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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* XTS: as defined in IEEE1619/D16
3 * http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
4 *
5 * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
6 *
7 * Based on ecb.c
8 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 */
10#include <crypto/internal/skcipher.h>
11#include <crypto/scatterwalk.h>
12#include <linux/err.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/scatterlist.h>
17#include <linux/slab.h>
18
19#include <crypto/xts.h>
20#include <crypto/b128ops.h>
21#include <crypto/gf128mul.h>
22
23struct xts_tfm_ctx {
24 struct crypto_skcipher *child;
25 struct crypto_cipher *tweak;
26};
27
28struct xts_instance_ctx {
29 struct crypto_skcipher_spawn spawn;
30 char name[CRYPTO_MAX_ALG_NAME];
31};
32
33struct xts_request_ctx {
34 le128 t;
35 struct scatterlist *tail;
36 struct scatterlist sg[2];
37 struct skcipher_request subreq;
38};
39
40static int xts_setkey(struct crypto_skcipher *parent, const u8 *key,
41 unsigned int keylen)
42{
43 struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(parent);
44 struct crypto_skcipher *child;
45 struct crypto_cipher *tweak;
46 int err;
47
48 err = xts_verify_key(parent, key, keylen);
49 if (err)
50 return err;
51
52 keylen /= 2;
53
54 /* we need two cipher instances: one to compute the initial 'tweak'
55 * by encrypting the IV (usually the 'plain' iv) and the other
56 * one to encrypt and decrypt the data */
57
58 /* tweak cipher, uses Key2 i.e. the second half of *key */
59 tweak = ctx->tweak;
60 crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
61 crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
62 CRYPTO_TFM_REQ_MASK);
63 err = crypto_cipher_setkey(tweak, key + keylen, keylen);
64 if (err)
65 return err;
66
67 /* data cipher, uses Key1 i.e. the first half of *key */
68 child = ctx->child;
69 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
70 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
71 CRYPTO_TFM_REQ_MASK);
72 return crypto_skcipher_setkey(child, key, keylen);
73}
74
75/*
76 * We compute the tweak masks twice (both before and after the ECB encryption or
77 * decryption) to avoid having to allocate a temporary buffer and/or make
78 * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
79 * just doing the gf128mul_x_ble() calls again.
80 */
81static int xts_xor_tweak(struct skcipher_request *req, bool second_pass,
82 bool enc)
83{
84 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
85 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
86 const bool cts = (req->cryptlen % XTS_BLOCK_SIZE);
87 const int bs = XTS_BLOCK_SIZE;
88 struct skcipher_walk w;
89 le128 t = rctx->t;
90 int err;
91
92 if (second_pass) {
93 req = &rctx->subreq;
94 /* set to our TFM to enforce correct alignment: */
95 skcipher_request_set_tfm(req, tfm);
96 }
97 err = skcipher_walk_virt(&w, req, false);
98
99 while (w.nbytes) {
100 unsigned int avail = w.nbytes;
101 le128 *wsrc;
102 le128 *wdst;
103
104 wsrc = w.src.virt.addr;
105 wdst = w.dst.virt.addr;
106
107 do {
108 if (unlikely(cts) &&
109 w.total - w.nbytes + avail < 2 * XTS_BLOCK_SIZE) {
110 if (!enc) {
111 if (second_pass)
112 rctx->t = t;
113 gf128mul_x_ble(&t, &t);
114 }
115 le128_xor(wdst, &t, wsrc);
116 if (enc && second_pass)
117 gf128mul_x_ble(&rctx->t, &t);
118 skcipher_walk_done(&w, avail - bs);
119 return 0;
120 }
121
122 le128_xor(wdst++, &t, wsrc++);
123 gf128mul_x_ble(&t, &t);
124 } while ((avail -= bs) >= bs);
125
126 err = skcipher_walk_done(&w, avail);
127 }
128
129 return err;
130}
131
132static int xts_xor_tweak_pre(struct skcipher_request *req, bool enc)
133{
