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1/*
2 * Key Wrapping: RFC3394 / NIST SP800-38F
3 *
4 * Copyright (C) 2015, Stephan Mueller <smueller@chronox.de>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, and the entire permission notice in its entirety,
11 * including the disclaimer of warranties.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote
16 * products derived from this software without specific prior
17 * written permission.
18 *
19 * ALTERNATIVELY, this product may be distributed under the terms of
20 * the GNU General Public License, in which case the provisions of the GPL2
21 * are required INSTEAD OF the above restrictions. (This clause is
22 * necessary due to a potential bad interaction between the GPL and
23 * the restrictions contained in a BSD-style copyright.)
24 *
25 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
28 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
29 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
31 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
32 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
35 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
36 * DAMAGE.
37 */
38
39/*
40 * Note for using key wrapping:
41 *
42 * * The result of the encryption operation is the ciphertext starting
43 * with the 2nd semiblock. The first semiblock is provided as the IV.
44 * The IV used to start the encryption operation is the default IV.
45 *
46 * * The input for the decryption is the first semiblock handed in as an
47 * IV. The ciphertext is the data starting with the 2nd semiblock. The
48 * return code of the decryption operation will be EBADMSG in case an
49 * integrity error occurs.
50 *
51 * To obtain the full result of an encryption as expected by SP800-38F, the
52 * caller must allocate a buffer of plaintext + 8 bytes:
53 *
54 * unsigned int datalen = ptlen + crypto_skcipher_ivsize(tfm);
55 * u8 data[datalen];
56 * u8 *iv = data;
57 * u8 *pt = data + crypto_skcipher_ivsize(tfm);
58 * <ensure that pt contains the plaintext of size ptlen>
59 * sg_init_one(&sg, pt, ptlen);
60 * skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);
61 *
62 * ==> After encryption, data now contains full KW result as per SP800-38F.
63 *
64 * In case of decryption, ciphertext now already has the expected length
65 * and must be segmented appropriately:
66 *
67 * unsigned int datalen = CTLEN;
68 * u8 data[datalen];
69 * <ensure that data contains full ciphertext>
70 * u8 *iv = data;
71 * u8 *ct = data + crypto_skcipher_ivsize(tfm);
72 * unsigned int ctlen = datalen - crypto_skcipher_ivsize(tfm);
73 * sg_init_one(&sg, ct, ctlen);
74 * skcipher_request_set_crypt(req, &sg, &sg, ctlen, iv);
75 *
76 * ==> After decryption (which hopefully does not return EBADMSG), the ct
77 * pointer now points to the plaintext of size ctlen.
78 *
79 * Note 2: KWP is not implemented as this would defy in-place operation.
80 * If somebody wants to wrap non-aligned data, he should simply pad
81 * the input with zeros to fill it up to the 8 byte boundary.
82 */
83
84#include <linux/module.h>
85#include <linux/crypto.h>
86#include <linux/scatterlist.h>
87#include <crypto/scatterwalk.h>
88#include <crypto/internal/cipher.h>
89#include <crypto/internal/skcipher.h>
90
91struct crypto_kw_block {
92#define SEMIBSIZE 8
93 __be64 A;
94 __be64 R;
95};
96
97/*
98 * Fast forward the SGL to the "end" length minus SEMIBSIZE.
99 * The start in the SGL defined by the fast-forward is returned with
100 * the walk variable
101 */
102static void crypto_kw_scatterlist_ff(struct scatter_walk *walk,
103 struct scatterlist *sg,
104 unsigned int end)
105{
106 unsigned int skip = 0;
107
108 /* The caller should only operate on full SEMIBLOCKs. */
109 BUG_ON(end < SEMIBSIZE);
110
111 skip = end - SEMIBSIZE;
112 while (sg) {
113 if (sg->length > skip) {
114 scatterwalk_start(walk, sg);
115 scatterwalk_advance(walk, skip);
116 break;
117 }
118
119 skip -= sg->length;
120 sg = sg_next(sg);
121 }
122}
123
124static int crypto_kw_decrypt(struct skcipher_request *req)
125{
126 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
127 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
128 struct crypto_kw_block block;
129 struct scatterlist *src, *dst;
130 u64 t = 6 * ((req->cryptlen) >> 3);
131 unsigned int i;
132 int ret = 0;
133
134 /*
135 * Require at least 2 semiblocks (note, the 3rd semiblock that is
136 * required by SP800-38F is the IV.
