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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> | |
e236d4a8 | 14 | #include <crypto/authenc.h> |
42c271c6 | 15 | #include <crypto/scatterwalk.h> |
3c09f17c HX |
16 | #include <linux/err.h> |
17 | #include <linux/init.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
e236d4a8 | 20 | #include <linux/rtnetlink.h> |
3c09f17c HX |
21 | #include <linux/slab.h> |
22 | #include <linux/spinlock.h> | |
23 | ||
3c09f17c HX |
24 | struct authenc_instance_ctx { |
25 | struct crypto_spawn auth; | |
26 | struct crypto_spawn enc; | |
3c09f17c HX |
27 | }; |
28 | ||
29 | struct crypto_authenc_ctx { | |
30 | spinlock_t auth_lock; | |
31 | struct crypto_hash *auth; | |
32 | struct crypto_ablkcipher *enc; | |
33 | }; | |
34 | ||
35 | static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key, | |
36 | unsigned int keylen) | |
37 | { | |
3c09f17c | 38 | unsigned int authkeylen; |
e236d4a8 | 39 | unsigned int enckeylen; |
3c09f17c HX |
40 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); |
41 | struct crypto_hash *auth = ctx->auth; | |
42 | struct crypto_ablkcipher *enc = ctx->enc; | |
e236d4a8 HX |
43 | struct rtattr *rta = (void *)key; |
44 | struct crypto_authenc_key_param *param; | |
3c09f17c HX |
45 | int err = -EINVAL; |
46 | ||
e236d4a8 HX |
47 | if (keylen < sizeof(*rta)) |
48 | goto badkey; | |
49 | if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM) | |
50 | goto badkey; | |
51 | if (RTA_PAYLOAD(rta) < sizeof(*param)) | |
52 | goto badkey; | |
53 | ||
54 | param = RTA_DATA(rta); | |
55 | enckeylen = be32_to_cpu(param->enckeylen); | |
56 | ||
57 | key += RTA_ALIGN(rta->rta_len); | |
58 | keylen -= RTA_ALIGN(rta->rta_len); | |
59 | ||
60 | if (keylen < enckeylen) | |
61 | goto badkey; | |
62 | ||
3c09f17c HX |
63 | authkeylen = keylen - enckeylen; |
64 | ||
65 | crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK); | |
66 | crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) & | |
67 | CRYPTO_TFM_REQ_MASK); | |
68 | err = crypto_hash_setkey(auth, key, authkeylen); | |
69 | crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) & | |
70 | CRYPTO_TFM_RES_MASK); | |
71 | ||
72 | if (err) | |
73 | goto out; | |
74 | ||
75 | crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK); | |
76 | crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) & | |
77 | CRYPTO_TFM_REQ_MASK); | |
78 | err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen); | |
79 | crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) & | |
80 | CRYPTO_TFM_RES_MASK); | |
81 | ||
82 | out: | |
83 | return err; | |
e236d4a8 HX |
84 | |
85 | badkey: | |
86 | crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
87 | goto out; | |
3c09f17c HX |
88 | } |
89 | ||
90 | static int crypto_authenc_hash(struct aead_request *req) | |
91 | { | |
92 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
3c09f17c HX |
93 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); |
94 | struct crypto_hash *auth = ctx->auth; | |
95 | struct hash_desc desc = { | |
96 | .tfm = auth, | |
97 | }; | |
98 | u8 *hash = aead_request_ctx(req); | |
f347c4fa HX |
99 | struct scatterlist *dst = req->dst; |
100 | unsigned int cryptlen = req->cryptlen; | |
3c09f17c HX |
101 | int err; |
102 | ||
103 | hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth), | |
104 | crypto_hash_alignmask(auth) + 1); | |
105 | ||
106 | spin_lock_bh(&ctx->auth_lock); | |
107 | err = crypto_hash_init(&desc); | |
108 | if (err) | |
109 | goto auth_unlock; | |
110 | ||
111 | err = crypto_hash_update(&desc, req->assoc, req->assoclen); | |
112 | if (err) | |
113 | goto auth_unlock; | |
114 | ||
3c09f17c HX |
115 | err = crypto_hash_update(&desc, dst, cryptlen); |
116 | if (err) | |
117 | goto auth_unlock; | |
118 | ||
119 | err = crypto_hash_final(&desc, hash); | |
120 | auth_unlock: | |
121 | spin_unlock_bh(&ctx->auth_lock); | |
122 | ||
123 | if (err) | |
124 | return err; | |
125 | ||
7ba683a6 HX |
126 | scatterwalk_map_and_copy(hash, dst, cryptlen, |
127 | crypto_aead_authsize(authenc), 1); | |
3c09f17c HX |
128 | return 0; |
129 | } | |
130 | ||
131 | static void crypto_authenc_encrypt_done(struct crypto_async_request *req, | |
132 | int err) | |
133 | { | |
134 | if (!err) | |
135 | err = crypto_authenc_hash(req->data); | |
136 | ||
137 | aead_request_complete(req->data, err); | |
138 | } | |
139 | ||
140 | static int crypto_authenc_encrypt(struct aead_request *req) | |
141 | { | |
