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TOMOYO Linux Cross Reference
Linux/crypto/authenc.c

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  1 /*
  2  * Authenc: Simple AEAD wrapper for IPsec
  3  *
  4  * Copyright (c) 2007-2015 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/internal/aead.h>
 14 #include <crypto/internal/hash.h>
 15 #include <crypto/internal/skcipher.h>
 16 #include <crypto/authenc.h>
 17 #include <crypto/null.h>
 18 #include <crypto/scatterwalk.h>
 19 #include <linux/err.h>
 20 #include <linux/init.h>
 21 #include <linux/kernel.h>
 22 #include <linux/module.h>
 23 #include <linux/rtnetlink.h>
 24 #include <linux/slab.h>
 25 #include <linux/spinlock.h>
 26 
 27 struct authenc_instance_ctx {
 28         struct crypto_ahash_spawn auth;
 29         struct crypto_skcipher_spawn enc;
 30         unsigned int reqoff;
 31 };
 32 
 33 struct crypto_authenc_ctx {
 34         struct crypto_ahash *auth;
 35         struct crypto_ablkcipher *enc;
 36         struct crypto_blkcipher *null;
 37 };
 38 
 39 struct authenc_request_ctx {
 40         struct scatterlist src[2];
 41         struct scatterlist dst[2];
 42         char tail[];
 43 };
 44 
 45 static void authenc_request_complete(struct aead_request *req, int err)
 46 {
 47         if (err != -EINPROGRESS)
 48                 aead_request_complete(req, err);
 49 }
 50 
 51 int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
 52                                unsigned int keylen)
 53 {
 54         struct rtattr *rta = (struct rtattr *)key;
 55         struct crypto_authenc_key_param *param;
 56 
 57         if (!RTA_OK(rta, keylen))
 58                 return -EINVAL;
 59         if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
 60                 return -EINVAL;
 61         if (RTA_PAYLOAD(rta) < sizeof(*param))
 62                 return -EINVAL;
 63 
 64         param = RTA_DATA(rta);
 65         keys->enckeylen = be32_to_cpu(param->enckeylen);
 66 
 67         key += RTA_ALIGN(rta->rta_len);
 68         keylen -= RTA_ALIGN(rta->rta_len);
 69 
 70         if (keylen < keys->enckeylen)
 71                 return -EINVAL;
 72 
 73         keys->authkeylen = keylen - keys->enckeylen;
 74         keys->authkey = key;
 75         keys->enckey = key + keys->authkeylen;
 76 
 77         return 0;
 78 }
 79 EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
 80 
 81 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
 82                                  unsigned int keylen)
 83 {
 84         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
 85         struct crypto_ahash *auth = ctx->auth;
 86         struct crypto_ablkcipher *enc = ctx->enc;
 87         struct crypto_authenc_keys keys;
 88         int err = -EINVAL;
 89 
 90         if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
 91                 goto badkey;
 92 
 93         crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
 94         crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) &
 95                                     CRYPTO_TFM_REQ_MASK);
 96         err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
 97         crypto_aead_set_flags(authenc, crypto_ahash_get_flags(auth) &
 98                                        CRYPTO_TFM_RES_MASK);
 99 
100         if (err)
101                 goto out;
102 
103         crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
104         crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
105                                          CRYPTO_TFM_REQ_MASK);
106         err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen);
107         crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) &
108                                        CRYPTO_TFM_RES_MASK);
109 
110 out:
111         return err;
112 
113 badkey:
114         crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN);
115         goto out;
116 }
117 
118 static void authenc_geniv_ahash_done(struct crypto_async_request *areq, int err)
119 {
120         struct aead_request *req = areq->data;
121         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
122         struct aead_instance *inst = aead_alg_instance(authenc);
123         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
124         struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
125         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
126 
127         if (err)
128                 goto out;
129 
130         scatterwalk_map_and_copy(ahreq->result, req->dst,
131                                  req->assoclen + req->cryptlen,
132                                  crypto_aead_authsize(authenc), 1);
133 
134 out:
