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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
21struct authenc_instance_ctx {
22 struct crypto_ahash_spawn auth;
23 struct crypto_skcipher_spawn enc;
24 unsigned int reqoff;
25};
26
27struct crypto_authenc_ctx {
28 struct crypto_ahash *auth;
29 struct crypto_skcipher *enc;
30};
31
32struct authenc_request_ctx {
33 struct scatterlist src[2];
34 struct scatterlist dst[2];
35 char tail[];
36};
37
38static void authenc_request_complete(struct aead_request *req, int err)
39{
40 if (err != -EINPROGRESS && err != -EBUSY)
41 aead_request_complete(req, err);
42}
43
44int 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}
80EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
81
82static 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(tfm: 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(tfm: auth, CRYPTO_TFM_REQ_MASK);
95 crypto_ahash_set_flags(tfm: auth, flags: crypto_aead_get_flags(tfm: authenc) &
96 CRYPTO_TFM_REQ_MASK);
97 err = crypto_ahash_setkey(tfm: auth, key: keys.authkey, keylen: keys.authkeylen);
98 if (err)
99 goto out;
100
101 crypto_skcipher_clear_flags(tfm: enc, CRYPTO_TFM_REQ_MASK);
102 crypto_skcipher_set_flags(tfm: enc, flags: crypto_aead_get_flags(tfm: authenc) &
103 CRYPTO_TFM_REQ_MASK);
104 err = crypto_skcipher_setkey(tfm: enc, key: keys.enckey, keylen: keys.enckeylen);
105out:
106 memzero_explicit(s: &keys, count: sizeof(keys));
107 return err;
108}
109
110static void authenc_geniv_ahash_finish(struct aead_request *req)
111{
112 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
113 struct aead_instance *inst = aead_alg_instance(aead: authenc);
114 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
115 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
116 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
117
118 scatterwalk_map_and_copy(buf: ahreq->result, sg: req->dst,
119 start: req->assoclen + req->cryptlen,
120 nbytes: crypto_aead_authsize(tfm: authenc), out: 1);
121}
122
123static void authenc_geniv_ahash_done(void *data, int err)
124{
125 struct aead_request *req = data;
126
127 if (!err)
128 authenc_geniv_ahash_finish(req);
129 aead_request_complete(req, err);
130}
131
132/*
133 * Used when the ahash request was invoked in the async callback context
134 * of the previous skcipher request. Eat any EINPROGRESS notifications.
135 */
136static void authenc_geniv_ahash_done2(void *data, int err)
137{
138 struct aead_request *req = data;
139
140 if (!err)
141 authenc_geniv_ahash_finish(req);
142 authenc_request_complete(req, err);
143}
144
145static int crypto_authenc_genicv(struct aead_request *req, unsigned int mask)
146{
147 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
148 struct aead_instance *inst = aead_alg_instance(aead: authenc);
149 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
150 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
151 struct crypto_ahash *auth = ctx->auth;
152 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
153 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
154 unsigned int flags = aead_request_flags(req) & ~mask;
155 u8 *hash = areq_ctx->tail;
156 int err;
157
158 ahash_request_set_tfm(req: ahreq, tfm: auth);
159 ahash_request_set_crypt(req: ahreq, src: req->dst, result: hash,
160 nbytes: req->assoclen + req->cryptlen);
161 ahash_request_set_callback(req: ahreq, flags,
162 compl: mask ? authenc_geniv_ahash_done2 :
163 authenc_geniv_ahash_done, data: req);
164
165 err = crypto_ahash_digest(req: ahreq);
166 if (err)
167 return err;
168
169 scatterwalk_map_and_copy(buf: hash, sg: req->dst, start: req->assoclen + req->cryptlen,
170 nbytes: crypto_aead_authsize(tfm: authenc), out: 1);
171
172 return 0;
173}
174
175static void crypto_authenc_encrypt_done(void *data, int err)
176{
177 struct aead_request *areq = data;
178
179 if (err) {
180 aead_request_complete(req: areq, err);
181 return;
182 }
183 err = crypto_authenc_genicv(req: areq, CRYPTO_TFM_REQ_MAY_SLEEP);
184 authenc_request_complete(req: areq, err);
185}
186
187static int crypto_authenc_encrypt(struct aead_request *req)
188{
189 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
190 struct aead_instance *inst = aead_alg_instance(aead: authenc);
191 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
