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/null.h> |
16 | #include <crypto/scatterwalk.h> |
17 | #include <linux/err.h> |
18 | #include <linux/init.h> |
19 | #include <linux/kernel.h> |
20 | #include <linux/module.h> |
21 | #include <linux/rtnetlink.h> |
22 | #include <linux/slab.h> |
23 | #include <linux/spinlock.h> |
24 | |
25 | struct authenc_esn_instance_ctx { |
26 | struct crypto_ahash_spawn auth; |
27 | struct crypto_skcipher_spawn enc; |
28 | }; |
29 | |
30 | struct crypto_authenc_esn_ctx { |
31 | unsigned int reqoff; |
32 | struct crypto_ahash *auth; |
33 | struct crypto_skcipher *enc; |
34 | struct crypto_sync_skcipher *null; |
35 | }; |
36 | |
37 | struct authenc_esn_request_ctx { |
38 | struct scatterlist src[2]; |
39 | struct scatterlist dst[2]; |
40 | char tail[]; |
41 | }; |
42 | |
43 | static void authenc_esn_request_complete(struct aead_request *req, int err) |
44 | { |
45 | if (err != -EINPROGRESS) |
46 | aead_request_complete(req, err); |
47 | } |
48 | |
49 | static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn, |
50 | unsigned int authsize) |
51 | { |
52 | if (authsize > 0 && authsize < 4) |
53 | return -EINVAL; |
54 | |
55 | return 0; |
56 | } |
57 | |
58 | static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key, |
59 | unsigned int keylen) |
60 | { |
61 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
62 | struct crypto_ahash *auth = ctx->auth; |
63 | struct crypto_skcipher *enc = ctx->enc; |
64 | struct crypto_authenc_keys keys; |
65 | int err = -EINVAL; |
66 | |
67 | if (crypto_authenc_extractkeys(keys: &keys, key, keylen) != 0) |
68 | goto out; |
69 | |
70 | crypto_ahash_clear_flags(tfm: auth, CRYPTO_TFM_REQ_MASK); |
71 | crypto_ahash_set_flags(tfm: auth, flags: crypto_aead_get_flags(tfm: authenc_esn) & |
72 | CRYPTO_TFM_REQ_MASK); |
73 | err = crypto_ahash_setkey(tfm: auth, key: keys.authkey, keylen: keys.authkeylen); |
74 | if (err) |
75 | goto out; |
76 | |
77 | crypto_skcipher_clear_flags(tfm: enc, CRYPTO_TFM_REQ_MASK); |
78 | crypto_skcipher_set_flags(tfm: enc, flags: crypto_aead_get_flags(tfm: authenc_esn) & |
79 | CRYPTO_TFM_REQ_MASK); |
80 | err = crypto_skcipher_setkey(tfm: enc, key: keys.enckey, keylen: keys.enckeylen); |
81 | out: |
82 | memzero_explicit(s: &keys, count: sizeof(keys)); |
83 | return err; |
84 | } |
85 | |
86 | static int crypto_authenc_esn_genicv_tail(struct aead_request *req, |
87 | unsigned int flags) |
88 | { |
89 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
90 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); |
91 | u8 *hash = areq_ctx->tail; |
92 | unsigned int authsize = crypto_aead_authsize(tfm: authenc_esn); |
93 | unsigned int assoclen = req->assoclen; |
94 | unsigned int cryptlen = req->cryptlen; |
95 | struct scatterlist *dst = req->dst; |
96 | u32 tmp[2]; |
97 | |
98 | /* Move high-order bits of sequence number back. */ |
99 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 4, nbytes: 4, out: 0); |
100 | scatterwalk_map_and_copy(buf: tmp + 1, sg: dst, start: assoclen + cryptlen, nbytes: 4, out: 0); |
101 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 0, nbytes: 8, out: 1); |
102 | |
103 | scatterwalk_map_and_copy(buf: hash, sg: dst, start: assoclen + cryptlen, nbytes: authsize, out: 1); |
104 | return 0; |
105 | } |
106 | |
107 | static void authenc_esn_geniv_ahash_done(void *data, int err) |
108 | { |
109 | struct aead_request *req = data; |
110 | |
111 | err = err ?: crypto_authenc_esn_genicv_tail(req, flags: 0); |
