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3c09f17c HX |
1 | /* |
2 | * Authenc: Simple AEAD wrapper for IPsec | |
3 | * | |
4 | * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> | |
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 <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/spinlock.h> | |
20 | ||
21 | #include "scatterwalk.h" | |
22 | ||
23 | struct authenc_instance_ctx { | |
24 | struct crypto_spawn auth; | |
25 | struct crypto_spawn enc; | |
26 | ||
27 | unsigned int authsize; | |
28 | unsigned int enckeylen; | |
29 | }; | |
30 | ||
31 | struct crypto_authenc_ctx { | |
32 | spinlock_t auth_lock; | |
33 | struct crypto_hash *auth; | |
34 | struct crypto_ablkcipher *enc; | |
35 | }; | |
36 | ||
37 | static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, | |
38 | unsigned int keylen) | |
39 | { | |
40 | struct authenc_instance_ctx *ictx = | |
41 | crypto_instance_ctx(crypto_aead_alg_instance(authenc)); | |
42 | unsigned int enckeylen = ictx->enckeylen; | |
43 | unsigned int authkeylen; | |
44 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
45 | struct crypto_hash *auth = ctx->auth; | |
46 | struct crypto_ablkcipher *enc = ctx->enc; | |
47 | int err = -EINVAL; | |
48 | ||
49 | if (keylen < enckeylen) { | |
50 | crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
51 | goto out; | |
52 | } | |
53 | authkeylen = keylen - enckeylen; | |
54 | ||
55 | crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); | |
56 | crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) & | |
57 | CRYPTO_TFM_REQ_MASK); | |
58 | err = crypto_hash_setkey(auth, key, authkeylen); | |
59 | crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) & | |
60 | CRYPTO_TFM_RES_MASK); | |
61 | ||
62 | if (err) | |
63 | goto out; | |
64 | ||
65 | crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); | |
66 | crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) & | |
67 | CRYPTO_TFM_REQ_MASK); | |
68 | err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen); | |
69 | crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) & | |
70 | CRYPTO_TFM_RES_MASK); | |
71 | ||
72 | out: | |
73 | return err; | |
74 | } | |
75 | ||
76 | static int crypto_authenc_hash(struct aead_request *req) | |
77 | { | |
78 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
79 | struct authenc_instance_ctx *ictx = | |
80 | crypto_instance_ctx(crypto_aead_alg_instance(authenc)); | |
81 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
82 | struct crypto_hash *auth = ctx->auth; | |
83 | struct hash_desc desc = { | |
84 | .tfm = auth, | |
85 | }; | |
86 | u8 *hash = aead_request_ctx(req); | |
87 | struct scatterlist *dst; | |
88 | unsigned int cryptlen; | |
89 | int err; | |
90 | ||
91 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth), | |
92 | crypto_hash_alignmask(auth) + 1); | |
93 | ||
94 | spin_lock_bh(&ctx->auth_lock); | |
95 | err = crypto_hash_init(&desc); | |
96 | if (err) | |
97 | goto auth_unlock; | |
98 | ||
99 | err = crypto_hash_update(&desc, req->assoc, req->assoclen); | |
100 | if (err) | |
101 | goto auth_unlock; | |
102 | ||
103 | cryptlen = req->cryptlen; | |
104 | dst = req->dst; | |
105 | err = crypto_hash_update(&desc, dst, cryptlen); | |
106 | if (err) | |
107 | goto auth_unlock; | |
108 | ||
109 | err = crypto_hash_final(&desc, hash); | |
110 | auth_unlock: | |
111 | spin_unlock_bh(&ctx->auth_lock); | |
112 | ||
113 | if (err) | |
114 | return err; | |
115 | ||
116 | scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1); | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
121 | int err) | |
122 | { | |
123 | if (!err) | |
124 | err = crypto_authenc_hash(req->data); | |
125 | ||
126 | aead_request_complete(req->data, err); | |
127 | } | |
128 | ||
129 | static int crypto_authenc_encrypt(struct aead_request *req) | |
130 | { | |
131 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
132 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
133 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
134 | int err; | |
135 | ||
136 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
137 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
138 | crypto_authenc_encrypt_done, req); | |
139 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, | |
140 | req->iv); | |
141 | ||
142 | err = crypto_ablkcipher_encrypt(abreq); | |
