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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* LRW: as defined by Cyril Guyot in
3 * http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
4 *
5 * Copyright (c) 2006 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/* This implementation is checked against the test vectors in the above
11 * document and by a test vector provided by Ken Buchanan at
12 * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
13 *
14 * The test vectors are included in the testing module tcrypt.[ch] */
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/b128ops.h>
26#include <crypto/gf128mul.h>
27
28#define LRW_BLOCK_SIZE 16
29
30struct priv {
31 struct crypto_skcipher *child;
32
33 /*
34 * optimizes multiplying a random (non incrementing, as at the
35 * start of a new sector) value with key2, we could also have
36 * used 4k optimization tables or no optimization at all. In the
37 * latter case we would have to store key2 here
38 */
39 struct gf128mul_64k *table;
40
41 /*
42 * stores:
43 * key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
44 * key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
45 * key2*{ 0,0,...1,1,1,1,1 }, etc
46 * needed for optimized multiplication of incrementing values
47 * with key2
48 */
49 be128 mulinc[128];
50};
51
52struct rctx {
53 be128 t;
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
68static int setkey(struct crypto_skcipher *parent, const u8 *key,
69 unsigned int keylen)
70{
71 struct priv *ctx = crypto_skcipher_ctx(parent);
72 struct crypto_skcipher *child = ctx->child;
73 int err, bsize = LRW_BLOCK_SIZE;
74 const u8 *tweak = key + keylen - bsize;
75 be128 tmp = { 0 };
76 int i;
77
78 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
79 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
80 CRYPTO_TFM_REQ_MASK);
81 err = crypto_skcipher_setkey(child, key, keylen - bsize);
82 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
83 CRYPTO_TFM_RES_MASK);
84 if (err)
85 return err;
86
87 if (ctx->table)
88 gf128mul_free_64k(ctx->table);
89
90 /* initialize multiplication table for Key2 */
91 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
92 if (!ctx->table)
93 return -ENOMEM;
94
95 /* initialize optimization table */
96 for (i = 0; i < 128; i++) {
97 setbit128_bbe(&tmp, i);
98 ctx->mulinc[i] = tmp;
99 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
100 }
101
102 return 0;
103}
104
105/*
106 * Returns the number of trailing '1' bits in the words of the counter, which is
107 * represented by 4 32-bit words, arranged from least to most significant.
108 * At the same time, increments the counter by one.
109 *
110 * For example:
111 *
112 * u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
113 * int i = next_index(&counter);
114 * // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
115 */
116static int next_index(u32 *counter)
117{
118 int i, res = 0;
119
120 for (i = 0; i < 4; i++) {
121 if (counter[i] + 1 != 0)
122 return res + ffz(counter[i]++);
123
124 counter[i] = 0;
125 res += 32;
126 }
127
128 /*
129 * If we get here, then x == 128 and we are incrementing the counter
130 * from all ones to all zeros. This means we must return index 127, i.e.
131 * the one corresponding to key2*{ 1,...,1 }.
132 */
133 return 127;
134}
135
136/*
137 * We compute the tweak masks twice (both before and after the ECB encryption or
138 * decryption) to avoid having to allocate a temporary buffer and/or make
139 * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
140 * just doing the next_index() calls again.