135         aead_request_complete(req, err);
136 }
137 
138 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
139 {
140         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
141         struct aead_instance *inst = aead_alg_instance(authenc);
142         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
143         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
144         struct crypto_ahash *auth = ctx->auth;
145         struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
146         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
147         u8 *hash = areq_ctx->tail;
148         int err;
149 
150         hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
151                            crypto_ahash_alignmask(auth) + 1);
152 
153         ahash_request_set_tfm(ahreq, auth);
154         ahash_request_set_crypt(ahreq, req->dst, hash,
155                                 req->assoclen + req->cryptlen);
156         ahash_request_set_callback(ahreq, flags,
157                                    authenc_geniv_ahash_done, req);
158 
159         err = crypto_ahash_digest(ahreq);
160         if (err)
161                 return err;
162 
163         scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen,
164                                  crypto_aead_authsize(authenc), 1);
165 
166         return 0;
167 }
168 
169 static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
170                                         int err)
171 {
172         struct aead_request *areq = req->data;
173 
174         if (err)
175                 goto out;
176 
177         err = crypto_authenc_genicv(areq, 0);
178 
179 out:
180         authenc_request_complete(areq, err);
181 }
182 
183 static int crypto_authenc_copy_assoc(struct aead_request *req)
184 {
185         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
186         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
187         struct blkcipher_desc desc = {
188                 .tfm = ctx->null,
189         };
190 
191         return crypto_blkcipher_encrypt(&desc, req->dst, req->src,
192                                         req->assoclen);
193 }
194 
195 static int crypto_authenc_encrypt(struct aead_request *req)
196 {
197         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
198         struct aead_instance *inst = aead_alg_instance(authenc);
199         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
200         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
201         struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
202         struct crypto_ablkcipher *enc = ctx->enc;
203         unsigned int cryptlen = req->cryptlen;
204         struct ablkcipher_request *abreq = (void *)(areq_ctx->tail +
205                                                     ictx->reqoff);
206         struct scatterlist *src, *dst;
207         int err;
208 
209         sg_init_table(areq_ctx->src, 2);
210         src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
211         dst = src;
212 
213         if (req->src != req->dst) {
214                 err = crypto_authenc_copy_assoc(req);
215                 if (err)
216                         return err;
217 
218                 sg_init_table(areq_ctx->dst, 2);
219                 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
220         }
221 
222         ablkcipher_request_set_tfm(abreq, enc);
223         ablkcipher_request_set_callback(abreq, aead_request_flags(req),
224                                         crypto_authenc_encrypt_done, req);
225         ablkcipher_request_set_crypt(abreq, src, dst, cryptlen, req->iv);
226 
227         err = crypto_ablkcipher_encrypt(abreq);
228         if (err)
229                 return err;
230 
231         return crypto_authenc_genicv(req, aead_request_flags(req));
232 }
233 
234 static int crypto_authenc_decrypt_tail(struct aead_request *req,
235                                        unsigned int flags)
236 {
237         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
238         struct aead_instance *inst = aead_alg_instance(authenc);
239         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
240         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
241         struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
242         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
243         struct ablkcipher_request *abreq = (void *)(areq_ctx->tail +
244                                                     ictx->reqoff);
245         unsigned int authsize = crypto_aead_authsize(authenc);
246         u8 *ihash = ahreq->result + authsize;
247         struct scatterlist *src, *dst;
248 
