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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, &alg);
133 if (IS_ERR(inst))
134 return PTR_ERR(inst);
135
136 /* Block size must be >= 4 bytes. */
137 err = -EINVAL;
138 if (alg->cra_blocksize < 4)
139 goto out_free_inst;
140
141 /* If this is false we'd fail the alignment of crypto_inc. */
142 if (alg->cra_blocksize % 4)
143 goto out_free_inst;
144
145 /* CTR mode is a stream cipher. */
146 inst->alg.base.cra_blocksize = 1;
147
148 /*
149 * To simplify the implementation, configure the skcipher walk to only
150 * give a partial block at the very end, never earlier.
151 */
152 inst->alg.chunksize = alg->cra_blocksize;
153
154 inst->alg.encrypt = crypto_ctr_crypt;
155 inst->alg.decrypt = crypto_ctr_crypt;
156
157 err = skcipher_register_instance(tmpl, inst);
158 if (err)
159 goto out_free_inst;
160 goto out_put_alg;
161
162out_free_inst:
163 inst->free(inst);
164out_put_alg:
165 crypto_mod_put(alg);
166 return err;
167}
168
169static int crypto_rfc3686_setkey(struct crypto_skcipher *parent,
170 const u8 *key, unsigned int keylen)
171{
172 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
173 struct crypto_skcipher *child = ctx->child;
174 int err;
175
176 /* the nonce is stored in bytes at end of key */
177 if (keylen < CTR_RFC3686_NONCE_SIZE)
178 return -EINVAL;
179
180 memcpy(ctx->nonce, key + (keylen - CTR_RFC3686_NONCE_SIZE),
181 CTR_RFC3686_NONCE_SIZE);
182
183 keylen -= CTR_RFC3686_NONCE_SIZE;
184
185 crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
186 crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
187 CRYPTO_TFM_REQ_MASK);
188 err = crypto_skcipher_setkey(child, key, keylen);
189 crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
190 CRYPTO_TFM_RES_MASK);
191
192 return err;
193}
194
195static int crypto_rfc3686_crypt(struct skcipher_request *req)
196{
197 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
198 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
199 struct crypto_skcipher *child = ctx->child;
200 unsigned long align = crypto_skcipher_alignmask(tfm);
201 struct crypto_rfc3686_req_ctx *rctx =
202 (void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
203 struct skcipher_request *subreq = &rctx->subreq;
204 u8 *iv = rctx->iv;
205
206 /* set up counter block */
207 memcpy(iv, ctx->nonce, CTR_RFC3686_NONCE_SIZE);
208 memcpy(iv + CTR_RFC3686_NONCE_SIZE, req->iv, CTR_RFC3686_IV_SIZE);
209
210 /* initialize counter portion of counter block */
211 *(__be32 *)(iv + CTR_RFC3686_NONCE_SIZE + CTR_RFC3686_IV_SIZE) =
212 cpu_to_be32(1);
213
214 skcipher_request_set_tfm(subreq, child);
215 skcipher_request_set_callback(subreq, req->base.flags,
216 req->base.complete, req->base.data);
217 skcipher_request_set_crypt(subreq, req->src, req->dst,
218 req->cryptlen, iv);
219
220 return crypto_skcipher_encrypt(subreq);
221}
222
223static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
224{
225 struct skcipher_instance *inst = skcipher_alg_instance(tfm);
226 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
227 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
228 struct crypto_skcipher *cipher;
229 unsigned long align;
230 unsigned int reqsize;
231
232 cipher = crypto_spawn_skcipher(spawn);
233 if (IS_ERR(cipher))
234 return PTR_ERR(cipher);
235
236 ctx->child = cipher;
237
238 align = crypto_skcipher_alignmask(tfm);
239 align &= ~(crypto_tfm_ctx_alignment() - 1);
240 reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
241 crypto_skcipher_reqsize(cipher);
242 crypto_skcipher_set_reqsize(tfm, reqsize);
243
244 return 0;
245}
246
247static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
248{
249 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
250
251 crypto_free_skcipher(ctx->child);
252}
253
254static void crypto_rfc3686_free(struct skcipher_instance *inst)
255{
256 struct crypto_skcipher_spawn *spawn = skcipher_instance_ctx(inst);
257
258 crypto_drop_skcipher(spawn);
259 kfree(inst);
260}
261
262static int crypto_rfc3686_create(struct crypto_template *tmpl,