141 */
142static int xor_tweak(struct skcipher_request *req, bool second_pass)
143{
144 const int bs = LRW_BLOCK_SIZE;
145 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
146 struct priv *ctx = crypto_skcipher_ctx(tfm);
147 struct rctx *rctx = skcipher_request_ctx(req);
148 be128 t = rctx->t;
149 struct skcipher_walk w;
150 __be32 *iv;
151 u32 counter[4];
152 int err;
153
154 if (second_pass) {
155 req = &rctx->subreq;
156 /* set to our TFM to enforce correct alignment: */
157 skcipher_request_set_tfm(req, tfm);
158 }
159
160 err = skcipher_walk_virt(&w, req, false);
161 if (err)
162 return err;
163
164 iv = (__be32 *)w.iv;
165 counter[0] = be32_to_cpu(iv[3]);
166 counter[1] = be32_to_cpu(iv[2]);
167 counter[2] = be32_to_cpu(iv[1]);
168 counter[3] = be32_to_cpu(iv[0]);
169
170 while (w.nbytes) {
171 unsigned int avail = w.nbytes;
172 be128 *wsrc;
173 be128 *wdst;
174
175 wsrc = w.src.virt.addr;
176 wdst = w.dst.virt.addr;
177
178 do {
179 be128_xor(wdst++, &t, wsrc++);
180
181 /* T <- I*Key2, using the optimization
182 * discussed in the specification */
183 be128_xor(&t, &t, &ctx->mulinc[next_index(counter)]);
184 } while ((avail -= bs) >= bs);
185
186 if (second_pass && w.nbytes == w.total) {
187 iv[0] = cpu_to_be32(counter[3]);
188 iv[1] = cpu_to_be32(counter[2]);
189 iv[2] = cpu_to_be32(counter[1]);
190 iv[3] = cpu_to_be32(counter[0]);
191 }
192
193 err = skcipher_walk_done(&w, avail);
194 }
195
196 return err;
197}
198
199static int xor_tweak_pre(struct skcipher_request *req)
200{
201 return xor_tweak(req, false);
202}
203
204static int xor_tweak_post(struct skcipher_request *req)
205{
206 return xor_tweak(req, true);
207}
208
209static void crypt_done(struct crypto_async_request *areq, int err)
210{
211 struct skcipher_request *req = areq->data;
212
213 if (!err) {
214 struct rctx *rctx = skcipher_request_ctx(req);
215
216 rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
217 err = xor_tweak_post(req);
218 }
219
220 skcipher_request_complete(req, err);
221}
222
223static void init_crypt(struct skcipher_request *req)
224{
225 struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
226 struct rctx *rctx = skcipher_request_ctx(req);
227 struct skcipher_request *subreq = &rctx->subreq;
228
229 skcipher_request_set_tfm(subreq, ctx->child);
230 skcipher_request_set_callback(subreq, req->base.flags, crypt_done, req);
231 /* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
232 skcipher_request_set_crypt(subreq, req->dst, req->dst,
233 req->cryptlen, req->iv);
234
235 /* calculate first value of T */
236 memcpy(&rctx->t, req->iv, sizeof(rctx->t));
237
238 /* T <- I*Key2 */
239 gf128mul_64k_bbe(&rctx->t, ctx->table);
240}
241
242static int encrypt(struct skcipher_request *req)
243{
244 struct rctx *rctx = skcipher_request_ctx(req);
245 struct skcipher_request *subreq = &rctx->subreq;
246
247 init_crypt(req);
248 return xor_tweak_pre(req) ?:
249 crypto_skcipher_encrypt(subreq) ?:
250 xor_tweak_post(req);
251}
252
253static int decrypt(struct skcipher_request *req)
254{
255 struct rctx *rctx = skcipher_request_ctx(req);
256 struct skcipher_request *subreq = &rctx->subreq;
257
258 init_crypt(req);
259 return xor_tweak_pre(req) ?:
260 crypto_skcipher_decrypt(subreq) ?:
261 xor_tweak_post(req);
262}
263
264static int init_tfm(struct crypto_skcipher *tfm)
265{
266 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
267 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
268 struct priv *ctx = crypto_skcipher_ctx(tfm);
269 struct crypto_skcipher *cipher;
270
271 cipher = crypto_spawn_skcipher(spawn);
272 if (IS_ERR(cipher))
273 return PTR_ERR(cipher);
274
275 ctx->child = cipher;
276
277 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
278 sizeof(struct rctx));
279
280 return 0;
281}
282
283static void exit_tfm(struct crypto_skcipher *tfm)
284{
285 struct priv *ctx = crypto_skcipher_ctx(tfm);
286
287 if (ctx->table)
288 gf128mul_free_64k(ctx->table);
289 crypto_free_skcipher(ctx->child);
290}
291
292static void free(struct skcipher_instance *inst)
293{
294 crypto_drop_skcipher(skcipher_instance_ctx(inst));
295 kfree(inst);
296}
297
