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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#include <crypto/lrw.h>
32
33#define LRW_BUFFER_SIZE 128u
34
35struct priv {
36 struct crypto_skcipher *child;
37 struct lrw_table_ctx table;
38};
39
40struct rctx {
41 be128 buf[LRW_BUFFER_SIZE / sizeof(be128)];
42
43 be128 t;
44
45 be128 *ext;
46
47 struct scatterlist srcbuf[2];
48 struct scatterlist dstbuf[2];
49 struct scatterlist *src;
50 struct scatterlist *dst;
51
52 unsigned int left;
53
54 struct skcipher_request subreq;
55};
56
57static inline void setbit128_bbe(void *b, int bit)
58{
59 __set_bit(bit ^ (0x80 -
60#ifdef __BIG_ENDIAN
61 BITS_PER_LONG
62#else
63 BITS_PER_BYTE
64#endif
65 ), b);
66}
67
68int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
69{
70 be128 tmp = { 0 };
71 int i;
72
73 if (ctx->table)
74 gf128mul_free_64k(ctx->table);
75
76
77 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
78 if (!ctx->table)
79 return -ENOMEM;
80
81
82 for (i = 0; i < 128; i++) {
83 setbit128_bbe(&tmp, i);
84 ctx->mulinc[i] = tmp;
85 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
86 }
87
88 return 0;
89}
90EXPORT_SYMBOL_GPL(lrw_init_table);
91
92void lrw_free_table(struct lrw_table_ctx *ctx)
93{
94 if (ctx->table)
95 gf128mul_free_64k(ctx->table);
96}
97EXPORT_SYMBOL_GPL(lrw_free_table);
98
99static int setkey(struct crypto_skcipher *parent, const u8 *key,
100 unsigned int keylen)
101{
102 struct priv *ctx = crypto_skcipher_ctx(parent);
103 struct crypto_skcipher *child = ctx->child;
104 int err, bsize = LRW_BLOCK_SIZE;
105 const u8 *tweak = key + keylen - bsize;
106
107 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
108 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
109 CRYPTO_TFM_REQ_MASK);
110 err = crypto_skcipher_setkey(child, key, keylen - bsize);
111 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
112 CRYPTO_TFM_RES_MASK);
113 if (err)
114 return err;
115
116 return lrw_init_table(&ctx->table, tweak);
117}
118
119static inline void inc(be128 *iv)
120{
121 be64_add_cpu(&iv->b, 1);
122 if (!iv->b)
123 be64_add_cpu(&iv->a, 1);
124}
125
126
127
128static inline int get_index128(be128 *block)
129{
130 int x;
131 __be32 *p = (__be32 *) block;
132
133 for (p += 3, x = 0; x < 128; p--, x += 32) {
134 u32 val = be32_to_cpup(p);
135
136 if (!~val)
137 continue;
138
139 return x + ffz(val);
140 }
141
142 return x;
143}
144
145static int post_crypt(struct skcipher_request *req)
146{
147 struct rctx *rctx = skcipher_request_ctx(req);
148 be128 *buf = rctx->ext ?: rctx->buf;
149 struct skcipher_request *subreq;
150 const int bs = LRW_BLOCK_SIZE;
151 struct skcipher_walk w;
152 struct scatterlist *sg;
153 unsigned offset;
154 int err;
155
156 subreq = &rctx->subreq;
157 err = skcipher_walk_virt(&w, subreq, false);
158
159 while (w.nbytes) {
160 unsigned int avail = w.nbytes;
161 be128 *wdst;
162
163 wdst = w.dst.virt.addr;
164
165 do {
166 be128_xor(wdst, buf++, wdst);
167 wdst++;
168 } while ((avail -= bs) >= bs);
169
170 err = skcipher_walk_done(&w, avail);
171 }
172
173 rctx->left -= subreq->cryptlen;
174
175 if (err || !rctx->left)
176 goto out;
177
178 rctx->dst = rctx->dstbuf;
179
180 scatterwalk_done(&w.out, 0, 1);
181 sg = w.out.sg;
182 offset = w.out.offset;
183
184 if (rctx->dst != sg) {
185 rctx->dst[0] = *sg;
186 sg_unmark_end(rctx->dst);
187 scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
188 }
189 rctx->dst[0].length -= offset - sg->offset;
190 rctx->dst[0].offset = offset;
191
192out:
193 return err;
194}
195
196static int pre_crypt(struct skcipher_request *req)
