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/scatterwalk.h>
16 #include <linux/err.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/slab.h>
22 #include <linux/spinlock.h>
23
24 struct authenc_esn_instance_ctx {
25 struct crypto_ahash_spawn auth;
26 struct crypto_skcipher_spawn enc;
27 };
28
29 struct crypto_authenc_esn_ctx {
30 unsigned int reqoff;
31 struct crypto_ahash *auth;
32 struct crypto_skcipher *enc;
33 };
34
35 struct authenc_esn_request_ctx {
36 struct scatterlist src[2];
37 struct scatterlist dst[2];
38 char tail[];
39 };
40
authenc_esn_request_complete(struct aead_request * req,int err)41 static void authenc_esn_request_complete(struct aead_request *req, int err)
42 {
43 if (err != -EINPROGRESS)
44 aead_request_complete(req, err);
45 }
46
crypto_authenc_esn_setauthsize(struct crypto_aead * authenc_esn,unsigned int authsize)47 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
48 unsigned int authsize)
49 {
50 if (authsize > 0 && authsize < 4)
51 return -EINVAL;
52
53 return 0;
54 }
55
crypto_authenc_esn_setkey(struct crypto_aead * authenc_esn,const u8 * key,unsigned int keylen)56 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
57 unsigned int keylen)
58 {
59 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
60 struct crypto_ahash *auth = ctx->auth;
61 struct crypto_skcipher *enc = ctx->enc;
62 struct crypto_authenc_keys keys;
63 int err = -EINVAL;
64
65 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
66 goto out;
67
68 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
69 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
70 CRYPTO_TFM_REQ_MASK);
71 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
72 if (err)
73 goto out;
74
75 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
76 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
77 CRYPTO_TFM_REQ_MASK);
78 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
79 out:
80 memzero_explicit(&keys, sizeof(keys));
81 return err;
82 }
83
crypto_authenc_esn_genicv_tail(struct aead_request * req,unsigned int flags)84 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
85 unsigned int flags)
86 {
87 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
88 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
89 u8 *hash = areq_ctx->tail;
90 unsigned int authsize = crypto_aead_authsize(authenc_esn);
91 unsigned int assoclen = req->assoclen;
92 unsigned int cryptlen = req->cryptlen;
93 struct scatterlist *dst = req->dst;
94 u32 tmp[2];
95
96 /* Move high-order bits of sequence number back. */
97 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
98 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
99 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
100
101 scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
102 return 0;
103 }
104
authenc_esn_geniv_ahash_done(void * data,int err)105 static void authenc_esn_geniv_ahash_done(void *data, int err)
106 {
107 struct aead_request *req = data;
108
109 err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
110 aead_request_complete(req, err);
111 }
112
crypto_authenc_esn_genicv(struct aead_request * req,unsigned int flags)113 static int crypto_authenc_esn_genicv(struct aead_request *req,
114 unsigned int flags)
115 {
116 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
117 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
118 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
119 struct crypto_ahash *auth = ctx->auth;
120 u8 *hash = areq_ctx->tail;
121 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
122 unsigned int authsize = crypto_aead_authsize(authenc_esn);
123 unsigned int assoclen = req->assoclen;
124 unsigned int cryptlen = req->cryptlen;
125 struct scatterlist *dst = req->dst;
126 u32 tmp[2];
127
128 if (!authsize)
129 return 0;
130
131 /* Move high-order bits of sequence number to the end. */
132 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
133 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
134 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
135
136 sg_init_table(areq_ctx->dst, 2);
137 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
138
139 ahash_request_set_tfm(ahreq, auth);
140 ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
141 ahash_request_set_callback(ahreq, flags,
142 authenc_esn_geniv_ahash_done, req);
143
144 return crypto_ahash_digest(ahreq) ?:
145 crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
146 }
147
148
crypto_authenc_esn_encrypt_done(void * data,int err)149 static void crypto_authenc_esn_encrypt_done(void *data, int err)
150 {
151 struct aead_request *areq = data;
152
153 if (!err)
154 err = crypto_authenc_esn_genicv(areq, 0);
155
156 authenc_esn_request_complete(areq, err);
