1 /*
2 * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
3 * derived from authenc.c
4 *
5 * Copyright (C) 2010 secunet Security Networks AG
6 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
7 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 */
15
16 #include <crypto/internal/aead.h>
17 #include <crypto/internal/hash.h>
18 #include <crypto/internal/skcipher.h>
19 #include <crypto/authenc.h>
20 #include <crypto/null.h>
21 #include <crypto/scatterwalk.h>
22 #include <linux/err.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29
30 struct authenc_esn_instance_ctx {
31 struct crypto_ahash_spawn auth;
32 struct crypto_skcipher_spawn enc;
33 };
34
35 struct crypto_authenc_esn_ctx {
36 unsigned int reqoff;
37 struct crypto_ahash *auth;
38 struct crypto_ablkcipher *enc;
39 struct crypto_blkcipher *null;
40 };
41
42 struct authenc_esn_request_ctx {
43 struct scatterlist src[2];
44 struct scatterlist dst[2];
45 char tail[];
46 };
47
authenc_esn_request_complete(struct aead_request * req,int err)48 static void authenc_esn_request_complete(struct aead_request *req, int err)
49 {
50 if (err != -EINPROGRESS)
51 aead_request_complete(req, err);
52 }
53
crypto_authenc_esn_setauthsize(struct crypto_aead * authenc_esn,unsigned int authsize)54 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
55 unsigned int authsize)
56 {
57 if (authsize > 0 && authsize < 4)
58 return -EINVAL;
59
60 return 0;
61 }
62
crypto_authenc_esn_setkey(struct crypto_aead * authenc_esn,const u8 * key,unsigned int keylen)63 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
64 unsigned int keylen)
65 {
66 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
67 struct crypto_ahash *auth = ctx->auth;
68 struct crypto_ablkcipher *enc = ctx->enc;
69 struct crypto_authenc_keys keys;
70 int err = -EINVAL;
71
72 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
73 goto badkey;
74
75 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
76 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
77 CRYPTO_TFM_REQ_MASK);
78 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
79 crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
80 CRYPTO_TFM_RES_MASK);
81
82 if (err)
83 goto out;
84
85 crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
86 crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
87 CRYPTO_TFM_REQ_MASK);
88 err = crypto_ablkcipher_setkey(enc, keys.enckey, keys.enckeylen);
89 crypto_aead_set_flags(authenc_esn, crypto_ablkcipher_get_flags(enc) &
90 CRYPTO_TFM_RES_MASK);
91
92 out:
93 memzero_explicit(&keys, sizeof(keys));
94 return err;
95
96 badkey:
97 crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
98 goto out;
99 }
100
crypto_authenc_esn_genicv_tail(struct aead_request * req,unsigned int flags)101 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
102 unsigned int flags)
103 {
104 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
105 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
106 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
107 struct crypto_ahash *auth = ctx->auth;
108 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
109 crypto_ahash_alignmask(auth) + 1);
110 unsigned int authsize = crypto_aead_authsize(authenc_esn);
111 unsigned int assoclen = req->assoclen;
112 unsigned int cryptlen = req->cryptlen;
113 struct scatterlist *dst = req->dst;
114 u32 tmp[2];
115
116 /* Move high-order bits of sequence number back. */
117 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
118 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
119 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
120
121 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
122 return 0;
123 }
124
authenc_esn_geniv_ahash_done(struct crypto_async_request * areq,int err)125 static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
126 int err)
127 {
128 struct aead_request *req = areq->data;
129
130 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
131 aead_request_complete(req, err);
132 }
133
crypto_authenc_esn_genicv(struct aead_request * req,unsigned int flags)134 static int crypto_authenc_esn_genicv(struct aead_request *req,
135 unsigned int flags)
136 {
137 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
