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Herbert Xu8ff59092010-10-19 21:31:55 +08001/*
2 * algif_skcipher: User-space interface for skcipher algorithms
3 *
4 * This file provides the user-space API for symmetric key ciphers.
5 *
6 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the Free
10 * Software Foundation; either version 2 of the License, or (at your option)
11 * any later version.
12 *
13 */
14
15#include <crypto/scatterwalk.h>
16#include <crypto/skcipher.h>
17#include <crypto/if_alg.h>
18#include <linux/init.h>
19#include <linux/list.h>
20#include <linux/kernel.h>
21#include <linux/mm.h>
22#include <linux/module.h>
23#include <linux/net.h>
24#include <net/sock.h>
25
26struct skcipher_sg_list {
27 struct list_head list;
28
29 int cur;
30
31 struct scatterlist sg[0];
32};
33
34struct skcipher_ctx {
35 struct list_head tsgl;
36 struct af_alg_sgl rsgl;
37
38 void *iv;
39
40 struct af_alg_completion completion;
41
42 unsigned used;
43
44 unsigned int len;
45 bool more;
46 bool merge;
47 bool enc;
48
49 struct ablkcipher_request req;
50};
51
Ondrej Kozinae2cffb52014-08-25 11:49:54 +020052#define MAX_SGL_ENTS ((4096 - sizeof(struct skcipher_sg_list)) / \
Herbert Xu8ff59092010-10-19 21:31:55 +080053 sizeof(struct scatterlist) - 1)
54
Herbert Xu0f6bb832010-11-30 16:49:02 +080055static inline int skcipher_sndbuf(struct sock *sk)
Herbert Xu8ff59092010-10-19 21:31:55 +080056{
57 struct alg_sock *ask = alg_sk(sk);
58 struct skcipher_ctx *ctx = ask->private;
59
Herbert Xu0f6bb832010-11-30 16:49:02 +080060 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
61 ctx->used, 0);
62}
63
64static inline bool skcipher_writable(struct sock *sk)
65{
66 return PAGE_SIZE <= skcipher_sndbuf(sk);
Herbert Xu8ff59092010-10-19 21:31:55 +080067}
68
69static int skcipher_alloc_sgl(struct sock *sk)
70{
71 struct alg_sock *ask = alg_sk(sk);
72 struct skcipher_ctx *ctx = ask->private;
73 struct skcipher_sg_list *sgl;
74 struct scatterlist *sg = NULL;
75
76 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
77 if (!list_empty(&ctx->tsgl))
78 sg = sgl->sg;
79
80 if (!sg || sgl->cur >= MAX_SGL_ENTS) {
81 sgl = sock_kmalloc(sk, sizeof(*sgl) +
82 sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
83 GFP_KERNEL);
84 if (!sgl)
85 return -ENOMEM;
86
87 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
88 sgl->cur = 0;
89
90 if (sg)
91 scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
92
93 list_add_tail(&sgl->list, &ctx->tsgl);
94 }
95
96 return 0;
97}
98
99static void skcipher_pull_sgl(struct sock *sk, int used)
100{
101 struct alg_sock *ask = alg_sk(sk);
102 struct skcipher_ctx *ctx = ask->private;
103 struct skcipher_sg_list *sgl;
104 struct scatterlist *sg;
105 int i;
106
107 while (!list_empty(&ctx->tsgl)) {
108 sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,
109 list);
110 sg = sgl->sg;
111
112 for (i = 0; i < sgl->cur; i++) {
113 int plen = min_t(int, used, sg[i].length);
114
115 if (!sg_page(sg + i))
116 continue;
117
118 sg[i].length -= plen;
119 sg[i].offset += plen;
120
121 used -= plen;
122 ctx->used -= plen;
123
124 if (sg[i].length)
125 return;
126
127 put_page(sg_page(sg + i));
128 sg_assign_page(sg + i, NULL);
129 }
130
131 list_del(&sgl->list);
132 sock_kfree_s(sk, sgl,
133 sizeof(*sgl) + sizeof(sgl->sg[0]) *
134 (MAX_SGL_ENTS + 1));
135 }
136
137 if (!ctx->used)
138 ctx->merge = 0;
139}
140
141static void skcipher_free_sgl(struct sock *sk)
