projects/linux·blob master · refs

464 lines · 13.2 KiB

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 <[email protected]>
8 * Copyright (c) 2015 Herbert Xu <[email protected]>
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
24struct authenc_esn_instance_ctx {
25 struct crypto_ahash_spawn auth;
26 struct crypto_skcipher_spawn enc;
27};
28
29struct crypto_authenc_esn_ctx {
30 unsigned int reqoff;
31 struct crypto_ahash *auth;
32 struct crypto_skcipher *enc;
33};
34
35struct authenc_esn_request_ctx {
36 struct scatterlist src[2];
37 struct scatterlist dst[2];
38 char tail[];
39};
40
41static void authenc_esn_request_complete(struct aead_request *req, int err)
42{
43 if (err != -EINPROGRESS)
44 aead_request_complete(req, err);
45}
46
47static 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
56static 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);
79out:
80 memzero_explicit(&keys, sizeof(keys));
81 return err;
82}
83
84static 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 memcpy_from_sglist(tmp, dst, 4, 4);
98 memcpy_from_sglist(tmp + 1, dst, assoclen + cryptlen, 4);
99 memcpy_to_sglist(dst, 0, tmp, 8);
100
101 memcpy_to_sglist(dst, assoclen + cryptlen, hash, authsize);
102 return 0;
103}
104
105static 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
113static 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 memcpy_from_sglist(tmp, dst, 0, 8);
133 memcpy_to_sglist(dst, 4, tmp, 4);
134 memcpy_to_sglist(dst, assoclen + cryptlen, tmp + 1, 4);
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
149static 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
159static 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 if (assoclen < 8)
173 return -EINVAL;
174
175 sg_init_table(areq_ctx->src, 2);
176 src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
177 dst = src;
178
179 if (req->src != req->dst) {
180 memcpy_sglist(req->dst, req->src, assoclen);
181 sg_init_table(areq_ctx->dst, 2);
182 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
183 }
184
185 skcipher_request_set_tfm(skreq, enc);
186 skcipher_request_set_callback(skreq, aead_request_flags(req),
187 crypto_authenc_esn_encrypt_done, req);
188 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
189
190 err = crypto_skcipher_encrypt(skreq);
191 if (err)
192 return err;
193
194 return crypto_authenc_esn_genicv(req, aead_request_flags(req));
195}
196
197static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
198 unsigned int flags)
199{
200 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
201 unsigned int authsize = crypto_aead_authsize(authenc_esn);
202 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
203 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
204 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
205 ctx->reqoff);
206 struct crypto_ahash *auth = ctx->auth;
207 u8 *ohash = areq_ctx->tail;
208 unsigned int cryptlen = req->cryptlen - authsize;
209 unsigned int assoclen = req->assoclen;
210 struct scatterlist *src = req->src;
211 struct scatterlist *dst = req->dst;
212 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
213 u32 tmp[2];
214
215 if (!authsize)
216 goto decrypt;
217
218 if (src == dst) {
219 /* Move high-order bits of sequence number back. */
220 memcpy_from_sglist(tmp, dst, 4, 4);
221 memcpy_from_sglist(tmp + 1, dst, assoclen + cryptlen, 4);
222 memcpy_to_sglist(dst, 0, tmp, 8);
223 } else
224 memcpy_sglist(dst, src, assoclen);
225
226 if (crypto_memneq(ihash, ohash, authsize))
227 return -EBADMSG;
228
229decrypt:
230
231 dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
232 if (req->src == req->dst)
233 src = dst;
234 else
235 src = scatterwalk_ffwd(areq_ctx->src, src, assoclen);
236
237 skcipher_request_set_tfm(skreq, ctx->enc);
238 skcipher_request_set_callback(skreq, flags,
239 req->base.complete, req->base.data);
240 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
241
242 return crypto_skcipher_decrypt(skreq);
243}
244
245static void authenc_esn_verify_ahash_done(void *data, int err)
246{
247 struct aead_request *req = data;
248
249 err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
250 authenc_esn_request_complete(req, err);
251}
252
253static int crypto_authenc_esn_decrypt(struct aead_request *req)
254{
255 struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
256 struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
257 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
258 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
259 unsigned int authsize = crypto_aead_authsize(authenc_esn);
260 struct crypto_ahash *auth = ctx->auth;
261 u8 *ohash = areq_ctx->tail;
262 unsigned int assoclen = req->assoclen;
263 unsigned int cryptlen = req->cryptlen;
264 u8 *ihash = ohash + crypto_ahash_digestsize(auth);
265 struct scatterlist *src = req->src;
266 struct scatterlist *dst = req->dst;
267 u32 tmp[2];
268 int err;
269
270 if (assoclen < 8)
271 return -EINVAL;
272
273 if (!authsize)
274 goto tail;
275
276 cryptlen -= authsize;
277 memcpy_from_sglist(ihash, req->src, assoclen + cryptlen, authsize);
278
279 /* Move high-order bits of sequence number to the end. */
280 memcpy_from_sglist(tmp, src, 0, 8);
281 if (src == dst) {
282 memcpy_to_sglist(dst, 4, tmp, 4);