143 | if (err) | |
144 | return err; | |
145 | ||
146 | return crypto_authenc_hash(req); | |
147 | } | |
148 | ||
149 | static int crypto_authenc_verify(struct aead_request *req) | |
150 | { | |
151 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
152 | struct authenc_instance_ctx *ictx = | |
153 | crypto_instance_ctx(crypto_aead_alg_instance(authenc)); | |
154 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
155 | struct crypto_hash *auth = ctx->auth; | |
156 | struct hash_desc desc = { | |
157 | .tfm = auth, | |
158 | .flags = aead_request_flags(req), | |
159 | }; | |
160 | u8 *ohash = aead_request_ctx(req); | |
161 | u8 *ihash; | |
162 | struct scatterlist *src; | |
163 | unsigned int cryptlen; | |
164 | unsigned int authsize; | |
165 | int err; | |
166 | ||
167 | ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth), | |
168 | crypto_hash_alignmask(auth) + 1); | |
169 | ihash = ohash + crypto_hash_digestsize(auth); | |
170 | ||
171 | spin_lock_bh(&ctx->auth_lock); | |
172 | err = crypto_hash_init(&desc); | |
173 | if (err) | |
174 | goto auth_unlock; | |
175 | ||
176 | err = crypto_hash_update(&desc, req->assoc, req->assoclen); | |
177 | if (err) | |
178 | goto auth_unlock; | |
179 | ||
180 | cryptlen = req->cryptlen; | |
181 | src = req->src; | |
182 | err = crypto_hash_update(&desc, src, cryptlen); | |
183 | if (err) | |
184 | goto auth_unlock; | |
185 | ||
186 | err = crypto_hash_final(&desc, ohash); | |
187 | auth_unlock: | |
188 | spin_unlock_bh(&ctx->auth_lock); | |
189 | ||
190 | if (err) | |
191 | return err; | |
192 | ||
193 | authsize = ictx->authsize; | |
194 | scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0); | |
195 | return memcmp(ihash, ohash, authsize) ? -EINVAL : 0; | |
196 | } | |
197 | ||
198 | static void crypto_authenc_decrypt_done(struct crypto_async_request *req, | |
199 | int err) | |
200 | { | |
201 | aead_request_complete(req->data, err); | |
202 | } | |
203 | ||
204 | static int crypto_authenc_decrypt(struct aead_request *req) | |
205 | { | |
206 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
207 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
208 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
209 | int err; | |
210 | ||
211 | err = crypto_authenc_verify(req); | |
212 | if (err) | |
213 | return err; | |
214 | ||
215 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
216 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
217 | crypto_authenc_decrypt_done, req); | |
218 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, | |
219 | req->iv); | |
220 | ||
221 | return crypto_ablkcipher_decrypt(abreq); | |
222 | } | |
223 | ||
224 | static int crypto_authenc_init_tfm(struct crypto_tfm *tfm) | |
225 | { | |
226 | struct crypto_instance *inst = (void *)tfm->__crt_alg; | |
227 | struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst); | |
228 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
229 | struct crypto_hash *auth; | |
230 | struct crypto_ablkcipher *enc; | |
231 | unsigned int digestsize; | |
232 | int err; | |
233 | ||
234 | auth = crypto_spawn_hash(&ictx->auth); | |
235 | if (IS_ERR(auth)) | |
236 | return PTR_ERR(auth); | |
237 | ||
238 | err = -EINVAL; | |
239 | digestsize = crypto_hash_digestsize(auth); | |
240 | if (ictx->authsize > digestsize) | |
241 | goto err_free_hash; | |
242 | ||
243 | enc = crypto_spawn_ablkcipher(&ictx->enc); | |
244 | err = PTR_ERR(enc); | |
245 | if (IS_ERR(enc)) | |
246 | goto err_free_hash; | |
247 | ||
248 | ctx->auth = auth; | |
249 | ctx->enc = enc; | |
250 | tfm->crt_aead.reqsize = max_t(unsigned int, | |
251 | (crypto_hash_alignmask(auth) & | |
252 | ~(crypto_tfm_ctx_alignment() - 1)) + | |
253 | digestsize * 2, | |
254 | sizeof(struct ablkcipher_request) + | |
255 | crypto_ablkcipher_reqsize(enc)); | |
256 | ||
257 | spin_lock_init(&ctx->auth_lock); | |
258 | ||
259 | return 0; | |
260 | ||
261 | err_free_hash: | |
262 | crypto_free_hash(auth); | |
263 | return err; | |
264 | } | |
265 | ||
266 | static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm) | |
267 | { | |
268 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
269 | ||
270 | crypto_free_hash(ctx->auth); | |
271 | crypto_free_ablkcipher(ctx->enc); | |
272 | } | |
273 | ||
274 | static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb) | |
