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/aead.h>
14 #include <crypto/internal/hash.h>
15 #include <crypto/internal/skcipher.h>
16 #include <crypto/authenc.h>
17 #include <crypto/scatterwalk.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/rtnetlink.h>
23 #include <linux/slab.h>
24 #include <linux/spinlock.h>
25
26 struct authenc_instance_ctx {
27 struct crypto_spawn auth;
28 struct crypto_skcipher_spawn enc;
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 unsigned int authkeylen;
41 unsigned int enckeylen;
42 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
43 struct crypto_hash *auth = ctx->auth;
44 struct crypto_ablkcipher *enc = ctx->enc;
45 struct rtattr *rta = (void *)key;
46 struct crypto_authenc_key_param *param;
47 int err = -EINVAL;
48
49 if (!RTA_OK(rta, keylen))
50 goto badkey;
51 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
52 goto badkey;
53 if (RTA_PAYLOAD(rta) < sizeof(*param))
54 goto badkey;
55
56 param = RTA_DATA(rta);
57 enckeylen = be32_to_cpu(param->enckeylen);
58
59 key += RTA_ALIGN(rta->rta_len);
60 keylen -= RTA_ALIGN(rta->rta_len);
61
62 if (keylen < enckeylen)
63 goto badkey;
64
65 authkeylen = keylen - enckeylen;
66
67 crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
68 crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) &
69 CRYPTO_TFM_REQ_MASK);
70 err = crypto_hash_setkey(auth, key, authkeylen);
71 crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) &
72 CRYPTO_TFM_RES_MASK);
73
74 if (err)
75 goto out;
76
77 crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
78 crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
79 CRYPTO_TFM_REQ_MASK);
80 err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen);
81 crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) &
82 CRYPTO_TFM_RES_MASK);
83
84 out:
85 return err;
86
87 badkey:
88 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN);
89 goto out;
90 }
91
92 static void authenc_chain(struct scatterlist *head, struct scatterlist *sg,
93 int chain)
94 {
95 if (chain) {
96 head->length += sg->length;
97 sg = scatterwalk_sg_next(sg);
98 }
99
100 if (sg)
101 scatterwalk_sg_chain(head, 2, sg);
102 else
103 sg_mark_end(head);
104 }
105
106 static u8 *crypto_authenc_hash(struct aead_request *req, unsigned int flags,
107 struct scatterlist *cipher,
108 unsigned int cryptlen)
109 {
110 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
111 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
112 struct crypto_hash *auth = ctx->auth;
113 struct hash_desc desc = {
114 .tfm = auth,
115 .flags = aead_request_flags(req) & flags,
116 };
117 u8 *hash = aead_request_ctx(req);
118 int err;
119
120 hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth),
121 crypto_hash_alignmask(auth) + 1);
122
123 spin_lock_bh(&ctx->auth_lock);
124 err = crypto_hash_init(&desc);
125 if (err)
126 goto auth_unlock;
127
128 err = crypto_hash_update(&desc, req->assoc, req->assoclen);
129 if (err)
130 goto auth_unlock;
131
132 err = crypto_hash_update(&desc, cipher, cryptlen);
133 if (err)
134 goto auth_unlock;
135
136 err = crypto_hash_final(&desc, hash);
137 auth_unlock:
138 spin_unlock_bh(&ctx->auth_lock);
139
140 if (err)
141 return ERR_PTR(err);
142
143 return hash;
144 }
145
146 static int crypto_authenc_genicv(struct aead_request *req, u8 *iv,
147 unsigned int flags)
148 {
149 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
150 struct scatterlist *dst = req->dst;
151 struct scatterlist cipher[2];
