1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16#include <crypto/internal/skcipher.h>
17#include <crypto/rng.h>
18#include <linux/err.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/spinlock.h>
23#include <linux/string.h>
24#include <linux/workqueue.h>
25
26enum {
27 CHAINIV_STATE_INUSE = 0,
28};
29
30struct chainiv_ctx {
31 spinlock_t lock;
32 char iv[];
33};
34
35struct async_chainiv_ctx {
36 unsigned long state;
37
38 spinlock_t lock;
39 int err;
40
41 struct crypto_queue queue;
42 struct work_struct postponed;
43
44 char iv[];
45};
46
47static int chainiv_givencrypt(struct skcipher_givcrypt_request *req)
48{
49 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
50 struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
51 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
52 unsigned int ivsize;
53 int err;
54
55 ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
56 ablkcipher_request_set_callback(subreq, req->creq.base.flags &
57 ~CRYPTO_TFM_REQ_MAY_SLEEP,
58 req->creq.base.complete,
59 req->creq.base.data);
60 ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
61 req->creq.nbytes, req->creq.info);
62
63 spin_lock_bh(&ctx->lock);
64
65 ivsize = crypto_ablkcipher_ivsize(geniv);
66
67 memcpy(req->giv, ctx->iv, ivsize);
68 memcpy(subreq->info, ctx->iv, ivsize);
69
70 err = crypto_ablkcipher_encrypt(subreq);
71 if (err)
72 goto unlock;
73
74 memcpy(ctx->iv, subreq->info, ivsize);
75
76unlock:
77 spin_unlock_bh(&ctx->lock);
78
79 return err;
80}
81
82static int chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
83{
84 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
85 struct chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
86 int err = 0;
87
88 spin_lock_bh(&ctx->lock);
89 if (crypto_ablkcipher_crt(geniv)->givencrypt !=
90 chainiv_givencrypt_first)
91 goto unlock;
92
93 crypto_ablkcipher_crt(geniv)->givencrypt = chainiv_givencrypt;
94 err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
95 crypto_ablkcipher_ivsize(geniv));
96
97unlock:
98 spin_unlock_bh(&ctx->lock);
99
100 if (err)
101 return err;
102
103 return chainiv_givencrypt(req);
104}
105
106static int chainiv_init_common(struct crypto_tfm *tfm)
107{
108 tfm->crt_ablkcipher.reqsize = sizeof(struct ablkcipher_request);
109
110 return skcipher_geniv_init(tfm);
111}
112
113static int chainiv_init(struct crypto_tfm *tfm)
114{
115 struct chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
116
117 spin_lock_init(&ctx->lock);
118
119 return chainiv_init_common(tfm);
120}
121
122static int async_chainiv_schedule_work(struct async_chainiv_ctx *ctx)
123{
124 int queued;
125 int err = ctx->err;
126
127 if (!ctx->queue.qlen) {
128 smp_mb__before_clear_bit();
129 clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
130
131 if (!ctx->queue.qlen ||
132 test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
133 goto out;
134 }
135
136 queued = schedule_work(&ctx->postponed);
137 BUG_ON(!queued);
138
139out:
140 return err;
141}
142
143static int async_chainiv_postpone_request(struct skcipher_givcrypt_request *req)
144{
145 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
146 struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
147 int err;
148
149 spin_lock_bh(&ctx->lock);
150 err = skcipher_enqueue_givcrypt(&ctx->queue, req);
151 spin_unlock_bh(&ctx->lock);
152
153 if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
154 return err;
155
156 ctx->err = err;
157 return async_chainiv_schedule_work(ctx);
158}
159
160static int async_chainiv_givencrypt_tail(struct skcipher_givcrypt_request *req)
161{
162 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
163 struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
164 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
165 unsigned int ivsize = crypto_ablkcipher_ivsize(geniv);
166
167 memcpy(req->giv, ctx->iv, ivsize);
168 memcpy(subreq->info, ctx->iv, ivsize);
169
170 ctx->err = crypto_ablkcipher_encrypt(subreq);
171 if (ctx->err)
172 goto out;
173
174 memcpy(ctx->iv, subreq->info, ivsize);
175
176out:
177 return async_chainiv_schedule_work(ctx);
178}
179
180static int async_chainiv_givencrypt(struct skcipher_givcrypt_request *req)
181{
182 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
183 struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
184 struct ablkcipher_request *subreq = skcipher_givcrypt_reqctx(req);
185
186 ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