137 */
138 if (req->cryptlen < (2 * SEMIBSIZE) || req->cryptlen % SEMIBSIZE)
139 return -EINVAL;
140
141 /* Place the IV into block A */
142 memcpy(&block.A, req->iv, SEMIBSIZE);
143
144 /*
145 * src scatterlist is read-only. dst scatterlist is r/w. During the
146 * first loop, src points to req->src and dst to req->dst. For any
147 * subsequent round, the code operates on req->dst only.
148 */
149 src = req->src;
150 dst = req->dst;
151
152 for (i = 0; i < 6; i++) {
153 struct scatter_walk src_walk, dst_walk;
154 unsigned int nbytes = req->cryptlen;
155
156 while (nbytes) {
157 /* move pointer by nbytes in the SGL */
158 crypto_kw_scatterlist_ff(&src_walk, src, nbytes);
159 /* get the source block */
160 scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
161 false);
162
163 /* perform KW operation: modify IV with counter */
164 block.A ^= cpu_to_be64(t);
165 t--;
166 /* perform KW operation: decrypt block */
167 crypto_cipher_decrypt_one(cipher, (u8 *)&block,
168 (u8 *)&block);
169
170 /* move pointer by nbytes in the SGL */
171 crypto_kw_scatterlist_ff(&dst_walk, dst, nbytes);
172 /* Copy block->R into place */
173 scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
174 true);
175
176 nbytes -= SEMIBSIZE;
177 }
178
179 /* we now start to operate on the dst SGL only */
180 src = req->dst;
181 dst = req->dst;
182 }
183
184 /* Perform authentication check */
185 if (block.A != cpu_to_be64(0xa6a6a6a6a6a6a6a6ULL))
186 ret = -EBADMSG;
187
188 memzero_explicit(&block, sizeof(struct crypto_kw_block));
189
190 return ret;
191}
192
193static int crypto_kw_encrypt(struct skcipher_request *req)
194{
195 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
196 struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
197 struct crypto_kw_block block;
198 struct scatterlist *src, *dst;
199 u64 t = 1;
200 unsigned int i;
201
202 /*
203 * Require at least 2 semiblocks (note, the 3rd semiblock that is
204 * required by SP800-38F is the IV that occupies the first semiblock.
205 * This means that the dst memory must be one semiblock larger than src.
206 * Also ensure that the given data is aligned to semiblock.
207 */
208 if (req->cryptlen < (2 * SEMIBSIZE) || req->cryptlen % SEMIBSIZE)
209 return -EINVAL;
210
211 /*
212 * Place the predefined IV into block A -- for encrypt, the caller
213 * does not need to provide an IV, but he needs to fetch the final IV.
214 */
215 block.A = cpu_to_be64(0xa6a6a6a6a6a6a6a6ULL);
216
217 /*
218 * src scatterlist is read-only. dst scatterlist is r/w. During the
219 * first loop, src points to req->src and dst to req->dst. For any
220 * subsequent round, the code operates on req->dst only.