112 | aead_request_complete(req, err); |
113 | } |
114 | |
115 | static int crypto_authenc_esn_genicv(struct aead_request *req, |
116 | unsigned int flags) |
117 | { |
118 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
119 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); |
120 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
121 | struct crypto_ahash *auth = ctx->auth; |
122 | u8 *hash = areq_ctx->tail; |
123 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); |
124 | unsigned int authsize = crypto_aead_authsize(tfm: authenc_esn); |
125 | unsigned int assoclen = req->assoclen; |
126 | unsigned int cryptlen = req->cryptlen; |
127 | struct scatterlist *dst = req->dst; |
128 | u32 tmp[2]; |
129 | |
130 | if (!authsize) |
131 | return 0; |
132 | |
133 | /* Move high-order bits of sequence number to the end. */ |
134 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 0, nbytes: 8, out: 0); |
135 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 4, nbytes: 4, out: 1); |
136 | scatterwalk_map_and_copy(buf: tmp + 1, sg: dst, start: assoclen + cryptlen, nbytes: 4, out: 1); |
137 | |
138 | sg_init_table(areq_ctx->dst, 2); |
139 | dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: dst, len: 4); |
140 | |
141 | ahash_request_set_tfm(req: ahreq, tfm: auth); |
142 | ahash_request_set_crypt(req: ahreq, src: dst, result: hash, nbytes: assoclen + cryptlen); |
143 | ahash_request_set_callback(req: ahreq, flags, |
144 | compl: authenc_esn_geniv_ahash_done, data: req); |
145 | |
146 | return crypto_ahash_digest(req: ahreq) ?: |
147 | crypto_authenc_esn_genicv_tail(req, flags: aead_request_flags(req)); |
148 | } |
149 | |
150 | |
151 | static void crypto_authenc_esn_encrypt_done(void *data, int err) |
152 | { |
153 | struct aead_request *areq = data; |
154 | |
155 | if (!err) |
156 | err = crypto_authenc_esn_genicv(req: areq, flags: 0); |
157 | |
158 | authenc_esn_request_complete(req: areq, err); |
159 | } |
160 | |
161 | static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len) |
162 | { |
163 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
164 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
165 | SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null); |
166 | |
167 | skcipher_request_set_sync_tfm(req: skreq, tfm: ctx->null); |
168 | skcipher_request_set_callback(req: skreq, flags: aead_request_flags(req), |
169 | NULL, NULL); |
170 | skcipher_request_set_crypt(req: skreq, src: req->src, dst: req->dst, cryptlen: len, NULL); |
171 | |
172 | return crypto_skcipher_encrypt(req: skreq); |
173 | } |
174 | |
175 | static int crypto_authenc_esn_encrypt(struct aead_request *req) |
176 | { |
177 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
178 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); |
179 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
180 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + |
181 | ctx->reqoff); |
182 | struct crypto_skcipher *enc = ctx->enc; |
183 | unsigned int assoclen = req->assoclen; |
184 | unsigned int cryptlen = req->cryptlen; |
185 | struct scatterlist *src, *dst; |
186 | int err; |
187 | |
188 | sg_init_table(areq_ctx->src, 2); |
189 | src = scatterwalk_ffwd(dst: areq_ctx->src, src: req->src, len: assoclen); |
190 | dst = src; |
191 | |
192 | if (req->src != req->dst) { |
193 | err = crypto_authenc_esn_copy(req, len: assoclen); |
194 | if (err) |
195 | return err; |
196 | |
197 | sg_init_table(areq_ctx->dst, 2); |