263 struct rtattr **tb)
264{
265 struct crypto_attr_type *algt;
266 struct skcipher_instance *inst;
267 struct skcipher_alg *alg;
268 struct crypto_skcipher_spawn *spawn;
269 const char *cipher_name;
270 u32 mask;
271
272 int err;
273
274 algt = crypto_get_attr_type(tb);
275 if (IS_ERR(algt))
276 return PTR_ERR(algt);
277
278 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
279 return -EINVAL;
280
281 cipher_name = crypto_attr_alg_name(tb[1]);
282 if (IS_ERR(cipher_name))
283 return PTR_ERR(cipher_name);
284
285 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
286 if (!inst)
287 return -ENOMEM;
288
289 mask = crypto_requires_sync(algt->type, algt->mask) |
290 crypto_requires_off(algt->type, algt->mask,
291 CRYPTO_ALG_NEED_FALLBACK);
292
293 spawn = skcipher_instance_ctx(inst);
294
295 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
296 err = crypto_grab_skcipher(spawn, cipher_name, 0, mask);
297 if (err)
298 goto err_free_inst;
299
300 alg = crypto_spawn_skcipher_alg(spawn);
301
302 /* We only support 16-byte blocks. */
303 err = -EINVAL;
304 if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
305 goto err_drop_spawn;
306
307 /* Not a stream cipher? */
308 if (alg->base.cra_blocksize != 1)
309 goto err_drop_spawn;
310
311 err = -ENAMETOOLONG;
312 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
313 "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
314 goto err_drop_spawn;
315 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
316 "rfc3686(%s)", alg->base.cra_driver_name) >=
317 CRYPTO_MAX_ALG_NAME)
318 goto err_drop_spawn;
319
320 inst->alg.base.cra_priority = alg->base.cra_priority;
321 inst->alg.base.cra_blocksize = 1;
322 inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
323
324 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
325
326 inst->alg.ivsize = CTR_RFC3686_IV_SIZE;
327 inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg);
328 inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) +
329 CTR_RFC3686_NONCE_SIZE;
330 inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) +
331 CTR_RFC3686_NONCE_SIZE;
332
333 inst->alg.setkey = crypto_rfc3686_setkey;
334 inst->alg.encrypt = crypto_rfc3686_crypt;
335 inst->alg.decrypt = crypto_rfc3686_crypt;
336
337 inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
338
339 inst->alg.init = crypto_rfc3686_init_tfm;
340 inst->alg.exit = crypto_rfc3686_exit_tfm;
341
342 inst->free = crypto_rfc3686_free;
343
344 err = skcipher_register_instance(tmpl, inst);
345 if (err)
346 goto err_drop_spawn;
347
348out:
349 return err;
350
351err_drop_spawn:
352 crypto_drop_skcipher(spawn);
353err_free_inst:
354 kfree(inst);
355 goto out;
356}
357
358static struct crypto_template crypto_ctr_tmpls[] = {
359 {
360 .name = "ctr",
361 .create = crypto_ctr_create,
362 .module = THIS_MODULE,
363 }, {
364 .name = "rfc3686",
365 .create = crypto_rfc3686_create,
366 .module = THIS_MODULE,
367 },
368};
369
370static int __init crypto_ctr_module_init(void)
371{
372 return crypto_register_templates(crypto_ctr_tmpls,
373 ARRAY_SIZE(crypto_ctr_tmpls));
374}
375
376static void __exit crypto_ctr_module_exit(void)
377{
378 crypto_unregister_templates(crypto_ctr_tmpls,
379 ARRAY_SIZE(crypto_ctr_tmpls));
380}
381
382subsys_initcall(crypto_ctr_module_init);
383module_exit(crypto_ctr_module_exit);
384
385MODULE_LICENSE("GPL");
386MODULE_DESCRIPTION("CTR block cipher mode of operation");
387MODULE_ALIAS_CRYPTO("rfc3686");
388MODULE_ALIAS_CRYPTO("ctr");
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_skcipher *child;
30 u8 nonce[CTR_RFC3686_NONCE_SIZE];
31};
32
33struct crypto_rfc3686_req_ctx {
34 u8 iv[CTR_RFC3686_BLOCK_SIZE];
35 struct skcipher_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_skcipher *parent,
253 const u8 *key, unsigned int keylen)
254{
255 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(parent);
256 struct crypto_skcipher *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_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);
274
275 return err;
276}
277
