1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
4 * derived from authenc.c
5 *
6 * Copyright (C) 2010 secunet Security Networks AG
7 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
8 * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
9 */
10
11 #include <crypto/internal/aead.h>
12 #include <crypto/internal/hash.h>
13 #include <crypto/internal/skcipher.h>
14 #include <crypto/authenc.h>
15 #include <crypto/null.h>
16 #include <crypto/scatterwalk.h>
17 #include <linux/err.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/rtnetlink.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24
25 struct authenc_esn_instance_ctx {
26 struct crypto_ahash_spawn auth;
27 struct crypto_skcipher_spawn enc;
28 };
29
30 struct crypto_authenc_esn_ctx {
31 unsigned int reqoff;
32 struct crypto_ahash *auth;
33 struct crypto_skcipher *enc;
34 struct crypto_sync_skcipher *null;
35 };
36
37 struct authenc_esn_request_ctx {
38 struct scatterlist src[2];
39 struct scatterlist dst[2];
40 char tail[];
41 };
42
authenc_esn_request_complete(struct aead_request * req,int err)43 static void authenc_esn_request_complete(struct aead_request *req, int err)
44 {
45 if (err != -EINPROGRESS)
46 aead_request_complete(req, err);
47 }
48
crypto_authenc_esn_setauthsize(struct crypto_aead * authenc_esn,unsigned int authsize)49 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
50 unsigned int authsize)
51 {
52 if (authsize > 0 && authsize < 4)
53 return -EINVAL;
54
55 return 0;
56 }
57
crypto_authenc_esn_setkey(struct crypto_aead * authenc_esn,const u8 * key,unsigned int keylen)58 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
59 unsigned int keylen)
60 {
61 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
62 struct crypto_ahash *auth = ctx->auth;
63 struct crypto_skcipher *enc = ctx->enc;
64 struct crypto_authenc_keys keys;
65 int err = -EINVAL;
66
67 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
68 goto out;
69
70 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
71 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
72 CRYPTO_TFM_REQ_MASK);
73 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
74 if (err)
75 goto out;
76
77 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
78 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
79 CRYPTO_TFM_REQ_MASK);
80 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
81 out:
82 memzero_explicit(&keys, sizeof(keys));
83 return err;
84 }
85
crypto_authenc_esn_genicv_tail(struct aead_request * req,unsigned int flags)86 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
87 unsigned int flags)
88 {
89 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
90 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
91 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
92 struct crypto_ahash *auth = ctx->auth;
93 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
94 crypto_ahash_alignmask(auth) + 1);
95 unsigned int authsize = crypto_aead_authsize(authenc_esn);
96 unsigned int assoclen = req->assoclen;
97 unsigned int cryptlen = req->cryptlen;
98 struct scatterlist *dst = req->dst;
99 u32 tmp[2];
100
101 /* Move high-order bits of sequence number back. */
102 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
103 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
104 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
105
106 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
107 return 0;
108 }
109
authenc_esn_geniv_ahash_done(struct crypto_async_request * areq,int err)110 static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
111 int err)
112 {
113 struct aead_request *req = areq->data;
114
115 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
116 aead_request_complete(req, err);
117 }
118
crypto_authenc_esn_genicv(struct aead_request * req,unsigned int flags)119 static int crypto_authenc_esn_genicv(struct aead_request *req,
120 unsigned int flags)
121 {
122 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
123 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
124 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
125 struct crypto_ahash *auth = ctx->auth;
126 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
127 crypto_ahash_alignmask(auth) + 1);
128 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
129 unsigned int authsize = crypto_aead_authsize(authenc_esn);
130 unsigned int assoclen = req->assoclen;
131 unsigned int cryptlen = req->cryptlen;
132 struct scatterlist *dst = req->dst;
133 u32 tmp[2];
134
135 if (!authsize)
136 return 0;
137
138 /* Move high-order bits of sequence number to the end. */
139 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
140 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
141 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
142
143 sg_init_table(areq_ctx->dst, 2);
144 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
145
146 ahash_request_set_tfm(ahreq, auth);
147 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
148 ahash_request_set_callback(ahreq, flags,
149 authenc_esn_geniv_ahash_done, req);
150
151 return crypto_ahash_digest(ahreq) ?:
152 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
153 }
154
155
crypto_authenc_esn_encrypt_done(struct crypto_async_request * req,int err)156 static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
157 int err)
158 {
