i++)
274                                 be128_xor(dst + i, dst + i, &t_buf[i]);
275 
276                         src += nblocks;
277                         dst += nblocks;
278                         nbytes -= nblocks * bsize;
279                         nblocks = min(nbytes / bsize, max_blks);
280                 } while (nblocks > 0);
281 
282                 err = blkcipher_walk_done(desc, &walk, nbytes);
283                 nbytes = walk.nbytes;
284                 if (!nbytes)
285                         break;
286 
287                 nblocks = min(nbytes / bsize, max_blks);
288                 src = (be128 *)walk.src.virt.addr;
289                 dst = (be128 *)walk.dst.virt.addr;
290         }
291 
292         return err;
293 }
294 EXPORT_SYMBOL_GPL(lrw_crypt);
295 
296 static int init_tfm(struct crypto_tfm *tfm)
297 {
298         struct crypto_cipher *cipher;
299         struct crypto_instance *inst = (void *)tfm->__crt_alg;
300         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
301         struct priv *ctx = crypto_tfm_ctx(tfm);
302         u32 *flags = &tfm->crt_flags;
303 
304         cipher = crypto_spawn_cipher(spawn);
305         if (IS_ERR(cipher))
306                 return PTR_ERR(cipher);
307 
308         if (crypto_cipher_blocksize(cipher) != LRW_BLOCK_SIZE) {
309                 *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
310                 crypto_free_cipher(cipher);
311                 return -EINVAL;
312         }
313 
314         ctx->child = cipher;
315         return 0;
316 }
317 
318 static void exit_tfm(struct crypto_tfm *tfm)
319 {
320         struct priv *ctx = crypto_tfm_ctx(tfm);
321 
322         lrw_free_table(&ctx->table);
323         crypto_free_cipher(ctx->child);
324 }
325 
326 static struct crypto_instance *alloc(struct rtattr **tb)
327 {
328         struct crypto_instance *inst;
329         struct crypto_alg *alg;
330         int err;
331 
332         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
333         if (err)
334                 return ERR_PTR(err);
335 
336         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
337                                   CRYPTO_ALG_TYPE_MASK);
338         if (IS_ERR(alg))
339                 return ERR_CAST(alg);
340 
341         inst = crypto_alloc_instance("lrw", alg);
342         if (IS_ERR(inst))
343                 goto out_put_alg;
344 
345         inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
346         inst->alg.cra_priority = alg->cra_priority;
347         inst->alg.cra_blocksize = alg->cra_blocksize;
348 
349         if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
350         else inst->alg.cra_alignmask = alg->cra_alignmask;
351         inst->alg.cra_type = &crypto_blkcipher_type;
352 
353         if (!(alg->cra_blocksize % 4))
354                 inst->alg.cra_alignmask |= 3;
355         inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
356         inst->alg.cra_blkcipher.min_keysize =
357                 alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
358         inst->alg.cra_blkcipher.max_keysize =
359                 alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;
360 
361         inst->alg.cra_ctxsize = sizeof(struct priv);
362 
363         inst->alg.cra_init = init_tfm;
364         inst->alg.cra_exit = exit_tfm;
365 
366         inst->alg.cra_blkcipher.setkey = setkey;
367         inst->alg.cra_blkcipher.encrypt = encrypt;
368         inst->alg.cra_blkcipher.decrypt = decrypt;
369 
370 out_put_alg:
371         crypto_mod_put(alg);
372         return inst;
373 }
374 
375 static void free(struct crypto_instance *inst)
376 {
377         crypto_drop_spawn(crypto_instance_ctx(inst));
378         kfree(inst);
379 }
380 
381 static struct crypto_template crypto_tmpl = {
382         .name = "lrw",
383         .alloc = alloc,
384         .free = free,
385         .module = THIS_MODULE,
386 };
387 
388 static int __init crypto_module_init(void)
389 {
390         return crypto_register_template(&crypto_tmpl);
391 }
392 
393 static void __exit crypto_module_exit(void)
394 {
395         crypto_unregister_template(&crypto_tmpl);
396 }
397 
398 module_init(crypto_module_init);
399 module_exit(crypto_module_exit);
400 
401 MODULE_LICENSE("GPL");
402 MODULE_DESCRIPTION("LRW block cipher mode");
403 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp