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(void * data,int err)110 static void authenc_esn_geniv_ahash_done(void *data, int err)
111 {
112 struct aead_request *req = data;
113
114 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
115 aead_request_complete(req, err);
116 }
117
crypto_authenc_esn_genicv(struct aead_request * req,unsigned int flags)118 static int crypto_authenc_esn_genicv(struct aead_request *req,
119 unsigned int flags)
120 {
121 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
122 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
123 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
124 struct crypto_ahash *auth = ctx->auth;
125 u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
126 crypto_ahash_alignmask(auth) + 1);
127 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
128 unsigned int authsize = crypto_aead_authsize(authenc_esn);
129 unsigned int assoclen = req->assoclen;
130 unsigned int cryptlen = req->cryptlen;
131 struct scatterlist *dst = req->dst;
132 u32 tmp[2];
133
134 if (!authsize)
135 return 0;
136
137 /* Move high-order bits of sequence number to the end. */
138 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
139 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
140 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
141
142 sg_init_table(areq_ctx->dst, 2);
143 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
144
145 ahash_request_set_tfm(ahreq, auth);
146 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
147 ahash_request_set_callback(ahreq, flags,
148 authenc_esn_geniv_ahash_done, req);
149
150 return crypto_ahash_digest(ahreq) ?:
151 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
152 }
153
154
crypto_authenc_esn_encrypt_done(void * data,int err)155 static void crypto_authenc_esn_encrypt_done(void *data, int err)
156 {
157 struct aead_request *areq = data;
158
159 if (!err)
160 err = crypto_authenc_esn_genicv(areq, 0);
161
162 authenc_esn_request_complete(areq, err);
163 }
164
crypto_authenc_esn_copy(struct aead_request * req,unsigned int len)165 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
166 {
167 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
168 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
169 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
170
171 skcipher_request_set_sync_tfm(skreq, ctx->null);
172 skcipher_request_set_callback(skreq, aead_request_flags(req),
173 NULL, NULL);
174 skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
175
176 return crypto_skcipher_encrypt(skreq);
177 }
178
crypto_authenc_esn_encrypt(struct aead_request * req)179 static int crypto_authenc_esn_encrypt(struct aead_request *req)
180 {
181 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
182 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
183 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
184 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
185 ctx->reqoff);
186 struct crypto_skcipher *enc = ctx->enc;
187 unsigned int assoclen = req->assoclen;
188 unsigned int cryptlen = req->cryptlen;
189 struct scatterlist *src, *dst;
190 int err;
191
192 sg_init_table(areq_ctx->src, 2);
193 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
194 dst = src;
195
196 if (req->src != req->dst) {
197 err = crypto_authenc_esn_copy(req, assoclen);
198 if (err)
199 return err;
200
201 sg_init_table(areq_ctx->dst, 2);
202 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
203 }
204
205 skcipher_request_set_tfm(skreq, enc);
206 skcipher_request_set_callback(skreq, aead_request_flags(req),
207 crypto_authenc_esn_encrypt_done, req);
208 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
209
210 err = crypto_skcipher_encrypt(skreq);
211 if (err)
212 return err;
213
214 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
215 }
216
crypto_authenc_esn_decrypt_tail(struct aead_request * req,unsigned int flags)217 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
218 unsigned int flags)
219 {
220 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
221 unsigned int authsize = crypto_aead_authsize(authenc_esn);
222 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
223 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
224 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
225 ctx->reqoff);
226 struct crypto_ahash *auth = ctx->auth;
227 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
228 crypto_ahash_alignmask(auth) + 1);
229 unsigned int cryptlen = req->cryptlen - authsize;
230 unsigned int assoclen = req->assoclen;
231 struct scatterlist *dst = req->dst;
232 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
233 u32 tmp[2];
234
235 if (!authsize)
236 goto decrypt;
237
238 /* Move high-order bits of sequence number back. */
239 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
240 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
241 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
242
243 if (crypto_memneq(ihash, ohash, authsize))
244 return -EBADMSG;
245
246 decrypt:
247
248 sg_init_table(areq_ctx->dst, 2);
249 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
250
251 skcipher_request_set_tfm(skreq, ctx->enc);
252 skcipher_request_set_callback(skreq, flags,
253 req->base.complete, req->base.data);
254 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
255
256 return crypto_skcipher_decrypt(skreq);
257 }
258
authenc_esn_verify_ahash_done(void * data,int err)259 static void authenc_esn_verify_ahash_done(void *data, int err)
260 {
261 struct aead_request *req = data;
262
263 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
264 authenc_esn_request_complete(req, err);
265 }
266
crypto_authenc_esn_decrypt(struct aead_request * req)267 static int crypto_authenc_esn_decrypt(struct aead_request *req)
268 {
269 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
270 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
271 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
272 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
273 unsigned int authsize = crypto_aead_authsize(authenc_esn);
274 struct crypto_ahash *auth = ctx->auth;
275 u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
276 crypto_ahash_alignmask(auth) + 1);
277 unsigned int assoclen = req->assoclen;