221 */
222 src = req->src;
223 dst = req->dst;
224
225 for (i = 0; i < 6; i++) {
226 struct scatter_walk src_walk, dst_walk;
227 unsigned int nbytes = req->cryptlen;
228
229 scatterwalk_start(&src_walk, src);
230 scatterwalk_start(&dst_walk, dst);
231
232 while (nbytes) {
233 /* get the source block */
234 scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
235 false);
236
237 /* perform KW operation: encrypt block */
238 crypto_cipher_encrypt_one(cipher, (u8 *)&block,
239 (u8 *)&block);
240 /* perform KW operation: modify IV with counter */
241 block.A ^= cpu_to_be64(t);
242 t++;
243
244 /* Copy block->R into place */
245 scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
246 true);
247
248 nbytes -= SEMIBSIZE;
249 }
250
251 /* we now start to operate on the dst SGL only */
252 src = req->dst;
253 dst = req->dst;
254 }
255
256 /* establish the IV for the caller to pick up */
257 memcpy(req->iv, &block.A, SEMIBSIZE);
258
259 memzero_explicit(&block, sizeof(struct crypto_kw_block));
260
261 return 0;
262}
263
264static int crypto_kw_create(struct crypto_template *tmpl, struct rtattr **tb)
265{
266 struct skcipher_instance *inst;
267 struct crypto_alg *alg;
268 int err;
269
270 inst = skcipher_alloc_instance_simple(tmpl, tb);
271 if (IS_ERR(inst))
272 return PTR_ERR(inst);
273
274 alg = skcipher_ialg_simple(inst);
275
276 err = -EINVAL;
277 /* Section 5.1 requirement for KW */
278 if (alg->cra_blocksize != sizeof(struct crypto_kw_block))
279 goto out_free_inst;
280
281 inst->alg.base.cra_blocksize = SEMIBSIZE;
282 inst->alg.base.cra_alignmask = 0;
283 inst->alg.ivsize = SEMIBSIZE;
284
285 inst->alg.encrypt = crypto_kw_encrypt;
286 inst->alg.decrypt = crypto_kw_decrypt;
287
288 err = skcipher_register_instance(tmpl, inst);
289 if (err) {
290out_free_inst:
291 inst->free(inst);
292 }
293
294 return err;
295}
296
297static struct crypto_template crypto_kw_tmpl = {
298 .name = "kw",
299 .create = crypto_kw_create,
300 .module = THIS_MODULE,
301};
302
303static int __init crypto_kw_init(void)
304{
305 return crypto_register_template(&crypto_kw_tmpl);
306}
307
308static void __exit crypto_kw_exit(void)
309{
310 crypto_unregister_template(&crypto_kw_tmpl);
311}
312
313subsys_initcall(crypto_kw_init);
314module_exit(crypto_kw_exit);
315
316MODULE_LICENSE("Dual BSD/GPL");
317MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
318MODULE_DESCRIPTION("Key Wrapping (RFC3394 / NIST SP800-38F)");
319MODULE_ALIAS_CRYPTO("kw");
320MODULE_IMPORT_NS(CRYPTO_INTERNAL);
1/*
2 * Key Wrapping: RFC3394 / NIST SP800-38F
3 *
4 * Copyright (C) 2015, Stephan Mueller <smueller@chronox.de>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, and the entire permission notice in its entirety,
11 * including the disclaimer of warranties.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote
16 * products derived from this software without specific prior
17 * written permission.
18 *
19 * ALTERNATIVELY, this product may be distributed under the terms of
20 * the GNU General Public License, in which case the provisions of the GPL2
21 * are required INSTEAD OF the above restrictions. (This clause is
22 * necessary due to a potential bad interaction between the GPL and
23 * the restrictions contained in a BSD-style copyright.)
24 *
25 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
28 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
29 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
31 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
32 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
33 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
35 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
36 * DAMAGE.
37 */
38
39/*
40 * Note for using key wrapping:
41 *
42 * * The result of the encryption operation is the ciphertext starting
43 * with the 2nd semiblock. The first semiblock is provided as the IV.
44 * The IV used to start the encryption operation is the default IV.
45 *
46 * * The input for the decryption is the first semiblock handed in as an
47 * IV. The ciphertext is the data starting with the 2nd semiblock. The
48 * return code of the decryption operation will be EBADMSG in case an
49 * integrity error occurs.