278static int crypto_rfc3686_crypt(struct skcipher_request *req)
279{
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);
284 struct crypto_rfc3686_req_ctx *rctx =
285 (void *)PTR_ALIGN((u8 *)skcipher_request_ctx(req), align + 1);
286 struct skcipher_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->iv, 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 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);
302
303 return crypto_skcipher_encrypt(subreq);
304}
305
306static int crypto_rfc3686_init_tfm(struct crypto_skcipher *tfm)
307{
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;
312 unsigned long align;
313 unsigned int reqsize;
314
315 cipher = crypto_spawn_skcipher(spawn);
316 if (IS_ERR(cipher))
317 return PTR_ERR(cipher);
318
319 ctx->child = cipher;
320
321 align = crypto_skcipher_alignmask(tfm);
322 align &= ~(crypto_tfm_ctx_alignment() - 1);
323 reqsize = align + sizeof(struct crypto_rfc3686_req_ctx) +
324 crypto_skcipher_reqsize(cipher);
325 crypto_skcipher_set_reqsize(tfm, reqsize);
326
327 return 0;
328}
329
330static void crypto_rfc3686_exit_tfm(struct crypto_skcipher *tfm)
331{
332 struct crypto_rfc3686_ctx *ctx = crypto_skcipher_ctx(tfm);
333
334 crypto_free_skcipher(ctx->child);
335}
336
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);
343}
344
345static int crypto_rfc3686_create(struct crypto_template *tmpl,
346 struct rtattr **tb)
347{
348 struct crypto_attr_type *algt;
349 struct skcipher_instance *inst;
350 struct skcipher_alg *alg;
351 struct crypto_skcipher_spawn *spawn;
352 const char *cipher_name;
353 int err;
354
355 algt = crypto_get_attr_type(tb);
356 if (IS_ERR(algt))
357 return PTR_ERR(algt);
358
359 if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
360 return -EINVAL;
361
362 cipher_name = crypto_attr_alg_name(tb[1]);
363 if (IS_ERR(cipher_name))
364 return PTR_ERR(cipher_name);
365
366 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
367 if (!inst)
368 return -ENOMEM;
369
370 spawn = skcipher_instance_ctx(inst);
371
372 crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
373 err = crypto_grab_skcipher(spawn, cipher_name, 0,
374 crypto_requires_sync(algt->type,
375 algt->mask));
376 if (err)
377 goto err_free_inst;
378
379 alg = crypto_spawn_skcipher_alg(spawn);
380
381 /* We only support 16-byte blocks. */
382 err = -EINVAL;
383 if (crypto_skcipher_alg_ivsize(alg) != CTR_RFC3686_BLOCK_SIZE)
384 goto err_drop_spawn;
385
386 /* Not a stream cipher? */
387 if (alg->base.cra_blocksize != 1)
388 goto err_drop_spawn;
389
390 err = -ENAMETOOLONG;
391 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
392 "rfc3686(%s)", alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
393 goto err_drop_spawn;
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)
397 goto err_drop_spawn;
398
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;
402
403 inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
404
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;
411
412 inst->alg.setkey = crypto_rfc3686_setkey;
413 inst->alg.encrypt = crypto_rfc3686_crypt;
414 inst->alg.decrypt = crypto_rfc3686_crypt;
415
416 inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc3686_ctx);
417
418 inst->alg.init = crypto_rfc3686_init_tfm;
419 inst->alg.exit = crypto_rfc3686_exit_tfm;
420
421 inst->free = crypto_rfc3686_free;
422
423 err = skcipher_register_instance(tmpl, inst);
424 if (err)
425 goto err_drop_spawn;
426
427out:
428 return err;
429
430err_drop_spawn:
431 crypto_drop_skcipher(spawn);
432err_free_inst:
433 kfree(inst);
434 goto out;
435}
436
437static struct crypto_template crypto_rfc3686_tmpl = {
438 .name = "rfc3686",
439 .create = crypto_rfc3686_create,
440 .module = THIS_MODULE,
441};
442
443static int __init crypto_ctr_module_init(void)
444{
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;
461}
462
463static void __exit crypto_ctr_module_exit(void)
464{
465 crypto_unregister_template(&crypto_rfc3686_tmpl);
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");
474MODULE_ALIAS_CRYPTO("rfc3686");
475MODULE_ALIAS_CRYPTO("ctr");