278 unsigned int cryptlen = req->cryptlen;
279 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
280 struct scatterlist *dst = req->dst;
281 u32 tmp[2];
282 int err;
283
284 cryptlen -= authsize;
285
286 if (req->src != dst) {
287 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
288 if (err)
289 return err;
290 }
291
292 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
293 authsize, 0);
294
295 if (!authsize)
296 goto tail;
297
298 /* Move high-order bits of sequence number to the end. */
299 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
300 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
301 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
302
303 sg_init_table(areq_ctx->dst, 2);
304 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
305
306 ahash_request_set_tfm(ahreq, auth);
307 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
308 ahash_request_set_callback(ahreq, aead_request_flags(req),
309 authenc_esn_verify_ahash_done, req);
310
311 err = crypto_ahash_digest(ahreq);
312 if (err)
313 return err;
314
315 tail:
316 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
317 }
318
crypto_authenc_esn_init_tfm(struct crypto_aead * tfm)319 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
320 {
321 struct aead_instance *inst = aead_alg_instance(tfm);
322 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
323 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
324 struct crypto_ahash *auth;
325 struct crypto_skcipher *enc;
326 struct crypto_sync_skcipher *null;
327 int err;
328
329 auth = crypto_spawn_ahash(&ictx->auth);
330 if (IS_ERR(auth))
331 return PTR_ERR(auth);
332
333 enc = crypto_spawn_skcipher(&ictx->enc);
334 err = PTR_ERR(enc);
335 if (IS_ERR(enc))
336 goto err_free_ahash;
337
338 null = crypto_get_default_null_skcipher();
339 err = PTR_ERR(null);
340 if (IS_ERR(null))
341 goto err_free_skcipher;
342
343 ctx->auth = auth;
344 ctx->enc = enc;
345 ctx->null = null;
346
347 ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
348 crypto_ahash_alignmask(auth) + 1);
349
350 crypto_aead_set_reqsize(
351 tfm,
352 sizeof(struct authenc_esn_request_ctx) +
353 ctx->reqoff +
354 max_t(unsigned int,
355 crypto_ahash_reqsize(auth) +
356 sizeof(struct ahash_request),
357 sizeof(struct skcipher_request) +
358 crypto_skcipher_reqsize(enc)));
359
360 return 0;
361
362 err_free_skcipher:
363 crypto_free_skcipher(enc);
364 err_free_ahash:
365 crypto_free_ahash(auth);
366 return err;
367 }
368
crypto_authenc_esn_exit_tfm(struct crypto_aead * tfm)369 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
370 {
371 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
372
373 crypto_free_ahash(ctx->auth);
374 crypto_free_skcipher(ctx->enc);
375 crypto_put_default_null_skcipher();
376 }
377
crypto_authenc_esn_free(struct aead_instance * inst)378 static void crypto_authenc_esn_free(struct aead_instance *inst)
379 {
380 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
381
382 crypto_drop_skcipher(&ctx->enc);
383 crypto_drop_ahash(&ctx->auth);
384 kfree(inst);
385 }
386
crypto_authenc_esn_create(struct crypto_template * tmpl,struct rtattr ** tb)387 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
388 struct rtattr **tb)
389 {
390 u32 mask;
391 struct aead_instance *inst;
392 struct authenc_esn_instance_ctx *ctx;
393 struct hash_alg_common *auth;
394 struct crypto_alg *auth_base;
395 struct skcipher_alg *enc;
396 int err;
397
398 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
399 if (err)
400 return err;
401
402 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
403 if (!inst)
404 return -ENOMEM;
405 ctx = aead_instance_ctx(inst);
406
407 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
408 crypto_attr_alg_name(tb[1]), 0, mask);
409 if (err)
410 goto err_free_inst;
411 auth = crypto_spawn_ahash_alg(&ctx->auth);
412 auth_base = &auth->base;
413
414 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
415 crypto_attr_alg_name(tb[2]), 0, mask);
416 if (err)
417 goto err_free_inst;
418 enc = crypto_spawn_skcipher_alg(&ctx->enc);
419
420 err = -ENAMETOOLONG;
421 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
422 "authencesn(%s,%s)", auth_base->cra_name,
423 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
424 goto err_free_inst;
425
426 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
427 "authencesn(%s,%s)", auth_base->cra_driver_name,
428 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
429 goto err_free_inst;
430
431 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
432 auth_base->cra_priority;
433 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
434 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
435 enc->base.cra_alignmask;
436 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
437
438 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
439 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
440 inst->alg.maxauthsize = auth->digestsize;
441
442 inst->alg.init = crypto_authenc_esn_init_tfm;
443 inst->alg.exit = crypto_authenc_esn_exit_tfm;
444
445 inst->alg.setkey = crypto_authenc_esn_setkey;
446 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
447 inst->alg.encrypt = crypto_authenc_esn_encrypt;
448 inst->alg.decrypt = crypto_authenc_esn_decrypt;
449
450 inst->free = crypto_authenc_esn_free;
451
452 err = aead_register_instance(tmpl, inst);
453 if (err) {
454 err_free_inst:
455 crypto_authenc_esn_free(inst);
456 }
457 return err;
458 }
459
460 static struct crypto_template crypto_authenc_esn_tmpl = {
461 .name = "authencesn",
462 .create = crypto_authenc_esn_create,
463 .module = THIS_MODULE,
464 };
465
crypto_authenc_esn_module_init(void)466 static int __init crypto_authenc_esn_module_init(void)
467 {
468 return crypto_register_template(&crypto_authenc_esn_tmpl);
469 }
470
crypto_authenc_esn_module_exit(void)471 static void __exit crypto_authenc_esn_module_exit(void)
472 {
473 crypto_unregister_template(&crypto_authenc_esn_tmpl);
474 }
475
476 subsys_initcall(crypto_authenc_esn_module_init);
477 module_exit(crypto_authenc_esn_module_exit);
478
479 MODULE_LICENSE("GPL");
480 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
481 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
482 MODULE_ALIAS_CRYPTO("authencesn");
483