134 return xts_xor_tweak(req, false, enc);
135}
136
137static int xts_xor_tweak_post(struct skcipher_request *req, bool enc)
138{
139 return xts_xor_tweak(req, true, enc);
140}
141
142static void xts_cts_done(struct crypto_async_request *areq, int err)
143{
144 struct skcipher_request *req = areq->data;
145 le128 b;
146
147 if (!err) {
148 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
149
150 scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
151 le128_xor(&b, &rctx->t, &b);
152 scatterwalk_map_and_copy(&b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
153 }
154
155 skcipher_request_complete(req, err);
156}
157
158static int xts_cts_final(struct skcipher_request *req,
159 int (*crypt)(struct skcipher_request *req))
160{
161 const struct xts_tfm_ctx *ctx =
162 crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
163 int offset = req->cryptlen & ~(XTS_BLOCK_SIZE - 1);
164 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
165 struct skcipher_request *subreq = &rctx->subreq;
166 int tail = req->cryptlen % XTS_BLOCK_SIZE;
167 le128 b[2];
168 int err;
169
170 rctx->tail = scatterwalk_ffwd(rctx->sg, req->dst,
171 offset - XTS_BLOCK_SIZE);
172
173 scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
174 b[1] = b[0];
175 scatterwalk_map_and_copy(b, req->src, offset, tail, 0);
176
177 le128_xor(b, &rctx->t, b);
178
179 scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE + tail, 1);
180
181 skcipher_request_set_tfm(subreq, ctx->child);
182 skcipher_request_set_callback(subreq, req->base.flags, xts_cts_done,
183 req);
184 skcipher_request_set_crypt(subreq, rctx->tail, rctx->tail,
185 XTS_BLOCK_SIZE, NULL);
186
187 err = crypt(subreq);
188 if (err)
189 return err;
190
191 scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 0);
192 le128_xor(b, &rctx->t, b);
193 scatterwalk_map_and_copy(b, rctx->tail, 0, XTS_BLOCK_SIZE, 1);
194
195 return 0;
196}
197
198static void xts_encrypt_done(struct crypto_async_request *areq, int err)
199{
200 struct skcipher_request *req = areq->data;
201
202 if (!err) {
203 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
204
205 rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
206 err = xts_xor_tweak_post(req, true);
207
208 if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
209 err = xts_cts_final(req, crypto_skcipher_encrypt);
210 if (err == -EINPROGRESS)
211 return;
212 }
213 }
214
215 skcipher_request_complete(req, err);
216}
217
218static void xts_decrypt_done(struct crypto_async_request *areq, int err)
219{
220 struct skcipher_request *req = areq->data;
221
222 if (!err) {
223 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
224
225 rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
226 err = xts_xor_tweak_post(req, false);
227
228 if (!err && unlikely(req->cryptlen % XTS_BLOCK_SIZE)) {
229 err = xts_cts_final(req, crypto_skcipher_decrypt);
230 if (err == -EINPROGRESS)
231 return;
232 }
233 }
234
235 skcipher_request_complete(req, err);
236}
237
238static int xts_init_crypt(struct skcipher_request *req,
239 crypto_completion_t compl)
240{
241 const struct xts_tfm_ctx *ctx =
242 crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
243 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
244 struct skcipher_request *subreq = &rctx->subreq;
245
246 if (req->cryptlen < XTS_BLOCK_SIZE)
247 return -EINVAL;
248
249 skcipher_request_set_tfm(subreq, ctx->child);
250 skcipher_request_set_callback(subreq, req->base.flags, compl, req);
251 skcipher_request_set_crypt(subreq, req->dst, req->dst,
252 req->cryptlen & ~(XTS_BLOCK_SIZE - 1), NULL);
253
254 /* calculate first value of T */
255 crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
