1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Authenc: Simple AEAD wrapper for IPsec
4 *
5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8 #include <crypto/internal/aead.h>
9 #include <crypto/internal/hash.h>
10 #include <crypto/internal/skcipher.h>
11 #include <crypto/authenc.h>
12 #include <crypto/null.h>
13 #include <crypto/scatterwalk.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21
22 struct authenc_instance_ctx {
23 struct crypto_ahash_spawn auth;
24 struct crypto_skcipher_spawn enc;
25 unsigned int reqoff;
26 };
27
28 struct crypto_authenc_ctx {
29 struct crypto_ahash *auth;
30 struct crypto_skcipher *enc;
31 struct crypto_sync_skcipher *null;
32 };
33
34 struct authenc_request_ctx {
35 struct scatterlist src[2];
36 struct scatterlist dst[2];
37 char tail[];
38 };
39
authenc_request_complete(struct aead_request * req,int err)40 static void authenc_request_complete(struct aead_request *req, int err)
41 {
42 if (err != -EINPROGRESS)
43 aead_request_complete(req, err);
44 }
45
crypto_authenc_extractkeys(struct crypto_authenc_keys * keys,const u8 * key,unsigned int keylen)46 int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
47 unsigned int keylen)
48 {
49 struct rtattr *rta = (struct rtattr *)key;
50 struct crypto_authenc_key_param *param;
51
52 if (!RTA_OK(rta, keylen))
53 return -EINVAL;
54 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
55 return -EINVAL;
56
57 /*
58 * RTA_OK() didn't align the rtattr's payload when validating that it
59 * fits in the buffer. Yet, the keys should start on the next 4-byte
60 * aligned boundary. To avoid confusion, require that the rtattr
61 * payload be exactly the param struct, which has a 4-byte aligned size.
62 */
63 if (RTA_PAYLOAD(rta) != sizeof(*param))
64 return -EINVAL;
65 BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO);
66
67 param = RTA_DATA(rta);
68 keys->enckeylen = be32_to_cpu(param->enckeylen);
69
70 key += rta->rta_len;
71 keylen -= rta->rta_len;
72
73 if (keylen < keys->enckeylen)
74 return -EINVAL;
75
76 keys->authkeylen = keylen - keys->enckeylen;
77 keys->authkey = key;
78 keys->enckey = key + keys->authkeylen;
79
80 return 0;
81 }
82 EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
83
crypto_authenc_setkey(struct crypto_aead * authenc,const u8 * key,unsigned int keylen)84 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
85 unsigned int keylen)
86 {
87 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
88 struct crypto_ahash *auth = ctx->auth;
89 struct crypto_skcipher *enc = ctx->enc;
90 struct crypto_authenc_keys keys;
91 int err = -EINVAL;
92
93 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
94 goto out;
95
96 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
97 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) &
98 CRYPTO_TFM_REQ_MASK);
99 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
100 if (err)
101 goto out;
102
103 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
104 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
105 CRYPTO_TFM_REQ_MASK);
106 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
107 out:
108 memzero_explicit(&keys, sizeof(keys));
109 return err;
110 }
111
authenc_geniv_ahash_done(void * data,int err)112 static void authenc_geniv_ahash_done(void *data, int err)
113 {
114 struct aead_request *req = data;
115 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
116 struct aead_instance *inst = aead_alg_instance(authenc);
117 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
118 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
119 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
120
121 if (err)
122 goto out;
123
124 scatterwalk_map_and_copy(ahreq->result, req->dst,
125 req->assoclen + req->cryptlen,
126 crypto_aead_authsize(authenc), 1);
127
128 out:
129 aead_request_complete(req, err);
130 }
131
crypto_authenc_genicv(struct aead_request * req,unsigned int flags)132 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
133 {
134 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
135 struct aead_instance *inst = aead_alg_instance(authenc);
136 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
137 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
138 struct crypto_ahash *auth = ctx->auth;
139 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
140 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
141 u8 *hash = areq_ctx->tail;
142 int err;
143
144 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
145 crypto_ahash_alignmask(auth) + 1);
146
147 ahash_request_set_tfm(ahreq, auth);
148 ahash_request_set_crypt(ahreq, req->dst, hash,
149 req->assoclen + req->cryptlen);
150 ahash_request_set_callback(ahreq, flags,
151 authenc_geniv_ahash_done, req);
152
153 err = crypto_ahash_digest(ahreq);
154 if (err)
155 return err;
156
157 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen,
158 crypto_aead_authsize(authenc), 1);
