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CommitLineData
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1/*
2 * CTR: Counter mode
3 *
4 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <crypto/algapi.h>
5311f248 14#include <crypto/ctr.h>
69d3150c 15#include <crypto/internal/skcipher.h>
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16#include <linux/err.h>
17#include <linux/init.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/random.h>
21#include <linux/scatterlist.h>
22#include <linux/slab.h>
23
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24struct crypto_ctr_ctx {
25 struct crypto_cipher *child;
5311f248
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26};
27
28struct crypto_rfc3686_ctx {
b2b39c2f 29 struct crypto_skcipher *child;
5311f248 30 u8 nonce[CTR_RFC3686_NONCE_SIZE];
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31};
32
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33struct crypto_rfc3686_req_ctx {
34 u8 iv[CTR_RFC3686_BLOCK_SIZE];
b2b39c2f 35 struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
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36};
37
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38static int crypto_ctr_setkey(struct crypto_tfm *parent, const u8 *key,
39 unsigned int keylen)
40{
41 struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(parent);
42 struct crypto_cipher *child = ctx->child;
5311f248 43 int err;
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44
45 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
46 crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
47 CRYPTO_TFM_REQ_MASK);
48 err = crypto_cipher_setkey(child, key, keylen);
49 crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
50 CRYPTO_TFM_RES_MASK);
51
52 return err;
53}
54
0971eb0d 55static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
5311f248 56 struct crypto_cipher *tfm)
0971eb0d
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57{
58 unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248
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59 unsigned long alignmask = crypto_cipher_alignmask(tfm);
60 u8 *ctrblk = walk->iv;
61 u8 tmp[bsize + alignmask];
62 u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
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63 u8 *src = walk->src.virt.addr;
64 u8 *dst = walk->dst.virt.addr;
65 unsigned int nbytes = walk->nbytes;
66
67 crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
68 crypto_xor(keystream, src, nbytes);
69 memcpy(dst, keystream, nbytes);
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70
71 crypto_inc(ctrblk, bsize);
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72}
73
23e353c8 74static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
5311f248 75 struct crypto_cipher *tfm)
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76{
77 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
78 crypto_cipher_alg(tfm)->cia_encrypt;
79 unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248 80 u8 *ctrblk = walk->iv;
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81 u8 *src = walk->src.virt.addr;
82 u8 *dst = walk->dst.virt.addr;
83 unsigned int nbytes = walk->nbytes;
84
85 do {
86 /* create keystream */
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87 fn(crypto_cipher_tfm(tfm), dst, ctrblk);
88 crypto_xor(dst, src, bsize);
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89
90 /* increment counter in counterblock */
5311f248 91 crypto_inc(ctrblk, bsize);
23e353c8 92
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93 src += bsize;
94 dst += bsize;
0971eb0d 95 } while ((nbytes -= bsize) >= bsize);
23e353c8 96
0971eb0d 97 return nbytes;
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98}
99
100static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
5311f248 101 struct crypto_cipher *tfm)
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102{
103 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
104 crypto_cipher_alg(tfm)->cia_encrypt;
105 unsigned int bsize = crypto_cipher_blocksize(tfm);
5311f248 106 unsigned long alignmask = crypto_cipher_alignmask(tfm);
23e353c8 107 unsigned int nbytes = walk->nbytes;
5311f248 108 u8 *ctrblk = walk->iv;
23e353c8 109 u8 *src = walk->src.virt.addr;
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110 u8 tmp[bsize + alignmask];
111 u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
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112
113 do {
114 /* create keystream */
115 fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
