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
22struct authenc_instance_ctx {
23 struct crypto_ahash_spawn auth;
24 struct crypto_skcipher_spawn enc;
25 unsigned int reqoff;
26};
27
28struct crypto_authenc_ctx {
29 struct crypto_ahash *auth;
30 struct crypto_skcipher *enc;
31 struct crypto_sync_skcipher *null;
32};
33
34struct authenc_request_ctx {
35 struct scatterlist src[2];
36 struct scatterlist dst[2];
37 char tail[];
38};
39
40static void authenc_request_complete(struct aead_request *req, int err)
41{
42 if (err != -EINPROGRESS)
43 aead_request_complete(req, err);
44}
45
46int 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}
82EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
83
84static 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(tfm: 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(tfm: auth, CRYPTO_TFM_REQ_MASK);
97 crypto_ahash_set_flags(tfm: auth, flags: crypto_aead_get_flags(tfm: authenc) &
98 CRYPTO_TFM_REQ_MASK);
99 err = crypto_ahash_setkey(tfm: auth, key: keys.authkey, keylen: keys.authkeylen);
100 if (err)
101 goto out;
102
103 crypto_skcipher_clear_flags(tfm: enc, CRYPTO_TFM_REQ_MASK);
104 crypto_skcipher_set_flags(tfm: enc, flags: crypto_aead_get_flags(tfm: authenc) &
105 CRYPTO_TFM_REQ_MASK);
106 err = crypto_skcipher_setkey(tfm: enc, key: keys.enckey, keylen: keys.enckeylen);
107out:
108 memzero_explicit(s: &keys, count: sizeof(keys));
109 return err;
110}
111
112static 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(aead: 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(buf: ahreq->result, sg: req->dst,
125 start: req->assoclen + req->cryptlen,
126 nbytes: crypto_aead_authsize(tfm: authenc), out: 1);
127
128out:
129 aead_request_complete(req, err);
130}
131
132static 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(aead: authenc);
136 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: 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 ahash_request_set_tfm(req: ahreq, tfm: auth);
145 ahash_request_set_crypt(req: ahreq, src: req->dst, result: hash,
146 nbytes: req->assoclen + req->cryptlen);
147 ahash_request_set_callback(req: ahreq, flags,
148 compl: authenc_geniv_ahash_done, data: req);
149
150 err = crypto_ahash_digest(req: ahreq);
151 if (err)
152 return err;
153
154 scatterwalk_map_and_copy(buf: hash, sg: req->dst, start: req->assoclen + req->cryptlen,
155 nbytes: crypto_aead_authsize(tfm: authenc), out: 1);
156
157 return 0;
158}
159
160static void crypto_authenc_encrypt_done(void *data, int err)
161{
162 struct aead_request *areq = data;
163
164 if (err)
165 goto out;
166
167 err = crypto_authenc_genicv(req: areq, flags: 0);
168
169out:
170 authenc_request_complete(req: areq, err);
171}
172
173static int crypto_authenc_copy_assoc(struct aead_request *req)
174{
175 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
176 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
177 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
178
179 skcipher_request_set_sync_tfm(req: skreq, tfm: ctx->null);
180 skcipher_request_set_callback(req: skreq, flags: aead_request_flags(req),
181 NULL, NULL);
182 skcipher_request_set_crypt(req: skreq, src: req->src, dst: req->dst, cryptlen: req->assoclen,
183 NULL);
184
185 return crypto_skcipher_encrypt(req: skreq);
186}
187
188static int crypto_authenc_encrypt(struct aead_request *req)
189{
190 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
191 struct aead_instance *inst = aead_alg_instance(aead: authenc);
192 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
193 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
194 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
195 struct crypto_skcipher *enc = ctx->enc;
196 unsigned int cryptlen = req->cryptlen;
197 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
198 ictx->reqoff);
199 struct scatterlist *src, *dst;
200 int err;
201
202 src = scatterwalk_ffwd(dst: areq_ctx->src, src: req->src, len: req->assoclen);
203 dst = src;
204
205 if (req->src != req->dst) {
206 err = crypto_authenc_copy_assoc(req);
