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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>
14#include <crypto/ctr.h>
15#include <crypto/internal/skcipher.h>
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
24struct crypto_ctr_ctx {
25 struct crypto_cipher *child;
26};
27
28struct crypto_rfc3686_ctx {
29 struct crypto_ablkcipher *child;
30 u8 nonce[CTR_RFC3686_NONCE_SIZE];
31};
32
33struct crypto_rfc3686_req_ctx {
34 u8 iv[CTR_RFC3686_BLOCK_SIZE];
35 struct ablkcipher_request subreq CRYPTO_MINALIGN_ATTR;
36};
37
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;
43 int err;
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
55static void crypto_ctr_crypt_final(struct blkcipher_walk *walk,
56 struct crypto_cipher *tfm)
57{
58 unsigned int bsize = crypto_cipher_blocksize(tfm);
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);
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);
70
71 crypto_inc(ctrblk, bsize);
72}
73
74static int crypto_ctr_crypt_segment(struct blkcipher_walk *walk,
75 struct crypto_cipher *tfm)
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);
80 u8 *ctrblk = walk->iv;
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 */
87 fn(crypto_cipher_tfm(tfm), dst, ctrblk);
88 crypto_xor(dst, src, bsize);
89
90 /* increment counter in counterblock */
91 crypto_inc(ctrblk, bsize);
92
93 src += bsize;
94 dst += bsize;
95 } while ((nbytes -= bsize) >= bsize);
96
97 return nbytes;
98}
99
100static int crypto_ctr_crypt_inplace(struct blkcipher_walk *walk,
101 struct crypto_cipher *tfm)
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);
106 unsigned long alignmask = crypto_cipher_alignmask(tfm);
107 unsigned int nbytes = walk->nbytes;
108 u8 *ctrblk = walk->iv;
109 u8 *src = walk->src.virt.addr;
110 u8 tmp[bsize + alignmask];
111 u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
112
113 do {
114 /* create keystream */
115 fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
116 crypto_xor(src, keystream, bsize);
117
118 /* increment counter in counterblock */
119 crypto_inc(ctrblk, bsize);
120
121 src += bsize;
122 } while ((nbytes -= bsize) >= bsize);
123
124 return nbytes;
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);
136 int err;
137
138 blkcipher_walk_init(&walk, dst, src, nbytes);
139 err = blkcipher_walk_virt_block(desc, &walk, bsize);
140
141 while (walk.nbytes >= bsize) {
142 if (walk.src.virt.addr == walk.dst.virt.addr)
143 nbytes = crypto_ctr_crypt_inplace(&walk, child);
144 else
145 nbytes = crypto_ctr_crypt_segment(&walk, child);
146
147 err = blkcipher_walk_done(desc, &walk, nbytes);
148 }
149
150 if (walk.nbytes) {
151 crypto_ctr_crypt_final(&walk, child);
152 err = blkcipher_walk_done(desc, &walk, 0);
153 }
154
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;
161 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
162 struct crypto_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
163 struct crypto_cipher *cipher;
164
165 cipher = crypto_spawn_cipher(spawn);
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
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;
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))
194 return ERR_CAST(alg);
195
196 /* Block size must be >= 4 bytes. */
197 err = -EINVAL;
198 if (alg->cra_blocksize < 4)
199 goto out_put_alg;
200
201 /* If this is false we'd fail the alignment of crypto_inc. */
202 if (alg->cra_blocksize % 4)
203 goto out_put_alg;
204
205 inst = crypto_alloc_instance("ctr", alg);