152 struct page *dstp;
153 unsigned int ivsize = crypto_aead_ivsize(authenc);
154 unsigned int cryptlen;
155 u8 *vdst;
156 u8 *hash;
157
158 dstp = sg_page(dst);
159 vdst = PageHighMem(dstp) ? NULL : page_address(dstp) + dst->offset;
160
161 if (ivsize) {
162 sg_init_table(cipher, 2);
163 sg_set_buf(cipher, iv, ivsize);
164 authenc_chain(cipher, dst, vdst == iv + ivsize);
165 dst = cipher;
166 }
167
168 cryptlen = req->cryptlen + ivsize;
169 hash = crypto_authenc_hash(req, flags, dst, cryptlen);
170 if (IS_ERR(hash))
171 return PTR_ERR(hash);
172
173 scatterwalk_map_and_copy(hash, dst, cryptlen,
174 crypto_aead_authsize(authenc), 1);
175 return 0;
176 }
177
178 static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
179 int err)
180 {
181 struct aead_request *areq = req->data;
182
183 if (!err) {
184 struct crypto_aead *authenc = crypto_aead_reqtfm(areq);
185 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
186 struct ablkcipher_request *abreq = aead_request_ctx(areq);
187 u8 *iv = (u8 *)(abreq + 1) +
188 crypto_ablkcipher_reqsize(ctx->enc);
189
190 err = crypto_authenc_genicv(areq, iv, 0);
191 }
192
193 aead_request_complete(areq, err);
194 }
195
196 static int crypto_authenc_encrypt(struct aead_request *req)
197 {
198 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
199 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
200 struct ablkcipher_request *abreq = aead_request_ctx(req);
201 struct crypto_ablkcipher *enc = ctx->enc;
202 struct scatterlist *dst = req->dst;
203 unsigned int cryptlen = req->cryptlen;
204 u8 *iv = (u8 *)(abreq + 1) + crypto_ablkcipher_reqsize(enc);
205 int err;
206
207 ablkcipher_request_set_tfm(abreq, enc);
208 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
209 crypto_authenc_encrypt_done, req);
210 ablkcipher_request_set_crypt(abreq, req->src, dst, cryptlen, req->iv);
211
212 memcpy(iv, req->iv, crypto_aead_ivsize(authenc));
213
214 err = crypto_ablkcipher_encrypt(abreq);
215 if (err)
216 return err;
217
218 return crypto_authenc_genicv(req, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
219 }
220
221 static void crypto_authenc_givencrypt_done(struct crypto_async_request *req,
222 int err)
223 {
224 struct aead_request *areq = req->data;
225
226 if (!err) {
227 struct skcipher_givcrypt_request *greq = aead_request_ctx(areq);
228
229 err = crypto_authenc_genicv(areq, greq->giv, 0);
230 }
231
232 aead_request_complete(areq, err);
233 }
234
235 static int crypto_authenc_givencrypt(struct aead_givcrypt_request *req)
236 {
237 struct crypto_aead *authenc = aead_givcrypt_reqtfm(req);
238 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
239 struct aead_request *areq = &req->areq;
240 struct skcipher_givcrypt_request *greq = aead_request_ctx(areq);
241 u8 *iv = req->giv;
242 int err;
243
244 skcipher_givcrypt_set_tfm(greq, ctx->enc);
245 skcipher_givcrypt_set_callback(greq, aead_request_flags(areq),
246 crypto_authenc_givencrypt_done, areq);
247 skcipher_givcrypt_set_crypt(greq, areq->src, areq->dst, areq->cryptlen,
248 areq->iv);
249 skcipher_givcrypt_set_giv(greq, iv, req->seq);
250
251 err = crypto_skcipher_givencrypt(greq);
252 if (err)
253 return err;
254
255 return crypto_authenc_genicv(areq, iv, CRYPTO_TFM_REQ_MAY_SLEEP);
256 }
257
258 static int crypto_authenc_verify(struct aead_request *req,
259 struct scatterlist *cipher,
260 unsigned int cryptlen)
261 {
262 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
263 u8 *ohash;
264 u8 *ihash;