256
257 return 0;
258}
259
260static int xts_encrypt(struct skcipher_request *req)
261{
262 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
263 struct skcipher_request *subreq = &rctx->subreq;
264 int err;
265
266 err = xts_init_crypt(req, xts_encrypt_done) ?:
267 xts_xor_tweak_pre(req, true) ?:
268 crypto_skcipher_encrypt(subreq) ?:
269 xts_xor_tweak_post(req, true);
270
271 if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
272 return err;
273
274 return xts_cts_final(req, crypto_skcipher_encrypt);
275}
276
277static int xts_decrypt(struct skcipher_request *req)
278{
279 struct xts_request_ctx *rctx = skcipher_request_ctx(req);
280 struct skcipher_request *subreq = &rctx->subreq;
281 int err;
282
283 err = xts_init_crypt(req, xts_decrypt_done) ?:
284 xts_xor_tweak_pre(req, false) ?:
285 crypto_skcipher_decrypt(subreq) ?:
286 xts_xor_tweak_post(req, false);
287
288 if (err || likely((req->cryptlen % XTS_BLOCK_SIZE) == 0))
289 return err;
290
291 return xts_cts_final(req, crypto_skcipher_decrypt);
292}
293
294static int xts_init_tfm(struct crypto_skcipher *tfm)
295{
296 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
297 struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
298 struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
299 struct crypto_skcipher *child;
300 struct crypto_cipher *tweak;
301
302 child = crypto_spawn_skcipher(&ictx->spawn);
303 if (IS_ERR(child))
304 return PTR_ERR(child);
305
306 ctx->child = child;
307
308 tweak = crypto_alloc_cipher(ictx->name, 0, 0);
309 if (IS_ERR(tweak)) {
310 crypto_free_skcipher(ctx->child);
311 return PTR_ERR(tweak);
312 }
313
314 ctx->tweak = tweak;
315
316 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
317 sizeof(struct xts_request_ctx));
318
319 return 0;
320}
321
322static void xts_exit_tfm(struct crypto_skcipher *tfm)
323{
324 struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
325
326 crypto_free_skcipher(ctx->child);
327 crypto_free_cipher(ctx->tweak);
328}
329
330static void xts_free_instance(struct skcipher_instance *inst)
331{
332 struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
333
334 crypto_drop_skcipher(&ictx->spawn);
335 kfree(inst);
336}
337
338static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
339{
340 struct skcipher_instance *inst;
341 struct xts_instance_ctx *ctx;
342 struct skcipher_alg *alg;
343 const char *cipher_name;
344 u32 mask;
345 int err;
346
347 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
348 if (err)
349 return err;
350
351 cipher_name = crypto_attr_alg_name(tb[1]);
352 if (IS_ERR(cipher_name))
353 return PTR_ERR(cipher_name);
354
355 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
356 if (!inst)
357 return -ENOMEM;
358
359 ctx = skcipher_instance_ctx(inst);
360
361 err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
362 cipher_name, 0, mask);
363 if (err == -ENOENT) {
364 err = -ENAMETOOLONG;
365 if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
366 cipher_name) >= CRYPTO_MAX_ALG_NAME)
367 goto err_free_inst;
368
369 err = crypto_grab_skcipher(&ctx->spawn,
370 skcipher_crypto_instance(inst),
371 ctx->name, 0, mask);
372 }
373
374 if (err)
375 goto err_free_inst;
376
377 alg = crypto_skcipher_spawn_alg(&ctx->spawn);
378
379 err = -EINVAL;
380 if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
381 goto err_free_inst;
382
383 if (crypto_skcipher_alg_ivsize(alg))
384 goto err_free_inst;
385
386 err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
387 &alg->base);
388 if (err)
389 goto err_free_inst;
390
391 err = -EINVAL;
392 cipher_name = alg->base.cra_name;
393
394 /* Alas we screwed up the naming so we have to mangle the
395 * cipher name.
