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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>
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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>
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21#include <linux/slab.h>
22#include <linux/spinlock.h>
23
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24struct authenc_instance_ctx {
25 struct crypto_spawn auth;
26 struct crypto_spawn enc;
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27};
28
29struct crypto_authenc_ctx {
30 spinlock_t auth_lock;
31 struct crypto_hash *auth;
32 struct crypto_ablkcipher *enc;
33};
34
35static 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;
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40 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
41 struct crypto_hash *auth = ctx->auth;
42 struct crypto_ablkcipher *enc = ctx->enc;
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43 struct rtattr *rta = (void *)key;
44 struct crypto_authenc_key_param *param;
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45 int err = -EINVAL;
46
12dc5e62 47 if (!RTA_OK(rta, keylen))
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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
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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
82out:
83 return err;
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84
85badkey:
86 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN);
87 goto out;
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88}
89
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90static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags,
91 struct scatterlist *cipher,
92 unsigned int cryptlen)
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93{
94 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
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95 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
96 struct crypto_hash *auth = ctx->auth;
97 struct hash_desc desc = {
98 .tfm = auth,
7c3d703f 99 .flags = aead_request_flags(req) & flags,
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100 };
101 u8 *hash = aead_request_ctx(req);
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102 int err;
103
104 hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth),
105 crypto_hash_alignmask(auth) + 1);
106
107 spin_lock_bh(&ctx->auth_lock);
108 err = crypto_hash_init(&desc);
109 if (err)
110 goto auth_unlock;
111
112 err = crypto_hash_update(&desc, req->assoc, req->assoclen);
113 if (err)
114 goto auth_unlock;
115
7c3d703f 116 err = crypto_hash_update(&desc, cipher, cryptlen);
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117 if (err)
118 goto auth_unlock;
119
120 err = crypto_hash_final(&desc, hash);
121auth_unlock:
122 spin_unlock_bh(&ctx->auth_lock);
123
124 if (err)
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125 return ERR_PTR(err);
126
127 return hash;
128}
129
130static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
131{
132 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
133 struct scatterlist *dst = req->dst;
134 unsigned int cryptlen = req->cryptlen;
135 u8 *hash;
136
137 hash = crypto_authenc_hash(req, flags, dst, cryptlen);
138 if (IS_ERR(hash))
139 return PTR_ERR(hash);
3c09f17c 140
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141 scatterwalk_map_and_copy(hash, dst, cryptlen,
142 crypto_aead_authsize(authenc), 1);
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143 return 0;
144}
145
146static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
147 int err)
148{
149 if (!err)
7c3d703f 150 err = crypto_authenc_genicv(req->data, 0);
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151
152 aead_request_complete(req->data, err);
153}
154
155static int crypto_authenc_encrypt(struct aead_request *req)
156{
157 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
158 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
159 struct ablkcipher_request *abreq = aead_request_ctx(req);
160 int err;
161
162 ablkcipher_request_set_tfm(abreq, ctx->enc);
163 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
164 crypto_authenc_encrypt_done, req);
165 ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
166 req->iv);
167
168 err = crypto_ablkcipher_encrypt(abreq);
169 if (err)
170 return err;
171
7c3d703f 172 return crypto_authenc_genicv(req, CRYPTO_TFM_REQ_MAY_SLEEP);
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173}
174
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175static int crypto_authenc_verify(struct aead_request *req,
176 unsigned int cryptlen)
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177{
178 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
7c3d703f 179 u8 *ohash;
3c09f17c 180 u8 *ihash;
f347c4fa 181 struct scatterlist *src = req->src;
3c09f17c 182 unsigned int authsize;
3c09f17c 183
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184 ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, src,
185 cryptlen);
186 if (IS_ERR(ohash))
187 return PTR_ERR(ohash);
3c09f17c 188
7ba683a6 189 authsize = crypto_aead_authsize(authenc);
7c3d703f 190 ihash = ohash + authsize;
3c09f17c 191 scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0);
fe70f5df 192 return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0;
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193}
194
195static void crypto_authenc_decrypt_done(struct crypto_async_request *req,
196 int err)
197{
198 aead_request_complete(req->data, err);
199}
200
201static int crypto_authenc_decrypt(struct aead_request *req)
202{
203 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
204 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
205 struct ablkcipher_request *abreq = aead_request_ctx(req);
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206 unsigned int cryptlen = req->cryptlen;
207 unsigned int authsize = crypto_aead_authsize(authenc);
