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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 * https://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 lrw_tfm_ctx {
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 lrw_request_ctx {
53 be128 t;
54 struct skcipher_request subreq;
55};
56
57static inline void lrw_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 lrw_setkey(struct crypto_skcipher *parent, const u8 *key,
69 unsigned int keylen)
70{
71 struct lrw_tfm_ctx *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 if (err)
83 return err;
84
85 if (ctx->table)
86 gf128mul_free_64k(ctx->table);
87
88 /* initialize multiplication table for Key2 */
89 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
90 if (!ctx->table)
91 return -ENOMEM;
92
93 /* initialize optimization table */
94 for (i = 0; i < 128; i++) {
95 lrw_setbit128_bbe(&tmp, i);
96 ctx->mulinc[i] = tmp;
97 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
98 }
99
100 return 0;
101}
102
103/*
104 * Returns the number of trailing '1' bits in the words of the counter, which is
105 * represented by 4 32-bit words, arranged from least to most significant.
106 * At the same time, increments the counter by one.
107 *
108 * For example:
109 *
110 * u32 counter[4] = { 0xFFFFFFFF, 0x1, 0x0, 0x0 };
111 * int i = lrw_next_index(&counter);
112 * // i == 33, counter == { 0x0, 0x2, 0x0, 0x0 }
113 */
114static int lrw_next_index(u32 *counter)
115{
116 int i, res = 0;
117
118 for (i = 0; i < 4; i++) {
119 if (counter[i] + 1 != 0)
120 return res + ffz(counter[i]++);
121
122 counter[i] = 0;
123 res += 32;
124 }
125
126 /*
127 * If we get here, then x == 128 and we are incrementing the counter
128 * from all ones to all zeros. This means we must return index 127, i.e.
129 * the one corresponding to key2*{ 1,...,1 }.
130 */
131 return 127;
132}
133
134/*
135 * We compute the tweak masks twice (both before and after the ECB encryption or
136 * decryption) to avoid having to allocate a temporary buffer and/or make
137 * mutliple calls to the 'ecb(..)' instance, which usually would be slower than
138 * just doing the lrw_next_index() calls again.
139 */
140static int lrw_xor_tweak(struct skcipher_request *req, bool second_pass)
141{
142 const int bs = LRW_BLOCK_SIZE;
143 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
144 const struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
145 struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
146 be128 t = rctx->t;
147 struct skcipher_walk w;
148 __be32 *iv;
149 u32 counter[4];
150 int err;
151
152 if (second_pass) {
153 req = &rctx->subreq;
154 /* set to our TFM to enforce correct alignment: */
155 skcipher_request_set_tfm(req, tfm);
156 }
157
158 err = skcipher_walk_virt(&w, req, false);
159 if (err)
160 return err;
161
162 iv = (__be32 *)w.iv;
163 counter[0] = be32_to_cpu(iv[3]);
164 counter[1] = be32_to_cpu(iv[2]);
165 counter[2] = be32_to_cpu(iv[1]);
166 counter[3] = be32_to_cpu(iv[0]);
167
168 while (w.nbytes) {
169 unsigned int avail = w.nbytes;
170 be128 *wsrc;
171 be128 *wdst;
172
173 wsrc = w.src.virt.addr;
174 wdst = w.dst.virt.addr;
175
176 do {
177 be128_xor(wdst++, &t, wsrc++);
178
179 /* T <- I*Key2, using the optimization
180 * discussed in the specification */
181 be128_xor(&t, &t,
182 &ctx->mulinc[lrw_next_index(counter)]);
183 } while ((avail -= bs) >= bs);
184
185 if (second_pass && w.nbytes == w.total) {
186 iv[0] = cpu_to_be32(counter[3]);
187 iv[1] = cpu_to_be32(counter[2]);
188 iv[2] = cpu_to_be32(counter[1]);
189 iv[3] = cpu_to_be32(counter[0]);
190 }
191
192 err = skcipher_walk_done(&w, avail);
193 }
194
195 return err;
196}
197
198static int lrw_xor_tweak_pre(struct skcipher_request *req)
199{
200 return lrw_xor_tweak(req, false);
201}
202
203static int lrw_xor_tweak_post(struct skcipher_request *req)
204{
205 return lrw_xor_tweak(req, true);
206}
207
208static void lrw_crypt_done(void *data, int err)
209{
210 struct skcipher_request *req = data;
211
212 if (!err) {
213 struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
214
215 rctx->subreq.base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
216 err = lrw_xor_tweak_post(req);
217 }
218
219 skcipher_request_complete(req, err);
220}
221
222static void lrw_init_crypt(struct skcipher_request *req)
223{
224 const struct lrw_tfm_ctx *ctx =
225 crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
226 struct lrw_request_ctx *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, lrw_crypt_done,
231 req);
232 /* pass req->iv as IV (will be used by xor_tweak, ECB will ignore it) */
233 skcipher_request_set_crypt(subreq, req->dst, req->dst,
234 req->cryptlen, req->iv);
235
236 /* calculate first value of T */
237 memcpy(&rctx->t, req->iv, sizeof(rctx->t));
238
239 /* T <- I*Key2 */
240 gf128mul_64k_bbe(&rctx->t, ctx->table);
241}
242
243static int lrw_encrypt(struct skcipher_request *req)
244{
