Loading...
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/internal/skcipher.h>
21#include <crypto/scatterwalk.h>
22#include <linux/err.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/scatterlist.h>
27#include <linux/slab.h>
28
29#include <crypto/b128ops.h>
30#include <crypto/gf128mul.h>
31
32#define LRW_BUFFER_SIZE 128u
33
34#define LRW_BLOCK_SIZE 16
35
36struct priv {
37 struct crypto_skcipher *child;
38
39 /*
40 * optimizes multiplying a random (non incrementing, as at the
41 * start of a new sector) value with key2, we could also have
42 * used 4k optimization tables or no optimization at all. In the
43 * latter case we would have to store key2 here
44 */
45 struct gf128mul_64k *table;
46
47 /*
48 * stores:
49 * key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
50 * key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
51 * key2*{ 0,0,...1,1,1,1,1 }, etc
52 * needed for optimized multiplication of incrementing values
53 * with key2
54 */
55 be128 mulinc[128];
56};
57
58struct rctx {
59 be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];
60
61 be128 t;
62
63 be128 *ext;
64
65 struct scatterlist srcbuf[2];
66 struct scatterlist dstbuf[2];
67 struct scatterlist *src;
68 struct scatterlist *dst;
69
70 unsigned int left;
71
72 struct skcipher_request subreq;
73};
74
75static inline void setbit128_bbe(void *b, int bit)
76{
77 __set_bit(bit ^ (0x80 -
78#ifdef __BIG_ENDIAN
79 BITS_PER_LONG
80#else
81 BITS_PER_BYTE
82#endif
83 ), b);
84}
85
86static int setkey(struct crypto_skcipher *parent, const u8 *key,
87 unsigned int keylen)
88{
89 struct priv *ctx = crypto_skcipher_ctx(parent);
90 struct crypto_skcipher *child = ctx->child;
91 int err, bsize = LRW_BLOCK_SIZE;
92 const u8 *tweak = key + keylen - bsize;
93 be128 tmp = { 0 };
94 int i;
95
96 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
97 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
98 CRYPTO_TFM_REQ_MASK);
99 err = crypto_skcipher_setkey(child, key, keylen - bsize);
100 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
101 CRYPTO_TFM_RES_MASK);
102 if (err)
103 return err;
104
105 if (ctx->table)
106 gf128mul_free_64k(ctx->table);
107
108 /* initialize multiplication table for Key2 */
109 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
110 if (!ctx->table)
111 return -ENOMEM;
112
113 /* initialize optimization table */
114 for (i = 0; i < 128; i++) {
115 setbit128_bbe(&tmp, i);
116 ctx->mulinc[i] = tmp;
117 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
118 }
119
120 return 0;
121}
122
123static inline void inc(be128 *iv)
124{
125 be64_add_cpu(&iv->b, 1);
126 if (!iv->b)
127 be64_add_cpu(&iv->a, 1);
128}
129
130/* this returns the number of consequative 1 bits starting
131 * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
132static inline int get_index128(be128 *block)
133{
134 int x;
135 __be32 *p = (__be32 *) block;
136
137 for (p += 3, x = 0; x < 128; p--, x += 32) {
138 u32 val = be32_to_cpup(p);
139
140 if (!~val)
141 continue;
142
143 return x + ffz(val);
144 }
145
146 return x;
147}
148
149static int post_crypt(struct skcipher_request *req)
150{
151 struct rctx *rctx = skcipher_request_ctx(req);
152 be128 *buf = rctx->ext ?: rctx->buf;
153 struct skcipher_request *subreq;
154 const int bs = LRW_BLOCK_SIZE;
155 struct skcipher_walk w;
156 struct scatterlist *sg;
157 unsigned offset;
158 int err;
159
160 subreq = &rctx->subreq;
161 err = skcipher_walk_virt(&w, subreq, false);
162
163 while (w.nbytes) {
164 unsigned int avail = w.nbytes;
165 be128 *wdst;
166
167 wdst = w.dst.virt.addr;
168
169 do {
170 be128_xor(wdst, buf++, wdst);
171 wdst++;
172 } while ((avail -= bs) >= bs);
173
174 err = skcipher_walk_done(&w, avail);
175 }
176
177 rctx->left -= subreq->cryptlen;
178
179 if (err || !rctx->left)
180 goto out;
181
182 rctx->dst = rctx->dstbuf;
183
184 scatterwalk_done(&w.out, 0, 1);
185 sg = w.out.sg;
186 offset = w.out.offset;
187
188 if (rctx->dst != sg) {
189 rctx->dst[0] = *sg;
190 sg_unmark_end(rctx->dst);