0971eb0d 116 crypto_xor(src, keystream, bsize);
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117
118 /* increment counter in counterblock */
5311f248 119 crypto_inc(ctrblk, bsize);
23e353c8 120
23e353c8 121 src += bsize;
0971eb0d 122 } while ((nbytes -= bsize) >= bsize);
23e353c8 123
0971eb0d 124 return nbytes;
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125}
126
127static int crypto_ctr_crypt(struct blkcipher_desc *desc,
128 struct scatterlist *dst, struct scatterlist *src,
129 unsigned int nbytes)
130{
131 struct blkcipher_walk walk;
132 struct crypto_blkcipher *tfm = desc->tfm;
133 struct crypto_ctr_ctx *ctx = crypto_blkcipher_ctx(tfm);
134 struct crypto_cipher *child = ctx->child;
135 unsigned int bsize = crypto_cipher_blocksize(child);
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136 int err;
137
138 blkcipher_walk_init(&walk, dst, src, nbytes);
139 err = blkcipher_walk_virt_block(desc, &walk, bsize);
140
0971eb0d 141 while (walk.nbytes >= bsize) {
23e353c8 142 if (walk.src.virt.addr == walk.dst.virt.addr)
5311f248 143 nbytes = crypto_ctr_crypt_inplace(&walk, child);
23e353c8 144 else
5311f248 145 nbytes = crypto_ctr_crypt_segment(&walk, child);
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146
147 err = blkcipher_walk_done(desc, &walk, nbytes);
148 }
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149
150 if (walk.nbytes) {
5311f248 151 crypto_ctr_crypt_final(&walk, child);
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152 err = blkcipher_walk_done(desc, &walk, 0);
153 }
154
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155 return err;
156}
157
158static int crypto_ctr_init_tfm(struct crypto_tfm *tfm)
159{
160 struct crypto_instance *inst = (void *)tfm->__crt_alg;
5311f248 161 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
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162 struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
163 struct crypto_cipher *cipher;
164
5311f248 165 cipher = crypto_spawn_cipher(spawn);
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166 if (IS_ERR(cipher))
167 return PTR_ERR(cipher);
168
169 ctx->child = cipher;
170
171 return 0;
172}
173
174static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
175{
176 struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
177
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178 crypto_free_cipher(ctx->child);
179}
180
181static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
182{
183 struct crypto_instance *inst;
184 struct crypto_alg *alg;
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185 int err;
186
187 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
188 if (err)
189 return ERR_PTR(err);
190
191 alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
192 CRYPTO_ALG_TYPE_MASK);
193 if (IS_ERR(alg))
8db05078 194 return ERR_CAST(alg);
23e353c8 195
5311f248 196 /* Block size must be >= 4 bytes. */
23e353c8 197 err = -EINVAL;
5311f248 198 if (alg->cra_blocksize < 4)
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199 goto out_put_alg;
200
3f8214ea 201 /* If this is false we'd fail the alignment of crypto_inc. */
5311f248 202 if (alg->cra_blocksize % 4)
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203 goto out_put_alg;
204
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205 inst = crypto_alloc_instance("ctr", alg);
206 if (IS_ERR(inst))
207 goto out;
23e353c8 208
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209 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
210 inst->alg.cra_priority = alg->cra_priority;
211 inst->alg.cra_blocksize = 1;
0971eb0d 212 inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
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213 inst->alg.cra_type = &crypto_blkcipher_type;
214
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215 inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;
216 inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
217 inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
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218
219 inst->alg.cra_ctxsize = sizeof(struct crypto_ctr_ctx);
220
221 inst->alg.cra_init = crypto_ctr_init_tfm;
222 inst->alg.cra_exit = crypto_ctr_exit_tfm;
223
224 inst->alg.cra_blkcipher.setkey = crypto_ctr_setkey;
225 inst->alg.cra_blkcipher.encrypt = crypto_ctr_crypt;
226 inst->alg.cra_blkcipher.decrypt = crypto_ctr_crypt;
227
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228 inst->alg.cra_blkcipher.geniv = "chainiv";
229
5311f248 230out:
23e353c8 231 crypto_mod_put(alg);