198 | dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: req->dst, len: assoclen); |
199 | } |
200 | |
201 | skcipher_request_set_tfm(req: skreq, tfm: enc); |
202 | skcipher_request_set_callback(req: skreq, flags: aead_request_flags(req), |
203 | compl: crypto_authenc_esn_encrypt_done, data: req); |
204 | skcipher_request_set_crypt(req: skreq, src, dst, cryptlen, iv: req->iv); |
205 | |
206 | err = crypto_skcipher_encrypt(req: skreq); |
207 | if (err) |
208 | return err; |
209 | |
210 | return crypto_authenc_esn_genicv(req, flags: aead_request_flags(req)); |
211 | } |
212 | |
213 | static int crypto_authenc_esn_decrypt_tail(struct aead_request *req, |
214 | unsigned int flags) |
215 | { |
216 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
217 | unsigned int authsize = crypto_aead_authsize(tfm: authenc_esn); |
218 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); |
219 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
220 | struct skcipher_request *skreq = (void *)(areq_ctx->tail + |
221 | ctx->reqoff); |
222 | struct crypto_ahash *auth = ctx->auth; |
223 | u8 *ohash = areq_ctx->tail; |
224 | unsigned int cryptlen = req->cryptlen - authsize; |
225 | unsigned int assoclen = req->assoclen; |
226 | struct scatterlist *dst = req->dst; |
227 | u8 *ihash = ohash + crypto_ahash_digestsize(tfm: auth); |
228 | u32 tmp[2]; |
229 | |
230 | if (!authsize) |
231 | goto decrypt; |
232 | |
233 | /* Move high-order bits of sequence number back. */ |
234 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 4, nbytes: 4, out: 0); |
235 | scatterwalk_map_and_copy(buf: tmp + 1, sg: dst, start: assoclen + cryptlen, nbytes: 4, out: 0); |
236 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 0, nbytes: 8, out: 1); |
237 | |
238 | if (crypto_memneq(a: ihash, b: ohash, size: authsize)) |
239 | return -EBADMSG; |
240 | |
241 | decrypt: |
242 | |
243 | sg_init_table(areq_ctx->dst, 2); |
244 | dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: dst, len: assoclen); |
245 | |
246 | skcipher_request_set_tfm(req: skreq, tfm: ctx->enc); |
247 | skcipher_request_set_callback(req: skreq, flags, |
248 | compl: req->base.complete, data: req->base.data); |
249 | skcipher_request_set_crypt(req: skreq, src: dst, dst, cryptlen, iv: req->iv); |
250 | |
251 | return crypto_skcipher_decrypt(req: skreq); |
252 | } |
253 | |
254 | static void authenc_esn_verify_ahash_done(void *data, int err) |
255 | { |
256 | struct aead_request *req = data; |
257 | |
258 | err = err ?: crypto_authenc_esn_decrypt_tail(req, flags: 0); |
259 | authenc_esn_request_complete(req, err); |
260 | } |
261 | |
262 | static int crypto_authenc_esn_decrypt(struct aead_request *req) |
263 | { |
264 | struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req); |
265 | struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req); |
266 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm: authenc_esn); |
267 | struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff); |
268 | unsigned int authsize = crypto_aead_authsize(tfm: authenc_esn); |
269 | struct crypto_ahash *auth = ctx->auth; |
270 | u8 *ohash = areq_ctx->tail; |
271 | unsigned int assoclen = req->assoclen; |
272 | unsigned int cryptlen = req->cryptlen; |
273 | u8 *ihash = ohash + crypto_ahash_digestsize(tfm: auth); |
274 | struct scatterlist *dst = req->dst; |
275 | u32 tmp[2]; |
276 | int err; |
277 | |
278 | cryptlen -= authsize; |
279 | |
280 | if (req->src != dst) { |
281 | err = crypto_authenc_esn_copy(req, len: assoclen + cryptlen); |