396 */
397 if (!strncmp(cipher_name, "ecb(", 4)) {
398 unsigned len;
399
400 len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
401 if (len < 2 || len >= sizeof(ctx->name))
402 goto err_free_inst;
403
404 if (ctx->name[len - 1] != ')')
405 goto err_free_inst;
406
407 ctx->name[len - 1] = 0;
408
409 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
410 "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
411 err = -ENAMETOOLONG;
412 goto err_free_inst;
413 }
414 } else
415 goto err_free_inst;
416
417 inst->alg.base.cra_priority = alg->base.cra_priority;
418 inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
419 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
420 (__alignof__(u64) - 1);
421
422 inst->alg.ivsize = XTS_BLOCK_SIZE;
423 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
424 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
425
426 inst->alg.base.cra_ctxsize = sizeof(struct xts_tfm_ctx);
427
428 inst->alg.init = xts_init_tfm;
429 inst->alg.exit = xts_exit_tfm;
430
431 inst->alg.setkey = xts_setkey;
432 inst->alg.encrypt = xts_encrypt;
433 inst->alg.decrypt = xts_decrypt;
434
435 inst->free = xts_free_instance;
436
437 err = skcipher_register_instance(tmpl, inst);
438 if (err) {
439err_free_inst:
440 xts_free_instance(inst);
441 }
442 return err;
443}
444
445static struct crypto_template xts_tmpl = {
446 .name = "xts",
447 .create = xts_create,
448 .module = THIS_MODULE,
449};
450
451static int __init xts_module_init(void)
452{
453 return crypto_register_template(&xts_tmpl);
454}
455
456static void __exit xts_module_exit(void)
457{
458 crypto_unregister_template(&xts_tmpl);
459}
460
461subsys_initcall(xts_module_init);
462module_exit(xts_module_exit);
463
464MODULE_LICENSE("GPL");
465MODULE_DESCRIPTION("XTS block cipher mode");
466MODULE_ALIAS_CRYPTO("xts");
1/* XTS: as defined in IEEE1619/D16
2 * http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
3 * (sector sizes which are not a multiple of 16 bytes are,
4 * however currently unsupported)
5 *
6 * Copyright (c) 2007 Rik Snel <rsnel@cube.dyndns.org>
7 *
8 * Based on ecb.c
9 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 */
16#include <crypto/internal/skcipher.h>
17#include <crypto/scatterwalk.h>
18#include <linux/err.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/scatterlist.h>
23#include <linux/slab.h>
24
25#include <crypto/xts.h>
26#include <crypto/b128ops.h>
27#include <crypto/gf128mul.h>
28
29#define XTS_BUFFER_SIZE 128u
30
31struct priv {
32 struct crypto_skcipher *child;
33 struct crypto_cipher *tweak;
34};
35
36struct xts_instance_ctx {
37 struct crypto_skcipher_spawn spawn;
38 char name[CRYPTO_MAX_ALG_NAME];
39};
40
41struct rctx {
42 le128 buf[XTS_BUFFER_SIZE / sizeof(le128)];
43
44 le128 t;
45
46 le128 *ext;
47
48 struct scatterlist srcbuf[2];
49 struct scatterlist dstbuf[2];
50 struct scatterlist *src;
51 struct scatterlist *dst;
52
53 unsigned int left;
54
55 struct skcipher_request subreq;
56};
57
58static int setkey(struct crypto_skcipher *parent, const u8 *key,
59 unsigned int keylen)
60{
61 struct priv *ctx = crypto_skcipher_ctx(parent);
62 struct crypto_skcipher *child;
63 struct crypto_cipher *tweak;
64 int err;
65
66 err = xts_verify_key(parent, key, keylen);
67 if (err)
68 return err;
69
70 keylen /= 2;
71
72 /* we need two cipher instances: one to compute the initial 'tweak'
73 * by encrypting the IV (usually the 'plain' iv) and the other
74 * one to encrypt and decrypt the data */
75
76 /* tweak cipher, uses Key2 i.e. the second half of *key */
77 tweak = ctx->tweak;
78 crypto_cipher_clear_flags(tweak, CRYPTO_TFM_REQ_MASK);
79 crypto_cipher_set_flags(tweak, crypto_skcipher_get_flags(parent) &
80 CRYPTO_TFM_REQ_MASK);
81 err = crypto_cipher_setkey(tweak, key + keylen, keylen);