197{
198 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
199 struct rctx *rctx = skcipher_request_ctx(req);
200 struct priv *ctx = crypto_skcipher_ctx(tfm);
201 be128 *buf = rctx->ext ?: rctx->buf;
202 struct skcipher_request *subreq;
203 const int bs = LRW_BLOCK_SIZE;
204 struct skcipher_walk w;
205 struct scatterlist *sg;
206 unsigned cryptlen;
207 unsigned offset;
208 be128 *iv;
209 bool more;
210 int err;
211
212 subreq = &rctx->subreq;
213 skcipher_request_set_tfm(subreq, tfm);
214
215 cryptlen = subreq->cryptlen;
216 more = rctx->left > cryptlen;
217 if (!more)
218 cryptlen = rctx->left;
219
220 skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
221 cryptlen, req->iv);
222
223 err = skcipher_walk_virt(&w, subreq, false);
224 iv = w.iv;
225
226 while (w.nbytes) {
227 unsigned int avail = w.nbytes;
228 be128 *wsrc;
229 be128 *wdst;
230
231 wsrc = w.src.virt.addr;
232 wdst = w.dst.virt.addr;
233
234 do {
235 *buf++ = rctx->t;
236 be128_xor(wdst++, &rctx->t, wsrc++);
237
238
239
240 be128_xor(&rctx->t, &rctx->t,
241 &ctx->table.mulinc[get_index128(iv)]);
242 inc(iv);
243 } while ((avail -= bs) >= bs);
244
245 err = skcipher_walk_done(&w, avail);
246 }
247
248 skcipher_request_set_tfm(subreq, ctx->child);
249 skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
250 cryptlen, NULL);
251
252 if (err || !more)
253 goto out;
254
255 rctx->src = rctx->srcbuf;
256
257 scatterwalk_done(&w.in, 0, 1);
258 sg = w.in.sg;
259 offset = w.in.offset;
260
261 if (rctx->src != sg) {
262 rctx->src[0] = *sg;
263 sg_unmark_end(rctx->src);
264 scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
265 }
266 rctx->src[0].length -= offset - sg->offset;
267 rctx->src[0].offset = offset;
268
269out:
270 return err;
271}
272
273static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
274{
275 struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
276 struct rctx *rctx = skcipher_request_ctx(req);
277 struct skcipher_request *subreq;
278 gfp_t gfp;
279
280 subreq = &rctx->subreq;
281 skcipher_request_set_callback(subreq, req->base.flags, done, req);
282
283 gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
284 GFP_ATOMIC;
285 rctx->ext = NULL;
286
287 subreq->cryptlen = LRW_BUFFER_SIZE;
288 if (req->cryptlen > LRW_BUFFER_SIZE) {
289 unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
290
291 rctx->ext = kmalloc(n, gfp);
292 if (rctx->ext)
293 subreq->cryptlen = n;
294 }
295
296 rctx->src = req->src;
297 rctx->dst = req->dst;
298 rctx->left = req->cryptlen;
299
300
301 memcpy(&rctx->t, req->iv, sizeof(rctx->t));
302
303
304 gf128mul_64k_bbe(&rctx->t, ctx->table.table);
305
306 return 0;
307}
308
309static void exit_crypt(struct skcipher_request *req)
310{
311 struct rctx *rctx = skcipher_request_ctx(req);
312
313 rctx->left = 0;
314
315 if (rctx->ext)
316 kfree(rctx->ext);
317}
318
319static int do_encrypt(struct skcipher_request *req, int err)
320{
321 struct rctx *rctx = skcipher_request_ctx(req);
322 struct skcipher_request *subreq;
323
324 subreq = &rctx->subreq;
325
326 while (!err && rctx->left) {
327 err = pre_crypt(req) ?:
328 crypto_skcipher_encrypt(subreq) ?:
329 post_crypt(req);
330
331 if (err == -EINPROGRESS ||
332 (err == -EBUSY &&
333 req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
334 return err;
335 }
336
337 exit_crypt(req);
338 return err;
339}
340
341static void encrypt_done(struct crypto_async_request *areq, int err)
342{
343 struct skcipher_request *req = areq->data;
344 struct skcipher_request *subreq;
345 struct rctx *rctx;
346
