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1/* LRW: as defined by Cyril Guyot in
2 * http://grouper.ieee.org/groups/1619/email/pdf00017.pdf
3 *
4 * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
5 *
6 * Based on ecb.c
7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 */
14/* This implementation is checked against the test vectors in the above
15 * document and by a test vector provided by Ken Buchanan at
16 * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
17 *
18 * The test vectors are included in the testing module tcrypt.[ch] */
19
20#include <crypto/algapi.h>
21#include <linux/err.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/scatterlist.h>
26#include <linux/slab.h>
27
28#include <crypto/b128ops.h>
29#include <crypto/gf128mul.h>
30#include <crypto/lrw.h>
31
32struct priv {
33 struct crypto_cipher *child;
34 struct lrw_table_ctx table;
35};
36
37static inline void setbit128_bbe(void *b, int bit)
38{
39 __set_bit(bit ^ (0x80 -
40#ifdef __BIG_ENDIAN
41 BITS_PER_LONG
42#else
43 BITS_PER_BYTE
44#endif
45 ), b);
46}
47
48int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
49{
50 be128 tmp = { 0 };
51 int i;
52
53 if (ctx->table)
54 gf128mul_free_64k(ctx->table);
55
56 /* initialize multiplication table for Key2 */
57 ctx->table = gf128mul_init_64k_bbe((be128 *)tweak);
58 if (!ctx->table)
59 return -ENOMEM;
60
61 /* initialize optimization table */
62 for (i = 0; i < 128; i++) {
63 setbit128_bbe(&tmp, i);
64 ctx->mulinc[i] = tmp;
65 gf128mul_64k_bbe(&ctx->mulinc[i], ctx->table);
66 }
67
68 return 0;
69}
70EXPORT_SYMBOL_GPL(lrw_init_table);
71
72void lrw_free_table(struct lrw_table_ctx *ctx)
73{
74 if (ctx->table)
75 gf128mul_free_64k(ctx->table);
76}
77EXPORT_SYMBOL_GPL(lrw_free_table);
78
79static int setkey(struct crypto_tfm *parent, const u8 *key,
80 unsigned int keylen)
81{
82 struct priv *ctx = crypto_tfm_ctx(parent);
83 struct crypto_cipher *child = ctx->child;
84 int err, bsize = LRW_BLOCK_SIZE;
85 const u8 *tweak = key + keylen - bsize;
86
87 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
88 crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
89 CRYPTO_TFM_REQ_MASK);
90 err = crypto_cipher_setkey(child, key, keylen - bsize);
91 if (err)
92 return err;
93 crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
94 CRYPTO_TFM_RES_MASK);
95
96 return lrw_init_table(&ctx->table, tweak);
97}
98
99struct sinfo {
100 be128 t;
101 struct crypto_tfm *tfm;
102 void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
103};
104
105static inline void inc(be128 *iv)
106{
107 be64_add_cpu(&iv->b, 1);
108 if (!iv->b)
109 be64_add_cpu(&iv->a, 1);
110}
111
112static inline void lrw_round(struct sinfo *s, void *dst, const void *src)
113{
114 be128_xor(dst, &s->t, src); /* PP <- T xor P */
115 s->fn(s->tfm, dst, dst); /* CC <- E(Key2,PP) */
116 be128_xor(dst, dst, &s->t); /* C <- T xor CC */
117}
118
119/* this returns the number of consequative 1 bits starting
120 * from the right, get_index128(00 00 00 00 00 00 ... 00 00 10 FB) = 2 */
121static inline int get_index128(be128 *block)
122{
123 int x;
124 __be32 *p = (__be32 *) block;
125
126 for (p += 3, x = 0; x < 128; p--, x += 32) {
127 u32 val = be32_to_cpup(p);
128
129 if (!~val)
130 continue;
131
132 return x + ffz(val);
133 }
134
135 return x;
136}
137
138static int crypt(struct blkcipher_desc *d,