282 | if (err) |
283 | return err; |
284 | } |
285 | |
286 | scatterwalk_map_and_copy(buf: ihash, sg: req->src, start: assoclen + cryptlen, |
287 | nbytes: authsize, out: 0); |
288 | |
289 | if (!authsize) |
290 | goto tail; |
291 | |
292 | /* Move high-order bits of sequence number to the end. */ |
293 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 0, nbytes: 8, out: 0); |
294 | scatterwalk_map_and_copy(buf: tmp, sg: dst, start: 4, nbytes: 4, out: 1); |
295 | scatterwalk_map_and_copy(buf: tmp + 1, sg: dst, start: assoclen + cryptlen, nbytes: 4, out: 1); |
296 | |
297 | sg_init_table(areq_ctx->dst, 2); |
298 | dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: dst, len: 4); |
299 | |
300 | ahash_request_set_tfm(req: ahreq, tfm: auth); |
301 | ahash_request_set_crypt(req: ahreq, src: dst, result: ohash, nbytes: assoclen + cryptlen); |
302 | ahash_request_set_callback(req: ahreq, flags: aead_request_flags(req), |
303 | compl: authenc_esn_verify_ahash_done, data: req); |
304 | |
305 | err = crypto_ahash_digest(req: ahreq); |
306 | if (err) |
307 | return err; |
308 | |
309 | tail: |
310 | return crypto_authenc_esn_decrypt_tail(req, flags: aead_request_flags(req)); |
311 | } |
312 | |
313 | static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm) |
314 | { |
315 | struct aead_instance *inst = aead_alg_instance(aead: tfm); |
316 | struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst); |
317 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); |
318 | struct crypto_ahash *auth; |
319 | struct crypto_skcipher *enc; |
320 | struct crypto_sync_skcipher *null; |
321 | int err; |
322 | |
323 | auth = crypto_spawn_ahash(spawn: &ictx->auth); |
324 | if (IS_ERR(ptr: auth)) |
325 | return PTR_ERR(ptr: auth); |
326 | |
327 | enc = crypto_spawn_skcipher(spawn: &ictx->enc); |
328 | err = PTR_ERR(ptr: enc); |
329 | if (IS_ERR(ptr: enc)) |
330 | goto err_free_ahash; |
331 | |
332 | null = crypto_get_default_null_skcipher(); |
333 | err = PTR_ERR(ptr: null); |
334 | if (IS_ERR(ptr: null)) |
335 | goto err_free_skcipher; |
336 | |
337 | ctx->auth = auth; |
338 | ctx->enc = enc; |
339 | ctx->null = null; |
340 | |
341 | ctx->reqoff = 2 * crypto_ahash_digestsize(tfm: auth); |
342 | |
343 | crypto_aead_set_reqsize( |
344 | aead: tfm, |
345 | reqsize: sizeof(struct authenc_esn_request_ctx) + |
346 | ctx->reqoff + |
347 | max_t(unsigned int, |
348 | crypto_ahash_reqsize(auth) + |
349 | sizeof(struct ahash_request), |
350 | sizeof(struct skcipher_request) + |
351 | crypto_skcipher_reqsize(enc))); |
352 | |
353 | return 0; |
354 | |
355 | err_free_skcipher: |
356 | crypto_free_skcipher(tfm: enc); |
357 | err_free_ahash: |
358 | crypto_free_ahash(tfm: auth); |
359 | return err; |
360 | } |
361 | |
362 | static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm) |
363 | { |
364 | struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm); |
365 | |
366 | crypto_free_ahash(tfm: ctx->auth); |
367 | crypto_free_skcipher(tfm: ctx->enc); |
368 | crypto_put_default_null_skcipher(); |
369 | } |
370 | |
371 | static void crypto_authenc_esn_free(struct aead_instance *inst) |
372 | { |
373 | struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst); |
374 | |
375 | crypto_drop_skcipher(spawn: &ctx->enc); |
376 | crypto_drop_ahash(spawn: &ctx->auth); |
377 | kfree(objp: inst); |
378 | } |
379 | |
380 | static int crypto_authenc_esn_create(struct crypto_template *tmpl, |
381 | struct rtattr **tb) |
382 | { |
383 | u32 mask; |