157 }
158
crypto_authenc_esn_encrypt(struct aead_request * req)159 static int crypto_authenc_esn_encrypt(struct aead_request *req)
160 {
161 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
162 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
163 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
164 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
165 ctx->reqoff);
166 struct crypto_skcipher *enc = ctx->enc;
167 unsigned int assoclen = req->assoclen;
168 unsigned int cryptlen = req->cryptlen;
169 struct scatterlist *src, *dst;
170 int err;
171
172 sg_init_table(areq_ctx->src, 2);
173 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
174 dst = src;
175
176 if (req->src != req->dst) {
177 memcpy_sglist(req->dst, req->src, assoclen);
178 sg_init_table(areq_ctx->dst, 2);
179 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
180 }
181
182 skcipher_request_set_tfm(skreq, enc);
183 skcipher_request_set_callback(skreq, aead_request_flags(req),
184 crypto_authenc_esn_encrypt_done, req);
185 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
186
187 err = crypto_skcipher_encrypt(skreq);
188 if (err)
189 return err;
190
191 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
192 }
193
crypto_authenc_esn_decrypt_tail(struct aead_request * req,unsigned int flags)194 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
195 unsigned int flags)
196 {
197 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
198 unsigned int authsize = crypto_aead_authsize(authenc_esn);
199 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
200 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
201 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
202 ctx->reqoff);
203 struct crypto_ahash *auth = ctx->auth;
204 u8 *ohash = areq_ctx->tail;
205 unsigned int cryptlen = req->cryptlen - authsize;
206 unsigned int assoclen = req->assoclen;
207 struct scatterlist *dst = req->dst;
208 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
209 u32 tmp[2];
210
211 if (!authsize)
212 goto decrypt;
213
214 /* Move high-order bits of sequence number back. */
215 scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
216 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
217 scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
218
219 if (crypto_memneq(ihash, ohash, authsize))
220 return -EBADMSG;
221
222 decrypt:
223
224 sg_init_table(areq_ctx->dst, 2);
225 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
226
227 skcipher_request_set_tfm(skreq, ctx->enc);
228 skcipher_request_set_callback(skreq, flags,
229 req->base.complete, req->base.data);
230 skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
231
232 return crypto_skcipher_decrypt(skreq);
233 }
234
authenc_esn_verify_ahash_done(void * data,int err)235 static void authenc_esn_verify_ahash_done(void *data, int err)
236 {
237 struct aead_request *req = data;
238
239 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
240 authenc_esn_request_complete(req, err);
241 }
242
crypto_authenc_esn_decrypt(struct aead_request * req)243 static int crypto_authenc_esn_decrypt(struct aead_request *req)
244 {
245 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
246 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
247 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
248 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
249 unsigned int authsize = crypto_aead_authsize(authenc_esn);
250 struct crypto_ahash *auth = ctx->auth;
251 u8 *ohash = areq_ctx->tail;
252 unsigned int assoclen = req->assoclen;
253 unsigned int cryptlen = req->cryptlen;
254 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
255 struct scatterlist *dst = req->dst;
256 u32 tmp[2];
257 int err;
258
259 cryptlen -= authsize;
260
261 if (req->src != dst)
262 memcpy_sglist(dst, req->src, assoclen + cryptlen);
263
264 scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
265 authsize, 0);
266
267 if (!authsize)
268 goto tail;
269
270 /* Move high-order bits of sequence number to the end. */
271 scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
272 scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
273 scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
274
275 sg_init_table(areq_ctx->dst, 2);
276 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
277
278 ahash_request_set_tfm(ahreq, auth);
279 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
280 ahash_request_set_callback(ahreq, aead_request_flags(req),
281 authenc_esn_verify_ahash_done, req);
282
283 err = crypto_ahash_digest(ahreq);
284 if (err)
285 return err;
286
287 tail:
288 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
289 }
290