298static int create(struct crypto_template *tmpl, struct rtattr **tb)
299{
300 struct crypto_skcipher_spawn *spawn;
301 struct skcipher_instance *inst;
302 struct crypto_attr_type *algt;
303 struct skcipher_alg *alg;
304 const char *cipher_name;
305 char ecb_name[CRYPTO_MAX_ALG_NAME];
306 int err;
307
308 algt = crypto_get_attr_type(tb);
309 if (IS_ERR(algt))
310 return PTR_ERR(algt);
311
312 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
313 return -EINVAL;
314
315 cipher_name = crypto_attr_alg_name(tb[1]);
316 if (IS_ERR(cipher_name))
317 return PTR_ERR(cipher_name);
318
319 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
320 if (!inst)
321 return -ENOMEM;
322
323 spawn = skcipher_instance_ctx(inst);
324
325 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
326 err = crypto_grab_skcipher(spawn, cipher_name, 0,
327 crypto_requires_sync(algt->type,
328 algt->mask));
329 if (err == -ENOENT) {
330 err = -ENAMETOOLONG;
331 if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
332 cipher_name) >= CRYPTO_MAX_ALG_NAME)
333 goto err_free_inst;
334
335 err = crypto_grab_skcipher(spawn, ecb_name, 0,
336 crypto_requires_sync(algt->type,
337 algt->mask));
338 }
339
340 if (err)
341 goto err_free_inst;
342
343 alg = crypto_skcipher_spawn_alg(spawn);
344
345 err = -EINVAL;
346 if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
347 goto err_drop_spawn;
348
349 if (crypto_skcipher_alg_ivsize(alg))
350 goto err_drop_spawn;
351
352 err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
353 &alg->base);
354 if (err)
355 goto err_drop_spawn;
356
357 err = -EINVAL;
358 cipher_name = alg->base.cra_name;
359
360 /* Alas we screwed up the naming so we have to mangle the
361 * cipher name.
362 */
363 if (!strncmp(cipher_name, "ecb(", 4)) {
364 unsigned len;
365
366 len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
367 if (len < 2 || len >= sizeof(ecb_name))
368 goto err_drop_spawn;
369
370 if (ecb_name[len - 1] != ')')
371 goto err_drop_spawn;
372
373 ecb_name[len - 1] = 0;
374
375 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
376 "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
377 err = -ENAMETOOLONG;
378 goto err_drop_spawn;
379 }
380 } else
381 goto err_drop_spawn;
382
383 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
384 inst->alg.base.cra_priority = alg->base.cra_priority;
385 inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
386 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
387 (__alignof__(be128) - 1);
388
389 inst->alg.ivsize = LRW_BLOCK_SIZE;
390 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
391 LRW_BLOCK_SIZE;
392 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
393 LRW_BLOCK_SIZE;
394
395 inst->alg.base.cra_ctxsize = sizeof(struct priv);
396
397 inst->alg.init = init_tfm;
398 inst->alg.exit = exit_tfm;
399
400 inst->alg.setkey = setkey;
401 inst->alg.encrypt = encrypt;
402 inst->alg.decrypt = decrypt;
403
404 inst->free = free;
405
406 err = skcipher_register_instance(tmpl, inst);
407 if (err)
408 goto err_drop_spawn;
409
410out:
411 return err;
412
413err_drop_spawn:
414 crypto_drop_skcipher(spawn);
415err_free_inst:
416 kfree(inst);
417 goto out;
418}
419
420static struct crypto_template crypto_tmpl = {
421 .name = "lrw",
422 .create = create,
423 .module = THIS_MODULE,
424};
425
426static int __init crypto_module_init(void)
427{
428 return crypto_register_template(&crypto_tmpl);
429}
430
431static void __exit crypto_module_exit(void)
432{
433 crypto_unregister_template(&crypto_tmpl);
434}
435
436subsys_initcall(crypto_module_init);
437module_exit(crypto_module_exit);
438
439MODULE_LICENSE("GPL");
440MODULE_DESCRIPTION("LRW block cipher mode");
441MODULE_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/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 /* initialize multiplication table for Key2 */
77 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
78 if (!ctx->table)
79 return -ENOMEM;
80
81 /* initialize optimization table */
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/* this returns the number of consequative 1 bits starting