207 if (err)
208 return err;
209
210 dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: req->dst, len: req->assoclen);
211 }
212
213 skcipher_request_set_tfm(req: skreq, tfm: enc);
214 skcipher_request_set_callback(req: skreq, flags: aead_request_flags(req),
215 compl: crypto_authenc_encrypt_done, data: req);
216 skcipher_request_set_crypt(req: skreq, src, dst, cryptlen, iv: req->iv);
217
218 err = crypto_skcipher_encrypt(req: skreq);
219 if (err)
220 return err;
221
222 return crypto_authenc_genicv(req, flags: aead_request_flags(req));
223}
224
225static int crypto_authenc_decrypt_tail(struct aead_request *req,
226 unsigned int flags)
227{
228 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
229 struct aead_instance *inst = aead_alg_instance(aead: authenc);
230 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
231 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
232 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
233 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
234 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
235 ictx->reqoff);
236 unsigned int authsize = crypto_aead_authsize(tfm: authenc);
237 u8 *ihash = ahreq->result + authsize;
238 struct scatterlist *src, *dst;
239
240 scatterwalk_map_and_copy(buf: ihash, sg: req->src, start: ahreq->nbytes, nbytes: authsize, out: 0);
241
242 if (crypto_memneq(a: ihash, b: ahreq->result, size: authsize))
243 return -EBADMSG;
244
245 src = scatterwalk_ffwd(dst: areq_ctx->src, src: req->src, len: req->assoclen);
246 dst = src;
247
248 if (req->src != req->dst)
249 dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: req->dst, len: req->assoclen);
250
251 skcipher_request_set_tfm(req: skreq, tfm: ctx->enc);
252 skcipher_request_set_callback(req: skreq, flags,
253 compl: req->base.complete, data: req->base.data);
254 skcipher_request_set_crypt(req: skreq, src, dst,
255 cryptlen: req->cryptlen - authsize, iv: req->iv);
256
257 return crypto_skcipher_decrypt(req: skreq);
258}
259
260static void authenc_verify_ahash_done(void *data, int err)
261{
262 struct aead_request *req = data;
263
264 if (err)
265 goto out;
266
267 err = crypto_authenc_decrypt_tail(req, flags: 0);
268
269out:
270 authenc_request_complete(req, err);
271}
272
273static int crypto_authenc_decrypt(struct aead_request *req)
274{
275 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
276 unsigned int authsize = crypto_aead_authsize(tfm: authenc);
277 struct aead_instance *inst = aead_alg_instance(aead: authenc);
278 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
279 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
280 struct crypto_ahash *auth = ctx->auth;
281 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
282 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
283 u8 *hash = areq_ctx->tail;
284 int err;
285
286 ahash_request_set_tfm(req: ahreq, tfm: auth);
287 ahash_request_set_crypt(req: ahreq, src: req->src, result: hash,
288 nbytes: req->assoclen + req->cryptlen - authsize);
289 ahash_request_set_callback(req: ahreq, flags: aead_request_flags(req),
290 compl: authenc_verify_ahash_done, data: req);
291
292 err = crypto_ahash_digest(req: ahreq);
293 if (err)
294 return err;
295
296 return crypto_authenc_decrypt_tail(req, flags: aead_request_flags(req));
297}
298
299static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
300{
301 struct aead_instance *inst = aead_alg_instance(aead: tfm);
302 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
303 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
304 struct crypto_ahash *auth;
305 struct crypto_skcipher *enc;
306 struct crypto_sync_skcipher *null;
307 int err;
308
309 auth = crypto_spawn_ahash(spawn: &ictx->auth);
310 if (IS_ERR(ptr: auth))
311 return PTR_ERR(ptr: auth);
312
313 enc = crypto_spawn_skcipher(spawn: &ictx->enc);
314 err = PTR_ERR(ptr: enc);
315 if (IS_ERR(ptr: enc))
316 goto err_free_ahash;
317
318 null = crypto_get_default_null_skcipher();
319 err = PTR_ERR(ptr: null);
320 if (IS_ERR(ptr: null))
321 goto err_free_skcipher;
322
323 ctx->auth = auth;