50 *
51 * To obtain the full result of an encryption as expected by SP800-38F, the
52 * caller must allocate a buffer of plaintext + 8 bytes:
53 *
54 * unsigned int datalen = ptlen + crypto_skcipher_ivsize(tfm);
55 * u8 data[datalen];
56 * u8 *iv = data;
57 * u8 *pt = data + crypto_skcipher_ivsize(tfm);
58 * <ensure that pt contains the plaintext of size ptlen>
59 * sg_init_one(&sg, ptdata, ptlen);
60 * skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);
61 *
62 * ==> After encryption, data now contains full KW result as per SP800-38F.
63 *
64 * In case of decryption, ciphertext now already has the expected length
65 * and must be segmented appropriately:
66 *
67 * unsigned int datalen = CTLEN;
68 * u8 data[datalen];
69 * <ensure that data contains full ciphertext>
70 * u8 *iv = data;
71 * u8 *ct = data + crypto_skcipher_ivsize(tfm);
72 * unsigned int ctlen = datalen - crypto_skcipher_ivsize(tfm);
73 * sg_init_one(&sg, ctdata, ctlen);
74 * skcipher_request_set_crypt(req, &sg, &sg, ptlen, iv);
75 *
76 * ==> After decryption (which hopefully does not return EBADMSG), the ct
77 * pointer now points to the plaintext of size ctlen.
78 *
79 * Note 2: KWP is not implemented as this would defy in-place operation.
80 * If somebody wants to wrap non-aligned data, he should simply pad
81 * the input with zeros to fill it up to the 8 byte boundary.
82 */
83
84#include <linux/module.h>
85#include <linux/crypto.h>
86#include <linux/scatterlist.h>
87#include <crypto/scatterwalk.h>
88#include <crypto/internal/skcipher.h>
89
90struct crypto_kw_ctx {
91 struct crypto_cipher *child;
92};
93
94struct crypto_kw_block {
95#define SEMIBSIZE 8
96 __be64 A;
97 __be64 R;
98};
99
100/*
101 * Fast forward the SGL to the "end" length minus SEMIBSIZE.
102 * The start in the SGL defined by the fast-forward is returned with
103 * the walk variable
104 */
105static void crypto_kw_scatterlist_ff(struct scatter_walk *walk,
106 struct scatterlist *sg,
107 unsigned int end)
108{
109 unsigned int skip = 0;
110
111 /* The caller should only operate on full SEMIBLOCKs. */
112 BUG_ON(end < SEMIBSIZE);
113
114 skip = end - SEMIBSIZE;
115 while (sg) {
116 if (sg->length > skip) {
117 scatterwalk_start(walk, sg);
118 scatterwalk_advance(walk, skip);
119 break;
120 } else
121 skip -= sg->length;
122
123 sg = sg_next(sg);
124 }
125}
126
127static int crypto_kw_decrypt(struct blkcipher_desc *desc,
128 struct scatterlist *dst, struct scatterlist *src,
129 unsigned int nbytes)
130{
131 struct crypto_blkcipher *tfm = desc->tfm;
132 struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm);
133 struct crypto_cipher *child = ctx->child;
134 struct crypto_kw_block block;
135 struct scatterlist *lsrc, *ldst;
136 u64 t = 6 * ((nbytes) >> 3);
137 unsigned int i;
138 int ret = 0;
139
140 /*
141 * Require at least 2 semiblocks (note, the 3rd semiblock that is
142 * required by SP800-38F is the IV.
143 */
144 if (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE)
145 return -EINVAL;
146
147 /* Place the IV into block A */
148 memcpy(&block.A, desc->info, SEMIBSIZE);
149
150 /*
151 * src scatterlist is read-only. dst scatterlist is r/w. During the
152 * first loop, lsrc points to src and ldst to dst. For any
153 * subsequent round, the code operates on dst only.