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208 int err;
209
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210 if (cryptlen < authsize)
211 return -EINVAL;
212 cryptlen -= authsize;
213
214 err = crypto_authenc_verify(req, cryptlen);
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215 if (err)
216 return err;
217
218 ablkcipher_request_set_tfm(abreq, ctx->enc);
219 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
220 crypto_authenc_decrypt_done, req);
481f34ae 221 ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen,
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222 req->iv);
223
224 return crypto_ablkcipher_decrypt(abreq);
225}
226
227static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
228{
229 struct crypto_instance *inst = (void *)tfm->__crt_alg;
230 struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst);
231 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
232 struct crypto_hash *auth;
233 struct crypto_ablkcipher *enc;
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234 int err;
235
236 auth = crypto_spawn_hash(&ictx->auth);
237 if (IS_ERR(auth))
238 return PTR_ERR(auth);
239
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240 enc = crypto_spawn_ablkcipher(&ictx->enc);
241 err = PTR_ERR(enc);
242 if (IS_ERR(enc))
243 goto err_free_hash;
244
245 ctx->auth = auth;
246 ctx->enc = enc;
247 tfm->crt_aead.reqsize = max_t(unsigned int,
248 (crypto_hash_alignmask(auth) &
249 ~(crypto_tfm_ctx_alignment() - 1)) +
7ba683a6 250 crypto_hash_digestsize(auth) * 2,
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251 sizeof(struct ablkcipher_request) +
252 crypto_ablkcipher_reqsize(enc));
253
254 spin_lock_init(&ctx->auth_lock);
255
256 return 0;
257
258err_free_hash:
259 crypto_free_hash(auth);
260 return err;
261}
262
263static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm)
264{
265 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
266
267 crypto_free_hash(ctx->auth);
268 crypto_free_ablkcipher(ctx->enc);
269}
270
271static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
272{
273 struct crypto_instance *inst;
274 struct crypto_alg *auth;
275 struct crypto_alg *enc;
276 struct authenc_instance_ctx *ctx;
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277 int err;
278
279 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);
280 if (err)
281 return ERR_PTR(err);
282
283 auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
284 CRYPTO_ALG_TYPE_HASH_MASK);
285 if (IS_ERR(auth))
286 return ERR_PTR(PTR_ERR(auth));
287
7ba683a6 288 enc = crypto_attr_alg(tb[2], CRYPTO_ALG_TYPE_BLKCIPHER,
332f8840 289 CRYPTO_ALG_TYPE_BLKCIPHER_MASK);
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290 inst = ERR_PTR(PTR_ERR(enc));
291 if (IS_ERR(enc))
292 goto out_put_auth;
293
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294 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
295 err = -ENOMEM;
296 if (!inst)
297 goto out_put_enc;
298
299 err = -ENAMETOOLONG;
300 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
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301 "authenc(%s,%s)", auth->cra_name, enc->cra_name) >=
302 CRYPTO_MAX_ALG_NAME)
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303 goto err_free_inst;
304
305 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
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306 "authenc(%s,%s)", auth->cra_driver_name,
307 enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
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308 goto err_free_inst;
309
310 ctx = crypto_instance_ctx(inst);
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311
312 err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK);
313 if (err)
314 goto err_free_inst;
315
316 err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK);
317 if (err)
318 goto err_drop_auth;
319
320 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
321 inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority;
322 inst->alg.cra_blocksize = enc->cra_blocksize;
e29bc6ad 323 inst->alg.cra_alignmask = auth->cra_alignmask | enc->cra_alignmask;
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324 inst->alg.cra_type = &crypto_aead_type;
325
c2c61f51 326 inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize;
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327 inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ?
328 auth->cra_hash.digestsize :
329 auth->cra_digest.dia_digestsize;
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330
331 inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
332
333 inst->alg.cra_init = crypto_authenc_init_tfm;
334 inst->alg.cra_exit = crypto_authenc_exit_tfm;
335
336 inst->alg.cra_aead.setkey = crypto_authenc_setkey;
337 inst->alg.cra_aead.encrypt = crypto_authenc_encrypt;
338 inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
339
340out:
341 crypto_mod_put(enc);
342out_put_auth:
343 crypto_mod_put(auth);
344 return inst;
345
346err_drop_auth:
347 crypto_drop_spawn(&ctx->auth);
348err_free_inst:
349 kfree(inst);
350out_put_enc:
351 inst = ERR_PTR(err);
352 goto out;
353}
354
355static void crypto_authenc_free(struct crypto_instance *inst)
356{
357 struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst);
358
359 crypto_drop_spawn(&ctx->enc);
360 crypto_drop_spawn(&ctx->auth);
361 kfree(inst);
362}
363
364static struct crypto_template crypto_authenc_tmpl = {
365 .name = "authenc",
366 .alloc = crypto_authenc_alloc,
367 .free = crypto_authenc_free,
368 .module = THIS_MODULE,
369};
370
371static int __init crypto_authenc_module_init(void)
372{
373 return crypto_register_template(&crypto_authenc_tmpl);
374}
375
376static void __exit crypto_authenc_module_exit(void)
377{
378 crypto_unregister_template(&crypto_authenc_tmpl);
379}
380
381module_init(crypto_authenc_module_init);
382module_exit(crypto_authenc_module_exit);
383
384MODULE_LICENSE("GPL");
385MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");