159 struct aead_request *areq = req->data;
160
161 if (!err)
162 err = crypto_authenc_esn_genicv(areq, 0);
163
164 authenc_esn_request_complete(areq, err);
165 }
166
crypto_authenc_esn_copy(struct aead_request * req,unsigned int len)167 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
168 {
169 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
170 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
171 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
172
173 skcipher_request_set_sync_tfm(skreq, ctx->null);
174 skcipher_request_set_callback(skreq, aead_request_flags(req),
175 NULL, NULL);
176 skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
177
178 return crypto_skcipher_encrypt(skreq);
179 }
180
crypto_authenc_esn_encrypt(struct aead_request * req)181 static int crypto_authenc_esn_encrypt(struct aead_request *req)
182 {
183 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
184 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
185 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
186 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
187 ctx->reqoff);
188 struct crypto_skcipher *enc = ctx->enc;
189 unsigned int assoclen = req->assoclen;
190 unsigned int cryptlen = req->cryptlen;
191 struct scatterlist *src, *dst;
192 int err;
193
194 sg_init_table(areq_ctx->src, 2);
195 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
196 dst = src;
197
198 if (req->src != req->dst) {
199 err = crypto_authenc_esn_copy(req, assoclen);
200 if (err)
201 return err;
202
203 sg_init_table(areq_ctx->dst, 2);
204 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
205 }
206
207 skcipher_request_set_tfm(skreq, enc);
208 skcipher_request_set_callback(skreq, aead_request_flags(req),
209 crypto_authenc_esn_encrypt_done, req);
210 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
211
212 err = crypto_skcipher_encrypt(skreq);
213 if (err)
214 return err;
215
216 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
217 }
218
crypto_authenc_esn_decrypt_tail(struct aead_request * req,unsigned int flags)219 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
220 unsigned int flags)
221 {
222 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
223 unsigned int authsize = crypto_aead_authsize(authenc_esn);
224 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
225 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
226 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
227 ctx->reqoff);
228 struct crypto_ahash *auth = ctx->auth;
229 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
230 crypto_ahash_alignmask(auth) + 1);
231 unsigned int cryptlen = req->cryptlen - authsize;
232 unsigned int assoclen = req->assoclen;
233 struct scatterlist *dst = req->dst;
234 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
235 u32 tmp[2];
236
237 if (!authsize)
238 goto decrypt;
239
240 /* Move high-order bits of sequence number back. */
241 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
242 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
243 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
244
245 if (crypto_memneq(ihash, ohash, authsize))
246 return -EBADMSG;
247
248 decrypt:
249
250 sg_init_table(areq_ctx->dst, 2);
251 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
252
253 skcipher_request_set_tfm(skreq, ctx->enc);
254 skcipher_request_set_callback(skreq, flags,
255 req->base.complete, req->base.data);
256 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
257
258 return crypto_skcipher_decrypt(skreq);
259 }
260
authenc_esn_verify_ahash_done(struct crypto_async_request * areq,int err)261 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
262 int err)
263 {
264 struct aead_request *req = areq->data;
265
266 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
267 authenc_esn_request_complete(req, err);
268 }
269
crypto_authenc_esn_decrypt(struct aead_request * req)270 static int crypto_authenc_esn_decrypt(struct aead_request *req)
271 {
272 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
273 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
274 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
275 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
276 unsigned int authsize = crypto_aead_authsize(authenc_esn);
277 struct crypto_ahash *auth = ctx->auth;
278 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
279 crypto_ahash_alignmask(auth) + 1);
280 unsigned int assoclen = req->assoclen;
281 unsigned int cryptlen = req->cryptlen;
282 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
283 struct scatterlist *dst = req->dst;
284 u32 tmp[2];
285 int err;
286
287 cryptlen -= authsize;
288
289 if (req->src != dst) {
290 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
291 if (err)
292 return err;
293 }
294
295 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
296 authsize, 0);
297
298 if (!authsize)
299 goto tail;
300
301 /* Move high-order bits of sequence number to the end. */
302 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
303 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
304 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
305
306 sg_init_table(areq_ctx->dst, 2);
307 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
308
309 ahash_request_set_tfm(ahreq, auth);
310 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