192 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
193 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
194 struct crypto_skcipher *enc = ctx->enc;
195 unsigned int cryptlen = req->cryptlen;
196 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
197 ictx->reqoff);
198 struct scatterlist *src, *dst;
199 int err;
200
201 src = scatterwalk_ffwd(dst: areq_ctx->src, src: req->src, len: req->assoclen);
202 dst = src;
203
204 if (req->src != req->dst) {
205 memcpy_sglist(dst: req->dst, src: req->src, nbytes: req->assoclen);
206 dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: req->dst, len: req->assoclen);
207 }
208
209 skcipher_request_set_tfm(req: skreq, tfm: enc);
210 skcipher_request_set_callback(req: skreq, flags: aead_request_flags(req),
211 compl: crypto_authenc_encrypt_done, data: req);
212 skcipher_request_set_crypt(req: skreq, src, dst, cryptlen, iv: req->iv);
213
214 err = crypto_skcipher_encrypt(req: skreq);
215 if (err)
216 return err;
217
218 return crypto_authenc_genicv(req, mask: 0);
219}
220
221static void authenc_decrypt_tail_done(void *data, int err)
222{
223 struct aead_request *req = data;
224
225 authenc_request_complete(req, err);
226}
227
228static int crypto_authenc_decrypt_tail(struct aead_request *req,
229 unsigned int mask)
230{
231 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
232 struct aead_instance *inst = aead_alg_instance(aead: authenc);
233 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
234 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
235 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
236 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
237 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
238 ictx->reqoff);
239 unsigned int authsize = crypto_aead_authsize(tfm: authenc);
240 unsigned int flags = aead_request_flags(req) & ~mask;
241 u8 *ihash = ahreq->result + authsize;
242 struct scatterlist *src, *dst;
243
244 scatterwalk_map_and_copy(buf: ihash, sg: req->src, start: ahreq->nbytes, nbytes: authsize, out: 0);
245
246 if (crypto_memneq(a: ihash, b: ahreq->result, size: authsize))
247 return -EBADMSG;
248
249 src = scatterwalk_ffwd(dst: areq_ctx->src, src: req->src, len: req->assoclen);
250 dst = src;
251
252 if (req->src != req->dst)
253 dst = scatterwalk_ffwd(dst: areq_ctx->dst, src: req->dst, len: req->assoclen);
254
255 skcipher_request_set_tfm(req: skreq, tfm: ctx->enc);
256 skcipher_request_set_callback(req: skreq, flags,
257 compl: mask ? authenc_decrypt_tail_done :
258 req->base.complete,
259 data: mask ? req : req->base.data);
260 skcipher_request_set_crypt(req: skreq, src, dst,
261 cryptlen: req->cryptlen - authsize, iv: req->iv);
262
263 return crypto_skcipher_decrypt(req: skreq);
264}
265
266static void authenc_verify_ahash_done(void *data, int err)
267{
268 struct aead_request *req = data;
269
270 if (err) {
271 aead_request_complete(req, err);
272 return;
273 }
274 err = crypto_authenc_decrypt_tail(req, CRYPTO_TFM_REQ_MAY_SLEEP);
275 authenc_request_complete(req, err);
276}
277
278static int crypto_authenc_decrypt(struct aead_request *req)
279{
280 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
281 unsigned int authsize = crypto_aead_authsize(tfm: authenc);
282 struct aead_instance *inst = aead_alg_instance(aead: authenc);
283 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm: authenc);
284 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
285 struct crypto_ahash *auth = ctx->auth;
286 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
287 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
288 u8 *hash = areq_ctx->tail;
289 int err;
290
291 ahash_request_set_tfm(req: ahreq, tfm: auth);
292 ahash_request_set_crypt(req: ahreq, src: req->src, result: hash,
293 nbytes: req->assoclen + req->cryptlen - authsize);
294 ahash_request_set_callback(req: ahreq, flags: aead_request_flags(req),
295 compl: authenc_verify_ahash_done, data: req);
296
297 err = crypto_ahash_digest(req: ahreq);
298 if (err)
299 return err;
300
301 return crypto_authenc_decrypt_tail(req, mask: 0);
302}
303
304static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
305{
306 struct aead_instance *inst = aead_alg_instance(aead: tfm);
307 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