82 crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(tweak) &
83 CRYPTO_TFM_RES_MASK);
84 if (err)
85 return err;
86
87 /* data cipher, uses Key1 i.e. the first half of *key */
88 child = ctx->child;
89 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
90 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
91 CRYPTO_TFM_REQ_MASK);
92 err = crypto_skcipher_setkey(child, key, keylen);
93 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
94 CRYPTO_TFM_RES_MASK);
95
96 return err;
97}
98
99static int post_crypt(struct skcipher_request *req)
100{
101 struct rctx *rctx = skcipher_request_ctx(req);
102 le128 *buf = rctx->ext ?: rctx->buf;
103 struct skcipher_request *subreq;
104 const int bs = XTS_BLOCK_SIZE;
105 struct skcipher_walk w;
106 struct scatterlist *sg;
107 unsigned offset;
108 int err;
109
110 subreq = &rctx->subreq;
111 err = skcipher_walk_virt(&w, subreq, false);
112
113 while (w.nbytes) {
114 unsigned int avail = w.nbytes;
115 le128 *wdst;
116
117 wdst = w.dst.virt.addr;
118
119 do {
120 le128_xor(wdst, buf++, wdst);
121 wdst++;
122 } while ((avail -= bs) >= bs);
123
124 err = skcipher_walk_done(&w, avail);
125 }
126
127 rctx->left -= subreq->cryptlen;
128
129 if (err || !rctx->left)
130 goto out;
131
132 rctx->dst = rctx->dstbuf;
133
134 scatterwalk_done(&w.out, 0, 1);
135 sg = w.out.sg;
136 offset = w.out.offset;
137
138 if (rctx->dst != sg) {
139 rctx->dst[0] = *sg;
140 sg_unmark_end(rctx->dst);
141 scatterwalk_crypto_chain(rctx->dst, sg_next(sg), 0, 2);
142 }
143 rctx->dst[0].length -= offset - sg->offset;
144 rctx->dst[0].offset = offset;
145
146out:
147 return err;
148}
149
150static int pre_crypt(struct skcipher_request *req)
151{
152 struct rctx *rctx = skcipher_request_ctx(req);
153 le128 *buf = rctx->ext ?: rctx->buf;
154 struct skcipher_request *subreq;
155 const int bs = XTS_BLOCK_SIZE;
156 struct skcipher_walk w;
157 struct scatterlist *sg;
158 unsigned cryptlen;
159 unsigned offset;
160 bool more;
161 int err;
162
163 subreq = &rctx->subreq;
164 cryptlen = subreq->cryptlen;
165
166 more = rctx->left > cryptlen;
167 if (!more)
168 cryptlen = rctx->left;
169
170 skcipher_request_set_crypt(subreq, rctx->src, rctx->dst,
171 cryptlen, NULL);
172
173 err = skcipher_walk_virt(&w, subreq, false);
174
175 while (w.nbytes) {
176 unsigned int avail = w.nbytes;
177 le128 *wsrc;
178 le128 *wdst;
179
180 wsrc = w.src.virt.addr;
181 wdst = w.dst.virt.addr;
182
183 do {
184 *buf++ = rctx->t;
185 le128_xor(wdst++, &rctx->t, wsrc++);
186 gf128mul_x_ble(&rctx->t, &rctx->t);
187 } while ((avail -= bs) >= bs);
188
189 err = skcipher_walk_done(&w, avail);
190 }
191
192 skcipher_request_set_crypt(subreq, rctx->dst, rctx->dst,
193 cryptlen, NULL);
194
195 if (err || !more)
196 goto out;
197
198 rctx->src = rctx->srcbuf;
199
200 scatterwalk_done(&w.in, 0, 1);
201 sg = w.in.sg;
202 offset = w.in.offset;
203
204 if (rctx->src != sg) {
205 rctx->src[0] = *sg;
206 sg_unmark_end(rctx->src);
207 scatterwalk_crypto_chain(rctx->src, sg_next(sg), 0, 2);
208 }
209 rctx->src[0].length -= offset - sg->offset;
210 rctx->src[0].offset = offset;
211
212out:
213 return err;
214}
215
216static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
217{
218 struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
219 struct rctx *rctx = skcipher_request_ctx(req);
220 struct skcipher_request *subreq;
221 gfp_t gfp;
222
223 subreq = &rctx->subreq;
224 skcipher_request_set_tfm(subreq, ctx->child);
225 skcipher_request_set_callback(subreq, req->base.flags, done, req);
226
227 gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
228 GFP_ATOMIC;
229 rctx->ext = NULL;
230
231 subreq->cryptlen = XTS_BUFFER_SIZE;
232 if (req->cryptlen > XTS_BUFFER_SIZE) {
233 unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