154 */
155 lsrc = src;
156 ldst = dst;
157
158 for (i = 0; i < 6; i++) {
159 struct scatter_walk src_walk, dst_walk;
160 unsigned int tmp_nbytes = nbytes;
161
162 while (tmp_nbytes) {
163 /* move pointer by tmp_nbytes in the SGL */
164 crypto_kw_scatterlist_ff(&src_walk, lsrc, tmp_nbytes);
165 /* get the source block */
166 scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
167 false);
168
169 /* perform KW operation: modify IV with counter */
170 block.A ^= cpu_to_be64(t);
171 t--;
172 /* perform KW operation: decrypt block */
173 crypto_cipher_decrypt_one(child, (u8*)&block,
174 (u8*)&block);
175
176 /* move pointer by tmp_nbytes in the SGL */
177 crypto_kw_scatterlist_ff(&dst_walk, ldst, tmp_nbytes);
178 /* Copy block->R into place */
179 scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
180 true);
181
182 tmp_nbytes -= SEMIBSIZE;
183 }
184
185 /* we now start to operate on the dst SGL only */
186 lsrc = dst;
187 ldst = dst;
188 }
189
190 /* Perform authentication check */
191 if (block.A != cpu_to_be64(0xa6a6a6a6a6a6a6a6ULL))
192 ret = -EBADMSG;
193
194 memzero_explicit(&block, sizeof(struct crypto_kw_block));
195
196 return ret;
197}
198
199static int crypto_kw_encrypt(struct blkcipher_desc *desc,
200 struct scatterlist *dst, struct scatterlist *src,
201 unsigned int nbytes)
202{
203 struct crypto_blkcipher *tfm = desc->tfm;
204 struct crypto_kw_ctx *ctx = crypto_blkcipher_ctx(tfm);
205 struct crypto_cipher *child = ctx->child;
206 struct crypto_kw_block block;
207 struct scatterlist *lsrc, *ldst;
208 u64 t = 1;
209 unsigned int i;
210
211 /*
212 * Require at least 2 semiblocks (note, the 3rd semiblock that is
213 * required by SP800-38F is the IV that occupies the first semiblock.
214 * This means that the dst memory must be one semiblock larger than src.
215 * Also ensure that the given data is aligned to semiblock.
216 */
217 if (nbytes < (2 * SEMIBSIZE) || nbytes % SEMIBSIZE)
218 return -EINVAL;
219
220 /*
221 * Place the predefined IV into block A -- for encrypt, the caller
222 * does not need to provide an IV, but he needs to fetch the final IV.
223 */
224 block.A = cpu_to_be64(0xa6a6a6a6a6a6a6a6ULL);
225
226 /*
227 * src scatterlist is read-only. dst scatterlist is r/w. During the
228 * first loop, lsrc points to src and ldst to dst. For any
229 * subsequent round, the code operates on dst only.
230 */
231 lsrc = src;
232 ldst = dst;
233
234 for (i = 0; i < 6; i++) {
235 struct scatter_walk src_walk, dst_walk;
236 unsigned int tmp_nbytes = nbytes;
237
238 scatterwalk_start(&src_walk, lsrc);
239 scatterwalk_start(&dst_walk, ldst);
240
241 while (tmp_nbytes) {
242 /* get the source block */
243 scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
244 false);
245
246 /* perform KW operation: encrypt block */
247 crypto_cipher_encrypt_one(child, (u8 *)&block,
248 (u8 *)&block);
249 /* perform KW operation: modify IV with counter */
250 block.A ^= cpu_to_be64(t);
251 t++;
252
253 /* Copy block->R into place */
254 scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
255 true);
256
257 tmp_nbytes -= SEMIBSIZE;
258 }
259
260 /* we now start to operate on the dst SGL only */
261 lsrc = dst;
262 ldst = dst;
263 }
264
265 /* establish the IV for the caller to pick up */
266 memcpy(desc->info, &block.A, SEMIBSIZE);
267
268 memzero_explicit(&block, sizeof(struct crypto_kw_block));