159
160 return 0;
161 }
162
crypto_authenc_encrypt_done(void * data,int err)163 static void crypto_authenc_encrypt_done(void *data, int err)
164 {
165 struct aead_request *areq = data;
166
167 if (err)
168 goto out;
169
170 err = crypto_authenc_genicv(areq, 0);
171
172 out:
173 authenc_request_complete(areq, err);
174 }
175
crypto_authenc_copy_assoc(struct aead_request * req)176 static int crypto_authenc_copy_assoc(struct aead_request *req)
177 {
178 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
179 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
180 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
181
182 skcipher_request_set_sync_tfm(skreq, ctx->null);
183 skcipher_request_set_callback(skreq, aead_request_flags(req),
184 NULL, NULL);
185 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen,
186 NULL);
187
188 return crypto_skcipher_encrypt(skreq);
189 }
190
crypto_authenc_encrypt(struct aead_request * req)191 static int crypto_authenc_encrypt(struct aead_request *req)
192 {
193 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
194 struct aead_instance *inst = aead_alg_instance(authenc);
195 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
196 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
197 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
198 struct crypto_skcipher *enc = ctx->enc;
199 unsigned int cryptlen = req->cryptlen;
200 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
201 ictx->reqoff);
202 struct scatterlist *src, *dst;
203 int err;
204
205 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
206 dst = src;
207
208 if (req->src != req->dst) {
209 err = crypto_authenc_copy_assoc(req);
210 if (err)
211 return err;
212
213 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
214 }
215
216 skcipher_request_set_tfm(skreq, enc);
217 skcipher_request_set_callback(skreq, aead_request_flags(req),
218 crypto_authenc_encrypt_done, req);
219 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
220
221 err = crypto_skcipher_encrypt(skreq);
222 if (err)
223 return err;
224
225 return crypto_authenc_genicv(req, aead_request_flags(req));
226 }
227
crypto_authenc_decrypt_tail(struct aead_request * req,unsigned int flags)228 static int crypto_authenc_decrypt_tail(struct aead_request *req,
229 unsigned int flags)
230 {
231 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
232 struct aead_instance *inst = aead_alg_instance(authenc);
233 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
234 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
235 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
236 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
237 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
238 ictx->reqoff);
239 unsigned int authsize = crypto_aead_authsize(authenc);
240 u8 *ihash = ahreq->result + authsize;
241 struct scatterlist *src, *dst;
242
243 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0);
244
245 if (crypto_memneq(ihash, ahreq->result, authsize))
246 return -EBADMSG;
247
248 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
249 dst = src;
250
251 if (req->src != req->dst)
252 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
253
254 skcipher_request_set_tfm(skreq, ctx->enc);
255 skcipher_request_set_callback(skreq, flags,
256 req->base.complete, req->base.data);
257 skcipher_request_set_crypt(skreq, src, dst,
258 req->cryptlen - authsize, req->iv);
259
260 return crypto_skcipher_decrypt(skreq);
261 }
262
authenc_verify_ahash_done(void * data,int err)263 static void authenc_verify_ahash_done(void *data, int err)
264 {
265 struct aead_request *req = data;
266
267 if (err)
268 goto out;
269
270 err = crypto_authenc_decrypt_tail(req, 0);
271
272 out:
273 authenc_request_complete(req, err);
274 }
275
crypto_authenc_decrypt(struct aead_request * req)276 static int crypto_authenc_decrypt(struct aead_request *req)
277 {
278 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
279 unsigned int authsize = crypto_aead_authsize(authenc);
280 struct aead_instance *inst = aead_alg_instance(authenc);
281 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
282 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
283 struct crypto_ahash *auth = ctx->auth;
284 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
285 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
286 u8 *hash = areq_ctx->tail;
287 int err;
288
289 hash = (u8 *)ALIGN((unsigned long)hash + crypto_ahash_alignmask(auth),
290 crypto_ahash_alignmask(auth) + 1);
291
292 ahash_request_set_tfm(ahreq, auth);
293 ahash_request_set_crypt(ahreq, req->src, hash,
294 req->assoclen + req->cryptlen - authsize);
295 ahash_request_set_callback(ahreq, aead_request_flags(req),
296 authenc_verify_ahash_done, req);
297
298 err = crypto_ahash_digest(ahreq);
299 if (err)
300 return err;
301
302 return crypto_authenc_decrypt_tail(req, aead_request_flags(req));
303 }
304