275 | { | |
276 | struct crypto_instance *inst; | |
277 | struct crypto_alg *auth; | |
278 | struct crypto_alg *enc; | |
279 | struct authenc_instance_ctx *ctx; | |
280 | unsigned int authsize; | |
281 | unsigned int enckeylen; | |
282 | int err; | |
283 | ||
284 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); | |
285 | if (err) | |
286 | return ERR_PTR(err); | |
287 | ||
288 | auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, | |
289 | CRYPTO_ALG_TYPE_HASH_MASK); | |
290 | if (IS_ERR(auth)) | |
291 | return ERR_PTR(PTR_ERR(auth)); | |
292 | ||
293 | err = crypto_attr_u32(tb[2], &authsize); | |
294 | inst = ERR_PTR(err); | |
295 | if (err) | |
296 | goto out_put_auth; | |
297 | ||
298 | enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER, | |
299 | CRYPTO_ALG_TYPE_MASK); | |
300 | inst = ERR_PTR(PTR_ERR(enc)); | |
301 | if (IS_ERR(enc)) | |
302 | goto out_put_auth; | |
303 | ||
304 | err = crypto_attr_u32(tb[4], &enckeylen); | |
305 | if (err) | |
306 | goto out_put_enc; | |
307 | ||
308 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
309 | err = -ENOMEM; | |
310 | if (!inst) | |
311 | goto out_put_enc; | |
312 | ||
313 | err = -ENAMETOOLONG; | |
314 | if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, | |
e4c5c6c9 | 315 | "authenc(%s,%u,%s,%u)", auth->cra_name, authsize, |
3c09f17c HX |
316 | enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME) |
317 | goto err_free_inst; | |
318 | ||
319 | if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
e4c5c6c9 | 320 | "authenc(%s,%u,%s,%u)", auth->cra_driver_name, |
3c09f17c HX |
321 | authsize, enc->cra_driver_name, enckeylen) >= |
322 | CRYPTO_MAX_ALG_NAME) | |
323 | goto err_free_inst; | |
324 | ||
325 | ctx = crypto_instance_ctx(inst); | |
326 | ctx->authsize = authsize; | |
327 | ctx->enckeylen = enckeylen; | |
328 | ||
329 | err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); | |
330 | if (err) | |
331 | goto err_free_inst; | |
332 | ||
333 | err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK); | |
334 | if (err) | |
335 | goto err_drop_auth; | |
336 | ||
337 | inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC; | |
338 | inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority; | |
339 | inst->alg.cra_blocksize = enc->cra_blocksize; | |
340 | inst->alg.cra_alignmask = max(auth->cra_alignmask, enc->cra_alignmask); | |
341 | inst->alg.cra_type = &crypto_aead_type; | |
342 | ||
343 | inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize; | |
344 | inst->alg.cra_aead.authsize = authsize; | |
345 | ||
346 | inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
347 | ||
348 | inst->alg.cra_init = crypto_authenc_init_tfm; | |
349 | inst->alg.cra_exit = crypto_authenc_exit_tfm; | |
350 | ||
351 | inst->alg.cra_aead.setkey = crypto_authenc_setkey; | |
352 | inst->alg.cra_aead.encrypt = crypto_authenc_encrypt; | |
353 | inst->alg.cra_aead.decrypt = crypto_authenc_decrypt; | |
354 | ||
355 | out: | |
356 | crypto_mod_put(enc); | |
357 | out_put_auth: | |
358 | crypto_mod_put(auth); | |
359 | return inst; | |
360 | ||
361 | err_drop_auth: | |
362 | crypto_drop_spawn(&ctx->auth); | |
363 | err_free_inst: | |
364 | kfree(inst); | |
365 | out_put_enc: | |
366 | inst = ERR_PTR(err); | |
367 | goto out; | |
368 | } | |
369 | ||
370 | static void crypto_authenc_free(struct crypto_instance *inst) | |
371 | { | |
372 | struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst); | |
373 | ||
374 | crypto_drop_spawn(&ctx->enc); | |
375 | crypto_drop_spawn(&ctx->auth); | |
376 | kfree(inst); | |
377 | } | |
378 | ||
379 | static struct crypto_template crypto_authenc_tmpl = { | |
380 | .name = "authenc", | |
381 | .alloc = crypto_authenc_alloc, | |
382 | .free = crypto_authenc_free, | |
383 | .module = THIS_MODULE, | |
384 | }; | |
385 | ||
386 | static int __init crypto_authenc_module_init(void) | |
387 | { | |
388 | return crypto_register_template(&crypto_authenc_tmpl); | |
389 | } | |
390 | ||
391 | static void __exit crypto_authenc_module_exit(void) | |
392 | { | |
393 | crypto_unregister_template(&crypto_authenc_tmpl); | |
394 | } | |
395 | ||
396 | module_init(crypto_authenc_module_init); | |
397 | module_exit(crypto_authenc_module_exit); | |
398 | ||
399 | MODULE_LICENSE("GPL"); | |
400 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); |