191 scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
192 }
193 rctx->dst[0].length -= offset - sg->offset;
194 rctx->dst[0].offset = offset;
195
196out:
197 return err;
198}
199
200static int pre_crypt(struct skcipher_request *req)
201{
202 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
203 struct rctx *rctx = skcipher_request_ctx(req);
204 struct priv *ctx = crypto_skcipher_ctx(tfm);
205 be128 *buf = rctx->ext ?: rctx->buf;
206 struct skcipher_request *subreq;
207 const int bs = LRW_BLOCK_SIZE;
208 struct skcipher_walk w;
209 struct scatterlist *sg;
210 unsigned cryptlen;
211 unsigned offset;
212 be128 *iv;
213 bool more;
214 int err;
215
216 subreq = &rctx->subreq;
217 skcipher_request_set_tfm(subreq, tfm);
218
219 cryptlen = subreq->cryptlen;
220 more = rctx->left > cryptlen;
221 if (!more)
222 cryptlen = rctx->left;
223
224 skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
225 cryptlen, req->iv);
226
227 err = skcipher_walk_virt(&w, subreq, false);
228 iv = w.iv;
229
230 while (w.nbytes) {
231 unsigned int avail = w.nbytes;
232 be128 *wsrc;
233 be128 *wdst;
234
235 wsrc = w.src.virt.addr;
236 wdst = w.dst.virt.addr;
237
238 do {
239 *buf++ = rctx->t;
240 be128_xor(wdst++, &rctx->t, wsrc++);
241
242 /* T <- I*Key2, using the optimization
243 * discussed in the specification */
244 be128_xor(&rctx->t, &rctx->t,
245 &ctx->mulinc[get_index128(iv)]);
246 inc(iv);
247 } while ((avail -= bs) >= bs);
248
249 err = skcipher_walk_done(&w, avail);
250 }
251
252 skcipher_request_set_tfm(subreq, ctx->child);
253 skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
254 cryptlen, NULL);
255
256 if (err || !more)
257 goto out;
258
259 rctx->src = rctx->srcbuf;
260
261 scatterwalk_done(&w.in, 0, 1);
262 sg = w.in.sg;
263 offset = w.in.offset;
264
265 if (rctx->src != sg) {
266 rctx->src[0] = *sg;
267 sg_unmark_end(rctx->src);
268 scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
269 }
270 rctx->src[0].length -= offset - sg->offset;
271 rctx->src[0].offset = offset;
272
273out:
274 return err;
275}
276
277static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
278{
279 struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
280 struct rctx *rctx = skcipher_request_ctx(req);
281 struct skcipher_request *subreq;
282 gfp_t gfp;
283
284 subreq = &rctx->subreq;
285 skcipher_request_set_callback(subreq, req->base.flags, done, req);
286
287 gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
288 GFP_ATOMIC;
289 rctx->ext = NULL;
290
291 subreq->cryptlen = LRW_BUFFER_SIZE;
292 if (req->cryptlen > LRW_BUFFER_SIZE) {
293 unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
294
295 rctx->ext = kmalloc(n, gfp);
296 if (rctx->ext)
297 subreq->cryptlen = n;
298 }
299
300 rctx->src = req->src;
301 rctx->dst = req->dst;
302 rctx->left = req->cryptlen;
303
304 /* calculate first value of T */
305 memcpy(&rctx->t, req->iv, sizeof(rctx->t));
306
307 /* T <- I*Key2 */
308 gf128mul_64k_bbe(&rctx->t, ctx->table);
309
310 return 0;
311}
312
313static void exit_crypt(struct skcipher_request *req)
314{
315 struct rctx *rctx = skcipher_request_ctx(req);
316
317 rctx->left = 0;
318
319 if (rctx->ext)
320 kzfree(rctx->ext);
321}
322
323static int do_encrypt(struct skcipher_request *req, int err)
324{
325 struct rctx *rctx = skcipher_request_ctx(req);
326 struct skcipher_request *subreq;
327
328 subreq = &rctx->subreq;
329
330 while (!err && rctx->left) {
331 err = pre_crypt(req) ?:
332 crypto_skcipher_encrypt(subreq) ?:
333 post_crypt(req);
334
335 if (err == -EINPROGRESS || err == -EBUSY)
336 return err;
337 }
338
339 exit_crypt(req);
340 return err;
341}
342
343static void encrypt_done(struct crypto_async_request *areq, int err)
344{
345 struct skcipher_request *req = areq->data;
346 struct skcipher_request *subreq;
347 struct rctx *rctx;
348
349 rctx = skcipher_request_ctx(req);
350
351 if (err == -EINPROGRESS) {
352 if (rctx->left != req->cryptlen)
353 return;
354 goto out;
355 }
356
357 subreq = &rctx->subreq;