249         scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0);
250 
251         if (crypto_memneq(ihash, ahreq->result, authsize))
252                 return -EBADMSG;
253 
254         sg_init_table(areq_ctx->src, 2);
255         src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
256         dst = src;
257 
258         if (req->src != req->dst) {
259                 sg_init_table(areq_ctx->dst, 2);
260                 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
261         }
262 
263         ablkcipher_request_set_tfm(abreq, ctx->enc);
264         ablkcipher_request_set_callback(abreq, aead_request_flags(req),
265                                         req->base.complete, req->base.data);
266         ablkcipher_request_set_crypt(abreq, src, dst,
267                                      req->cryptlen - authsize, req->iv);
268 
269         return crypto_ablkcipher_decrypt(abreq);
270 }
271 
272 static void authenc_verify_ahash_done(struct crypto_async_request *areq,
273                                       int err)
274 {
275         struct aead_request *req = areq->data;
276 
277         if (err)
278                 goto out;
279 
280         err = crypto_authenc_decrypt_tail(req, 0);
281 
282 out:
283         authenc_request_complete(req, err);
284 }
285 
286 static int crypto_authenc_decrypt(struct aead_request *req)
287 {
288         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
289         unsigned int authsize = crypto_aead_authsize(authenc);
290         struct aead_instance *inst = aead_alg_instance(authenc);
291         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
292         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
293         struct crypto_ahash *auth = ctx->auth;
294         struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
295         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
296         u8 *hash = areq_ctx->tail;
297         int err;
298 
299         hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
300                            crypto_ahash_alignmask(auth) + 1);
301 
302         ahash_request_set_tfm(ahreq, auth);
303         ahash_request_set_crypt(ahreq, req->src, hash,
304                                 req->assoclen + req->cryptlen - authsize);
305         ahash_request_set_callback(ahreq, aead_request_flags(req),
306                                    authenc_verify_ahash_done, req);
307 
308         err = crypto_ahash_digest(ahreq);
309         if (err)
310                 return err;
311 
312         return crypto_authenc_decrypt_tail(req, aead_request_flags(req));
313 }
314 
315 static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
316 {
317         struct aead_instance *inst = aead_alg_instance(tfm);
318         struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
319         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
320         struct crypto_ahash *auth;
321         struct crypto_ablkcipher *enc;
322         struct crypto_blkcipher *null;
323         int err;
324 
325         auth = crypto_spawn_ahash(&ictx->auth);
326         if (IS_ERR(auth))
327                 return PTR_ERR(auth);
328 
329         enc = crypto_spawn_skcipher(&ictx->enc);
330         err = PTR_ERR(enc);
331         if (IS_ERR(enc))
332                 goto err_free_ahash;
333 
334         null = crypto_get_default_null_skcipher();
335         err = PTR_ERR(null);
336         if (IS_ERR(null))
337                 goto err_free_skcipher;
338 
339         ctx->auth = auth;
340         ctx->enc = enc;
341         ctx->null = null;
342 
343         crypto_aead_set_reqsize(
344                 tfm,
345                 sizeof(struct authenc_request_ctx) +
346                 ictx->reqoff +
347                 max_t(unsigned int,
348                       crypto_ahash_reqsize(auth) +
349                       sizeof(struct ahash_request),
350                       sizeof(struct ablkcipher_request) +
351                       crypto_ablkcipher_reqsize(enc)));
352 
353         return 0;
354 
355 err_free_skcipher:
356         crypto_free_ablkcipher(enc);
357 err_free_ahash:
358         crypto_free_ahash(auth);
359         return err;
360 }
361 
362 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
363 {
364         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
365 
366         crypto_free_ahash(ctx->auth);
367         crypto_free_ablkcipher(ctx->enc);
368         crypto_put_default_null_skcipher();
369 }
370 
371 static void crypto_authenc_free(struct aead_instance *inst)
372 {
373         struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
374 
375         crypto_drop_skcipher(&ctx->enc);
376         crypto_drop_ahash(&ctx->auth);