234
235 rctx->ext = kmalloc(n, gfp);
236 if (rctx->ext)
237 subreq->cryptlen = n;
238 }
239
240 rctx->src = req->src;
241 rctx->dst = req->dst;
242 rctx->left = req->cryptlen;
243
244 /* calculate first value of T */
245 crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
246
247 return 0;
248}
249
250static void exit_crypt(struct skcipher_request *req)
251{
252 struct rctx *rctx = skcipher_request_ctx(req);
253
254 rctx->left = 0;
255
256 if (rctx->ext)
257 kzfree(rctx->ext);
258}
259
260static int do_encrypt(struct skcipher_request *req, int err)
261{
262 struct rctx *rctx = skcipher_request_ctx(req);
263 struct skcipher_request *subreq;
264
265 subreq = &rctx->subreq;
266
267 while (!err && rctx->left) {
268 err = pre_crypt(req) ?:
269 crypto_skcipher_encrypt(subreq) ?:
270 post_crypt(req);
271
272 if (err == -EINPROGRESS || err == -EBUSY)
273 return err;
274 }
275
276 exit_crypt(req);
277 return err;
278}
279
280static void encrypt_done(struct crypto_async_request *areq, int err)
281{
282 struct skcipher_request *req = areq->data;
283 struct skcipher_request *subreq;
284 struct rctx *rctx;
285
286 rctx = skcipher_request_ctx(req);
287
288 if (err == -EINPROGRESS) {
289 if (rctx->left != req->cryptlen)
290 return;
291 goto out;
292 }
293
294 subreq = &rctx->subreq;
295 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
296
297 err = do_encrypt(req, err ?: post_crypt(req));
298 if (rctx->left)
299 return;
300
301out:
302 skcipher_request_complete(req, err);
303}
304
305static int encrypt(struct skcipher_request *req)
306{
307 return do_encrypt(req, init_crypt(req, encrypt_done));
308}
309
310static int do_decrypt(struct skcipher_request *req, int err)
311{
312 struct rctx *rctx = skcipher_request_ctx(req);
313 struct skcipher_request *subreq;
314
315 subreq = &rctx->subreq;
316
317 while (!err && rctx->left) {
318 err = pre_crypt(req) ?:
319 crypto_skcipher_decrypt(subreq) ?:
320 post_crypt(req);
321
322 if (err == -EINPROGRESS || err == -EBUSY)
323 return err;
324 }
325
326 exit_crypt(req);
327 return err;
328}
329
330static void decrypt_done(struct crypto_async_request *areq, int err)
331{
332 struct skcipher_request *req = areq->data;
333 struct skcipher_request *subreq;
334 struct rctx *rctx;
335
336 rctx = skcipher_request_ctx(req);
337
338 if (err == -EINPROGRESS) {
339 if (rctx->left != req->cryptlen)
340 return;
341 goto out;
342 }
343
344 subreq = &rctx->subreq;
345 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
346
347 err = do_decrypt(req, err ?: post_crypt(req));
348 if (rctx->left)
349 return;
350
351out:
352 skcipher_request_complete(req, err);
353}
354
355static int decrypt(struct skcipher_request *req)
356{
357 return do_decrypt(req, init_crypt(req, decrypt_done));
358}
359
360static int init_tfm(struct crypto_skcipher *tfm)
361{
362 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
363 struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
364 struct priv *ctx = crypto_skcipher_ctx(tfm);
365 struct crypto_skcipher *child;
366 struct crypto_cipher *tweak;
367
368 child = crypto_spawn_skcipher(&ictx->spawn);
369 if (IS_ERR(child))
370 return PTR_ERR(child);
371
372 ctx->child = child;
373
374 tweak = crypto_alloc_cipher(ictx->name, 0, 0);
375 if (IS_ERR(tweak)) {
376 crypto_free_skcipher(ctx->child);
377 return PTR_ERR(tweak);
378 }
379
380 ctx->tweak = tweak;
381
382 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
383 sizeof(struct rctx));
384
385 return 0;
386}
387
388static void exit_tfm(struct crypto_skcipher *tfm)
389{
390 struct priv *ctx = crypto_skcipher_ctx(tfm);
391
392 crypto_free_skcipher(ctx->child);
393 crypto_free_cipher(ctx->tweak);
394}
395
396static void free(struct skcipher_instance *inst)
397{
398 crypto_drop_skcipher(skcipher_instance_ctx(inst));