347 rctx = skcipher_request_ctx(req);
348
349 if (err == -EINPROGRESS) {
350 if (rctx->left != req->cryptlen)
351 return;
352 goto out;
353 }
354
355 subreq = &rctx->subreq;
356 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
357
358 err = do_encrypt(req, err ?: post_crypt(req));
359 if (rctx->left)
360 return;
361
362out:
363 skcipher_request_complete(req, err);
364}
365
366static int encrypt(struct skcipher_request *req)
367{
368 return do_encrypt(req, init_crypt(req, encrypt_done));
369}
370
371static int do_decrypt(struct skcipher_request *req, int err)
372{
373 struct rctx *rctx = skcipher_request_ctx(req);
374 struct skcipher_request *subreq;
375
376 subreq = &rctx->subreq;
377
378 while (!err && rctx->left) {
379 err = pre_crypt(req) ?:
380 crypto_skcipher_decrypt(subreq) ?:
381 post_crypt(req);
382
383 if (err == -EINPROGRESS ||
384 (err == -EBUSY &&
385 req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
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
423int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
424 struct scatterlist *ssrc, unsigned int nbytes,
425 struct lrw_crypt_req *req)
426{
427 const unsigned int bsize = LRW_BLOCK_SIZE;
428 const unsigned int max_blks = req->tbuflen / bsize;
429 struct lrw_table_ctx *ctx = req->table_ctx;
430 struct blkcipher_walk walk;
431 unsigned int nblocks;
432 be128 *iv, *src, *dst, *t;
433 be128 *t_buf = req->tbuf;
434 int err, i;
435
436 BUG_ON(max_blks < 1);
437
438 blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
439
440 err = blkcipher_walk_virt(desc, &walk);
441 nbytes = walk.nbytes;
442 if (!nbytes)
443 return err;
444
445 nblocks = min(walk.nbytes / bsize, max_blks);
446 src = (be128 *)walk.src.virt.addr;
447 dst = (be128 *)walk.dst.virt.addr;
448
449
450 iv = (be128 *)walk.iv;
451 t_buf[0] = *iv;
452
453
454 gf128mul_64k_bbe(&t_buf[0], ctx->table);
455
456 i = 0;
457 goto first;
458
459 for (;;) {
460 do {
461 for (i = 0; i < nblocks; i++) {
462
463
464 be128_xor(&t_buf[i], t,
465 &ctx->mulinc[get_index128(iv)]);
466 inc(iv);
467first:
468 t = &t_buf[i];
469
470
471 be128_xor(dst + i, t, src + i);
472 }
473
474
475 req->crypt_fn(req->crypt_ctx, (u8 *)dst,
476 nblocks * bsize);
477
478
479 for (i = 0; i < nblocks; i++)
480 be128_xor(dst + i, dst + i, &t_buf[i]);
481
482 src += nblocks;
483 dst += nblocks;
484 nbytes -= nblocks * bsize;
485 nblocks = min(nbytes / bsize, max_blks);
486 } while (nblocks > 0);
487
488 err = blkcipher_walk_done(desc, &walk, nbytes);
489 nbytes = walk.nbytes;
490 if (!nbytes)
491 break;
492
493 nblocks = min(nbytes / bsize, max_blks);
494 src = (be128 *)walk.src.virt.addr;
495 dst = (be128 *)walk.dst.virt.addr;
496 }
497
498 return err;
499}
500EXPORT_SYMBOL_GPL(lrw_crypt);
501
502static int init_tfm(struct crypto_skcipher *tfm)
503{
504 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
505 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
506 struct priv *ctx = crypto_skcipher_ctx(tfm);
507 struct crypto_skcipher *cipher;
508
509 cipher = crypto_spawn_skcipher(spawn);
510 if (IS_ERR(cipher))
511 return PTR_ERR(cipher);
512
513 ctx->child = cipher;
514
515 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
516 sizeof(struct rctx));
517
518 return 0;
519}
520
521static void exit_tfm(struct crypto_skcipher *tfm)
522{
523 struct priv *ctx = crypto_skcipher_ctx(tfm);
524
525 lrw_free_table(&ctx->table);
526 crypto_free_skcipher(ctx->child);
527}
528
529static void free(struct skcipher_instance *inst)
530{
531 crypto_drop_skcipher(skcipher_instance_ctx(inst));
532 kfree(inst);
533}
534