crypto_authenc_init_tfm(struct crypto_aead * tfm)305 static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
306 {
307 struct aead_instance *inst = aead_alg_instance(tfm);
308 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
309 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
310 struct crypto_ahash *auth;
311 struct crypto_skcipher *enc;
312 struct crypto_sync_skcipher *null;
313 int err;
314
315 auth = crypto_spawn_ahash(&ictx->auth);
316 if (IS_ERR(auth))
317 return PTR_ERR(auth);
318
319 enc = crypto_spawn_skcipher(&ictx->enc);
320 err = PTR_ERR(enc);
321 if (IS_ERR(enc))
322 goto err_free_ahash;
323
324 null = crypto_get_default_null_skcipher();
325 err = PTR_ERR(null);
326 if (IS_ERR(null))
327 goto err_free_skcipher;
328
329 ctx->auth = auth;
330 ctx->enc = enc;
331 ctx->null = null;
332
333 crypto_aead_set_reqsize(
334 tfm,
335 sizeof(struct authenc_request_ctx) +
336 ictx->reqoff +
337 max_t(unsigned int,
338 crypto_ahash_reqsize(auth) +
339 sizeof(struct ahash_request),
340 sizeof(struct skcipher_request) +
341 crypto_skcipher_reqsize(enc)));
342
343 return 0;
344
345 err_free_skcipher:
346 crypto_free_skcipher(enc);
347 err_free_ahash:
348 crypto_free_ahash(auth);
349 return err;
350 }
351
crypto_authenc_exit_tfm(struct crypto_aead * tfm)352 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
353 {
354 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
355
356 crypto_free_ahash(ctx->auth);
357 crypto_free_skcipher(ctx->enc);
358 crypto_put_default_null_skcipher();
359 }
360
crypto_authenc_free(struct aead_instance * inst)361 static void crypto_authenc_free(struct aead_instance *inst)
362 {
363 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
364
365 crypto_drop_skcipher(&ctx->enc);
366 crypto_drop_ahash(&ctx->auth);
367 kfree(inst);
368 }
369
crypto_authenc_create(struct crypto_template * tmpl,struct rtattr ** tb)370 static int crypto_authenc_create(struct crypto_template *tmpl,
371 struct rtattr **tb)
372 {
373 u32 mask;
374 struct aead_instance *inst;
375 struct authenc_instance_ctx *ctx;
376 struct hash_alg_common *auth;
377 struct crypto_alg *auth_base;
378 struct skcipher_alg *enc;
379 int err;
380
381 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
382 if (err)
383 return err;
384
385 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
386 if (!inst)
387 return -ENOMEM;
388 ctx = aead_instance_ctx(inst);
389
390 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
391 crypto_attr_alg_name(tb[1]), 0, mask);
392 if (err)
393 goto err_free_inst;
394 auth = crypto_spawn_ahash_alg(&ctx->auth);
395 auth_base = &auth->base;
396
397 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
398 crypto_attr_alg_name(tb[2]), 0, mask);
399 if (err)
400 goto err_free_inst;
401 enc = crypto_spawn_skcipher_alg(&ctx->enc);
402
403 ctx->reqoff = ALIGN(2 * auth->digestsize + auth_base->cra_alignmask,
404 auth_base->cra_alignmask + 1);
405
406 err = -ENAMETOOLONG;
407 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
408 "authenc(%s,%s)", auth_base->cra_name,
409 enc->base.cra_name) >=
410 CRYPTO_MAX_ALG_NAME)
411 goto err_free_inst;
412
413 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
414 "authenc(%s,%s)", auth_base->cra_driver_name,
415 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
416 goto err_free_inst;
417
418 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
419 auth_base->cra_priority;
420 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
421 inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
422 enc->base.cra_alignmask;
423 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
424
425 inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
426 inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
427 inst->alg.maxauthsize = auth->digestsize;
428
429 inst->alg.init = crypto_authenc_init_tfm;
430 inst->alg.exit = crypto_authenc_exit_tfm;
431
432 inst->alg.setkey = crypto_authenc_setkey;
433 inst->alg.encrypt = crypto_authenc_encrypt;
434 inst->alg.decrypt = crypto_authenc_decrypt;
435
436 inst->free = crypto_authenc_free;
437
438 err = aead_register_instance(tmpl, inst);
439 if (err) {
440 err_free_inst:
441 crypto_authenc_free(inst);
442 }
443 return err;
444 }
445
446 static struct crypto_template crypto_authenc_tmpl = {
447 .name = "authenc",
448 .create = crypto_authenc_create,
449 .module = THIS_MODULE,
450 };
451
crypto_authenc_module_init(void)452 static int __init crypto_authenc_module_init(void)
453 {
454 return crypto_register_template(&crypto_authenc_tmpl);
455 }
456
crypto_authenc_module_exit(void)457 static void __exit crypto_authenc_module_exit(void)
458 {
459 crypto_unregister_template(&crypto_authenc_tmpl);
460 }
461
462 subsys_initcall(crypto_authenc_module_init);
463 module_exit(crypto_authenc_module_exit);
464
465 MODULE_LICENSE("GPL");
466 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
467 MODULE_ALIAS_CRYPTO("authenc");
468