308 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
309 struct crypto_ahash *auth;
310 struct crypto_skcipher *enc;
311 int err;
312
313 auth = crypto_spawn_ahash(spawn: &ictx->auth);
314 if (IS_ERR(ptr: auth))
315 return PTR_ERR(ptr: auth);
316
317 enc = crypto_spawn_skcipher(spawn: &ictx->enc);
318 err = PTR_ERR(ptr: enc);
319 if (IS_ERR(ptr: enc))
320 goto err_free_ahash;
321
322 ctx->auth = auth;
323 ctx->enc = enc;
324
325 crypto_aead_set_reqsize(
326 aead: tfm,
327 reqsize: sizeof(struct authenc_request_ctx) +
328 ictx->reqoff +
329 max_t(unsigned int,
330 crypto_ahash_reqsize(auth) +
331 sizeof(struct ahash_request),
332 sizeof(struct skcipher_request) +
333 crypto_skcipher_reqsize(enc)));
334
335 return 0;
336
337err_free_ahash:
338 crypto_free_ahash(tfm: auth);
339 return err;
340}
341
342static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
343{
344 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
345
346 crypto_free_ahash(tfm: ctx->auth);
347 crypto_free_skcipher(tfm: ctx->enc);
348}
349
350static void crypto_authenc_free(struct aead_instance *inst)
351{
352 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
353
354 crypto_drop_skcipher(spawn: &ctx->enc);
355 crypto_drop_ahash(spawn: &ctx->auth);
356 kfree(objp: inst);
357}
358
359static int crypto_authenc_create(struct crypto_template *tmpl,
360 struct rtattr **tb)
361{
362 u32 mask;
363 struct aead_instance *inst;
364 struct authenc_instance_ctx *ctx;
365 struct skcipher_alg_common *enc;
366 struct hash_alg_common *auth;
367 struct crypto_alg *auth_base;
368 int err;
369
370 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, mask_ret: &mask);
371 if (err)
372 return err;
373
374 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
375 if (!inst)
376 return -ENOMEM;
377 ctx = aead_instance_ctx(inst);
378
379 err = crypto_grab_ahash(spawn: &ctx->auth, inst: aead_crypto_instance(inst),
380 name: crypto_attr_alg_name(rta: tb[1]), type: 0, mask);
381 if (err)
382 goto err_free_inst;
383 auth = crypto_spawn_ahash_alg(spawn: &ctx->auth);
384 auth_base = &auth->base;
385
386 err = crypto_grab_skcipher(spawn: &ctx->enc, inst: aead_crypto_instance(inst),
387 name: crypto_attr_alg_name(rta: tb[2]), type: 0, mask);
388 if (err)
389 goto err_free_inst;
390 enc = crypto_spawn_skcipher_alg_common(spawn: &ctx->enc);
391
392 ctx->reqoff = 2 * auth->digestsize;
393
394 err = -ENAMETOOLONG;
395 if (snprintf(buf: inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
396 fmt: "authenc(%s,%s)", auth_base->cra_name,
397 enc->base.cra_name) >=
398 CRYPTO_MAX_ALG_NAME)
399 goto err_free_inst;
400
401 if (snprintf(buf: inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
402 fmt: "authenc(%s,%s)", auth_base->cra_driver_name,
403 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
404 goto err_free_inst;
405
406 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
407 auth_base->cra_priority;
408 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
409 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
410 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
411
412 inst->alg.ivsize = enc->ivsize;
413 inst->alg.chunksize = enc->chunksize;
414 inst->alg.maxauthsize = auth->digestsize;
415
416 inst->alg.init = crypto_authenc_init_tfm;
417 inst->alg.exit = crypto_authenc_exit_tfm;
418
419 inst->alg.setkey = crypto_authenc_setkey;
420 inst->alg.encrypt = crypto_authenc_encrypt;
421 inst->alg.decrypt = crypto_authenc_decrypt;
422
423 inst->free = crypto_authenc_free;
424
425 err = aead_register_instance(tmpl, inst);
426 if (err) {
427err_free_inst:
428 crypto_authenc_free(inst);
429 }
430 return err;
431}
432
433static struct crypto_template crypto_authenc_tmpl = {
434 .name = "authenc",
435 .create = crypto_authenc_create,
436 .module = THIS_MODULE,
437};
438
439static int __init crypto_authenc_module_init(void)
440{
441 return crypto_register_template(tmpl: &crypto_authenc_tmpl);
442}
443
444static void __exit crypto_authenc_module_exit(void)
445{
446 crypto_unregister_template(tmpl: &crypto_authenc_tmpl);
447}
448
449module_init(crypto_authenc_module_init);
450module_exit(crypto_authenc_module_exit);
451
452MODULE_LICENSE("GPL");
453MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
454MODULE_ALIAS_CRYPTO("authenc");
455

source code of linux/crypto/authenc.c