265 unsigned int authsize;
266
267 ohash = crypto_authenc_hash(req, CRYPTO_TFM_REQ_MAY_SLEEP, cipher,
268 cryptlen);
269 if (IS_ERR(ohash))
270 return PTR_ERR(ohash);
271
272 authsize = crypto_aead_authsize(authenc);
273 ihash = ohash + authsize;
274 scatterwalk_map_and_copy(ihash, cipher, cryptlen, authsize, 0);
275 return memcmp(ihash, ohash, authsize) ? -EBADMSG: 0;
276 }
277
278 static int crypto_authenc_iverify(struct aead_request *req, u8 *iv,
279 unsigned int cryptlen)
280 {
281 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
282 struct scatterlist *src = req->src;
283 struct scatterlist cipher[2];
284 struct page *srcp;
285 unsigned int ivsize = crypto_aead_ivsize(authenc);
286 u8 *vsrc;
287
288 srcp = sg_page(src);
289 vsrc = PageHighMem(srcp) ? NULL : page_address(srcp) + src->offset;
290
291 if (ivsize) {
292 sg_init_table(cipher, 2);
293 sg_set_buf(cipher, iv, ivsize);
294 authenc_chain(cipher, src, vsrc == iv + ivsize);
295 src = cipher;
296 }
297
298 return crypto_authenc_verify(req, src, cryptlen + ivsize);
299 }
300
301 static int crypto_authenc_decrypt(struct aead_request *req)
302 {
303 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
304 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
305 struct ablkcipher_request *abreq = aead_request_ctx(req);
306 unsigned int cryptlen = req->cryptlen;
307 unsigned int authsize = crypto_aead_authsize(authenc);
308 u8 *iv = req->iv;
309 int err;
310
311 if (cryptlen < authsize)
312 return -EINVAL;
313 cryptlen -= authsize;
314
315 err = crypto_authenc_iverify(req, iv, cryptlen);
316 if (err)
317 return err;
318
319 ablkcipher_request_set_tfm(abreq, ctx->enc);
320 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
321 req->base.complete, req->base.data);
322 ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen, iv);
323
324 return crypto_ablkcipher_decrypt(abreq);
325 }
326
327 static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
328 {
329 struct crypto_instance *inst = (void *)tfm->__crt_alg;
330 struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst);
331 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
332 struct crypto_hash *auth;
333 struct crypto_ablkcipher *enc;
334 int err;
335
336 auth = crypto_spawn_hash(&ictx->auth);
337 if (IS_ERR(auth))
338 return PTR_ERR(auth);
339
340 enc = crypto_spawn_skcipher(&ictx->enc);
341 err = PTR_ERR(enc);
342 if (IS_ERR(enc))
343 goto err_free_hash;
344
345 ctx->auth = auth;
346 ctx->enc = enc;
347 tfm->crt_aead.reqsize = max_t(unsigned int,
348 (crypto_hash_alignmask(auth) &
349 ~(crypto_tfm_ctx_alignment() - 1)) +
350 crypto_hash_digestsize(auth) * 2,
351 sizeof(struct skcipher_givcrypt_request) +
352 crypto_ablkcipher_reqsize(enc) +
353 crypto_ablkcipher_ivsize(enc));
354
355 spin_lock_init(&ctx->auth_lock);
356
357 return 0;
358
359 err_free_hash:
360 crypto_free_hash(auth);
361 return err;
362 }
363
364 static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm)
365 {
366 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
367
368 crypto_free_hash(ctx->auth);
369 crypto_free_ablkcipher(ctx->enc);
370 }
371
372 static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
373 {
374 struct crypto_attr_type *algt;
375 struct crypto_instance *inst;
376 struct crypto_alg *auth;
377 struct crypto_alg *enc;
378 struct authenc_instance_ctx *ctx;
379 const char *enc_name;
380 int err;
381
382 algt = crypto_get_attr_type(tb);
383 err = PTR_ERR(algt);
384 if (IS_ERR(algt))
385 return ERR_PTR(err);
386