245 struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
246 struct skcipher_request *subreq = &rctx->subreq;
247
248 lrw_init_crypt(req);
249 return lrw_xor_tweak_pre(req) ?:
250 crypto_skcipher_encrypt(subreq) ?:
251 lrw_xor_tweak_post(req);
252}
253
254static int lrw_decrypt(struct skcipher_request *req)
255{
256 struct lrw_request_ctx *rctx = skcipher_request_ctx(req);
257 struct skcipher_request *subreq = &rctx->subreq;
258
259 lrw_init_crypt(req);
260 return lrw_xor_tweak_pre(req) ?:
261 crypto_skcipher_decrypt(subreq) ?:
262 lrw_xor_tweak_post(req);
263}
264
265static int lrw_init_tfm(struct crypto_skcipher *tfm)
266{
267 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
268 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
269 struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
270 struct crypto_skcipher *cipher;
271
272 cipher = crypto_spawn_skcipher(spawn);
273 if (IS_ERR(cipher))
274 return PTR_ERR(cipher);
275
276 ctx->child = cipher;
277
278 crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(cipher) +
279 sizeof(struct lrw_request_ctx));
280
281 return 0;
282}
283
284static void lrw_exit_tfm(struct crypto_skcipher *tfm)
285{
286 struct lrw_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
287
288 if (ctx->table)
289 gf128mul_free_64k(ctx->table);
290 crypto_free_skcipher(ctx->child);
291}
292
293static void lrw_free_instance(struct skcipher_instance *inst)
294{
295 crypto_drop_skcipher(skcipher_instance_ctx(inst));
296 kfree(inst);
297}
298
299static int lrw_create(struct crypto_template *tmpl, struct rtattr **tb)
300{
301 struct crypto_skcipher_spawn *spawn;
302 struct skcipher_alg_common *alg;
303 struct skcipher_instance *inst;
304 const char *cipher_name;
305 char ecb_name[CRYPTO_MAX_ALG_NAME];
306 u32 mask;
307 int err;
308
309 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
310 if (err)
311 return err;
312
313 cipher_name = crypto_attr_alg_name(tb[1]);
314 if (IS_ERR(cipher_name))
315 return PTR_ERR(cipher_name);
316
317 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
318 if (!inst)
319 return -ENOMEM;
320
321 spawn = skcipher_instance_ctx(inst);
322
323 err = crypto_grab_skcipher(spawn, skcipher_crypto_instance(inst),
324 cipher_name, 0, mask);
325 if (err == -ENOENT) {
326 err = -ENAMETOOLONG;
327 if (snprintf(ecb_name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
328 cipher_name) >= CRYPTO_MAX_ALG_NAME)
329 goto err_free_inst;
330
331 err = crypto_grab_skcipher(spawn,
332 skcipher_crypto_instance(inst),
333 ecb_name, 0, mask);
334 }
335
336 if (err)
337 goto err_free_inst;
338
339 alg = crypto_spawn_skcipher_alg_common(spawn);
340
341 err = -EINVAL;
342 if (alg->base.cra_blocksize != LRW_BLOCK_SIZE)
343 goto err_free_inst;
344
345 if (alg->ivsize)
346 goto err_free_inst;
347
348 err = crypto_inst_setname(skcipher_crypto_instance(inst), "lrw",
349 &alg->base);
350 if (err)
351 goto err_free_inst;
352
353 err = -EINVAL;
354 cipher_name = alg->base.cra_name;
355
356 /* Alas we screwed up the naming so we have to mangle the
357 * cipher name.
358 */
359 if (!strncmp(cipher_name, "ecb(", 4)) {
360 int len;
361
362 len = strscpy(ecb_name, cipher_name + 4, sizeof(ecb_name));
363 if (len < 2)
364 goto err_free_inst;
365
366 if (ecb_name[len - 1] != ')')
367 goto err_free_inst;
368
369 ecb_name[len - 1] = 0;
370
371 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
372 "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
373 err = -ENAMETOOLONG;
374 goto err_free_inst;
375 }
376 } else
377 goto err_free_inst;
378
379 inst->alg.base.cra_priority = alg->base.cra_priority;
380 inst->alg.base.cra_blocksize = LRW_BLOCK_SIZE;
381 inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
382 (__alignof__(be128) - 1);
383
384 inst->alg.ivsize = LRW_BLOCK_SIZE;
385 inst->alg.min_keysize = alg->min_keysize + LRW_BLOCK_SIZE;
386 inst->alg.max_keysize = alg->max_keysize + LRW_BLOCK_SIZE;
387
388 inst->alg.base.cra_ctxsize = sizeof(struct lrw_tfm_ctx);
389
390 inst->alg.init = lrw_init_tfm;
391 inst->alg.exit = lrw_exit_tfm;
392
393 inst->alg.setkey = lrw_setkey;
394 inst->alg.encrypt = lrw_encrypt;
395 inst->alg.decrypt = lrw_decrypt;
396
397 inst->free = lrw_free_instance;
398
399 err = skcipher_register_instance(tmpl, inst);
400 if (err) {
401err_free_inst:
402 lrw_free_instance(inst);
403 }
404 return err;
405}
406
407static struct crypto_template lrw_tmpl = {
408 .name = "lrw",
409 .create = lrw_create,
410 .module = THIS_MODULE,
411};
412
413static int __init lrw_module_init(void)
414{
415 return crypto_register_template(&lrw_tmpl);
416}
417
418static void __exit lrw_module_exit(void)
419{
420 crypto_unregister_template(&lrw_tmpl);
421}
422
423subsys_initcall(lrw_module_init);
424module_exit(lrw_module_exit);
425
426MODULE_LICENSE("GPL");
427MODULE_DESCRIPTION("LRW block cipher mode");
428MODULE_ALIAS_CRYPTO("lrw");
429MODULE_SOFTDEP("pre: ecb");
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");