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13#include <crypto/algapi.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20
21#include "scatterwalk.h"
22
23struct authenc_instance_ctx {
24 struct crypto_spawn auth;
25 struct crypto_spawn enc;
26
27 unsigned int authsize;
28 unsigned int enckeylen;
29};
30
31struct crypto_authenc_ctx {
32 spinlock_t auth_lock;
33 struct crypto_hash *auth;
34 struct crypto_ablkcipher *enc;
35};
36
37static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
38 unsigned int keylen)
39{
40 struct authenc_instance_ctx *ictx =
41 crypto_instance_ctx(crypto_aead_alg_instance(authenc));
42 unsigned int enckeylen = ictx->enckeylen;
43 unsigned int authkeylen;
44 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
45 struct crypto_hash *auth = ctx->auth;
46 struct crypto_ablkcipher *enc = ctx->enc;
47 int err = -EINVAL;
48
49 if (keylen < enckeylen) {
50 crypto_aead_set_flags(authenc, CRYPTO_TFM_RES_BAD_KEY_LEN);
51 goto out;
52 }
53 authkeylen = keylen - enckeylen;
54
55 crypto_hash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
56 crypto_hash_set_flags(auth, crypto_aead_get_flags(authenc) &
57 CRYPTO_TFM_REQ_MASK);
58 err = crypto_hash_setkey(auth, key, authkeylen);
59 crypto_aead_set_flags(authenc, crypto_hash_get_flags(auth) &
60 CRYPTO_TFM_RES_MASK);
61
62 if (err)
63 goto out;
64
65 crypto_ablkcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
66 crypto_ablkcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
67 CRYPTO_TFM_REQ_MASK);
68 err = crypto_ablkcipher_setkey(enc, key + authkeylen, enckeylen);
69 crypto_aead_set_flags(authenc, crypto_ablkcipher_get_flags(enc) &
70 CRYPTO_TFM_RES_MASK);
71
72out:
73 return err;
74}
75
76static int crypto_authenc_hash(struct aead_request *req)
77{
78 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
79 struct authenc_instance_ctx *ictx =
80 crypto_instance_ctx(crypto_aead_alg_instance(authenc));
81 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
82 struct crypto_hash *auth = ctx->auth;
83 struct hash_desc desc = {
84 .tfm = auth,
85 };
86 u8 *hash = aead_request_ctx(req);
87 struct scatterlist *dst = req->dst;
88 unsigned int cryptlen = req->cryptlen;
89 int err;
90
91 hash = (u8 *)ALIGN((unsigned long)hash + crypto_hash_alignmask(auth),
92 crypto_hash_alignmask(auth) + 1);
93
94 spin_lock_bh(&ctx->auth_lock);
95 err = crypto_hash_init(&desc);
96 if (err)
97 goto auth_unlock;
98
99 err = crypto_hash_update(&desc, req->assoc, req->assoclen);
100 if (err)
101 goto auth_unlock;
102
103 err = crypto_hash_update(&desc, dst, cryptlen);
104 if (err)
105 goto auth_unlock;
106
107 err = crypto_hash_final(&desc, hash);
108auth_unlock:
109 spin_unlock_bh(&ctx->auth_lock);
110
111 if (err)
112 return err;
113
114 scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1);
115 return 0;
116}
117
118static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
119 int err)
120{
121 if (!err)
122 err = crypto_authenc_hash(req->data);
123
124 aead_request_complete(req->data, err);
125}
126
127static int crypto_authenc_encrypt(struct aead_request *req)
128{
129 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
130 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
131 struct ablkcipher_request *abreq = aead_request_ctx(req);
132 int err;
133
134 ablkcipher_request_set_tfm(abreq, ctx->enc);
135 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
136 crypto_authenc_encrypt_done, req);
137 ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
138 req->iv);
139
140 err = crypto_ablkcipher_encrypt(abreq);
141 if (err)