127 * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
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 /* T <- I*Key2, using the optimization
239 * discussed in the specification */
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 /* calculate first value of T */
301 memcpy(&rctx->t, req->iv, sizeof(rctx->t));
302
303 /* T <- I*Key2 */
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 subreq = &rctx->subreq;
349 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
350
351 err = do_encrypt(req, err ?: post_crypt(req));
352 if (rctx->left)
353 return;
354
355 skcipher_request_complete(req, err);
356}
357
358static int encrypt(struct skcipher_request *req)
359{
360 return do_encrypt(req, init_crypt(req, encrypt_done));
361}
362
363static int do_decrypt(struct skcipher_request *req, int err)
364{
365 struct rctx *rctx = skcipher_request_ctx(req);
366 struct skcipher_request *subreq;
367
368 subreq = &rctx->subreq;
369
370 while (!err && rctx->left) {
371 err = pre_crypt(req) ?:
372 crypto_skcipher_decrypt(subreq) ?:
373 post_crypt(req);
374
375 if (err == -EINPROGRESS ||
376 (err == -EBUSY &&
377 req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
378 return err;
379 }
380
381 exit_crypt(req);
382 return err;
383}
384
385static void decrypt_done(struct crypto_async_request *areq, int err)
386{
387 struct skcipher_request *req = areq->data;
388 struct skcipher_request *subreq;
389 struct rctx *rctx;
390
391 rctx = skcipher_request_ctx(req);
392 subreq = &rctx->subreq;
393 subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
394
395 err = do_decrypt(req, err ?: post_crypt(req));
396 if (rctx->left)
397 return;
398
399 skcipher_request_complete(req, err);
400}
401
402static int decrypt(struct skcipher_request *req)
403{
404 return do_decrypt(req, init_crypt(req, decrypt_done));
405}
406
407int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
408 struct scatterlist *ssrc, unsigned int nbytes,
409 struct lrw_crypt_req *req)
410{
411 const unsigned int bsize = LRW_BLOCK_SIZE;
412 const unsigned int max_blks = req->tbuflen / bsize;
413 struct lrw_table_ctx *ctx = req->table_ctx;
414 struct blkcipher_walk walk;
415 unsigned int nblocks;
416 be128 *iv, *src, *dst, *t;
417 be128 *t_buf = req->tbuf;
418 int err, i;
419
420 BUG_ON(max_blks < 1);
421
422 blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
423
424 err = blkcipher_walk_virt(desc, &walk);
425 nbytes = walk.nbytes;
426 if (!nbytes)
427 return err;
428
429 nblocks = min(walk.nbytes / bsize, max_blks);
430 src = (be128 *)walk.src.virt.addr;
431 dst = (be128 *)walk.dst.virt.addr;
432
433 /* calculate first value of T */
434 iv = (be128 *)walk.iv;
435 t_buf[0] = *iv;
436
437 /* T <- I*Key2 */
438 gf128mul_64k_bbe(&t_buf[0], ctx->table);
439
440 i = 0;
441 goto first;
442
443 for (;;) {
444 do {
445 for (i = 0; i < nblocks; i++) {
446 /* T <- I*Key2, using the optimization
447 * discussed in the specification */
448 be128_xor(&t_buf[i], t,
449 &ctx->mulinc[get_index128(iv)]);
450 inc(iv);
451first:
452 t = &t_buf[i];
453
454 /* PP <- T xor P */
455 be128_xor(dst + i, t, src + i);
456 }
457
458 /* CC <- E(Key2,PP) */
459 req->crypt_fn(req->crypt_ctx, (u8 *)dst,
460 nblocks * bsize);
461
462 /* C <- T xor CC */
463 for (i = 0; i < nblocks; i++)
464 be128_xor(dst + i, dst + i, &t_buf[i]);
465
466 src += nblocks;
467 dst += nblocks;
468 nbytes -= nblocks * bsize;
469 nblocks = min(nbytes / bsize, max_blks);
470 } while (nblocks > 0);
471
472 err = blkcipher_walk_done(desc, &walk, nbytes);
473 nbytes = walk.nbytes;
474 if (!nbytes)
475 break;
476
477 nblocks = min(nbytes / bsize, max_blks);
478 src = (be128 *)walk.src.virt.addr;
479 dst = (be128 *)walk.dst.virt.addr;
480 }
481
482 return err;
483}
484EXPORT_SYMBOL_GPL(lrw_crypt);
485
486static int init_tfm(struct crypto_skcipher *tfm)
487{
488 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
489 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
490 struct priv *ctx = crypto_skcipher_ctx(tfm);
491 struct crypto_skcipher *cipher;
492
493 cipher = crypto_spawn_skcipher(spawn);
494 if (IS_ERR(cipher))
495 return PTR_ERR(cipher);
496
