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 | |
22 | struct authenc_instance_ctx { |
23 | struct crypto_ahash_spawn auth; |
24 | struct crypto_skcipher_spawn enc; |
25 | unsigned int reqoff; |
26 | }; |
27 | |
28 | struct crypto_authenc_ctx { |
29 | struct crypto_ahash *auth; |
30 | struct crypto_skcipher *enc; |
31 | struct crypto_sync_skcipher *null; |
32 | }; |
33 | |
34 | struct authenc_request_ctx { |
35 | struct scatterlist src[2]; |
36 | struct scatterlist dst[2]; |
37 | char tail[]; |
38 | }; |
39 | |
40 | static void authenc_request_complete(struct aead_request *req, int err) |
41 | { |
42 | if (err != -EINPROGRESS) |
43 | aead_request_complete(req, err); |
44 | } |
45 | |
46 | int (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 | } |
82 | EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys); |
83 | |
84 | static 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); |
107 | out: |
108 | memzero_explicit(s: &keys, count: sizeof(keys)); |
109 | return err; |
110 | } |
111 | |
112 | static 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 | |
128 | out: |
129 | aead_request_complete(req, err); |
130 | } |
131 | |
132 | static 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 | |
160 | static 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 | |
169 | out: |
170 | authenc_request_complete(req: areq, err); |
171 | } |
172 | |
173 | static 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 | |
188 | static 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 | |
225 | static 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 | |
260 | static 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 | |
269 | out: |
270 | authenc_request_complete(req, err); |
271 | } |
272 | |
273 | static 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 | |
299 | static 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 | |
339 | err_free_skcipher: |
340 | crypto_free_skcipher(tfm: enc); |
341 | err_free_ahash: |
342 | crypto_free_ahash(tfm: auth); |
343 | return err; |
344 | } |
345 | |
346 | static 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 | |
355 | static 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 | |
364 | static 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) { |
432 | err_free_inst: |
433 | crypto_authenc_free(inst); |
434 | } |
435 | return err; |
436 | } |
437 | |
438 | static struct crypto_template crypto_authenc_tmpl = { |
439 | .name = "authenc" , |
440 | .create = crypto_authenc_create, |
441 | .module = THIS_MODULE, |
442 | }; |
443 | |
444 | static int __init crypto_authenc_module_init(void) |
445 | { |
446 | return crypto_register_template(tmpl: &crypto_authenc_tmpl); |
447 | } |
448 | |
449 | static void __exit crypto_authenc_module_exit(void) |
450 | { |
451 | crypto_unregister_template(tmpl: &crypto_authenc_tmpl); |
452 | } |
453 | |
454 | subsys_initcall(crypto_authenc_module_init); |
455 | module_exit(crypto_authenc_module_exit); |
456 | |
457 | MODULE_LICENSE("GPL" ); |
458 | MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec" ); |
459 | MODULE_ALIAS_CRYPTO("authenc" ); |
460 | |