23e353c8 232 return inst;
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233
234out_put_alg:
235 inst = ERR_PTR(err);
236 goto out;
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237}
238
239static void crypto_ctr_free(struct crypto_instance *inst)
240{
5311f248 241 crypto_drop_spawn(crypto_instance_ctx(inst));
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242 kfree(inst);
243}
244
245static struct crypto_template crypto_ctr_tmpl = {
246 .name = "ctr",
247 .alloc = crypto_ctr_alloc,
248 .free = crypto_ctr_free,
249 .module = THIS_MODULE,
250};
251
b2b39c2f 252static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
69d3150c 253 const u8 *key, unsigned int keylen)
5311f248 254{
b2b39c2f
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255 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
256 struct crypto_skcipher *child = ctx->child;
5311f248
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257 int err;
258
259 /* the nonce is stored in bytes at end of key */
260 if (keylen < CTR_RFC3686_NONCE_SIZE)
261 return -EINVAL;
262
263 memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
264 CTR_RFC3686_NONCE_SIZE);
265
266 keylen -= CTR_RFC3686_NONCE_SIZE;
267
b2b39c2f
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268 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
269 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
270 CRYPTO_TFM_REQ_MASK);
271 err = crypto_skcipher_setkey(child, key, keylen);
272 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
273 CRYPTO_TFM_RES_MASK);
5311f248
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274
275 return err;
276}
277
b2b39c2f 278static int crypto_rfc3686_crypt(struct skcipher_request *req)
5311f248 279{
b2b39c2f
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280 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
281 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
282 struct crypto_skcipher *child = ctx->child;
283 unsigned long align = crypto_skcipher_alignmask(tfm);
69d3150c 284 struct crypto_rfc3686_req_ctx *rctx =
b2b39c2f
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285 (void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
286 struct skcipher_request *subreq = &rctx->subreq;
69d3150c 287 u8 *iv = rctx->iv;
5311f248
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288
289 /* set up counter block */
290 memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
b2b39c2f 291 memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
5311f248
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292
293 /* initialize counter portion of counter block */
294 *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
295 cpu_to_be32(1);
296
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297 skcipher_request_set_tfm(subreq, child);
298 skcipher_request_set_callback(subreq, req->base.flags,
299 req->base.complete, req->base.data);
300 skcipher_request_set_crypt(subreq, req->src, req->dst,
301 req->cryptlen, iv);
5311f248 302
b2b39c2f 303 return crypto_skcipher_encrypt(subreq);
5311f248
HX
304}
305
b2b39c2f 306static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
5311f248 307{
b2b39c2f
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308 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
309 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
310 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
311 struct crypto_skcipher *cipher;
69d3150c 312 unsigned long align;
b2b39c2f 313 unsigned int reqsize;
5311f248 314
60425a8b 315 cipher = crypto_spawn_skcipher(spawn);
5311f248
HX
316 if (IS_ERR(cipher))
317 return PTR_ERR(cipher);
318
319 ctx->child = cipher;
320
b2b39c2f 321 align = crypto_skcipher_alignmask(tfm);
69d3150c 322 align &= ~(crypto_tfm_ctx_alignment() - 1);
b2b39c2f
HX
323 reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
324 crypto_skcipher_reqsize(cipher);
325 crypto_skcipher_set_reqsize(tfm, reqsize);
69d3150c 326
5311f248
HX
327 return 0;
328}
329
b2b39c2f 330static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
5311f248 331{
b2b39c2f
HX
332 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
333
334 crypto_free_skcipher(ctx->child);
335}
5311f248 336
b2b39c2f
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337static void crypto_rfc3686_free(struct skcipher_instance *inst)
338{
339 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
340
341 crypto_drop_skcipher(spawn);
342 kfree(inst);
5311f248
HX
343}
344
b2b39c2f
HX
345static int crypto_rfc3686_create(struct crypto_template *tmpl,
346 struct rtattr **tb)
