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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); | |
f347c4fa HX |
87 | struct scatterlist *dst = req->dst; |
88 | unsigned int cryptlen = req->cryptlen; | |
3c09f17c HX |
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 | ||
3c09f17c HX |
103 | err = crypto_hash_update(&desc, dst, cryptlen); |
104 | if (err) | |
105 | goto auth_unlock; | |
106 | ||
107 | err = crypto_hash_final(&desc, hash); | |
108 | auth_unlock: | |
109 | spin_unlock_bh(&ctx->auth_lock); | |
110 | ||
111 | if (err) | |
112 | return err; | |
113 | ||
114 | scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
119 | int err) | |
120 | { | |
121 | if (!err) | |
122 | err = crypto_authenc_hash(req->data); | |
123 | ||
124 | aead_request_complete(req->data, err); | |
125 | } | |
126 | ||
127 | static int crypto_authenc_encrypt(struct aead_request *req) | |
128 | { | |
129 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
130 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
131 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
132 | int err; | |
133 | ||
134 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
135 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
136 | crypto_authenc_encrypt_done, req); | |
137 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, | |
138 | req->iv); | |
139 | ||
140 | err = crypto_ablkcipher_encrypt(abreq); | |
141 | if (err) | |
142 | return err; | |
143 | ||
144 | return crypto_authenc_hash(req); | |
145 | } | |
146 | ||
147 | static int crypto_authenc_verify(struct aead_request *req) | |
148 | { | |
149 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
150 | struct authenc_instance_ctx *ictx = | |
151 | crypto_instance_ctx(crypto_aead_alg_instance(authenc)); | |
152 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
153 | struct crypto_hash *auth = ctx->auth; | |
154 | struct hash_desc desc = { | |
155 | .tfm = auth, | |
156 | .flags = aead_request_flags(req), | |
157 | }; | |
158 | u8 *ohash = aead_request_ctx(req); | |
159 | u8 *ihash; | |
f347c4fa HX |
160 | struct scatterlist *src = req->src; |
161 | unsigned int cryptlen = req->cryptlen; | |
3c09f17c HX |
162 | unsigned int authsize; |
163 | int err; | |
164 | ||
165 | ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth), | |
166 | crypto_hash_alignmask(auth) + 1); | |
167 | ihash = ohash + crypto_hash_digestsize(auth); | |
168 | ||
169 | spin_lock_bh(&ctx->auth_lock); | |
170 | err = crypto_hash_init(&desc); | |
171 | if (err) | |
172 | goto auth_unlock; | |
173 | ||
174 | err = crypto_hash_update(&desc, req->assoc, req->assoclen); | |
175 | if (err) | |
176 | goto auth_unlock; | |
177 | ||
3c09f17c HX |
178 | err = crypto_hash_update(&desc, src, cryptlen); |
179 | if (err) | |
180 | goto auth_unlock; | |
181 | ||
182 | err = crypto_hash_final(&desc, ohash); | |
183 | auth_unlock: | |
184 | spin_unlock_bh(&ctx->auth_lock); | |
185 | ||
186 | if (err) | |
187 | return err; | |
188 | ||
189 | authsize = ictx->authsize; | |
190 | scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0); | |
191 | return memcmp(ihash, ohash, authsize) ? -EINVAL : 0; | |
192 | } | |
193 | ||
194 | static void crypto_authenc_decrypt_done(struct crypto_async_request *req, | |
195 | int err) | |
196 | { | |
197 | aead_request_complete(req->data, err); | |
198 | } | |
199 | ||
200 | static int crypto_authenc_decrypt(struct aead_request *req) | |
201 | { | |
202 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
203 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
204 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
205 | int err; | |
206 | ||
207 | err = crypto_authenc_verify(req); | |
208 | if (err) | |
209 | return err; | |
210 | ||
211 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
212 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
213 | crypto_authenc_decrypt_done, req); | |
214 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, | |
215 | req->iv); | |
216 | ||
217 | return crypto_ablkcipher_decrypt(abreq); | |
218 | } | |
219 | ||
220 | static int crypto_authenc_init_tfm(struct crypto_tfm *tfm) | |
221 | { | |
222 | struct crypto_instance *inst = (void *)tfm->__crt_alg; | |
223 | struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst); | |
224 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
225 | struct crypto_hash *auth; | |
226 | struct crypto_ablkcipher *enc; | |
227 | unsigned int digestsize; | |
228 | int err; | |
229 | ||
230 | auth = crypto_spawn_hash(&ictx->auth); | |
231 | if (IS_ERR(auth)) | |
232 | return PTR_ERR(auth); | |
233 | ||
234 | err = -EINVAL; | |
235 | digestsize = crypto_hash_digestsize(auth); | |
236 | if (ictx->authsize > digestsize) | |
237 | goto err_free_hash; | |
238 | ||
239 | enc = crypto_spawn_ablkcipher(&ictx->enc); | |
240 | err = PTR_ERR(enc); | |
241 | if (IS_ERR(enc)) | |
242 | goto err_free_hash; | |
243 | ||
244 | ctx->auth = auth; | |
245 | ctx->enc = enc; | |
246 | tfm->crt_aead.reqsize = max_t(unsigned int, | |