142{
143 struct alg_sock *ask = alg_sk(sk);
144 struct skcipher_ctx *ctx = ask->private;
145
146 skcipher_pull_sgl(sk, ctx->used);
147}
148
149static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
150{
151 long timeout;
152 DEFINE_WAIT(wait);
153 int err = -ERESTARTSYS;
154
155 if (flags & MSG_DONTWAIT)
156 return -EAGAIN;
157
158 set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
159
160 for (;;) {
161 if (signal_pending(current))
162 break;
163 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
164 timeout = MAX_SCHEDULE_TIMEOUT;
165 if (sk_wait_event(sk, &timeout, skcipher_writable(sk))) {
166 err = 0;
167 break;
168 }
169 }
170 finish_wait(sk_sleep(sk), &wait);
171
172 return err;
173}
174
175static void skcipher_wmem_wakeup(struct sock *sk)
176{
177 struct socket_wq *wq;
178
179 if (!skcipher_writable(sk))
180 return;
181
182 rcu_read_lock();
183 wq = rcu_dereference(sk->sk_wq);
184 if (wq_has_sleeper(wq))
185 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
186 POLLRDNORM |
187 POLLRDBAND);
188 sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
189 rcu_read_unlock();
190}
191
192static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
193{
194 struct alg_sock *ask = alg_sk(sk);
195 struct skcipher_ctx *ctx = ask->private;
196 long timeout;
197 DEFINE_WAIT(wait);
198 int err = -ERESTARTSYS;
199
200 if (flags & MSG_DONTWAIT) {
201 return -EAGAIN;
202 }
203
204 set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
205
206 for (;;) {
207 if (signal_pending(current))
208 break;
209 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
210 timeout = MAX_SCHEDULE_TIMEOUT;
211 if (sk_wait_event(sk, &timeout, ctx->used)) {
212 err = 0;
213 break;
214 }
215 }
216 finish_wait(sk_sleep(sk), &wait);
217
218 clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
219
220 return err;
221}
222
223static void skcipher_data_wakeup(struct sock *sk)
224{
225 struct alg_sock *ask = alg_sk(sk);
226 struct skcipher_ctx *ctx = ask->private;
227 struct socket_wq *wq;
228
229 if (!ctx->used)
230 return;
231
232 rcu_read_lock();
233 wq = rcu_dereference(sk->sk_wq);
234 if (wq_has_sleeper(wq))
235 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
236 POLLRDNORM |
237 POLLRDBAND);
238 sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
239 rcu_read_unlock();
240}
241
242static int skcipher_sendmsg(struct kiocb *unused, struct socket *sock,
243 struct msghdr *msg, size_t size)
244{
245 struct sock *sk = sock->sk;
246 struct alg_sock *ask = alg_sk(sk);
247 struct skcipher_ctx *ctx = ask->private;
248 struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
249 unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
250 struct skcipher_sg_list *sgl;
251 struct af_alg_control con = {};
252 long copied = 0;
253 bool enc = 0;
Stephan Muellerf26b7b82014-11-30 10:55:26 +0100254 bool init = 0;
Herbert Xu8ff59092010-10-19 21:31:55 +0800255 int err;
256 int i;
257
258 if (msg->msg_controllen) {
259 err = af_alg_cmsg_send(msg, &con);
260 if (err)
261 return err;
262
Stephan Muellerf26b7b82014-11-30 10:55:26 +0100263 init = 1;
Herbert Xu8ff59092010-10-19 21:31:55 +0800264 switch (con.op) {
265 case ALG_OP_ENCRYPT:
266 enc = 1;
267 break;
268 case ALG_OP_DECRYPT:
269 enc = 0;
270 break;
271 default:
272 return -EINVAL;
273 }
274
275 if (con.iv && con.iv->ivlen != ivsize)
276 return -EINVAL;
277 }
278
279 err = -EINVAL;
280
281 lock_sock(sk);