206 if (IS_ERR(inst))
207 goto out;
208
209 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
210 inst->alg.cra_priority = alg->cra_priority;
211 inst->alg.cra_blocksize = 1;
212 inst->alg.cra_alignmask = alg->cra_alignmask | (__alignof__(u32) - 1);
213 inst->alg.cra_type = &crypto_blkcipher_type;
214
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;
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
228 inst->alg.cra_blkcipher.geniv = "chainiv";
229
230out:
231 crypto_mod_put(alg);
232 return inst;
233
234out_put_alg:
235 inst = ERR_PTR(err);
236 goto out;
237}
238
239static void crypto_ctr_free(struct crypto_instance *inst)
240{
241 crypto_drop_spawn(crypto_instance_ctx(inst));
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
252static int crypto_rfc3686_setkey(struct crypto_ablkcipher *parent,
253 const u8 *key, unsigned int keylen)
254{
255 struct crypto_rfc3686_ctx *ctx = crypto_ablkcipher_ctx(parent);
256 struct crypto_ablkcipher *child = ctx->child;
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
268 crypto_ablkcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
269 crypto_ablkcipher_set_flags(child, crypto_ablkcipher_get_flags(parent) &
270 CRYPTO_TFM_REQ_MASK);
271 err = crypto_ablkcipher_setkey(child, key, keylen);
272 crypto_ablkcipher_set_flags(parent, crypto_ablkcipher_get_flags(child) &
273 CRYPTO_TFM_RES_MASK);
274
275 return err;
276}
277
278static int crypto_rfc3686_crypt(struct ablkcipher_request *req)
279{
280 struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
281 struct crypto_rfc3686_ctx *ctx = crypto_ablkcipher_ctx(tfm);
282 struct crypto_ablkcipher *child = ctx->child;
283 unsigned long align = crypto_ablkcipher_alignmask(tfm);
284 struct crypto_rfc3686_req_ctx *rctx =
285 (void *)PTR_ALIGN((u8 *)ablkcipher_request_ctx(req), align + 1);
286 struct ablkcipher_request *subreq = &rctx->subreq;
287 u8 *iv = rctx->iv;
288
289 /* set up counter block */
290 memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
291 memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->info, CTR_RFC3686_IV_SIZE);
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
297 ablkcipher_request_set_tfm(subreq, child);
298 ablkcipher_request_set_callback(subreq, req->base.flags,
299 req->base.complete, req->base.data);
300 ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->nbytes,
301 iv);
302
303 return crypto_ablkcipher_encrypt(subreq);
304}
305
306static int crypto_rfc3686_init_tfm(struct crypto_tfm *tfm)
307{
308 struct crypto_instance *inst = (void *)tfm->__crt_alg;
309 struct crypto_skcipher_spawn *spawn = crypto_instance_ctx(inst);
310 struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
311 struct crypto_ablkcipher *cipher;
312 unsigned long align;
313
314 cipher = crypto_spawn_skcipher(spawn);
315 if (IS_ERR(cipher))
316 return PTR_ERR(cipher);
317
318 ctx->child = cipher;
319
320 align = crypto_tfm_alg_alignmask(tfm);
321 align &= ~(crypto_tfm_ctx_alignment() - 1);
322 tfm->crt_ablkcipher.reqsize = align +
323 sizeof(struct crypto_rfc3686_req_ctx) +
324 crypto_ablkcipher_reqsize(cipher);
325
326 return 0;
327}
328
329static void crypto_rfc3686_exit_tfm(struct crypto_tfm *tfm)
330{
331 struct crypto_rfc3686_ctx *ctx = crypto_tfm_ctx(tfm);
332
333 crypto_free_ablkcipher(ctx->child);
334}
335
336static struct crypto_instance *crypto_rfc3686_alloc(struct rtattr **tb)
337{
338 struct crypto_attr_type *algt;
339 struct crypto_instance *inst;
340 struct crypto_alg *alg;