138 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
139 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
140 struct crypto_ahash *auth = ctx->auth;
141 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
142 crypto_ahash_alignmask(auth) + 1);
143 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
144 unsigned int authsize = crypto_aead_authsize(authenc_esn);
145 unsigned int assoclen = req->assoclen;
146 unsigned int cryptlen = req->cryptlen;
147 struct scatterlist *dst = req->dst;
148 u32 tmp[2];
149
150 if (!authsize)
151 return 0;
152
153 /* Move high-order bits of sequence number to the end. */
154 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
155 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
156 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
157
158 sg_init_table(areq_ctx->dst, 2);
159 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
160
161 ahash_request_set_tfm(ahreq, auth);
162 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
163 ahash_request_set_callback(ahreq, flags,
164 authenc_esn_geniv_ahash_done, req);
165
166 return crypto_ahash_digest(ahreq) ?:
167 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
168 }
169
170
crypto_authenc_esn_encrypt_done(struct crypto_async_request * req,int err)171 static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
172 int err)
173 {
174 struct aead_request *areq = req->data;
175
176 if (!err)
177 err = crypto_authenc_esn_genicv(areq, 0);
178
179 authenc_esn_request_complete(areq, err);
180 }
181
crypto_authenc_esn_copy(struct aead_request * req,unsigned int len)182 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
183 {
184 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
185 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
186 struct blkcipher_desc desc = {
187 .tfm = ctx->null,
188 };
189
190 return crypto_blkcipher_encrypt(&desc, req->dst, req->src, len);
191 }
192
crypto_authenc_esn_encrypt(struct aead_request * req)193 static int crypto_authenc_esn_encrypt(struct aead_request *req)
194 {
195 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
196 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
197 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
198 struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
199 + ctx->reqoff);
200 struct crypto_ablkcipher *enc = ctx->enc;
201 unsigned int assoclen = req->assoclen;
202 unsigned int cryptlen = req->cryptlen;
203 struct scatterlist *src, *dst;
204 int err;
205
206 sg_init_table(areq_ctx->src, 2);
207 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
208 dst = src;
209
210 if (req->src != req->dst) {
211 err = crypto_authenc_esn_copy(req, assoclen);
212 if (err)
213 return err;
214
215 sg_init_table(areq_ctx->dst, 2);
216 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
217 }
218
219 ablkcipher_request_set_tfm(abreq, enc);
220 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
221 crypto_authenc_esn_encrypt_done, req);
222 ablkcipher_request_set_crypt(abreq, src, dst, cryptlen, req->iv);
223
224 err = crypto_ablkcipher_encrypt(abreq);
225 if (err)
226 return err;
227
228 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
229 }
230
crypto_authenc_esn_decrypt_tail(struct aead_request * req,unsigned int flags)231 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
232 unsigned int flags)
233 {
234 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
235 unsigned int authsize = crypto_aead_authsize(authenc_esn);
236 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
237 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
238 struct ablkcipher_request *abreq = (void *)(areq_ctx->tail
239 + ctx->reqoff);
240 struct crypto_ahash *auth = ctx->auth;
241 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
242 crypto_ahash_alignmask(auth) + 1);
243 unsigned int cryptlen = req->cryptlen - authsize;
244 unsigned int assoclen = req->assoclen;
245 struct scatterlist *dst = req->dst;
246 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
247 u32 tmp[2];
248
249 if (!authsize)
250 goto decrypt;
251
252 /* Move high-order bits of sequence number back. */
253 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