142 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
143 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
144 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
145 | int err; | |
146 | ||
147 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
148 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
149 | crypto_authenc_encrypt_done, req); | |
150 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen, | |
151 | req->iv); | |
152 | ||
153 | err = crypto_ablkcipher_encrypt(abreq); | |
154 | if (err) | |
155 | return err; | |
156 | ||
157 | return crypto_authenc_hash(req); | |
158 | } | |
159 | ||
481f34ae HX |
160 | static int crypto_authenc_verify(struct aead_request *req, |
161 | unsigned int cryptlen) | |
3c09f17c HX |
162 | { |
163 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
3c09f17c HX |
164 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); |
165 | struct crypto_hash *auth = ctx->auth; | |
166 | struct hash_desc desc = { | |
167 | .tfm = auth, | |
168 | .flags = aead_request_flags(req), | |
169 | }; | |
170 | u8 *ohash = aead_request_ctx(req); | |
171 | u8 *ihash; | |
f347c4fa | 172 | struct scatterlist *src = req->src; |
3c09f17c HX |
173 | unsigned int authsize; |
174 | int err; | |
175 | ||
176 | ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth), | |
177 | crypto_hash_alignmask(auth) + 1); | |
178 | ihash = ohash + crypto_hash_digestsize(auth); | |
179 | ||
180 | spin_lock_bh(&ctx->auth_lock); | |
181 | err = crypto_hash_init(&desc); | |
182 | if (err) | |
183 | goto auth_unlock; | |
184 | ||
185 | err = crypto_hash_update(&desc, req->assoc, req->assoclen); | |
186 | if (err) | |
187 | goto auth_unlock; | |
188 | ||
3c09f17c HX |
189 | err = crypto_hash_update(&desc, src, cryptlen); |
190 | if (err) | |
191 | goto auth_unlock; | |
192 | ||
193 | err = crypto_hash_final(&desc, ohash); | |
194 | auth_unlock: | |
195 | spin_unlock_bh(&ctx->auth_lock); | |
196 | ||
197 | if (err) | |
198 | return err; | |
199 | ||
7ba683a6 | 200 | authsize = crypto_aead_authsize(authenc); |
3c09f17c | 201 | scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0); |
fe70f5df | 202 | return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0; |
3c09f17c HX |
203 | } |
204 | ||
205 | static void crypto_authenc_decrypt_done(struct crypto_async_request *req, | |
206 | int err) | |
207 | { | |
208 | aead_request_complete(req->data, err); | |
209 | } | |
210 | ||
211 | static int crypto_authenc_decrypt(struct aead_request *req) | |
212 | { | |
213 | struct crypto_aead *authenc = crypto_aead_reqtfm(req); | |
214 | struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc); | |
215 | struct ablkcipher_request *abreq = aead_request_ctx(req); | |
481f34ae HX |
216 | unsigned int cryptlen = req->cryptlen; |
217 | unsigned int authsize = crypto_aead_authsize(authenc); | |
3c09f17c HX |
218 | int err; |
219 | ||
481f34ae HX |
220 | if (cryptlen < authsize) |
221 | return -EINVAL; | |
222 | cryptlen -= authsize; | |
223 | ||
224 | err = crypto_authenc_verify(req, cryptlen); | |
3c09f17c HX |
225 | if (err) |
226 | return err; | |
227 | ||
228 | ablkcipher_request_set_tfm(abreq, ctx->enc); | |
229 | ablkcipher_request_set_callback(abreq, aead_request_flags(req), | |
230 | crypto_authenc_decrypt_done, req); | |
481f34ae | 231 | ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, |
3c09f17c HX |
232 | req->iv); |
233 | ||
234 | return crypto_ablkcipher_decrypt(abreq); | |
235 | } | |
236 | ||
237 | static int crypto_authenc_init_tfm(struct crypto_tfm *tfm) | |
238 | { | |
239 | struct crypto_instance *inst = (void *)tfm->__crt_alg; | |
240 | struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst); | |
241 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
242 | struct crypto_hash *auth; | |
243 | struct crypto_ablkcipher *enc; | |
3c09f17c HX |
244 | int err; |
245 | ||
246 | auth = crypto_spawn_hash(&ictx->auth); | |
247 | if (IS_ERR(auth)) | |
248 | return PTR_ERR(auth); | |
249 | ||
3c09f17c HX |
250 | enc = crypto_spawn_ablkcipher(&ictx->enc); |
251 | err = PTR_ERR(enc); | |
252 | if (IS_ERR(enc)) | |
253 | goto err_free_hash; | |
254 | ||
255 | ctx->auth = auth; | |
256 | ctx->enc = enc; | |
257 | tfm->crt_aead.reqsize = max_t(unsigned int, | |
258 | (crypto_hash_alignmask(auth) & | |
259 | ~(crypto_tfm_ctx_alignment() - 1)) + | |
7ba683a6 | 260 | crypto_hash_digestsize(auth) * 2, |
3c09f17c HX |
261 | sizeof(struct ablkcipher_request) + |
262 | crypto_ablkcipher_reqsize(enc)); | |