341 struct crypto_skcipher_spawn *spawn;
342 const char *cipher_name;
343 int err;
344
345 algt = crypto_get_attr_type(tb);
346 if (IS_ERR(algt))
347 return ERR_CAST(algt);
348
349 if ((algt->type ^ CRYPTO_ALG_TYPE_BLKCIPHER) & algt->mask)
350 return ERR_PTR(-EINVAL);
351
352 cipher_name = crypto_attr_alg_name(tb[1]);
353 if (IS_ERR(cipher_name))
354 return ERR_CAST(cipher_name);
355
356 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
357 if (!inst)
358 return ERR_PTR(-ENOMEM);
359
360 spawn = crypto_instance_ctx(inst);
361
362 crypto_set_skcipher_spawn(spawn, inst);
363 err = crypto_grab_skcipher(spawn, cipher_name, 0,
364 crypto_requires_sync(algt->type,
365 algt->mask));
366 if (err)
367 goto err_free_inst;
368
369 alg = crypto_skcipher_spawn_alg(spawn);
370
371 /* We only support 16-byte blocks. */
372 err = -EINVAL;
373 if (alg->cra_ablkcipher.ivsize != CTR_RFC3686_BLOCK_SIZE)
374 goto err_drop_spawn;
375
376 /* Not a stream cipher? */
377 if (alg->cra_blocksize != 1)
378 goto err_drop_spawn;
379
380 err = -ENAMETOOLONG;
381 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "rfc3686(%s)",
382 alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
383 goto err_drop_spawn;
384 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
385 "rfc3686(%s)", alg->cra_driver_name) >=
386 CRYPTO_MAX_ALG_NAME)
387 goto err_drop_spawn;
388
389 inst->alg.cra_priority = alg->cra_priority;
390 inst->alg.cra_blocksize = 1;
391 inst->alg.cra_alignmask = alg->cra_alignmask;
392
393 inst->alg.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER |
394 (alg->cra_flags & CRYPTO_ALG_ASYNC);
395 inst->alg.cra_type = &crypto_ablkcipher_type;
396
397 inst->alg.cra_ablkcipher.ivsize = CTR_RFC3686_IV_SIZE;
398 inst->alg.cra_ablkcipher.min_keysize =
399 alg->cra_ablkcipher.min_keysize + CTR_RFC3686_NONCE_SIZE;
400 inst->alg.cra_ablkcipher.max_keysize =
401 alg->cra_ablkcipher.max_keysize + CTR_RFC3686_NONCE_SIZE;
402
403 inst->alg.cra_ablkcipher.geniv = "seqiv";
404
405 inst->alg.cra_ablkcipher.setkey = crypto_rfc3686_setkey;
406 inst->alg.cra_ablkcipher.encrypt = crypto_rfc3686_crypt;
407 inst->alg.cra_ablkcipher.decrypt = crypto_rfc3686_crypt;
408
409 inst->alg.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
410
411 inst->alg.cra_init = crypto_rfc3686_init_tfm;
412 inst->alg.cra_exit = crypto_rfc3686_exit_tfm;
413
414 return inst;
415
416err_drop_spawn:
417 crypto_drop_skcipher(spawn);
418err_free_inst:
419 kfree(inst);
420 return ERR_PTR(err);
421}
422
423static void crypto_rfc3686_free(struct crypto_instance *inst)
424{
425 struct crypto_skcipher_spawn *spawn = crypto_instance_ctx(inst);
426
427 crypto_drop_skcipher(spawn);
428 kfree(inst);
429}
430
431static struct crypto_template crypto_rfc3686_tmpl = {
432 .name = "rfc3686",
433 .alloc = crypto_rfc3686_alloc,
434 .free = crypto_rfc3686_free,
435 .module = THIS_MODULE,
436};
437
438static int __init crypto_ctr_module_init(void)
439{
440 int err;
441
442 err = crypto_register_template(&crypto_ctr_tmpl);
443 if (err)
444 goto out;
445
446 err = crypto_register_template(&crypto_rfc3686_tmpl);
447 if (err)
448 goto out_drop_ctr;
449
450out:
451 return err;
452
453out_drop_ctr:
454 crypto_unregister_template(&crypto_ctr_tmpl);
455 goto out;
456}
457
458static void __exit crypto_ctr_module_exit(void)
459{
460 crypto_unregister_template(&crypto_rfc3686_tmpl);
461 crypto_unregister_template(&crypto_ctr_tmpl);
462}
463
464module_init(crypto_ctr_module_init);
465module_exit(crypto_ctr_module_exit);