142 return err;
143
144 return crypto_authenc_hash(req);
145}
146
147static int crypto_authenc_verify(struct aead_request *req)
148{
149 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
150 struct authenc_instance_ctx *ictx =
151 crypto_instance_ctx(crypto_aead_alg_instance(authenc));
152 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
153 struct crypto_hash *auth = ctx->auth;
154 struct hash_desc desc = {
155 .tfm = auth,
156 .flags = aead_request_flags(req),
157 };
158 u8 *ohash = aead_request_ctx(req);
159 u8 *ihash;
160 struct scatterlist *src = req->src;
161 unsigned int cryptlen = req->cryptlen;
162 unsigned int authsize;
163 int err;
164
165 ohash = (u8 *)ALIGN((unsigned long)ohash + crypto_hash_alignmask(auth),
166 crypto_hash_alignmask(auth) + 1);
167 ihash = ohash + crypto_hash_digestsize(auth);
168
169 spin_lock_bh(&ctx->auth_lock);
170 err = crypto_hash_init(&desc);
171 if (err)
172 goto auth_unlock;
173
174 err = crypto_hash_update(&desc, req->assoc, req->assoclen);
175 if (err)
176 goto auth_unlock;
177
178 err = crypto_hash_update(&desc, src, cryptlen);
179 if (err)
180 goto auth_unlock;
181
182 err = crypto_hash_final(&desc, ohash);
183auth_unlock:
184 spin_unlock_bh(&ctx->auth_lock);
185
186 if (err)
187 return err;
188
189 authsize = ictx->authsize;
190 scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0);
191 return memcmp(ihash, ohash, authsize) ? -EINVAL : 0;
192}
193
194static void crypto_authenc_decrypt_done(struct crypto_async_request *req,
195 int err)
196{
197 aead_request_complete(req->data, err);
198}
199
200static int crypto_authenc_decrypt(struct aead_request *req)
201{
202 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
203 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
204 struct ablkcipher_request *abreq = aead_request_ctx(req);
205 int err;
206
207 err = crypto_authenc_verify(req);
208 if (err)
209 return err;
210
211 ablkcipher_request_set_tfm(abreq, ctx->enc);
212 ablkcipher_request_set_callback(abreq, aead_request_flags(req),
213 crypto_authenc_decrypt_done, req);
214 ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
215 req->iv);
216
217 return crypto_ablkcipher_decrypt(abreq);
218}
219
220static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
221{
222 struct crypto_instance *inst = (void *)tfm->__crt_alg;
223 struct authenc_instance_ctx *ictx = crypto_instance_ctx(inst);
224 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
225 struct crypto_hash *auth;
226 struct crypto_ablkcipher *enc;
227 unsigned int digestsize;
228 int err;
229
230 auth = crypto_spawn_hash(&ictx->auth);
231 if (IS_ERR(auth))
232 return PTR_ERR(auth);
233
234 err = -EINVAL;
235 digestsize = crypto_hash_digestsize(auth);
236 if (ictx->authsize > digestsize)
237 goto err_free_hash;
238
239 enc = crypto_spawn_ablkcipher(&ictx->enc);
240 err = PTR_ERR(enc);
241 if (IS_ERR(enc))
242 goto err_free_hash;
243
244 ctx->auth = auth;
245 ctx->enc = enc;
246 tfm->crt_aead.reqsize = max_t(unsigned int,
247 (crypto_hash_alignmask(auth) &
248 ~(crypto_tfm_ctx_alignment() - 1)) +
249 digestsize * 2,
250 sizeof(struct ablkcipher_request) +
251 crypto_ablkcipher_reqsize(enc));
252
253 spin_lock_init(&ctx->auth_lock);
254
255 return 0;
256
257err_free_hash:
258 crypto_free_hash(auth);
259 return err;
260}
261
262static void crypto_authenc_exit_tfm(struct crypto_tfm *tfm)
263{
264 struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
265
266 crypto_free_hash(ctx->auth);
267 crypto_free_ablkcipher(ctx->enc);
268}
269
270static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