377         kfree(inst);
378 }
379 
380 static int crypto_authenc_create(struct crypto_template *tmpl,
381                                  struct rtattr **tb)
382 {
383         struct crypto_attr_type *algt;
384         struct aead_instance *inst;
385         struct hash_alg_common *auth;
386         struct crypto_alg *auth_base;
387         struct crypto_alg *enc;
388         struct authenc_instance_ctx *ctx;
389         const char *enc_name;
390         int err;
391 
392         algt = crypto_get_attr_type(tb);
393         if (IS_ERR(algt))
394                 return PTR_ERR(algt);
395 
396         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
397                 return -EINVAL;
398 
399         auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
400                                CRYPTO_ALG_TYPE_AHASH_MASK);
401         if (IS_ERR(auth))
402                 return PTR_ERR(auth);
403 
404         auth_base = &auth->base;
405 
406         enc_name = crypto_attr_alg_name(tb[2]);
407         err = PTR_ERR(enc_name);
408         if (IS_ERR(enc_name))
409                 goto out_put_auth;
410 
411         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
412         err = -ENOMEM;
413         if (!inst)
414                 goto out_put_auth;
415 
416         ctx = aead_instance_ctx(inst);
417 
418         err = crypto_init_ahash_spawn(&ctx->auth, auth,
419                                       aead_crypto_instance(inst));
420         if (err)
421                 goto err_free_inst;
422 
423         crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
424         err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
425                                    crypto_requires_sync(algt->type,
426                                                         algt->mask));
427         if (err)
428                 goto err_drop_auth;
429 
430         enc = crypto_skcipher_spawn_alg(&ctx->enc);
431 
432         ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask,
433                             auth_base->cra_alignmask + 1);
434 
435         err = -ENAMETOOLONG;
436         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
437                      "authenc(%s,%s)", auth_base->cra_name, enc->cra_name) >=
438             CRYPTO_MAX_ALG_NAME)
439                 goto err_drop_enc;
440 
441         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
442                      "authenc(%s,%s)", auth_base->cra_driver_name,
443                      enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
444                 goto err_drop_enc;
445 
446         inst->alg.base.cra_flags = enc->cra_flags & CRYPTO_ALG_ASYNC;
447         inst->alg.base.cra_priority = enc->cra_priority * 10 +
448                                       auth_base->cra_priority;
449         inst->alg.base.cra_blocksize = enc->cra_blocksize;
450         inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
451                                        enc->cra_alignmask;
452         inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
453 
454         inst->alg.ivsize = enc->cra_ablkcipher.ivsize;
455         inst->alg.maxauthsize = auth->digestsize;
456 
457         inst->alg.init = crypto_authenc_init_tfm;
458         inst->alg.exit = crypto_authenc_exit_tfm;
459 
460         inst->alg.setkey = crypto_authenc_setkey;
461         inst->alg.encrypt = crypto_authenc_encrypt;
462         inst->alg.decrypt = crypto_authenc_decrypt;
463 
464         inst->free = crypto_authenc_free;
465 
466         err = aead_register_instance(tmpl, inst);
467         if (err)
468                 goto err_drop_enc;
469 
470 out:
471         crypto_mod_put(auth_base);
472         return err;
473 
474 err_drop_enc:
475         crypto_drop_skcipher(&ctx->enc);
476 err_drop_auth:
477         crypto_drop_ahash(&ctx->auth);
478 err_free_inst:
479         kfree(inst);
480 out_put_auth:
481         goto out;
482 }
483 
484 static struct crypto_template crypto_authenc_tmpl = {
485         .name = "authenc",
486         .create = crypto_authenc_create,
487         .module = THIS_MODULE,
488 };
489 
490 static int __init crypto_authenc_module_init(void)
491 {
492         return crypto_register_template(&crypto_authenc_tmpl);
493 }
494 
495 static void __exit crypto_authenc_module_exit(void)
496 {
497         crypto_unregister_template(&crypto_authenc_tmpl);
498 }
499 
500 module_init(crypto_authenc_module_init);
501 module_exit(crypto_authenc_module_exit);
502 
503 MODULE_LICENSE("GPL");
504 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
505 MODULE_ALIAS_CRYPTO("authenc");
506 

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