384 | struct aead_instance *inst; |
385 | struct authenc_esn_instance_ctx *ctx; |
386 | struct skcipher_alg_common *enc; |
387 | struct hash_alg_common *auth; |
388 | struct crypto_alg *auth_base; |
389 | int err; |
390 | |
391 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, mask_ret: &mask); |
392 | if (err) |
393 | return err; |
394 | |
395 | inst = kzalloc(size: sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); |
396 | if (!inst) |
397 | return -ENOMEM; |
398 | ctx = aead_instance_ctx(inst); |
399 | |
400 | err = crypto_grab_ahash(spawn: &ctx->auth, inst: aead_crypto_instance(inst), |
401 | name: crypto_attr_alg_name(rta: tb[1]), type: 0, mask); |
402 | if (err) |
403 | goto err_free_inst; |
404 | auth = crypto_spawn_ahash_alg(spawn: &ctx->auth); |
405 | auth_base = &auth->base; |
406 | |
407 | err = crypto_grab_skcipher(spawn: &ctx->enc, inst: aead_crypto_instance(inst), |
408 | name: crypto_attr_alg_name(rta: tb[2]), type: 0, mask); |
409 | if (err) |
410 | goto err_free_inst; |
411 | enc = crypto_spawn_skcipher_alg_common(spawn: &ctx->enc); |
412 | |
413 | err = -ENAMETOOLONG; |
414 | if (snprintf(buf: inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME, |
415 | fmt: "authencesn(%s,%s)" , auth_base->cra_name, |
416 | enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME) |
417 | goto err_free_inst; |
418 | |
419 | if (snprintf(buf: inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME, |
420 | fmt: "authencesn(%s,%s)" , auth_base->cra_driver_name, |
421 | enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME) |
422 | goto err_free_inst; |
423 | |
424 | inst->alg.base.cra_priority = enc->base.cra_priority * 10 + |
425 | auth_base->cra_priority; |
426 | inst->alg.base.cra_blocksize = enc->base.cra_blocksize; |
427 | inst->alg.base.cra_alignmask = enc->base.cra_alignmask; |
428 | inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx); |
429 | |
430 | inst->alg.ivsize = enc->ivsize; |
431 | inst->alg.chunksize = enc->chunksize; |
432 | inst->alg.maxauthsize = auth->digestsize; |
433 | |
434 | inst->alg.init = crypto_authenc_esn_init_tfm; |
435 | inst->alg.exit = crypto_authenc_esn_exit_tfm; |
436 | |
437 | inst->alg.setkey = crypto_authenc_esn_setkey; |
438 | inst->alg.setauthsize = crypto_authenc_esn_setauthsize; |
439 | inst->alg.encrypt = crypto_authenc_esn_encrypt; |
440 | inst->alg.decrypt = crypto_authenc_esn_decrypt; |
441 | |
442 | inst->free = crypto_authenc_esn_free; |
443 | |
444 | err = aead_register_instance(tmpl, inst); |
445 | if (err) { |
446 | err_free_inst: |
447 | crypto_authenc_esn_free(inst); |
448 | } |
449 | return err; |
450 | } |
451 | |
452 | static struct crypto_template crypto_authenc_esn_tmpl = { |
453 | .name = "authencesn" , |
454 | .create = crypto_authenc_esn_create, |
455 | .module = THIS_MODULE, |
456 | }; |
457 | |
458 | static int __init crypto_authenc_esn_module_init(void) |
459 | { |
460 | return crypto_register_template(tmpl: &crypto_authenc_esn_tmpl); |
461 | } |
462 | |
463 | static void __exit crypto_authenc_esn_module_exit(void) |
464 | { |
465 | crypto_unregister_template(tmpl: &crypto_authenc_esn_tmpl); |
466 | } |
467 | |
468 | subsys_initcall(crypto_authenc_esn_module_init); |
469 | module_exit(crypto_authenc_esn_module_exit); |
470 | |
471 | MODULE_LICENSE("GPL" ); |
472 | MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>" ); |
473 | MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers" ); |
474 | MODULE_ALIAS_CRYPTO("authencesn" ); |
475 | |