271{
272 struct crypto_instance *inst;
273 struct crypto_alg *auth;
274 struct crypto_alg *enc;
275 struct authenc_instance_ctx *ctx;
276 unsigned int authsize;
277 unsigned int enckeylen;
278 int err;
279
280 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD);
281 if (err)
282 return ERR_PTR(err);
283
284 auth = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
285 CRYPTO_ALG_TYPE_HASH_MASK);
286 if (IS_ERR(auth))
287 return ERR_PTR(PTR_ERR(auth));
288
289 err = crypto_attr_u32(tb[2], &authsize);
290 inst = ERR_PTR(err);
291 if (err)
292 goto out_put_auth;
293
294 enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER,
295 CRYPTO_ALG_TYPE_MASK);
296 inst = ERR_PTR(PTR_ERR(enc));
297 if (IS_ERR(enc))
298 goto out_put_auth;
299
300 err = crypto_attr_u32(tb[4], &enckeylen);
301 if (err)
302 goto out_put_enc;
303
304 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
305 err = -ENOMEM;
306 if (!inst)
307 goto out_put_enc;
308
309 err = -ENAMETOOLONG;
310 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
311 "authenc(%s,%u,%s,%u)", auth->cra_name, authsize,
312 enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME)
313 goto err_free_inst;
314
315 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
316 "authenc(%s,%u,%s,%u)", auth->cra_driver_name,
317 authsize, enc->cra_driver_name, enckeylen) >=
318 CRYPTO_MAX_ALG_NAME)
319 goto err_free_inst;
320
321 ctx = crypto_instance_ctx(inst);
322 ctx->authsize = authsize;
323 ctx->enckeylen = enckeylen;
324
325 err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK);
326 if (err)
327 goto err_free_inst;
328
329 err = crypto_init_spawn(&ctx->enc, enc, inst, CRYPTO_ALG_TYPE_MASK);
330 if (err)
331 goto err_drop_auth;
332
333 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC;
334 inst->alg.cra_priority = enc->cra_priority * 10 + auth->cra_priority;
335 inst->alg.cra_blocksize = enc->cra_blocksize;
336 inst->alg.cra_alignmask = max(auth->cra_alignmask, enc->cra_alignmask);
337 inst->alg.cra_type = &crypto_aead_type;
338
339 inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize;
340 inst->alg.cra_aead.authsize = authsize;
341
342 inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
343
344 inst->alg.cra_init = crypto_authenc_init_tfm;
345 inst->alg.cra_exit = crypto_authenc_exit_tfm;
346
347 inst->alg.cra_aead.setkey = crypto_authenc_setkey;
348 inst->alg.cra_aead.encrypt = crypto_authenc_encrypt;
349 inst->alg.cra_aead.decrypt = crypto_authenc_decrypt;
350
351out:
352 crypto_mod_put(enc);
353out_put_auth:
354 crypto_mod_put(auth);
355 return inst;
356
357err_drop_auth:
358 crypto_drop_spawn(&ctx->auth);
359err_free_inst:
360 kfree(inst);
361out_put_enc:
362 inst = ERR_PTR(err);
363 goto out;
364}
365
366static void crypto_authenc_free(struct crypto_instance *inst)
367{
368 struct authenc_instance_ctx *ctx = crypto_instance_ctx(inst);
369
370 crypto_drop_spawn(&ctx->enc);
371 crypto_drop_spawn(&ctx->auth);
372 kfree(inst);
373}
374
375static struct crypto_template crypto_authenc_tmpl = {
376 .name = "authenc",
377 .alloc = crypto_authenc_alloc,
378 .free = crypto_authenc_free,
379 .module = THIS_MODULE,
380};
381
382static int __init crypto_authenc_module_init(void)
383{
384 return crypto_register_template(&crypto_authenc_tmpl);
385}
386
387static void __exit crypto_authenc_module_exit(void)
388{
389 crypto_unregister_template(&crypto_authenc_tmpl);
390}
391
392module_init(crypto_authenc_module_init);
393module_exit(crypto_authenc_module_exit);
394
395MODULE_LICENSE("GPL");
396MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
397