535static int create(struct crypto_template *tmpl, struct rtattr **tb)
536{
537 struct crypto_skcipher_spawn *spawn;
538 struct skcipher_instance *inst;
539 struct crypto_attr_type *algt;
540 struct skcipher_alg *alg;
541 const char *cipher_name;
542 char ecb_name[CRYPTO_MAX_ALG_NAME];
543 int err;
544
545 algt = crypto_get_attr_type(tb);
546 if (IS_ERR(algt))
547 return PTR_ERR(algt);
548
549 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
550 return -EINVAL;
551
552 cipher_name = crypto_attr_alg_name(tb[1]);
553 if (IS_ERR(cipher_name))
554 return PTR_ERR(cipher_name);
555
556 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
557 if (!inst)
558 return -ENOMEM;
559
560 spawn = skcipher_instance_ctx(inst);
561
562 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
563 err = crypto_grab_skcipher(spawn, cipher_name, 0,
564 crypto_requires_sync(algt->type,
565 algt->mask));
566 if (err == -ENOENT) {
567 err = -ENAMETOOLONG;
568 if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
569 cipher_name) >= CRYPTO_MAX_ALG_NAME)
570 goto err_free_inst;
571
572 err = crypto_grab_skcipher(spawn, ecb_name, 0,
573 crypto_requires_sync(algt->type,
574 algt->mask));
575 }
576
577 if (err)
578 goto err_free_inst;
579
580 alg = crypto_skcipher_spawn_alg(spawn);
581
582 err = -EINVAL;
583 if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
584 goto err_drop_spawn;
585
586 if (crypto_skcipher_alg_ivsize(alg))
587 goto err_drop_spawn;
588
589 err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
590 &alg->base);
591 if (err)
592 goto err_drop_spawn;
593
594 err = -EINVAL;
595 cipher_name = alg->base.cra_name;
596
597
598
599
600 if (!strncmp(cipher_name, "ecb(", 4)) {
601 unsigned len;
602
603 len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
604 if (len < 2 || len >= sizeof(ecb_name))
605 goto err_drop_spawn;
606
607 if (ecb_name[len - 1] != ')')
608 goto err_drop_spawn;
609
610 ecb_name[len - 1] = 0;
611
612 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
613 "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME)
614 return -ENAMETOOLONG;
615 }
616
617 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
618 inst->alg.base.cra_priority = alg->base.cra_priority;
619 inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
620 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
621 (__alignof__(u64) - 1);
622
623 inst->alg.ivsize = LRW_BLOCK_SIZE;
624 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
625 LRW_BLOCK_SIZE;
626 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
627 LRW_BLOCK_SIZE;
628
629 inst->alg.base.cra_ctxsize = sizeof(struct priv);
630
631 inst->alg.init = init_tfm;
632 inst->alg.exit = exit_tfm;
633
634 inst->alg.setkey = setkey;
635 inst->alg.encrypt = encrypt;
636 inst->alg.decrypt = decrypt;
637
638 inst->free = free;
639
640 err = skcipher_register_instance(tmpl, inst);
641 if (err)
642 goto err_drop_spawn;
643
644out:
645 return err;
646
647err_drop_spawn:
648 crypto_drop_skcipher(spawn);
649err_free_inst:
650 kfree(inst);
651 goto out;
652}
653
654static struct crypto_template crypto_tmpl = {
655 .name = "lrw",
656 .create = create,
657 .module = THIS_MODULE,
658};
659
660static int __init crypto_module_init(void)
661{
662 return crypto_register_template(&crypto_tmpl);
663}
664
665static void __exit crypto_module_exit(void)
666{
667 crypto_unregister_template(&crypto_tmpl);
668}
669
670module_init(crypto_module_init);
671module_exit(crypto_module_exit);
672
673MODULE_LICENSE("GPL");
674MODULE_DESCRIPTION("LRW block cipher mode");
675MODULE_ALIAS_CRYPTO("lrw");
676