139 struct blkcipher_walk *w, struct priv *ctx,
140 void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
141{
142 int err;
143 unsigned int avail;
144 const int bs = LRW_BLOCK_SIZE;
145 struct sinfo s = {
146 .tfm = crypto_cipher_tfm(ctx->child),
147 .fn = fn
148 };
149 be128 *iv;
150 u8 *wsrc;
151 u8 *wdst;
152
153 err = blkcipher_walk_virt(d, w);
154 if (!(avail = w->nbytes))
155 return err;
156
157 wsrc = w->src.virt.addr;
158 wdst = w->dst.virt.addr;
159
160 /* calculate first value of T */
161 iv = (be128 *)w->iv;
162 s.t = *iv;
163
164 /* T <- I*Key2 */
165 gf128mul_64k_bbe(&s.t, ctx->table.table);
166
167 goto first;
168
169 for (;;) {
170 do {
171 /* T <- I*Key2, using the optimization
172 * discussed in the specification */
173 be128_xor(&s.t, &s.t,
174 &ctx->table.mulinc[get_index128(iv)]);
175 inc(iv);
176
177first:
178 lrw_round(&s, wdst, wsrc);
179
180 wsrc += bs;
181 wdst += bs;
182 } while ((avail -= bs) >= bs);
183
184 err = blkcipher_walk_done(d, w, avail);
185 if (!(avail = w->nbytes))
186 break;
187
188 wsrc = w->src.virt.addr;
189 wdst = w->dst.virt.addr;
190 }
191
192 return err;
193}
194
195static int encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
196 struct scatterlist *src, unsigned int nbytes)
197{
198 struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
199 struct blkcipher_walk w;
200
201 blkcipher_walk_init(&w, dst, src, nbytes);
202 return crypt(desc, &w, ctx,
203 crypto_cipher_alg(ctx->child)->cia_encrypt);
204}
205
206static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
207 struct scatterlist *src, unsigned int nbytes)
208{
209 struct priv *ctx = crypto_blkcipher_ctx(desc->tfm);
210 struct blkcipher_walk w;
211
212 blkcipher_walk_init(&w, dst, src, nbytes);
213 return crypt(desc, &w, ctx,
214 crypto_cipher_alg(ctx->child)->cia_decrypt);
215}
216
217int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
218 struct scatterlist *ssrc, unsigned int nbytes,
219 struct lrw_crypt_req *req)
220{
221 const unsigned int bsize = LRW_BLOCK_SIZE;
222 const unsigned int max_blks = req->tbuflen / bsize;
223 struct lrw_table_ctx *ctx = req->table_ctx;
224 struct blkcipher_walk walk;
225 unsigned int nblocks;
226 be128 *iv, *src, *dst, *t;
227 be128 *t_buf = req->tbuf;
228 int err, i;
229
230 BUG_ON(max_blks < 1);
231
232 blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
233
234 err = blkcipher_walk_virt(desc, &walk);
235 nbytes = walk.nbytes;
236 if (!nbytes)
237 return err;
238
239 nblocks = min(walk.nbytes / bsize, max_blks);
240 src = (be128 *)walk.src.virt.addr;
241 dst = (be128 *)walk.dst.virt.addr;
242
243 /* calculate first value of T */
244 iv = (be128 *)walk.iv;
245 t_buf[0] = *iv;
246
247 /* T <- I*Key2 */
248 gf128mul_64k_bbe(&t_buf[0], ctx->table);
249
250 i = 0;
251 goto first;
252
253 for (;;) {
254 do {
255 for (i = 0; i < nblocks; i++) {
256 /* T <- I*Key2, using the optimization
257 * discussed in the specification */
258 be128_xor(&t_buf[i], t,
259 &ctx->mulinc[get_index128(iv)]);
260 inc(iv);
261first:
262 t = &t_buf[i];
263
264 /* PP <- T xor P */
265 be128_xor(dst + i, t, src + i);
266 }
267
268 /* CC <- E(Key2,PP) */
269 req->crypt_fn(req->crypt_ctx, (u8 *)dst,
270 nblocks * bsize);
271
272 /* C <- T xor CC */
273 for (i = 0; i < nblocks; i++)
274 be128_xor(dst + i, dst + i, &t_buf[i]);
275
276 src += nblocks;
277 dst += nblocks;
