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