466
467MODULE_LICENSE("GPL");
468MODULE_DESCRIPTION("CTR Counter block mode");
469MODULE_ALIAS_CRYPTO("rfc3686");
470MODULE_ALIAS_CRYPTO("ctr");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * CTR: Counter mode
4 *
5 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
6 */
7
8#include <crypto/algapi.h>
9#include <crypto/ctr.h>
10#include <crypto/internal/skcipher.h>
11#include <linux/err.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16
17struct crypto_rfc3686_ctx {
18 struct crypto_skcipher *child;
19 u8 nonce[CTR_RFC3686_NONCE_SIZE];
20};
21
22struct crypto_rfc3686_req_ctx {
23 u8 iv[CTR_RFC3686_BLOCK_SIZE];
24 struct skcipher_request subreq CRYPTO_MINALIGN_ATTR;
25};
26
27static void crypto_ctr_crypt_final(struct skcipher_walk *walk,
28 struct crypto_cipher *tfm)
29{
30 unsigned int bsize = crypto_cipher_blocksize(tfm);
31 unsigned long alignmask = crypto_cipher_alignmask(tfm);
32 u8 *ctrblk = walk->iv;
33 u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
34 u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
35 u8 *src = walk->src.virt.addr;
36 u8 *dst = walk->dst.virt.addr;
37 unsigned int nbytes = walk->nbytes;
38
39 crypto_cipher_encrypt_one(tfm, keystream, ctrblk);
40 crypto_xor_cpy(dst, keystream, src, nbytes);
41
42 crypto_inc(ctrblk, bsize);
43}
44
45static int crypto_ctr_crypt_segment(struct skcipher_walk *walk,
46 struct crypto_cipher *tfm)
47{
48 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
49 crypto_cipher_alg(tfm)->cia_encrypt;
50 unsigned int bsize = crypto_cipher_blocksize(tfm);
51 u8 *ctrblk = walk->iv;
52 u8 *src = walk->src.virt.addr;
53 u8 *dst = walk->dst.virt.addr;
54 unsigned int nbytes = walk->nbytes;
55
56 do {
57 /* create keystream */
58 fn(crypto_cipher_tfm(tfm), dst, ctrblk);
59 crypto_xor(dst, src, bsize);
60
61 /* increment counter in counterblock */
62 crypto_inc(ctrblk, bsize);
63
64 src += bsize;
65 dst += bsize;
66 } while ((nbytes -= bsize) >= bsize);
67
68 return nbytes;
69}
70
71static int crypto_ctr_crypt_inplace(struct skcipher_walk *walk,
72 struct crypto_cipher *tfm)
73{
74 void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =
75 crypto_cipher_alg(tfm)->cia_encrypt;
76 unsigned int bsize = crypto_cipher_blocksize(tfm);
77 unsigned long alignmask = crypto_cipher_alignmask(tfm);
78 unsigned int nbytes = walk->nbytes;
79 u8 *ctrblk = walk->iv;
80 u8 *src = walk->src.virt.addr;
81 u8 tmp[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
82 u8 *keystream = PTR_ALIGN(tmp + 0, alignmask + 1);
83
84 do {
85 /* create keystream */
86 fn(crypto_cipher_tfm(tfm), keystream, ctrblk);
87 crypto_xor(src, keystream, bsize);
88
89 /* increment counter in counterblock */
90 crypto_inc(ctrblk, bsize);
91
92 src += bsize;
93 } while ((nbytes -= bsize) >= bsize);
94
95 return nbytes;
96}
97
98static int crypto_ctr_crypt(struct skcipher_request *req)
99{
100 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
101 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
102 const unsigned int bsize = crypto_cipher_blocksize(cipher);
103 struct skcipher_walk walk;
104 unsigned int nbytes;
105 int err;
106
107 err = skcipher_walk_virt(&walk, req, false);
108
109 while (walk.nbytes >= bsize) {
110 if (walk.src.virt.addr == walk.dst.virt.addr)
111 nbytes = crypto_ctr_crypt_inplace(&walk, cipher);
112 else
113 nbytes = crypto_ctr_crypt_segment(&walk, cipher);
114
115 err = skcipher_walk_done(&walk, nbytes);
116 }
117
118 if (walk.nbytes) {
119 crypto_ctr_crypt_final(&walk, cipher);