269
270 return 0;
271}
272
273static int crypto_kw_setkey(struct crypto_tfm *parent, const u8 *key,
274 unsigned int keylen)
275{
276 struct crypto_kw_ctx *ctx = crypto_tfm_ctx(parent);
277 struct crypto_cipher *child = ctx->child;
278 int err;
279
280 crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
281 crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
282 CRYPTO_TFM_REQ_MASK);
283 err = crypto_cipher_setkey(child, key, keylen);
284 crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
285 CRYPTO_TFM_RES_MASK);
286 return err;
287}
288
289static int crypto_kw_init_tfm(struct crypto_tfm *tfm)
290{
291 struct crypto_instance *inst = crypto_tfm_alg_instance(tfm);
292 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
293 struct crypto_kw_ctx *ctx = crypto_tfm_ctx(tfm);
294 struct crypto_cipher *cipher;
295
296 cipher = crypto_spawn_cipher(spawn);
297 if (IS_ERR(cipher))
298 return PTR_ERR(cipher);
299
300 ctx->child = cipher;
301 return 0;
302}
303
304static void crypto_kw_exit_tfm(struct crypto_tfm *tfm)
305{
306 struct crypto_kw_ctx *ctx = crypto_tfm_ctx(tfm);
307
308 crypto_free_cipher(ctx->child);
309}
310
311static struct crypto_instance *crypto_kw_alloc(struct rtattr **tb)
312{
313 struct crypto_instance *inst = NULL;
314 struct crypto_alg *alg = NULL;
315 int err;
316
317 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
318 if (err)
319 return ERR_PTR(err);
320
321 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
322 CRYPTO_ALG_TYPE_MASK);
323 if (IS_ERR(alg))
324 return ERR_CAST(alg);
325
326 inst = ERR_PTR(-EINVAL);
327 /* Section 5.1 requirement for KW */
328 if (alg->cra_blocksize != sizeof(struct crypto_kw_block))
329 goto err;
330
331 inst = crypto_alloc_instance("kw", alg);
332 if (IS_ERR(inst))
333 goto err;
334
335 inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
336 inst->alg.cra_priority = alg->cra_priority;
337 inst->alg.cra_blocksize = SEMIBSIZE;
338 inst->alg.cra_alignmask = 0;
339 inst->alg.cra_type = &crypto_blkcipher_type;
340 inst->alg.cra_blkcipher.ivsize = SEMIBSIZE;
341 inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
342 inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
343
344 inst->alg.cra_ctxsize = sizeof(struct crypto_kw_ctx);
345
346 inst->alg.cra_init = crypto_kw_init_tfm;
347 inst->alg.cra_exit = crypto_kw_exit_tfm;
348
349 inst->alg.cra_blkcipher.setkey = crypto_kw_setkey;
350 inst->alg.cra_blkcipher.encrypt = crypto_kw_encrypt;
351 inst->alg.cra_blkcipher.decrypt = crypto_kw_decrypt;
352
353err:
354 crypto_mod_put(alg);
355 return inst;
356}
357
358static void crypto_kw_free(struct crypto_instance *inst)
359{
360 crypto_drop_spawn(crypto_instance_ctx(inst));
361 kfree(inst);
362}
363
364static struct crypto_template crypto_kw_tmpl = {
365 .name = "kw",
366 .alloc = crypto_kw_alloc,
367 .free = crypto_kw_free,
368 .module = THIS_MODULE,
369};
370
371static int __init crypto_kw_init(void)
372{
373 return crypto_register_template(&crypto_kw_tmpl);
374}
375
376static void __exit crypto_kw_exit(void)
377{
378 crypto_unregister_template(&crypto_kw_tmpl);
379}
380
381module_init(crypto_kw_init);
382module_exit(crypto_kw_exit);
383
384MODULE_LICENSE("Dual BSD/GPL");
385MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
386MODULE_DESCRIPTION("Key Wrapping (RFC3394 / NIST SP800-38F)");
387MODULE_ALIAS_CRYPTO("kw");