311 ahash_request_set_callback(ahreq, aead_request_flags(req),
312 authenc_esn_verify_ahash_done, req);
313
314 err = crypto_ahash_digest(ahreq);
315 if (err)
316 return err;
317
318 tail:
319 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
320 }
321
crypto_authenc_esn_init_tfm(struct crypto_aead * tfm)322 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
323 {
324 struct aead_instance *inst = aead_alg_instance(tfm);
325 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
326 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
327 struct crypto_ahash *auth;
328 struct crypto_skcipher *enc;
329 struct crypto_sync_skcipher *null;
330 int err;
331
332 auth = crypto_spawn_ahash(&ictx->auth);
333 if (IS_ERR(auth))
334 return PTR_ERR(auth);
335
336 enc = crypto_spawn_skcipher(&ictx->enc);
337 err = PTR_ERR(enc);
338 if (IS_ERR(enc))
339 goto err_free_ahash;
340
341 null = crypto_get_default_null_skcipher();
342 err = PTR_ERR(null);
343 if (IS_ERR(null))
344 goto err_free_skcipher;
345
346 ctx->auth = auth;
347 ctx->enc = enc;
348 ctx->null = null;
349
350 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
351 crypto_ahash_alignmask(auth) + 1);
352
353 crypto_aead_set_reqsize(
354 tfm,
355 sizeof(struct authenc_esn_request_ctx) +
356 ctx->reqoff +
357 max_t(unsigned int,
358 crypto_ahash_reqsize(auth) +
359 sizeof(struct ahash_request),
360 sizeof(struct skcipher_request) +
361 crypto_skcipher_reqsize(enc)));
362
363 return 0;
364
365 err_free_skcipher:
366 crypto_free_skcipher(enc);
367 err_free_ahash:
368 crypto_free_ahash(auth);
369 return err;
370 }
371
crypto_authenc_esn_exit_tfm(struct crypto_aead * tfm)372 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
373 {
374 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
375
376 crypto_free_ahash(ctx->auth);
377 crypto_free_skcipher(ctx->enc);
378 crypto_put_default_null_skcipher();
379 }
380
crypto_authenc_esn_free(struct aead_instance * inst)381 static void crypto_authenc_esn_free(struct aead_instance *inst)
382 {
383 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
384
385 crypto_drop_skcipher(&ctx->enc);
386 crypto_drop_ahash(&ctx->auth);
387 kfree(inst);
388 }
389
crypto_authenc_esn_create(struct crypto_template * tmpl,struct rtattr ** tb)390 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
391 struct rtattr **tb)
392 {
393 u32 mask;
394 struct aead_instance *inst;
395 struct authenc_esn_instance_ctx *ctx;
396 struct hash_alg_common *auth;
397 struct crypto_alg *auth_base;
398 struct skcipher_alg *enc;
399 int err;
400
401 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
402 if (err)
403 return err;
404
405 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
406 if (!inst)
407 return -ENOMEM;
408 ctx = aead_instance_ctx(inst);
409
410 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
411 crypto_attr_alg_name(tb[1]), 0, mask);
412 if (err)
413 goto err_free_inst;
414 auth = crypto_spawn_ahash_alg(&ctx->auth);
415 auth_base = &auth->base;
416
417 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
418 crypto_attr_alg_name(tb[2]), 0, mask);
419 if (err)
420 goto err_free_inst;
421 enc = crypto_spawn_skcipher_alg(&ctx->enc);
422
423 err = -ENAMETOOLONG;
424 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
425 "authencesn(%s,%s)", auth_base->cra_name,
426 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
427 goto err_free_inst;
428
429 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
430 "authencesn(%s,%s)", auth_base->cra_driver_name,
431 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
432 goto err_free_inst;
433
434 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
435 auth_base->cra_priority;
436 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
437 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
438 enc->base.cra_alignmask;
439 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
440
441 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
442 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
443 inst->alg.maxauthsize = auth->digestsize;
444
445 inst->alg.init = crypto_authenc_esn_init_tfm;
446 inst->alg.exit = crypto_authenc_esn_exit_tfm;
447
448 inst->alg.setkey = crypto_authenc_esn_setkey;
449 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
450 inst->alg.encrypt = crypto_authenc_esn_encrypt;
451 inst->alg.decrypt = crypto_authenc_esn_decrypt;
452
453 inst->free = crypto_authenc_esn_free;
454
455 err = aead_register_instance(tmpl, inst);
456 if (err) {
457 err_free_inst:
458 crypto_authenc_esn_free(inst);
459 }
460 return err;
461 }
462
463 static struct crypto_template crypto_authenc_esn_tmpl = {
464 .name = "authencesn",
465 .create = crypto_authenc_esn_create,
466 .module = THIS_MODULE,
467 };
468
crypto_authenc_esn_module_init(void)469 static int __init crypto_authenc_esn_module_init(void)
470 {
471 return crypto_register_template(&crypto_authenc_esn_tmpl);
472 }
473
crypto_authenc_esn_module_exit(void)474 static void __exit crypto_authenc_esn_module_exit(void)
475 {
476 crypto_unregister_template(&crypto_authenc_esn_tmpl);
477 }
478
479 subsys_initcall(crypto_authenc_esn_module_init);
480 module_exit(crypto_authenc_esn_module_exit);
481
482 MODULE_LICENSE("GPL");
483 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
484 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
485 MODULE_ALIAS_CRYPTO("authencesn");
486