187 ablkcipher_request_set_callback(subreq, req->creq.base.flags,
188 req->creq.base.complete,
189 req->creq.base.data);
190 ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
191 req->creq.nbytes, req->creq.info);
192
193 if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
194 goto postpone;
195
196 if (ctx->queue.qlen) {
197 clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
198 goto postpone;
199 }
200
201 return async_chainiv_givencrypt_tail(req);
202
203postpone:
204 return async_chainiv_postpone_request(req);
205}
206
207static int async_chainiv_givencrypt_first(struct skcipher_givcrypt_request *req)
208{
209 struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
210 struct async_chainiv_ctx *ctx = crypto_ablkcipher_ctx(geniv);
211 int err = 0;
212
213 if (test_and_set_bit(CHAINIV_STATE_INUSE, &ctx->state))
214 goto out;
215
216 if (crypto_ablkcipher_crt(geniv)->givencrypt !=
217 async_chainiv_givencrypt_first)
218 goto unlock;
219
220 crypto_ablkcipher_crt(geniv)->givencrypt = async_chainiv_givencrypt;
221 err = crypto_rng_get_bytes(crypto_default_rng, ctx->iv,
222 crypto_ablkcipher_ivsize(geniv));
223
224unlock:
225 clear_bit(CHAINIV_STATE_INUSE, &ctx->state);
226
227 if (err)
228 return err;
229
230out:
231 return async_chainiv_givencrypt(req);
232}
233
234static void async_chainiv_do_postponed(struct work_struct *work)
235{
236 struct async_chainiv_ctx *ctx = container_of(work,
237 struct async_chainiv_ctx,
238 postponed);
239 struct skcipher_givcrypt_request *req;
240 struct ablkcipher_request *subreq;
241 int err;
242
243
244 spin_lock_bh(&ctx->lock);
245 req = skcipher_dequeue_givcrypt(&ctx->queue);
246 spin_unlock_bh(&ctx->lock);
247
248 if (!req) {
249 async_chainiv_schedule_work(ctx);
250 return;
251 }
252
253 subreq = skcipher_givcrypt_reqctx(req);
254 subreq->base.flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
255
256 err = async_chainiv_givencrypt_tail(req);
257
258 local_bh_disable();
259 skcipher_givcrypt_complete(req, err);
260 local_bh_enable();
261}
262
263static int async_chainiv_init(struct crypto_tfm *tfm)
264{
265 struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
266
267 spin_lock_init(&ctx->lock);
268
269 crypto_init_queue(&ctx->queue, 100);
270 INIT_WORK(&ctx->postponed, async_chainiv_do_postponed);
271
272 return chainiv_init_common(tfm);
273}
274
275static void async_chainiv_exit(struct crypto_tfm *tfm)
276{
277 struct async_chainiv_ctx *ctx = crypto_tfm_ctx(tfm);
278
279 BUG_ON(test_bit(CHAINIV_STATE_INUSE, &ctx->state) || ctx->queue.qlen);
280
281 skcipher_geniv_exit(tfm);
282}
283
284static struct crypto_template chainiv_tmpl;
285
286static struct crypto_instance *chainiv_alloc(struct rtattr **tb)
287{
288 struct crypto_attr_type *algt;
289 struct crypto_instance *inst;
290 int err;
291
292 algt = crypto_get_attr_type(tb);
293 err = PTR_ERR(algt);
294 if (IS_ERR(algt))
295 return ERR_PTR(err);
296
297 err = crypto_get_default_rng();
298 if (err)
299 return ERR_PTR(err);
300
301 inst = skcipher_geniv_alloc(&chainiv_tmpl, tb, 0, 0);
302 if (IS_ERR(inst))
303 goto put_rng;
304
305 inst->alg.cra_ablkcipher.givencrypt = chainiv_givencrypt_first;
306
307 inst->alg.cra_init = chainiv_init;
308 inst->alg.cra_exit = skcipher_geniv_exit;
309
310 inst->alg.cra_ctxsize = sizeof(struct chainiv_ctx);
311
312 if (!crypto_requires_sync(algt->type, algt->mask)) {
313 inst->alg.cra_flags |= CRYPTO_ALG_ASYNC;
314
315 inst->alg.cra_ablkcipher.givencrypt =
316 async_chainiv_givencrypt_first;
317
318 inst->alg.cra_init = async_chainiv_init;
319 inst->alg.cra_exit = async_chainiv_exit;
320
321 inst->alg.cra_ctxsize = sizeof(struct async_chainiv_ctx);
322 }
323
324 inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
325
326out:
327 return inst;
328
329put_rng:
330 crypto_put_default_rng();
331 goto out;
332}
333
334static void chainiv_free(struct crypto_instance *inst)
335{
336 skcipher_geniv_free(inst);
337 crypto_put_default_rng();
338}
339
340static struct crypto_template chainiv_tmpl = {
341 .name = "chainiv",
342 .alloc = chainiv_alloc,
343 .free = chainiv_free,
344 .module = THIS_MODULE,
345};
346
347static int __init chainiv_module_init(void)
348{
349 return crypto_register_template(&chainiv_tmpl);
350}
351
352static void chainiv_module_exit(void)
353{
354 crypto_unregister_template(&chainiv_tmpl);
355}
356
357module_init(chainiv_module_init);
358module_exit(chainiv_module_exit);
359
360MODULE_LICENSE("GPL");
361MODULE_DESCRIPTION("Chain IV Generator");
362