358 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
359
360 err = do_encrypt(req, err ?: post_crypt(req));
361 if (rctx->left)
362 return;
363
364out:
365 skcipher_request_complete(req, err);
366}
367
368static int encrypt(struct skcipher_request *req)
369{
370 return do_encrypt(req, init_crypt(req, encrypt_done));
371}
372
373static int do_decrypt(struct skcipher_request *req, int err)
374{
375 struct rctx *rctx = skcipher_request_ctx(req);
376 struct skcipher_request *subreq;
377
378 subreq = &rctx->subreq;
379
380 while (!err && rctx->left) {
381 err = pre_crypt(req) ?:
382 crypto_skcipher_decrypt(subreq) ?:
383 post_crypt(req);
384
385 if (err == -EINPROGRESS || err == -EBUSY)
386 return err;
387 }
388
389 exit_crypt(req);
390 return err;
391}
392
393static void decrypt_done(struct crypto_async_request *areq, int err)
394{
395 struct skcipher_request *req = areq->data;
396 struct skcipher_request *subreq;
397 struct rctx *rctx;
398
399 rctx = skcipher_request_ctx(req);
400
401 if (err == -EINPROGRESS) {
402 if (rctx->left != req->cryptlen)
403 return;
404 goto out;
405 }
406
407 subreq = &rctx->subreq;
408 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
409
410 err = do_decrypt(req, err ?: post_crypt(req));
411 if (rctx->left)
412 return;
413
414out:
415 skcipher_request_complete(req, err);
416}
417
418static int decrypt(struct skcipher_request *req)
419{
420 return do_decrypt(req, init_crypt(req, decrypt_done));
421}
422
423static int init_tfm(struct crypto_skcipher *tfm)
424{
425 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
426 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
427 struct priv *ctx = crypto_skcipher_ctx(tfm);
428 struct crypto_skcipher *cipher;
429
430 cipher = crypto_spawn_skcipher(spawn);
431 if (IS_ERR(cipher))
432 return PTR_ERR(cipher);
433
434 ctx->child = cipher;
435
436 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
437 sizeof(struct rctx));
438
439 return 0;
440}
441
442static void exit_tfm(struct crypto_skcipher *tfm)
443{
444 struct priv *ctx = crypto_skcipher_ctx(tfm);
445
446 if (ctx->table)
447 gf128mul_free_64k(ctx->table);
448 crypto_free_skcipher(ctx->child);
449}
450
451static void free(struct skcipher_instance *inst)
452{
453 crypto_drop_skcipher(skcipher_instance_ctx(inst));
454 kfree(inst);
455}
456
457static int create(struct crypto_template *tmpl, struct rtattr **tb)
458{
459 struct crypto_skcipher_spawn *spawn;
460 struct skcipher_instance *inst;
461 struct crypto_attr_type *algt;
462 struct skcipher_alg *alg;
463 const char *cipher_name;
464 char ecb_name[CRYPTO_MAX_ALG_NAME];
465 int err;
466
467 algt = crypto_get_attr_type(tb);
468 if (IS_ERR(algt))
469 return PTR_ERR(algt);
470
471 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
472 return -EINVAL;
473
474 cipher_name = crypto_attr_alg_name(tb[1]);
475 if (IS_ERR(cipher_name))
476 return PTR_ERR(cipher_name);
477
478 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
479 if (!inst)
480 return -ENOMEM;
481
482 spawn = skcipher_instance_ctx(inst);
483
484 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
485 err = crypto_grab_skcipher(spawn, cipher_name, 0,
486 crypto_requires_sync(algt->type,
487 algt->mask));
488 if (err == -ENOENT) {
489 err = -ENAMETOOLONG;
490 if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
491 cipher_name) >= CRYPTO_MAX_ALG_NAME)
492 goto err_free_inst;
493
494 err = crypto_grab_skcipher(spawn, ecb_name, 0,
495 crypto_requires_sync(algt->type,
496 algt->mask));
497 }
498
499 if (err)
500 goto err_free_inst;
501
502 alg = crypto_skcipher_spawn_alg(spawn);
503
504 err = -EINVAL;
505 if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
506 goto err_drop_spawn;
507
508 if (crypto_skcipher_alg_ivsize(alg))
509 goto err_drop_spawn;
510
511 err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
512 &alg->base);
513 if (err)
514 goto err_drop_spawn;
515
516 err = -EINVAL;
517 cipher_name = alg->base.cra_name;
518
519 /* Alas we screwed up the naming so we have to mangle the
520 * cipher name.