254 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
255 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
256
257 if (crypto_memneq(ihash, ohash, authsize))
258 return -EBADMSG;
259
260 decrypt:
261
262 sg_init_table(areq_ctx->dst, 2);
263 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
264
265 ablkcipher_request_set_tfm(abreq, ctx->enc);
266 ablkcipher_request_set_callback(abreq, flags,
267 req->base.complete, req->base.data);
268 ablkcipher_request_set_crypt(abreq, dst, dst, cryptlen, req->iv);
269
270 return crypto_ablkcipher_decrypt(abreq);
271 }
272
authenc_esn_verify_ahash_done(struct crypto_async_request * areq,int err)273 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
274 int err)
275 {
276 struct aead_request *req = areq->data;
277
278 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
279 authenc_esn_request_complete(req, err);
280 }
281
crypto_authenc_esn_decrypt(struct aead_request * req)282 static int crypto_authenc_esn_decrypt(struct aead_request *req)
283 {
284 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
285 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
286 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
287 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
288 unsigned int authsize = crypto_aead_authsize(authenc_esn);
289 struct crypto_ahash *auth = ctx->auth;
290 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
291 crypto_ahash_alignmask(auth) + 1);
292 unsigned int assoclen = req->assoclen;
293 unsigned int cryptlen = req->cryptlen;
294 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
295 struct scatterlist *dst = req->dst;
296 u32 tmp[2];
297 int err;
298
299 cryptlen -= authsize;
300
301 if (req->src != dst) {
302 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
303 if (err)
304 return err;
305 }
306
307 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
308 authsize, 0);
309
310 if (!authsize)
311 goto tail;
312
313 /* Move high-order bits of sequence number to the end. */
314 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
315 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
316 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
317
318 sg_init_table(areq_ctx->dst, 2);
319 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
320
321 ahash_request_set_tfm(ahreq, auth);
322 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
323 ahash_request_set_callback(ahreq, aead_request_flags(req),
324 authenc_esn_verify_ahash_done, req);
325
326 err = crypto_ahash_digest(ahreq);
327 if (err)
328 return err;
329
330 tail:
331 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
332 }
333
crypto_authenc_esn_init_tfm(struct crypto_aead * tfm)334 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
335 {
336 struct aead_instance *inst = aead_alg_instance(tfm);
337 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
338 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
339 struct crypto_ahash *auth;
340 struct crypto_ablkcipher *enc;
341 struct crypto_blkcipher *null;
342 int err;
343
344 auth = crypto_spawn_ahash(&ictx->auth);
345 if (IS_ERR(auth))
346 return PTR_ERR(auth);
347
348 enc = crypto_spawn_skcipher(&ictx->enc);
349 err = PTR_ERR(enc);
350 if (IS_ERR(enc))
351 goto err_free_ahash;
352
353 null = crypto_get_default_null_skcipher();
354 err = PTR_ERR(null);
355 if (IS_ERR(null))
356 goto err_free_skcipher;
357
358 ctx->auth = auth;
359 ctx->enc = enc;
360 ctx->null = null;
361
362 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
363 crypto_ahash_alignmask(auth) + 1);
364
365 crypto_aead_set_reqsize(
366 tfm,
367 sizeof(struct authenc_esn_request_ctx) +
368 ctx->reqoff +
369 max_t(unsigned int,
370 crypto_ahash_reqsize(auth) +
371 sizeof(struct ahash_request),
372 sizeof(struct skcipher_givcrypt_request) +
373 crypto_ablkcipher_reqsize(enc)));
374
375 return 0;
376
377 err_free_skcipher:
378 crypto_free_ablkcipher(enc);
379 err_free_ahash:
380 crypto_free_ahash(auth);
381 return err;
382 }
383
crypto_authenc_esn_exit_tfm(struct crypto_aead * tfm)384 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
385 {
386 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
387