387 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
388 return ERR_PTR(-EINVAL);
389
390 auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
391 CRYPTO_ALG_TYPE_HASH_MASK);
392 if (IS_ERR(auth))
393 return ERR_PTR(PTR_ERR(auth));
394
395 enc_name = crypto_attr_alg_name(tb[2]);
396 err = PTR_ERR(enc_name);
397 if (IS_ERR(enc_name))
398 goto out_put_auth;
399
400 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
401 err = -ENOMEM;
402 if (!inst)
403 goto out_put_auth;
404
405 ctx = crypto_instance_ctx(inst);
406
407 err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK);
408 if (err)
409 goto err_free_inst;
410
411 crypto_set_skcipher_spawn(&ctx->enc, inst);
412 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
413 crypto_requires_sync(algt->type,
414 algt->mask));
415 if (err)
416 goto err_drop_auth;
417
418 enc = crypto_skcipher_spawn_alg(&ctx->enc);
419
420 err = -ENAMETOOLONG;
421 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
422 "authenc(%s,%s)", auth->cra_name, enc->cra_name) >=
423 CRYPTO_MAX_ALG_NAME)
424 goto err_drop_enc;
425
426 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
427 "authenc(%s,%s)", auth->cra_driver_name,
428 enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
429 goto err_drop_enc;
430
431 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
432 inst->alg.cra_flags |= enc->cra_flags & CRYPTO_ALG_ASYNC;
433 inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority;
434 inst->alg.cra_blocksize = enc->cra_blocksize;
435 inst->alg.cra_alignmask = auth->cra_alignmask | enc->cra_alignmask;
436 inst->alg.cra_type = &crypto_aead_type;
437
438 inst->alg.cra_aead.ivsize = enc->cra_ablkcipher.ivsize;
439 inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ?
440 auth->cra_hash.digestsize :
441 auth->cra_type ?
442 __crypto_shash_alg(auth)->digestsize :
443 auth->cra_digest.dia_digestsize;
444
445 inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
446
447 inst->alg.cra_init = crypto_authenc_init_tfm;
448 inst->alg.cra_exit = crypto_authenc_exit_tfm;
449
450 inst->alg.cra_aead.setkey = crypto_authenc_setkey;
451 inst->alg.cra_aead.encrypt = crypto_authenc_encrypt;
452 inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
453 inst->alg.cra_aead.givencrypt = crypto_authenc_givencrypt;
454
455 out:
456 crypto_mod_put(auth);
457 return inst;
458
459 err_drop_enc:
460 crypto_drop_skcipher(&ctx->enc);
461 err_drop_auth:
462 crypto_drop_spawn(&ctx->auth);
463 err_free_inst:
464 kfree(inst);
465 out_put_auth:
466 inst = ERR_PTR(err);
467 goto out;
468 }
469
470 static void crypto_authenc_free(struct crypto_instance *inst)
471 {
472 struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst);
473
474 crypto_drop_skcipher(&ctx->enc);
475 crypto_drop_spawn(&ctx->auth);
476 kfree(inst);
477 }
478
479 static struct crypto_template crypto_authenc_tmpl = {
480 .name = "authenc",
481 .alloc = crypto_authenc_alloc,
482 .free = crypto_authenc_free,
483 .module = THIS_MODULE,
484 };
485
486 static int __init crypto_authenc_module_init(void)
487 {
488 return crypto_register_template(&crypto_authenc_tmpl);
489 }
490
491 static void __exit crypto_authenc_module_exit(void)
492 {
493 crypto_unregister_template(&crypto_authenc_tmpl);
494 }
495
496 module_init(crypto_authenc_module_init);
497 module_exit(crypto_authenc_module_exit);
498
499 MODULE_LICENSE("GPL");
500 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
501
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