120 err = skcipher_walk_done(&walk, 0);
121 }
122
123 return err;
124}
125
126static int crypto_ctr_create(struct crypto_template *tmpl, struct rtattr **tb)
127{
128 struct skcipher_instance *inst;
129 struct crypto_alg *alg;
130 int err;
131
132 inst = skcipher_alloc_instance_simple(tmpl, tb);
133 if (IS_ERR(inst))
134 return PTR_ERR(inst);
135
136 alg = skcipher_ialg_simple(inst);
137
138 /* Block size must be >= 4 bytes. */
139 err = -EINVAL;
140 if (alg->cra_blocksize < 4)
141 goto out_free_inst;
142
143 /* If this is false we'd fail the alignment of crypto_inc. */
144 if (alg->cra_blocksize % 4)
145 goto out_free_inst;
146
147 /* CTR mode is a stream cipher. */
148 inst->alg.base.cra_blocksize = 1;
149
150 /*
151 * To simplify the implementation, configure the skcipher walk to only
152 * give a partial block at the very end, never earlier.
153 */
154 inst->alg.chunksize = alg->cra_blocksize;
155
156 inst->alg.encrypt = crypto_ctr_crypt;
157 inst->alg.decrypt = crypto_ctr_crypt;
158
159 err = skcipher_register_instance(tmpl, inst);
160 if (err) {
161out_free_inst:
162 inst->free(inst);
163 }
164
165 return err;
166}
167
168static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
169 const u8 *key, unsigned int keylen)
170{
171 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
172 struct crypto_skcipher *child = ctx->child;
173
174 /* the nonce is stored in bytes at end of key */
175 if (keylen < CTR_RFC3686_NONCE_SIZE)
176 return -EINVAL;
177
178 memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
179 CTR_RFC3686_NONCE_SIZE);
180
181 keylen -= CTR_RFC3686_NONCE_SIZE;
182
183 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
184 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
185 CRYPTO_TFM_REQ_MASK);
186 return crypto_skcipher_setkey(child, key, keylen);
187}
188
189static int crypto_rfc3686_crypt(struct skcipher_request *req)
190{
191 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
192 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
193 struct crypto_skcipher *child = ctx->child;
194 unsigned long align = crypto_skcipher_alignmask(tfm);
195 struct crypto_rfc3686_req_ctx *rctx =
196 (void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
197 struct skcipher_request *subreq = &rctx->subreq;
198 u8 *iv = rctx->iv;
199
200 /* set up counter block */
201 memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
202 memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
203
204 /* initialize counter portion of counter block */
205 *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
206 cpu_to_be32(1);
207
208 skcipher_request_set_tfm(subreq, child);
209 skcipher_request_set_callback(subreq, req->base.flags,
210 req->base.complete, req->base.data);
211 skcipher_request_set_crypt(subreq, req->src, req->dst,
212 req->cryptlen, iv);
213
214 return crypto_skcipher_encrypt(subreq);
215}
216
217static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
218{
219 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
220 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
221 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
222 struct crypto_skcipher *cipher;
223 unsigned long align;
224 unsigned int reqsize;
225
226 cipher = crypto_spawn_skcipher(spawn);
227 if (IS_ERR(cipher))
228 return PTR_ERR(cipher);
229
230 ctx->child = cipher;
231
232 align = crypto_skcipher_alignmask(tfm);
233 align &= ~(crypto_tfm_ctx_alignment() - 1);
234 reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