388 crypto_free_ahash(ctx->auth);
389 crypto_free_ablkcipher(ctx->enc);
390 crypto_put_default_null_skcipher();
391 }
392
crypto_authenc_esn_free(struct aead_instance * inst)393 static void crypto_authenc_esn_free(struct aead_instance *inst)
394 {
395 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
396
397 crypto_drop_skcipher(&ctx->enc);
398 crypto_drop_ahash(&ctx->auth);
399 kfree(inst);
400 }
401
crypto_authenc_esn_create(struct crypto_template * tmpl,struct rtattr ** tb)402 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
403 struct rtattr **tb)
404 {
405 struct crypto_attr_type *algt;
406 struct aead_instance *inst;
407 struct hash_alg_common *auth;
408 struct crypto_alg *auth_base;
409 struct crypto_alg *enc;
410 struct authenc_esn_instance_ctx *ctx;
411 const char *enc_name;
412 int err;
413
414 algt = crypto_get_attr_type(tb);
415 if (IS_ERR(algt))
416 return PTR_ERR(algt);
417
418 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
419 return -EINVAL;
420
421 auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
422 CRYPTO_ALG_TYPE_AHASH_MASK);
423 if (IS_ERR(auth))
424 return PTR_ERR(auth);
425
426 auth_base = &auth->base;
427
428 enc_name = crypto_attr_alg_name(tb[2]);
429 err = PTR_ERR(enc_name);
430 if (IS_ERR(enc_name))
431 goto out_put_auth;
432
433 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
434 err = -ENOMEM;
435 if (!inst)
436 goto out_put_auth;
437
438 ctx = aead_instance_ctx(inst);
439
440 err = crypto_init_ahash_spawn(&ctx->auth, auth,
441 aead_crypto_instance(inst));
442 if (err)
443 goto err_free_inst;
444
445 crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
446 err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
447 crypto_requires_sync(algt->type,
448 algt->mask));
449 if (err)
450 goto err_drop_auth;
451
452 enc = crypto_skcipher_spawn_alg(&ctx->enc);
453
454 err = -ENAMETOOLONG;
455 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
456 "authencesn(%s,%s)", auth_base->cra_name,
457 enc->cra_name) >= CRYPTO_MAX_ALG_NAME)
458 goto err_drop_enc;
459
460 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
461 "authencesn(%s,%s)", auth_base->cra_driver_name,
462 enc->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
463 goto err_drop_enc;
464
465 inst->alg.base.cra_flags = enc->cra_flags & CRYPTO_ALG_ASYNC;
466 inst->alg.base.cra_priority = enc->cra_priority * 10 +
467 auth_base->cra_priority;
468 inst->alg.base.cra_blocksize = enc->cra_blocksize;
469 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
470 enc->cra_alignmask;
471 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
472
473 inst->alg.ivsize = enc->cra_ablkcipher.ivsize;
474 inst->alg.maxauthsize = auth->digestsize;
475
476 inst->alg.init = crypto_authenc_esn_init_tfm;
477 inst->alg.exit = crypto_authenc_esn_exit_tfm;
478
479 inst->alg.setkey = crypto_authenc_esn_setkey;
480 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
481 inst->alg.encrypt = crypto_authenc_esn_encrypt;
482 inst->alg.decrypt = crypto_authenc_esn_decrypt;
483
484 inst->free = crypto_authenc_esn_free,
485
486 err = aead_register_instance(tmpl, inst);
487 if (err)
488 goto err_drop_enc;
489
490 out:
491 crypto_mod_put(auth_base);
492 return err;
493
494 err_drop_enc:
495 crypto_drop_skcipher(&ctx->enc);
496 err_drop_auth:
497 crypto_drop_ahash(&ctx->auth);
498 err_free_inst:
499 kfree(inst);
500 out_put_auth:
501 goto out;
502 }
503
504 static struct crypto_template crypto_authenc_esn_tmpl = {
505 .name = "authencesn",
506 .create = crypto_authenc_esn_create,
507 .module = THIS_MODULE,
508 };
509
crypto_authenc_esn_module_init(void)510 static int __init crypto_authenc_esn_module_init(void)
511 {
512 return crypto_register_template(&crypto_authenc_esn_tmpl);
513 }
514
crypto_authenc_esn_module_exit(void)515 static void __exit crypto_authenc_esn_module_exit(void)
516 {
517 crypto_unregister_template(&crypto_authenc_esn_tmpl);
518 }
519
520 module_init(crypto_authenc_esn_module_init);
521 module_exit(crypto_authenc_esn_module_exit);
522
523 MODULE_LICENSE("GPL");
524 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
525 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
526 MODULE_ALIAS_CRYPTO("authencesn");
527