497 ctx->child = cipher;
498
499 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
500 sizeof(struct rctx));
501
502 return 0;
503}
504
505static void exit_tfm(struct crypto_skcipher *tfm)
506{
507 struct priv *ctx = crypto_skcipher_ctx(tfm);
508
509 lrw_free_table(&ctx->table);
510 crypto_free_skcipher(ctx->child);
511}
512
513static void free(struct skcipher_instance *inst)
514{
515 crypto_drop_skcipher(skcipher_instance_ctx(inst));
516 kfree(inst);
517}
518
519static int create(struct crypto_template *tmpl, struct rtattr **tb)
520{
521 struct crypto_skcipher_spawn *spawn;
522 struct skcipher_instance *inst;
523 struct crypto_attr_type *algt;
524 struct skcipher_alg *alg;
525 const char *cipher_name;
526 char ecb_name[CRYPTO_MAX_ALG_NAME];
527 int err;
528
529 algt = crypto_get_attr_type(tb);
530 if (IS_ERR(algt))
531 return PTR_ERR(algt);
532
533 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
534 return -EINVAL;
535
536 cipher_name = crypto_attr_alg_name(tb[1]);
537 if (IS_ERR(cipher_name))
538 return PTR_ERR(cipher_name);
539
540 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
541 if (!inst)
542 return -ENOMEM;
543
544 spawn = skcipher_instance_ctx(inst);
545
546 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
547 err = crypto_grab_skcipher(spawn, cipher_name, 0,
548 crypto_requires_sync(algt->type,
549 algt->mask));
550 if (err == -ENOENT) {
551 err = -ENAMETOOLONG;
552 if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
553 cipher_name) >= CRYPTO_MAX_ALG_NAME)
554 goto err_free_inst;
555
556 err = crypto_grab_skcipher(spawn, ecb_name, 0,
557 crypto_requires_sync(algt->type,
558 algt->mask));
559 }
560
561 if (err)
562 goto err_free_inst;
563
564 alg = crypto_skcipher_spawn_alg(spawn);
565
566 err = -EINVAL;
567 if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
568 goto err_drop_spawn;
569
570 if (crypto_skcipher_alg_ivsize(alg))
571 goto err_drop_spawn;
572
573 err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
574 &alg->base);
575 if (err)
576 goto err_drop_spawn;
577
578 err = -EINVAL;
579 cipher_name = alg->base.cra_name;
580
581 /* Alas we screwed up the naming so we have to mangle the
582 * cipher name.
583 */
584 if (!strncmp(cipher_name, "ecb(", 4)) {
585 unsigned len;
586
587 len = strlcpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
588 if (len < 2 || len >= sizeof(ecb_name))
589 goto err_drop_spawn;
590
591 if (ecb_name[len - 1] != ')')
592 goto err_drop_spawn;
593
594 ecb_name[len - 1] = 0;
595
596 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
597 "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME)
598 return -ENAMETOOLONG;
599 }
600
601 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
602 inst->alg.base.cra_priority = alg->base.cra_priority;
603 inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
604 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
605 (__alignof__(u64) - 1);
606
607 inst->alg.ivsize = LRW_BLOCK_SIZE;
608 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
609 LRW_BLOCK_SIZE;
610 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
611 LRW_BLOCK_SIZE;
612
613 inst->alg.base.cra_ctxsize = sizeof(struct priv);
614
615 inst->alg.init = init_tfm;
616 inst->alg.exit = exit_tfm;
617
618 inst->alg.setkey = setkey;
619 inst->alg.encrypt = encrypt;
620 inst->alg.decrypt = decrypt;
621
622 inst->free = free;
623
624 err = skcipher_register_instance(tmpl, inst);
625 if (err)
626 goto err_drop_spawn;
627
628out:
629 return err;
630
631err_drop_spawn:
632 crypto_drop_skcipher(spawn);
633err_free_inst:
634 kfree(inst);
635 goto out;
636}
637
638static struct crypto_template crypto_tmpl = {
639 .name = "lrw",
640 .create = create,
641 .module = THIS_MODULE,
642};
643
644static int __init crypto_module_init(void)
645{
646 return crypto_register_template(&crypto_tmpl);
647}
648
649static void __exit crypto_module_exit(void)
650{
651 crypto_unregister_template(&crypto_tmpl);
652}
653
654module_init(crypto_module_init);
655module_exit(crypto_module_exit);
656
657MODULE_LICENSE("GPL");
658MODULE_DESCRIPTION("LRW block cipher mode");
659MODULE_ALIAS_CRYPTO("lrw");