crypto_authenc_esn_init_tfm(struct crypto_aead * tfm)291 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
292 {
293 struct aead_instance *inst = aead_alg_instance(tfm);
294 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
295 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
296 struct crypto_ahash *auth;
297 struct crypto_skcipher *enc;
298 int err;
299
300 auth = crypto_spawn_ahash(&ictx->auth);
301 if (IS_ERR(auth))
302 return PTR_ERR(auth);
303
304 enc = crypto_spawn_skcipher(&ictx->enc);
305 err = PTR_ERR(enc);
306 if (IS_ERR(enc))
307 goto err_free_ahash;
308
309 ctx->auth = auth;
310 ctx->enc = enc;
311
312 ctx->reqoff = 2 * crypto_ahash_digestsize(auth);
313
314 crypto_aead_set_reqsize(
315 tfm,
316 sizeof(struct authenc_esn_request_ctx) +
317 ctx->reqoff +
318 max_t(unsigned int,
319 crypto_ahash_reqsize(auth) +
320 sizeof(struct ahash_request),
321 sizeof(struct skcipher_request) +
322 crypto_skcipher_reqsize(enc)));
323
324 return 0;
325
326 err_free_ahash:
327 crypto_free_ahash(auth);
328 return err;
329 }
330
crypto_authenc_esn_exit_tfm(struct crypto_aead * tfm)331 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
332 {
333 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
334
335 crypto_free_ahash(ctx->auth);
336 crypto_free_skcipher(ctx->enc);
337 }
338
crypto_authenc_esn_free(struct aead_instance * inst)339 static void crypto_authenc_esn_free(struct aead_instance *inst)
340 {
341 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
342
343 crypto_drop_skcipher(&ctx->enc);
344 crypto_drop_ahash(&ctx->auth);
345 kfree(inst);
346 }
347
crypto_authenc_esn_create(struct crypto_template * tmpl,struct rtattr ** tb)348 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
349 struct rtattr **tb)
350 {
351 u32 mask;
352 struct aead_instance *inst;
353 struct authenc_esn_instance_ctx *ctx;
354 struct skcipher_alg_common *enc;
355 struct hash_alg_common *auth;
356 struct crypto_alg *auth_base;
357 int err;
358
359 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
360 if (err)
361 return err;
362
363 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
364 if (!inst)
365 return -ENOMEM;
366 ctx = aead_instance_ctx(inst);
367
368 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
369 crypto_attr_alg_name(tb[1]), 0, mask);
370 if (err)
371 goto err_free_inst;
372 auth = crypto_spawn_ahash_alg(&ctx->auth);
373 auth_base = &auth->base;
374
375 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
376 crypto_attr_alg_name(tb[2]), 0, mask);
377 if (err)
378 goto err_free_inst;
379 enc = crypto_spawn_skcipher_alg_common(&ctx->enc);
380
381 err = -ENAMETOOLONG;
382 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
383 "authencesn(%s,%s)", auth_base->cra_name,
384 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
385 goto err_free_inst;
386
387 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
388 "authencesn(%s,%s)", auth_base->cra_driver_name,
389 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
390 goto err_free_inst;
391
392 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
393 auth_base->cra_priority;
394 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
395 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
396 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
397
398 inst->alg.ivsize = enc->ivsize;
399 inst->alg.chunksize = enc->chunksize;
400 inst->alg.maxauthsize = auth->digestsize;
401
402 inst->alg.init = crypto_authenc_esn_init_tfm;
403 inst->alg.exit = crypto_authenc_esn_exit_tfm;
404
405 inst->alg.setkey = crypto_authenc_esn_setkey;
406 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
407 inst->alg.encrypt = crypto_authenc_esn_encrypt;
408 inst->alg.decrypt = crypto_authenc_esn_decrypt;
409
410 inst->free = crypto_authenc_esn_free;
411
412 err = aead_register_instance(tmpl, inst);
413 if (err) {
414 err_free_inst:
415 crypto_authenc_esn_free(inst);
416 }
417 return err;
418 }
419
420 static struct crypto_template crypto_authenc_esn_tmpl = {
421 .name = "authencesn",
422 .create = crypto_authenc_esn_create,
423 .module = THIS_MODULE,
424 };
425
crypto_authenc_esn_module_init(void)426 static int __init crypto_authenc_esn_module_init(void)
427 {
428 return crypto_register_template(&crypto_authenc_esn_tmpl);
429 }
430
crypto_authenc_esn_module_exit(void)431 static void __exit crypto_authenc_esn_module_exit(void)
432 {
433 crypto_unregister_template(&crypto_authenc_esn_tmpl);
434 }
435
436 module_init(crypto_authenc_esn_module_init);
437 module_exit(crypto_authenc_esn_module_exit);
438
439 MODULE_LICENSE("GPL");
440 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
441 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
442 MODULE_ALIAS_CRYPTO("authencesn");
443