263 | ||
264 | spin_lock_init(&ctx->auth_lock); | |
265 | ||
266 | return 0; | |
267 | ||
268 | err_free_hash: | |
269 | crypto_free_hash(auth); | |
270 | return err; | |
271 | } | |
272 | ||
273 | static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm) | |
274 | { | |
275 | struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm); | |
276 | ||
277 | crypto_free_hash(ctx->auth); | |
278 | crypto_free_ablkcipher(ctx->enc); | |
279 | } | |
280 | ||
281 | static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb) | |
282 | { | |
283 | struct crypto_instance *inst; | |
284 | struct crypto_alg *auth; | |
285 | struct crypto_alg *enc; | |
286 | struct authenc_instance_ctx *ctx; | |
3c09f17c HX |
287 | int err; |
288 | ||
289 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); | |
290 | if (err) | |
291 | return ERR_PTR(err); | |
292 | ||
293 | auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH, | |
294 | CRYPTO_ALG_TYPE_HASH_MASK); | |
295 | if (IS_ERR(auth)) | |
296 | return ERR_PTR(PTR_ERR(auth)); | |
297 | ||
7ba683a6 | 298 | enc = crypto_attr_alg(tb[2], CRYPTO_ALG_TYPE_BLKCIPHER, |
332f8840 | 299 | CRYPTO_ALG_TYPE_BLKCIPHER_MASK); |
3c09f17c HX |
300 | inst = ERR_PTR(PTR_ERR(enc)); |
301 | if (IS_ERR(enc)) | |
302 | goto out_put_auth; | |
303 | ||
3c09f17c HX |
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, | |
e236d4a8 HX |
311 | "authenc(%s,%s)", auth->cra_name, enc->cra_name) >= |
312 | CRYPTO_MAX_ALG_NAME) | |
3c09f17c HX |
313 | goto err_free_inst; |
314 | ||
315 | if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
e236d4a8 HX |
316 | "authenc(%s,%s)", auth->cra_driver_name, |
317 | enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
3c09f17c HX |
318 | goto err_free_inst; |
319 | ||
320 | ctx = crypto_instance_ctx(inst); | |
3c09f17c HX |
321 | |
322 | err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK); | |
323 | if (err) | |
324 | goto err_free_inst; | |
325 | ||
326 | err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK); | |
327 | if (err) | |
328 | goto err_drop_auth; | |
329 | ||
330 | inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC; | |
331 | inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority; | |
332 | inst->alg.cra_blocksize = enc->cra_blocksize; | |
e29bc6ad | 333 | inst->alg.cra_alignmask = auth->cra_alignmask | enc->cra_alignmask; |
3c09f17c HX |
334 | inst->alg.cra_type = &crypto_aead_type; |
335 | ||
336 | inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize; | |
7ba683a6 HX |
337 | inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ? |
338 | auth->cra_hash.digestsize : | |
339 | auth->cra_digest.dia_digestsize; | |
3c09f17c HX |
340 | |
341 | inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx); | |
342 | ||
343 | inst->alg.cra_init = crypto_authenc_init_tfm; | |
344 | inst->alg.cra_exit = crypto_authenc_exit_tfm; | |
345 | ||
346 | inst->alg.cra_aead.setkey = crypto_authenc_setkey; | |
347 | inst->alg.cra_aead.encrypt = crypto_authenc_encrypt; | |
348 | inst->alg.cra_aead.decrypt = crypto_authenc_decrypt; | |
349 | ||
350 | out: | |
351 | crypto_mod_put(enc); | |
352 | out_put_auth: | |
353 | crypto_mod_put(auth); | |
354 | return inst; | |
355 | ||
356 | err_drop_auth: | |
357 | crypto_drop_spawn(&ctx->auth); | |
358 | err_free_inst: | |
359 | kfree(inst); | |
360 | out_put_enc: | |
361 | inst = ERR_PTR(err); | |
362 | goto out; | |
363 | } | |
364 | ||
365 | static void crypto_authenc_free(struct crypto_instance *inst) | |
366 | { | |
367 | struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst); | |
368 | ||
369 | crypto_drop_spawn(&ctx->enc); | |
370 | crypto_drop_spawn(&ctx->auth); | |
371 | kfree(inst); | |
372 | } | |
373 | ||
374 | static struct crypto_template crypto_authenc_tmpl = { | |
375 | .name = "authenc", | |
376 | .alloc = crypto_authenc_alloc, | |
377 | .free = crypto_authenc_free, | |
378 | .module = THIS_MODULE, | |
379 | }; | |
380 | ||
381 | static int __init crypto_authenc_module_init(void) | |
382 | { | |
383 | return crypto_register_template(&crypto_authenc_tmpl); | |
384 | } | |
385 | ||
386 | static void __exit crypto_authenc_module_exit(void) | |
387 | { | |
388 | crypto_unregister_template(&crypto_authenc_tmpl); | |
389 | } | |
390 | ||
391 | module_init(crypto_authenc_module_init); | |
392 | module_exit(crypto_authenc_module_exit); | |
393 | ||
394 | MODULE_LICENSE("GPL"); | |
395 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec"); |