278 nbytes -= nblocks * bsize;
279 nblocks = min(nbytes / bsize, max_blks);
280 } while (nblocks > 0);
281
282 err = blkcipher_walk_done(desc, &walk, nbytes);
283 nbytes = walk.nbytes;
284 if (!nbytes)
285 break;
286
287 nblocks = min(nbytes / bsize, max_blks);
288 src = (be128 *)walk.src.virt.addr;
289 dst = (be128 *)walk.dst.virt.addr;
290 }
291
292 return err;
293}
294EXPORT_SYMBOL_GPL(lrw_crypt);
295
296static int init_tfm(struct crypto_tfm *tfm)
297{
298 struct crypto_cipher *cipher;
299 struct crypto_instance *inst = (void *)tfm->__crt_alg;
300 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
301 struct priv *ctx = crypto_tfm_ctx(tfm);
302 u32 *flags = &tfm->crt_flags;
303
304 cipher = crypto_spawn_cipher(spawn);
305 if (IS_ERR(cipher))
306 return PTR_ERR(cipher);
307
308 if (crypto_cipher_blocksize(cipher) != LRW_BLOCK_SIZE) {
309 *flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
310 crypto_free_cipher(cipher);
311 return -EINVAL;
312 }
313
314 ctx->child = cipher;
315 return 0;
316}
317
318static void exit_tfm(struct crypto_tfm *tfm)
319{
320 struct priv *ctx = crypto_tfm_ctx(tfm);
321
322 lrw_free_table(&ctx->table);
323 crypto_free_cipher(ctx->child);
324}
325
326static struct crypto_instance *alloc(struct rtattr **tb)
327{
328 struct crypto_instance *inst;
329 struct crypto_alg *alg;
330 int err;
331
332 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
333 if (err)
334 return ERR_PTR(err);
335
336 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
337 CRYPTO_ALG_TYPE_MASK);
338 if (IS_ERR(alg))
339 return ERR_CAST(alg);
340
341 inst = crypto_alloc_instance("lrw", alg);
342 if (IS_ERR(inst))
343 goto out_put_alg;
344
345 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
346 inst->alg.cra_priority = alg->cra_priority;
347 inst->alg.cra_blocksize = alg->cra_blocksize;
348
349 if (alg->cra_alignmask < 7) inst->alg.cra_alignmask = 7;
350 else inst->alg.cra_alignmask = alg->cra_alignmask;
351 inst->alg.cra_type = &crypto_blkcipher_type;
352
353 if (!(alg->cra_blocksize % 4))
354 inst->alg.cra_alignmask |= 3;
355 inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
356 inst->alg.cra_blkcipher.min_keysize =
357 alg->cra_cipher.cia_min_keysize + alg->cra_blocksize;
358 inst->alg.cra_blkcipher.max_keysize =
359 alg->cra_cipher.cia_max_keysize + alg->cra_blocksize;
360
361 inst->alg.cra_ctxsize = sizeof(struct priv);
362
363 inst->alg.cra_init = init_tfm;
364 inst->alg.cra_exit = exit_tfm;
365
366 inst->alg.cra_blkcipher.setkey = setkey;
367 inst->alg.cra_blkcipher.encrypt = encrypt;
368 inst->alg.cra_blkcipher.decrypt = decrypt;
369
370out_put_alg:
371 crypto_mod_put(alg);
372 return inst;
373}
374
375static void free(struct crypto_instance *inst)
376{
377 crypto_drop_spawn(crypto_instance_ctx(inst));
378 kfree(inst);
379}
380
381static struct crypto_template crypto_tmpl = {
382 .name = "lrw",
383 .alloc = alloc,
384 .free = free,
385 .module = THIS_MODULE,
386};
387
388static int __init crypto_module_init(void)
389{
390 return crypto_register_template(&crypto_tmpl);
391}
392
393static void __exit crypto_module_exit(void)
394{
395 crypto_unregister_template(&crypto_tmpl);
396}
397
398module_init(crypto_module_init);
399module_exit(crypto_module_exit);
400
401MODULE_LICENSE("GPL");
402MODULE_DESCRIPTION("LRW block cipher mode");
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");