324 ctx->enc = enc;
325 ctx->null = null;
326
327 crypto_aead_set_reqsize(
328 aead: tfm,
329 reqsize: sizeof(struct authenc_request_ctx) +
330 ictx->reqoff +
331 max_t(unsigned int,
332 crypto_ahash_reqsize(auth) +
333 sizeof(struct ahash_request),
334 sizeof(struct skcipher_request) +
335 crypto_skcipher_reqsize(enc)));
336
337 return 0;
338
339err_free_skcipher:
340 crypto_free_skcipher(tfm: enc);
341err_free_ahash:
342 crypto_free_ahash(tfm: auth);
343 return err;
344}
345
346static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
347{
348 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
349
350 crypto_free_ahash(tfm: ctx->auth);
351 crypto_free_skcipher(tfm: ctx->enc);
352 crypto_put_default_null_skcipher();
353}
354
355static void crypto_authenc_free(struct aead_instance *inst)
356{
357 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
358
359 crypto_drop_skcipher(spawn: &ctx->enc);
360 crypto_drop_ahash(spawn: &ctx->auth);
361 kfree(objp: inst);
362}
363
364static int crypto_authenc_create(struct crypto_template *tmpl,
365 struct rtattr **tb)
366{
367 u32 mask;
368 struct aead_instance *inst;
369 struct authenc_instance_ctx *ctx;
370 struct skcipher_alg_common *enc;
371 struct hash_alg_common *auth;
372 struct crypto_alg *auth_base;
373 int err;
374
375 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, mask_ret: &mask);
376 if (err)
377 return err;
378
379 inst = kzalloc(size: sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
380 if (!inst)
381 return -ENOMEM;
382 ctx = aead_instance_ctx(inst);
383
384 err = crypto_grab_ahash(spawn: &ctx->auth, inst: aead_crypto_instance(inst),
385 name: crypto_attr_alg_name(rta: tb[1]), type: 0, mask);
386 if (err)
387 goto err_free_inst;
388 auth = crypto_spawn_ahash_alg(spawn: &ctx->auth);
389 auth_base = &auth->base;
390
391 err = crypto_grab_skcipher(spawn: &ctx->enc, inst: aead_crypto_instance(inst),
392 name: crypto_attr_alg_name(rta: tb[2]), type: 0, mask);
393 if (err)
394 goto err_free_inst;
395 enc = crypto_spawn_skcipher_alg_common(spawn: &ctx->enc);
396
397 ctx->reqoff = 2 * auth->digestsize;
398
399 err = -ENAMETOOLONG;
400 if (snprintf(buf: inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
401 fmt: "authenc(%s,%s)", auth_base->cra_name,
402 enc->base.cra_name) >=
403 CRYPTO_MAX_ALG_NAME)
404 goto err_free_inst;
405
406 if (snprintf(buf: inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
407 fmt: "authenc(%s,%s)", auth_base->cra_driver_name,
408 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
409 goto err_free_inst;
410
411 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
412 auth_base->cra_priority;
413 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
414 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
415 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
416
417 inst->alg.ivsize = enc->ivsize;
418 inst->alg.chunksize = enc->chunksize;
419 inst->alg.maxauthsize = auth->digestsize;
420
421 inst->alg.init = crypto_authenc_init_tfm;
422 inst->alg.exit = crypto_authenc_exit_tfm;
423
424 inst->alg.setkey = crypto_authenc_setkey;
425 inst->alg.encrypt = crypto_authenc_encrypt;
426 inst->alg.decrypt = crypto_authenc_decrypt;
427
428 inst->free = crypto_authenc_free;
429
430 err = aead_register_instance(tmpl, inst);
431 if (err) {
432err_free_inst:
433 crypto_authenc_free(inst);
434 }
435 return err;
436}
437
438static struct crypto_template crypto_authenc_tmpl = {
439 .name = "authenc",
440 .create = crypto_authenc_create,
441 .module = THIS_MODULE,
442};
443
444static int __init crypto_authenc_module_init(void)
445{
446 return crypto_register_template(tmpl: &crypto_authenc_tmpl);
447}
448
449static void __exit crypto_authenc_module_exit(void)
450{
451 crypto_unregister_template(tmpl: &crypto_authenc_tmpl);
452}
453
454subsys_initcall(crypto_authenc_module_init);
455module_exit(crypto_authenc_module_exit);
456
457MODULE_LICENSE("GPL");
458MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
459MODULE_ALIAS_CRYPTO("authenc");
460

source code of linux/crypto/authenc.c