282 if (!ctx->more && ctx->used)
283 goto unlock;
284
Stephan Muellerf26b7b82014-11-30 10:55:26 +0100285 if (init) {
Herbert Xu8ff59092010-10-19 21:31:55 +0800286 ctx->enc = enc;
287 if (con.iv)
288 memcpy(ctx->iv, con.iv->iv, ivsize);
289 }
290
Herbert Xu8ff59092010-10-19 21:31:55 +0800291 while (size) {
292 struct scatterlist *sg;
293 unsigned long len = size;
294 int plen;
295
296 if (ctx->merge) {
297 sgl = list_entry(ctx->tsgl.prev,
298 struct skcipher_sg_list, list);
299 sg = sgl->sg + sgl->cur - 1;
300 len = min_t(unsigned long, len,
301 PAGE_SIZE - sg->offset - sg->length);
302
Al Viro6ce8e9c2014-04-06 21:25:44 -0400303 err = memcpy_from_msg(page_address(sg_page(sg)) +
304 sg->offset + sg->length,
305 msg, len);
Herbert Xu8ff59092010-10-19 21:31:55 +0800306 if (err)
307 goto unlock;
308
309 sg->length += len;
310 ctx->merge = (sg->offset + sg->length) &
311 (PAGE_SIZE - 1);
312
313 ctx->used += len;
314 copied += len;
315 size -= len;
Herbert Xu8ff59092010-10-19 21:31:55 +0800316 continue;
317 }
318
Herbert Xu0f6bb832010-11-30 16:49:02 +0800319 if (!skcipher_writable(sk)) {
Herbert Xu8ff59092010-10-19 21:31:55 +0800320 err = skcipher_wait_for_wmem(sk, msg->msg_flags);
321 if (err)
322 goto unlock;
Herbert Xu8ff59092010-10-19 21:31:55 +0800323 }
324
Herbert Xu0f6bb832010-11-30 16:49:02 +0800325 len = min_t(unsigned long, len, skcipher_sndbuf(sk));
Herbert Xu8ff59092010-10-19 21:31:55 +0800326
327 err = skcipher_alloc_sgl(sk);
328 if (err)
329 goto unlock;
330
331 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
332 sg = sgl->sg;
Tadeusz Struk0f477b62014-12-08 12:03:42 -0800333 sg_unmark_end(sg + sgl->cur);
Herbert Xu8ff59092010-10-19 21:31:55 +0800334 do {
335 i = sgl->cur;
336 plen = min_t(int, len, PAGE_SIZE);
337
338 sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
339 err = -ENOMEM;
340 if (!sg_page(sg + i))
341 goto unlock;
342
Al Viro6ce8e9c2014-04-06 21:25:44 -0400343 err = memcpy_from_msg(page_address(sg_page(sg + i)),
344 msg, plen);
Herbert Xu8ff59092010-10-19 21:31:55 +0800345 if (err) {
346 __free_page(sg_page(sg + i));
347 sg_assign_page(sg + i, NULL);
348 goto unlock;
349 }
350
351 sg[i].length = plen;
352 len -= plen;
353 ctx->used += plen;
354 copied += plen;
355 size -= plen;
Herbert Xu8ff59092010-10-19 21:31:55 +0800356 sgl->cur++;
357 } while (len && sgl->cur < MAX_SGL_ENTS);
358
Tadeusz Struk0f477b62014-12-08 12:03:42 -0800359 if (!size)
360 sg_mark_end(sg + sgl->cur - 1);
361
Herbert Xu8ff59092010-10-19 21:31:55 +0800362 ctx->merge = plen & (PAGE_SIZE - 1);
363 }
364
365 err = 0;
366
367 ctx->more = msg->msg_flags & MSG_MORE;
Herbert Xu8ff59092010-10-19 21:31:55 +0800368
369unlock:
370 skcipher_data_wakeup(sk);
371 release_sock(sk);
372
373 return copied ?: err;
374}
375
376static ssize_t skcipher_sendpage(struct socket *sock, struct page *page,
377 int offset, size_t size, int flags)
378{
379 struct sock *sk = sock->sk;
380 struct alg_sock *ask = alg_sk(sk);
381 struct skcipher_ctx *ctx = ask->private;
382 struct skcipher_sg_list *sgl;
383 int err = -EINVAL;
Herbert Xu8ff59092010-10-19 21:31:55 +0800384
Shawn Landdend3f7d562013-11-24 22:36:28 -0800385 if (flags & MSG_SENDPAGE_NOTLAST)
386 flags |= MSG_MORE;
387
Herbert Xu8ff59092010-10-19 21:31:55 +0800388 lock_sock(sk);
389 if (!ctx->more && ctx->used)
390 goto unlock;
391
392 if (!size)
393 goto done;
394
Herbert Xu0f6bb832010-11-30 16:49:02 +0800395 if (!skcipher_writable(sk)) {
