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
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
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
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
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 authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
91 u8 *hash = areq_ctx->tail;
92 unsigned int authsize = crypto_aead_authsize(authenc_esn);
93 unsigned int assoclen = req->assoclen;
94 unsigned int cryptlen = req->cryptlen;
95 struct scatterlist *dst = req->dst;
96 u32 tmp[2];
97
98 /* Move high-order bits of sequence number back. */
99 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
100 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
101 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
102
103 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
104 return 0;
105 }
106
107 static void authenc_esn_geniv_ahash_done(void *data, int err)
108 {
109 struct aead_request *req = data;
110
111 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
112 aead_request_complete(req, err);
113 }
114
115 static int crypto_authenc_esn_genicv(struct aead_request *req,
116 unsigned int flags)
117 {
118 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
119 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
120 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
121 struct crypto_ahash *auth = ctx->auth;
122 u8 *hash = areq_ctx->tail;
123 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
124 unsigned int authsize = crypto_aead_authsize(authenc_esn);
125 unsigned int assoclen = req->assoclen;
126 unsigned int cryptlen = req->cryptlen;
127 struct scatterlist *dst = req->dst;
128 u32 tmp[2];
129
130 if (!authsize)
131 return 0;
132
133 /* Move high-order bits of sequence number to the end. */
134 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
135 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
136 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
137
138 sg_init_table(areq_ctx->dst, 2);
139 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
140
141 ahash_request_set_tfm(ahreq, auth);
142 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
143 ahash_request_set_callback(ahreq, flags,
144 authenc_esn_geniv_ahash_done, req);
145
146 return crypto_ahash_digest(ahreq) ?:
147 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
148 }
149
150
151 static void crypto_authenc_esn_encrypt_done(void *data, int err)
152 {
153 struct aead_request *areq = data;
154
155 if (!err)
156 err = crypto_authenc_esn_genicv(areq, 0);
157
158 authenc_esn_request_complete(areq, err);
159 }
160
161 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
162 {
163 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
164 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
165 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
166
167 skcipher_request_set_sync_tfm(skreq, ctx->null);
168 skcipher_request_set_callback(skreq, aead_request_flags(req),
169 NULL, NULL);
170 skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
171
172 return crypto_skcipher_encrypt(skreq);
173 }
174
175 static int crypto_authenc_esn_encrypt(struct aead_request *req)
176 {
177 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
178 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
179 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
180 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
181 ctx->reqoff);
182 struct crypto_skcipher *enc = ctx->enc;
183 unsigned int assoclen = req->assoclen;
184 unsigned int cryptlen = req->cryptlen;
185 struct scatterlist *src, *dst;
186 int err;
187
188 sg_init_table(areq_ctx->src, 2);
189 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
190 dst = src;
191
192 if (req->src != req->dst) {
193 err = crypto_authenc_esn_copy(req, assoclen);
194 if (err)
195 return err;
196
197 sg_init_table(areq_ctx->dst, 2);
198 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
199 }
200
201 skcipher_request_set_tfm(skreq, enc);
202 skcipher_request_set_callback(skreq, aead_request_flags(req),
203 crypto_authenc_esn_encrypt_done, req);
204 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
205
206 err = crypto_skcipher_encrypt(skreq);
207 if (err)
208 return err;
209
210 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
211 }
212
213 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
214 unsigned int flags)
215 {
216 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
217 unsigned int authsize = crypto_aead_authsize(authenc_esn);
218 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
219 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
220 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
221 ctx->reqoff);
222 struct crypto_ahash *auth = ctx->auth;
223 u8 *ohash = areq_ctx->tail;
224 unsigned int cryptlen = req->cryptlen - authsize;
225 unsigned int assoclen = req->assoclen;
226 struct scatterlist *dst = req->dst;
227 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
228 u32 tmp[2];
229
230 if (!authsize)
231 goto decrypt;
232
233 /* Move high-order bits of sequence number back. */
234 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
235 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
236 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
237
238 if (crypto_memneq(ihash, ohash, authsize))
239 return -EBADMSG;
240
241 decrypt:
242
243 sg_init_table(areq_ctx->dst, 2);
244 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
245
246 skcipher_request_set_tfm(skreq, ctx->enc);
247 skcipher_request_set_callback(skreq, flags,
248 req->base.complete, req->base.data);
249 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
250
251 return crypto_skcipher_decrypt(skreq);
252 }
253
254 static void authenc_esn_verify_ahash_done(void *data, int err)
255 {
256 struct aead_request *req = data;
257
258 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
259 authenc_esn_request_complete(req, err);
260 }
261
262 static int crypto_authenc_esn_decrypt(struct aead_request *req)
263 {
264 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
265 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