399 kfree(inst);
400}
401
402static int create(struct crypto_template *tmpl, struct rtattr **tb)
403{
404 struct skcipher_instance *inst;
405 struct crypto_attr_type *algt;
406 struct xts_instance_ctx *ctx;
407 struct skcipher_alg *alg;
408 const char *cipher_name;
409 u32 mask;
410 int err;
411
412 algt = crypto_get_attr_type(tb);
413 if (IS_ERR(algt))
414 return PTR_ERR(algt);
415
416 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
417 return -EINVAL;
418
419 cipher_name = crypto_attr_alg_name(tb[1]);
420 if (IS_ERR(cipher_name))
421 return PTR_ERR(cipher_name);
422
423 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
424 if (!inst)
425 return -ENOMEM;
426
427 ctx = skcipher_instance_ctx(inst);
428
429 crypto_set_skcipher_spawn(&ctx->spawn, skcipher_crypto_instance(inst));
430
431 mask = crypto_requires_off(algt->type, algt->mask,
432 CRYPTO_ALG_NEED_FALLBACK |
433 CRYPTO_ALG_ASYNC);
434
435 err = crypto_grab_skcipher(&ctx->spawn, cipher_name, 0, mask);
436 if (err == -ENOENT) {
437 err = -ENAMETOOLONG;
438 if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
439 cipher_name) >= CRYPTO_MAX_ALG_NAME)
440 goto err_free_inst;
441
442 err = crypto_grab_skcipher(&ctx->spawn, ctx->name, 0, mask);
443 }
444
445 if (err)
446 goto err_free_inst;
447
448 alg = crypto_skcipher_spawn_alg(&ctx->spawn);
449
450 err = -EINVAL;
451 if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
452 goto err_drop_spawn;
453
454 if (crypto_skcipher_alg_ivsize(alg))
455 goto err_drop_spawn;
456
457 err = crypto_inst_setname(skcipher_crypto_instance(inst), "xts",
458 &alg->base);
459 if (err)
460 goto err_drop_spawn;
461
462 err = -EINVAL;
463 cipher_name = alg->base.cra_name;
464
465 /* Alas we screwed up the naming so we have to mangle the
466 * cipher name.
467 */
468 if (!strncmp(cipher_name, "ecb(", 4)) {
469 unsigned len;
470
471 len = strlcpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
472 if (len < 2 || len >= sizeof(ctx->name))
473 goto err_drop_spawn;
474
475 if (ctx->name[len - 1] != ')')
476 goto err_drop_spawn;
477
478 ctx->name[len - 1] = 0;
479
480 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
481 "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
482 err = -ENAMETOOLONG;
483 goto err_drop_spawn;
484 }
485 } else
486 goto err_drop_spawn;
487
488 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
489 inst->alg.base.cra_priority = alg->base.cra_priority;
490 inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
491 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
492 (__alignof__(u64) - 1);
493
494 inst->alg.ivsize = XTS_BLOCK_SIZE;
495 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
496 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
497
498 inst->alg.base.cra_ctxsize = sizeof(struct priv);
499
500 inst->alg.init = init_tfm;
501 inst->alg.exit = exit_tfm;
502
503 inst->alg.setkey = setkey;
504 inst->alg.encrypt = encrypt;
505 inst->alg.decrypt = decrypt;
506
507 inst->free = free;
508
509 err = skcipher_register_instance(tmpl, inst);
510 if (err)
511 goto err_drop_spawn;
512
513out:
514 return err;
515
516err_drop_spawn:
517 crypto_drop_skcipher(&ctx->spawn);
518err_free_inst:
519 kfree(inst);
520 goto out;
521}
522
523static struct crypto_template crypto_tmpl = {
524 .name = "xts",
525 .create = create,
526 .module = THIS_MODULE,
527};
528
529static int __init crypto_module_init(void)
530{
531 return crypto_register_template(&crypto_tmpl);
532}
533
534static void __exit crypto_module_exit(void)
535{
536 crypto_unregister_template(&crypto_tmpl);
537}
538
539module_init(crypto_module_init);
540module_exit(crypto_module_exit);
541
542MODULE_LICENSE("GPL");
543MODULE_DESCRIPTION("XTS block cipher mode");
544MODULE_ALIAS_CRYPTO("xts");