235 crypto_skcipher_reqsize(cipher);
236 crypto_skcipher_set_reqsize(tfm, reqsize);
237
238 return 0;
239}
240
241static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
242{
243 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
244
245 crypto_free_skcipher(ctx->child);
246}
247
248static void crypto_rfc3686_free(struct skcipher_instance *inst)
249{
250 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
251
252 crypto_drop_skcipher(spawn);
253 kfree(inst);
254}
255
256static int crypto_rfc3686_create(struct crypto_template *tmpl,
257 struct rtattr **tb)
258{
259 struct skcipher_instance *inst;
260 struct skcipher_alg *alg;
261 struct crypto_skcipher_spawn *spawn;
262 u32 mask;
263 int err;
264
265 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
266 if (err)
267 return err;
268
269 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
270 if (!inst)
271 return -ENOMEM;
272
273 spawn = skcipher_instance_ctx(inst);
274
275 err = crypto_grab_skcipher(spawn, skcipher_crypto_instance(inst),
276 crypto_attr_alg_name(tb[1]), 0, mask);
277 if (err)
278 goto err_free_inst;
279
280 alg = crypto_spawn_skcipher_alg(spawn);
281
282 /* We only support 16-byte blocks. */
283 err = -EINVAL;
284 if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
285 goto err_free_inst;
286
287 /* Not a stream cipher? */
288 if (alg->base.cra_blocksize != 1)
289 goto err_free_inst;
290
291 err = -ENAMETOOLONG;
292 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
293 "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
294 goto err_free_inst;
295 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
296 "rfc3686(%s)", alg->base.cra_driver_name) >=
297 CRYPTO_MAX_ALG_NAME)
298 goto err_free_inst;
299
300 inst->alg.base.cra_priority = alg->base.cra_priority;
301 inst->alg.base.cra_blocksize = 1;
302 inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
303
304 inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
305 inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
306 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
307 CTR_RFC3686_NONCE_SIZE;
308 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
309 CTR_RFC3686_NONCE_SIZE;
310
311 inst->alg.setkey = crypto_rfc3686_setkey;
312 inst->alg.encrypt = crypto_rfc3686_crypt;
313 inst->alg.decrypt = crypto_rfc3686_crypt;
314
315 inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
316
317 inst->alg.init = crypto_rfc3686_init_tfm;
318 inst->alg.exit = crypto_rfc3686_exit_tfm;
319
320 inst->free = crypto_rfc3686_free;
321
322 err = skcipher_register_instance(tmpl, inst);
323 if (err) {
324err_free_inst:
325 crypto_rfc3686_free(inst);
326 }
327 return err;
328}
329
330static struct crypto_template crypto_ctr_tmpls[] = {
331 {
332 .name = "ctr",
333 .create = crypto_ctr_create,
334 .module = THIS_MODULE,
335 }, {
336 .name = "rfc3686",
337 .create = crypto_rfc3686_create,
338 .module = THIS_MODULE,
339 },
340};
341
342static int __init crypto_ctr_module_init(void)
343{
344 return crypto_register_templates(crypto_ctr_tmpls,
345 ARRAY_SIZE(crypto_ctr_tmpls));
346}
347
348static void __exit crypto_ctr_module_exit(void)
349{
350 crypto_unregister_templates(crypto_ctr_tmpls,
351 ARRAY_SIZE(crypto_ctr_tmpls));
352}
353
354subsys_initcall(crypto_ctr_module_init);
355module_exit(crypto_ctr_module_exit);
356
357MODULE_LICENSE("GPL");
358MODULE_DESCRIPTION("CTR block cipher mode of operation");
359MODULE_ALIAS_CRYPTO("rfc3686");
360MODULE_ALIAS_CRYPTO("ctr");