247 | (crypto_hash_alignmask(auth) & | |
248 | ~(crypto_tfm_ctx_alignment() - 1)) + | |
249 | digestsize * 2, | |
250 | sizeof(struct ablkcipher_request) + | |
251 | crypto_ablkcipher_reqsize(enc)); | |
252 | ||
253 | spin_lock_init(&ctx->auth_lock); | |
254 | ||
255 | return 0; | |
256 | ||
257 | err_free_hash: | |
258 | crypto_free_hash(auth); | |
259 | return err; | |
260 | } | |
261 | ||
262 | static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm) | |
263 | { | |
264 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
265 | ||
266 | crypto_free_hash(ctx->auth); | |
267 | crypto_free_ablkcipher(ctx->enc); | |
268 | } | |
269 | ||
270 | static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb) | |
271 | { | |
272 | struct crypto_instance *inst; | |
273 | struct crypto_alg *auth; | |
274 | struct crypto_alg *enc; | |
275 | struct authenc_instance_ctx *ctx; | |
276 | unsigned int authsize; | |
277 | unsigned int enckeylen; | |
278 | int err; | |
279 | ||
280 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); | |
281 | if (err) | |
282 | return ERR_PTR(err); | |
283 | ||
284 | auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, | |
285 | CRYPTO_ALG_TYPE_HASH_MASK); | |
286 | if (IS_ERR(auth)) | |
287 | return ERR_PTR(PTR_ERR(auth)); | |
288 | ||
289 | err = crypto_attr_u32(tb[2], &authsize); | |
290 | inst = ERR_PTR(err); | |
291 | if (err) | |
292 | goto out_put_auth; | |
293 | ||
294 | enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER, | |
295 | CRYPTO_ALG_TYPE_MASK); | |
296 | inst = ERR_PTR(PTR_ERR(enc)); | |
297 | if (IS_ERR(enc)) | |
298 | goto out_put_auth; | |
299 | ||
300 | err = crypto_attr_u32(tb[4], &enckeylen); | |
301 | if (err) | |
302 | goto out_put_enc; | |
303 | ||
304 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
305 | err = -ENOMEM; | |
306 | if (!inst) | |
307 | goto out_put_enc; | |
308 | ||
309 | err = -ENAMETOOLONG; | |
310 | if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, | |
e4c5c6c9 | 311 | "authenc(%s,%u,%s,%u)", auth->cra_name, authsize, |
3c09f17c HX |
312 | enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME) |
313 | goto err_free_inst; | |
314 | ||
315 | if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
e4c5c6c9 | 316 | "authenc(%s,%u,%s,%u)", auth->cra_driver_name, |
3c09f17c HX |
317 | authsize, enc->cra_driver_name, enckeylen) >= |
318 | CRYPTO_MAX_ALG_NAME) | |
319 | goto err_free_inst; | |
320 | ||
321 | ctx = crypto_instance_ctx(inst); | |
322 | ctx->authsize = authsize; | |
323 | ctx->enckeylen = enckeylen; | |
324 | ||
325 | err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); | |
326 | if (err) | |
327 | goto err_free_inst; | |
328 | ||
329 | err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK); | |
330 | if (err) | |
331 | goto err_drop_auth; | |
332 | ||
333 | inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC; | |
334 | inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority; | |
335 | inst->alg.cra_blocksize = enc->cra_blocksize; | |
336 | inst->alg.cra_alignmask = max(auth->cra_alignmask, enc->cra_alignmask); | |
337 | inst->alg.cra_type = &crypto_aead_type; | |
338 | ||
339 | inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize; | |
340 | inst->alg.cra_aead.authsize = authsize; | |
341 | ||
342 | inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
343 | ||
344 | inst->alg.cra_init = crypto_authenc_init_tfm; | |
345 | inst->alg.cra_exit = crypto_authenc_exit_tfm; | |
346 | ||
347 | inst->alg.cra_aead.setkey = crypto_authenc_setkey; | |
348 | inst->alg.cra_aead.encrypt = crypto_authenc_encrypt; | |
349 | inst->alg.cra_aead.decrypt = crypto_authenc_decrypt; | |
350 | ||
351 | out: | |
352 | crypto_mod_put(enc); | |
353 | out_put_auth: | |
354 | crypto_mod_put(auth); | |
355 | return inst; | |
356 | ||
357 | err_drop_auth: | |
358 | crypto_drop_spawn(&ctx->auth); | |
359 | err_free_inst: | |
360 | kfree(inst); | |
361 | out_put_enc: | |
362 | inst = ERR_PTR(err); | |
363 | goto out; | |
364 | } | |
365 | ||
366 | static void crypto_authenc_free(struct crypto_instance *inst) | |
367 | { | |
368 | struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst); | |
369 | ||
370 | crypto_drop_spawn(&ctx->enc); | |
371 | crypto_drop_spawn(&ctx->auth); | |
372 | kfree(inst); | |
373 | } | |
374 | ||
375 | static struct crypto_template crypto_authenc_tmpl = { | |
376 | .name = "authenc", | |
377 | .alloc = crypto_authenc_alloc, | |
378 | .free = crypto_authenc_free, | |
379 | .module = THIS_MODULE, | |
380 | }; | |
381 | ||
382 | static int __init crypto_authenc_module_init(void) | |
383 | { | |
384 | return crypto_register_template(&crypto_authenc_tmpl); | |
385 | } | |
386 | ||
387 | static void __exit crypto_authenc_module_exit(void) | |
388 | { | |
389 | crypto_unregister_template(&crypto_authenc_tmpl); | |
390 | } | |
391 | ||
392 | module_init(crypto_authenc_module_init); | |
393 | module_exit(crypto_authenc_module_exit); | |
394 | ||
395 | MODULE_LICENSE("GPL"); | |
396 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); |