266 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
267 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
268 unsigned int authsize = crypto_aead_authsize(authenc_esn);
269 struct crypto_ahash *auth = ctx->auth;
270 u8 *ohash = areq_ctx->tail;
271 unsigned int assoclen = req->assoclen;
272 unsigned int cryptlen = req->cryptlen;
273 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
274 struct scatterlist *dst = req->dst;
275 u32 tmp[2];
276 int err;
277
278 cryptlen -= authsize;
279
280 if (req->src != dst) {
281 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
282 if (err)
283 return err;
284 }
285
286 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
287 authsize, 0);
288
289 if (!authsize)
290 goto tail;
291
292 /* Move high-order bits of sequence number to the end. */
293 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
294 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
295 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
296
297 sg_init_table(areq_ctx->dst, 2);
298 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
299
300 ahash_request_set_tfm(ahreq, auth);
301 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
302 ahash_request_set_callback(ahreq, aead_request_flags(req),
303 authenc_esn_verify_ahash_done, req);
304
305 err = crypto_ahash_digest(ahreq);
306 if (err)
307 return err;
308
309 tail:
310 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
311 }
312
313 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
314 {
315 struct aead_instance *inst = aead_alg_instance(tfm);
316 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
317 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
318 struct crypto_ahash *auth;
319 struct crypto_skcipher *enc;
320 struct crypto_sync_skcipher *null;
321 int err;
322
323 auth = crypto_spawn_ahash(&ictx->auth);
324 if (IS_ERR(auth))
325 return PTR_ERR(auth);
326
327 enc = crypto_spawn_skcipher(&ictx->enc);
328 err = PTR_ERR(enc);
329 if (IS_ERR(enc))
330 goto err_free_ahash;
331
332 null = crypto_get_default_null_skcipher();
333 err = PTR_ERR(null);
334 if (IS_ERR(null))
335 goto err_free_skcipher;
336
337 ctx->auth = auth;
338 ctx->enc = enc;
339 ctx->null = null;
340
341 ctx->reqoff = 2 * crypto_ahash_digestsize(auth);
342
343 crypto_aead_set_reqsize(
344 tfm,
345 sizeof(struct authenc_esn_request_ctx) +
346 ctx->reqoff +
347 max_t(unsigned int,
348 crypto_ahash_reqsize(auth) +
349 sizeof(struct ahash_request),
350 sizeof(struct skcipher_request) +
351 crypto_skcipher_reqsize(enc)));
352
353 return 0;
354
355 err_free_skcipher:
356 crypto_free_skcipher(enc);
357 err_free_ahash:
358 crypto_free_ahash(auth);
359 return err;
360 }
361
362 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
363 {
364 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
365
366 crypto_free_ahash(ctx->auth);
367 crypto_free_skcipher(ctx->enc);
368 crypto_put_default_null_skcipher();
369 }
370
371 static void crypto_authenc_esn_free(struct aead_instance *inst)
372 {
373 struct authenc_esn_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_esn_create(struct crypto_template *tmpl,
381 struct rtattr **tb)
382 {
383 u32 mask;
384 struct aead_instance *inst;
385 struct authenc_esn_instance_ctx *ctx;
386 struct skcipher_alg_common *enc;
387 struct hash_alg_common *auth;
388 struct crypto_alg *auth_base;
389 int err;
390
391 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
392 if (err)
393 return err;
394
395 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
396 if (!inst)
397 return -ENOMEM;
398 ctx = aead_instance_ctx(inst);
399
400 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
401 crypto_attr_alg_name(tb[1]), 0, mask);
402 if (err)
403 goto err_free_inst;
404 auth = crypto_spawn_ahash_alg(&ctx->auth);
405 auth_base = &auth->base;
406
407 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
408 crypto_attr_alg_name(tb[2]), 0, mask);
409 if (err)
410 goto err_free_inst;
411 enc = crypto_spawn_skcipher_alg_common(&ctx->enc);
412
413 err = -ENAMETOOLONG;
414 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
415 "authencesn(%s,%s)", auth_base->cra_name,
416 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
417 goto err_free_inst;
418
419 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
420 "authencesn(%s,%s)", auth_base->cra_driver_name,
421 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
422 goto err_free_inst;
423
424 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
425 auth_base->cra_priority;
426 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
427 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
428 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
429
430 inst->alg.ivsize = enc->ivsize;
431 inst->alg.chunksize = enc->chunksize;
432 inst->alg.maxauthsize = auth->digestsize;
433
434 inst->alg.init = crypto_authenc_esn_init_tfm;
435 inst->alg.exit = crypto_authenc_esn_exit_tfm;
436
437 inst->alg.setkey = crypto_authenc_esn_setkey;
438 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
439 inst->alg.encrypt = crypto_authenc_esn_encrypt;
440 inst->alg.decrypt = crypto_authenc_esn_decrypt;
441
442 inst->free = crypto_authenc_esn_free;
443
444 err = aead_register_instance(tmpl, inst);
445 if (err) {
446 err_free_inst:
447 crypto_authenc_esn_free(inst);
448 }
449 return err;
450 }
451
452 static struct crypto_template crypto_authenc_esn_tmpl = {
453 .name = "authencesn",
454 .create = crypto_authenc_esn_create,
455 .module = THIS_MODULE,
456 };
457
458 static int __init crypto_authenc_esn_module_init(void)
459 {
460 return crypto_register_template(&crypto_authenc_esn_tmpl);
461 }
462
463 static void __exit crypto_authenc_esn_module_exit(void)
464 {
465 crypto_unregister_template(&crypto_authenc_esn_tmpl);
466 }
467
468 subsys_initcall(crypto_authenc_esn_module_init);
469 module_exit(crypto_authenc_esn_module_exit);
470
471 MODULE_LICENSE("GPL");
472 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
473 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
474 MODULE_ALIAS_CRYPTO("authencesn");
475
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