521 */
522 if (!strncmp(cipher_name, "ecb(", 4)) {
523 unsigned len;
524
525 len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
526 if (len < 2 || len >= sizeof(ecb_name))
527 goto err_drop_spawn;
528
529 if (ecb_name[len - 1] != ')')
530 goto err_drop_spawn;
531
532 ecb_name[len - 1] = 0;
533
534 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
535 "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
536 err = -ENAMETOOLONG;
537 goto err_drop_spawn;
538 }
539 } else
540 goto err_drop_spawn;
541
542 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
543 inst->alg.base.cra_priority = alg->base.cra_priority;
544 inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
545 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
546 (__alignof__(u64) - 1);
547
548 inst->alg.ivsize = LRW_BLOCK_SIZE;
549 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
550 LRW_BLOCK_SIZE;
551 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
552 LRW_BLOCK_SIZE;
553
554 inst->alg.base.cra_ctxsize = sizeof(struct priv);
555
556 inst->alg.init = init_tfm;
557 inst->alg.exit = exit_tfm;
558
559 inst->alg.setkey = setkey;
560 inst->alg.encrypt = encrypt;
561 inst->alg.decrypt = decrypt;
562
563 inst->free = free;
564
565 err = skcipher_register_instance(tmpl, inst);
566 if (err)
567 goto err_drop_spawn;
568
569out:
570 return err;
571
572err_drop_spawn:
573 crypto_drop_skcipher(spawn);
574err_free_inst:
575 kfree(inst);
576 goto out;
577}
578
579static struct crypto_template crypto_tmpl = {
580 .name = "lrw",
581 .create = create,
582 .module = THIS_MODULE,
583};
584
585static int __init crypto_module_init(void)
586{
587 return crypto_register_template(&crypto_tmpl);
588}
589
590static void __exit crypto_module_exit(void)
591{
592 crypto_unregister_template(&crypto_tmpl);
593}
594
595module_init(crypto_module_init);
596module_exit(crypto_module_exit);
597
598MODULE_LICENSE("GPL");
599MODULE_DESCRIPTION("LRW block cipher mode");
600MODULE_ALIAS_CRYPTO("lrw");
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
32struct priv {
33 struct crypto_cipher *child;
34 struct lrw_table_ctx table;
35};
36
37static 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
48int 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}
70EXPORT_SYMBOL_GPL(lrw_init_table);
71
72void lrw_free_table(struct lrw_table_ctx *ctx)
73{
74 if (ctx->table)
75 gf128mul_free_64k(ctx->table);
76}
77EXPORT_SYMBOL_GPL(lrw_free_table);
78
79static 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
99struct sinfo {
100 be128 t;
101 struct crypto_tfm *tfm;
102 void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
103};
104
105static 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
112static 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 */
121static 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
138static 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
177first:
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
195static 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
206static 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
217int 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);
261first:
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}
294EXPORT_SYMBOL_GPL(lrw_crypt);
295
296static 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
318static 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
326static 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
370out_put_alg:
371 crypto_mod_put(alg);
372 return inst;
373}
374
375static void free(struct crypto_instance *inst)
376{
377 crypto_drop_spawn(crypto_instance_ctx(inst));
378 kfree(inst);
379}
380
381static struct crypto_template crypto_tmpl = {
382 .name = "lrw",
383 .alloc = alloc,
384 .free = free,
385 .module = THIS_MODULE,
386};
387
388static int __init crypto_module_init(void)
389{
390 return crypto_register_template(&crypto_tmpl);
391}
392
393static void __exit crypto_module_exit(void)
394{
395 crypto_unregister_template(&crypto_tmpl);
396}
397
398module_init(crypto_module_init);
399module_exit(crypto_module_exit);
400
401MODULE_LICENSE("GPL");
402MODULE_DESCRIPTION("LRW block cipher mode");
403MODULE_ALIAS_CRYPTO("lrw");