283 memcpy_to_sglist(dst, assoclen + cryptlen, tmp + 1, 4);
284 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
285 } else {
286 memcpy_to_sglist(dst, 0, tmp, 4);
287 memcpy_to_sglist(dst, assoclen + cryptlen - 4, tmp + 1, 4);
288
289 src = scatterwalk_ffwd(areq_ctx->src, src, 8);
290 dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
291 memcpy_sglist(dst, src, assoclen + cryptlen - 8);
292 dst = req->dst;
293 }
294
295 ahash_request_set_tfm(ahreq, auth);
296 ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
297 ahash_request_set_callback(ahreq, aead_request_flags(req),
298 authenc_esn_verify_ahash_done, req);
299
300 err = crypto_ahash_digest(ahreq);
301 if (err)
302 return err;
303
304tail:
305 return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
306}
307
308static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
309{
310 struct aead_instance *inst = aead_alg_instance(tfm);
311 struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
312 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
313 struct crypto_ahash *auth;
314 struct crypto_skcipher *enc;
315 int err;
316
317 auth = crypto_spawn_ahash(&ictx->auth);
318 if (IS_ERR(auth))
319 return PTR_ERR(auth);
320
321 enc = crypto_spawn_skcipher(&ictx->enc);
322 err = PTR_ERR(enc);
323 if (IS_ERR(enc))
324 goto err_free_ahash;
325
326 ctx->auth = auth;
327 ctx->enc = enc;
328
329 ctx->reqoff = 2 * crypto_ahash_digestsize(auth);
330
331 crypto_aead_set_reqsize(
332 tfm,
333 sizeof(struct authenc_esn_request_ctx) +
334 ctx->reqoff +
335 max_t(unsigned int,
336 crypto_ahash_reqsize(auth) +
337 sizeof(struct ahash_request),
338 sizeof(struct skcipher_request) +
339 crypto_skcipher_reqsize(enc)));
340
341 return 0;
342
343err_free_ahash:
344 crypto_free_ahash(auth);
345 return err;
346}
347
348static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
349{
350 struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
351
352 crypto_free_ahash(ctx->auth);
353 crypto_free_skcipher(ctx->enc);
354}
355
356static void crypto_authenc_esn_free(struct aead_instance *inst)
357{
358 struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
359
360 crypto_drop_skcipher(&ctx->enc);
361 crypto_drop_ahash(&ctx->auth);
362 kfree(inst);
363}
364
365static int crypto_authenc_esn_create(struct crypto_template *tmpl,
366 struct rtattr **tb)
367{
368 u32 mask;
369 struct aead_instance *inst;
370 struct authenc_esn_instance_ctx *ctx;
371 struct skcipher_alg_common *enc;
372 struct hash_alg_common *auth;
373 struct crypto_alg *auth_base;
374 int err;
375
376 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
377 if (err)
378 return err;
379
380 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
381 if (!inst)
382 return -ENOMEM;
383 ctx = aead_instance_ctx(inst);
384
385 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
386 crypto_attr_alg_name(tb[1]), 0, mask);
387 if (err)
388 goto err_free_inst;
389 auth = crypto_spawn_ahash_alg(&ctx->auth);
390 auth_base = &auth->base;
391
392 if (auth->digestsize > 0 && auth->digestsize < 4) {
393 err = -EINVAL;
394 goto err_free_inst;
395 }
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_common(&ctx->enc);
402
403 err = -ENAMETOOLONG;
404 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
405 "authencesn(%s,%s)", auth_base->cra_name,
406 enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
407 goto err_free_inst;
408
409 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
410 "authencesn(%s,%s)", auth_base->cra_driver_name,
411 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
412 goto err_free_inst;
413
414 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
415 auth_base->cra_priority;
416 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
417 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
418 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
419
420 inst->alg.ivsize = enc->ivsize;
421 inst->alg.chunksize = enc->chunksize;
422 inst->alg.maxauthsize = auth->digestsize;
423
424 inst->alg.init = crypto_authenc_esn_init_tfm;
425 inst->alg.exit = crypto_authenc_esn_exit_tfm;
426
427 inst->alg.setkey = crypto_authenc_esn_setkey;
428 inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
429 inst->alg.encrypt = crypto_authenc_esn_encrypt;
430 inst->alg.decrypt = crypto_authenc_esn_decrypt;
431
432 inst->free = crypto_authenc_esn_free;
433
434 err = aead_register_instance(tmpl, inst);
435 if (err) {
436err_free_inst:
437 crypto_authenc_esn_free(inst);
438 }
439 return err;
440}
441
442static struct crypto_template crypto_authenc_esn_tmpl = {
443 .name = "authencesn",
444 .create = crypto_authenc_esn_create,
445 .module = THIS_MODULE,
446};
447
448static int __init crypto_authenc_esn_module_init(void)
449{
450 return crypto_register_template(&crypto_authenc_esn_tmpl);
451}
452
453static void __exit crypto_authenc_esn_module_exit(void)
454{
455 crypto_unregister_template(&crypto_authenc_esn_tmpl);
456}
457
458module_init(crypto_authenc_esn_module_init);
459module_exit(crypto_authenc_esn_module_exit);
460
461MODULE_LICENSE("GPL");
462MODULE_AUTHOR("Steffen Klassert <[email protected]>");
463MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
464MODULE_ALIAS_CRYPTO("authencesn");