5311f248 347{
69d3150c 348 struct crypto_attr_type *algt;
b2b39c2f
HX
349 struct skcipher_instance *inst;
350 struct skcipher_alg *alg;
69d3150c
JK
351 struct crypto_skcipher_spawn *spawn;
352 const char *cipher_name;
5311f248
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353 int err;
354
69d3150c 355 algt = crypto_get_attr_type(tb);
69d3150c 356 if (IS_ERR(algt))
b2b39c2f 357 return PTR_ERR(algt);
5311f248 358
b2b39c2f
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359 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
360 return -EINVAL;
69d3150c
JK
361
362 cipher_name = crypto_attr_alg_name(tb[1]);
69d3150c 363 if (IS_ERR(cipher_name))
b2b39c2f 364 return PTR_ERR(cipher_name);
5311f248 365
69d3150c
JK
366 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
367 if (!inst)
b2b39c2f 368 return -ENOMEM;
69d3150c 369
b2b39c2f 370 spawn = skcipher_instance_ctx(inst);
69d3150c 371
b2b39c2f 372 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
a35528ec
EB
373 err = crypto_grab_skcipher(spawn, cipher_name, 0,
374 crypto_requires_sync(algt->type,
375 algt->mask));
69d3150c
JK
376 if (err)
377 goto err_free_inst;
378
b2b39c2f 379 alg = crypto_spawn_skcipher_alg(spawn);
69d3150c 380
5311f248
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381 /* We only support 16-byte blocks. */
382 err = -EINVAL;
b2b39c2f 383 if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
69d3150c 384 goto err_drop_spawn;
5311f248
HX
385
386 /* Not a stream cipher? */
b2b39c2f 387 if (alg->base.cra_blocksize != 1)
69d3150c 388 goto err_drop_spawn;
5311f248 389
69d3150c 390 err = -ENAMETOOLONG;
b2b39c2f
HX
391 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
392 "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
69d3150c 393 goto err_drop_spawn;
b2b39c2f
HX
394 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
395 "rfc3686(%s)", alg->base.cra_driver_name) >=
396 CRYPTO_MAX_ALG_NAME)
69d3150c 397 goto err_drop_spawn;
5311f248 398
b2b39c2f
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399 inst->alg.base.cra_priority = alg->base.cra_priority;
400 inst->alg.base.cra_blocksize = 1;
401 inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
5311f248 402
b2b39c2f 403 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
69d3150c 404
b2b39c2f
HX
405 inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
406 inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
407 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
408 CTR_RFC3686_NONCE_SIZE;
409 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
410 CTR_RFC3686_NONCE_SIZE;
5311f248 411
b2b39c2f
HX
412 inst->alg.setkey = crypto_rfc3686_setkey;
413 inst->alg.encrypt = crypto_rfc3686_crypt;
414 inst->alg.decrypt = crypto_rfc3686_crypt;
69d3150c 415
b2b39c2f 416 inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
0a270321 417
b2b39c2f
HX
418 inst->alg.init = crypto_rfc3686_init_tfm;
419 inst->alg.exit = crypto_rfc3686_exit_tfm;
5311f248 420
b2b39c2f 421 inst->free = crypto_rfc3686_free;
5311f248 422
b2b39c2f
HX
423 err = skcipher_register_instance(tmpl, inst);
424 if (err)
425 goto err_drop_spawn;
426
427out:
428 return err;
5311f248 429
69d3150c
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430err_drop_spawn:
431 crypto_drop_skcipher(spawn);
432err_free_inst:
433 kfree(inst);
b2b39c2f 434 goto out;
5311f248
HX
435}
436
437static struct crypto_template crypto_rfc3686_tmpl = {
438 .name = "rfc3686",
b2b39c2f 439 .create = crypto_rfc3686_create,
5311f248
HX
440 .module = THIS_MODULE,
441};
442
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443static int __init crypto_ctr_module_init(void)
444{
5311f248
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445 int err;
446
447 err = crypto_register_template(&crypto_ctr_tmpl);
448 if (err)
449 goto out;
450
451 err = crypto_register_template(&crypto_rfc3686_tmpl);
452 if (err)
453 goto out_drop_ctr;
454
455out:
456 return err;
457
458out_drop_ctr:
459 crypto_unregister_template(&crypto_ctr_tmpl);
460 goto out;
23e353c8
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461}
462
463static void __exit crypto_ctr_module_exit(void)
464{
5311f248 465 crypto_unregister_template(&crypto_rfc3686_tmpl);
23e353c8
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466 crypto_unregister_template(&crypto_ctr_tmpl);
467}
468
469module_init(crypto_ctr_module_init);
470module_exit(crypto_ctr_module_exit);
471
472MODULE_LICENSE("GPL");
473MODULE_DESCRIPTION("CTR Counter block mode");
5d26a105 474MODULE_ALIAS_CRYPTO("rfc3686");
4943ba16 475MODULE_ALIAS_CRYPTO("ctr");