Herbert Xu8ff59092010-10-19 21:31:55 +0800396 err = skcipher_wait_for_wmem(sk, flags);
397 if (err)
398 goto unlock;
Herbert Xu8ff59092010-10-19 21:31:55 +0800399 }
400
401 err = skcipher_alloc_sgl(sk);
402 if (err)
403 goto unlock;
404
405 ctx->merge = 0;
406 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
407
Tadeusz Struk0f477b62014-12-08 12:03:42 -0800408 if (sgl->cur)
409 sg_unmark_end(sgl->sg + sgl->cur - 1);
410
411 sg_mark_end(sgl->sg + sgl->cur);
Herbert Xu8ff59092010-10-19 21:31:55 +0800412 get_page(page);
413 sg_set_page(sgl->sg + sgl->cur, page, size, offset);
414 sgl->cur++;
415 ctx->used += size;
416
417done:
418 ctx->more = flags & MSG_MORE;
Herbert Xu8ff59092010-10-19 21:31:55 +0800419
420unlock:
421 skcipher_data_wakeup(sk);
422 release_sock(sk);
423
424 return err ?: size;
425}
426
427static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
428 struct msghdr *msg, size_t ignored, int flags)
429{
430 struct sock *sk = sock->sk;
431 struct alg_sock *ask = alg_sk(sk);
432 struct skcipher_ctx *ctx = ask->private;
433 unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(
434 &ctx->req));
435 struct skcipher_sg_list *sgl;
436 struct scatterlist *sg;
Herbert Xu8ff59092010-10-19 21:31:55 +0800437 int err = -EAGAIN;
438 int used;
439 long copied = 0;
440
441 lock_sock(sk);
Al Viro1d10eb22014-11-28 16:39:25 -0500442 while (iov_iter_count(&msg->msg_iter)) {
443 sgl = list_first_entry(&ctx->tsgl,
444 struct skcipher_sg_list, list);
445 sg = sgl->sg;
Herbert Xu8ff59092010-10-19 21:31:55 +0800446
Al Viro1d10eb22014-11-28 16:39:25 -0500447 while (!sg->length)
448 sg++;
Herbert Xu8ff59092010-10-19 21:31:55 +0800449
Linus Torvalds9399f0c2015-02-10 19:55:45 -0800450 if (!ctx->used) {
Al Viro1d10eb22014-11-28 16:39:25 -0500451 err = skcipher_wait_for_data(sk, flags);
452 if (err)
Herbert Xubc97e572010-11-30 17:04:31 +0800453 goto unlock;
Al Viro1d10eb22014-11-28 16:39:25 -0500454 }
Herbert Xubc97e572010-11-30 17:04:31 +0800455
Linus Torvalds9399f0c2015-02-10 19:55:45 -0800456 used = min_t(unsigned long, ctx->used, iov_iter_count(&msg->msg_iter));
Herbert Xu8ff59092010-10-19 21:31:55 +0800457
Al Viro1d10eb22014-11-28 16:39:25 -0500458 used = af_alg_make_sg(&ctx->rsgl, &msg->msg_iter, used);
459 err = used;
460 if (err < 0)
461 goto unlock;
Herbert Xu8ff59092010-10-19 21:31:55 +0800462
Al Viro1d10eb22014-11-28 16:39:25 -0500463 if (ctx->more || used < ctx->used)
464 used -= used % bs;
Herbert Xu8ff59092010-10-19 21:31:55 +0800465
Al Viro1d10eb22014-11-28 16:39:25 -0500466 err = -EINVAL;
467 if (!used)
468 goto free;
469
470 ablkcipher_request_set_crypt(&ctx->req, sg,
471 ctx->rsgl.sg, used,
472 ctx->iv);
473
474 err = af_alg_wait_for_completion(
Herbert Xu8ff59092010-10-19 21:31:55 +0800475 ctx->enc ?
476 crypto_ablkcipher_encrypt(&ctx->req) :
477 crypto_ablkcipher_decrypt(&ctx->req),
478 &ctx->completion);
479
Herbert Xubc97e572010-11-30 17:04:31 +0800480free:
Al Viro1d10eb22014-11-28 16:39:25 -0500481 af_alg_free_sg(&ctx->rsgl);
Herbert Xu8ff59092010-10-19 21:31:55 +0800482
Al Viro1d10eb22014-11-28 16:39:25 -0500483 if (err)
484 goto unlock;
Herbert Xu8ff59092010-10-19 21:31:55 +0800485
Al Viro1d10eb22014-11-28 16:39:25 -0500486 copied += used;
487 skcipher_pull_sgl(sk, used);
488 iov_iter_advance(&msg->msg_iter, used);
Herbert Xu8ff59092010-10-19 21:31:55 +0800489 }
490
491 err = 0;
492
493unlock:
494 skcipher_wmem_wakeup(sk);
495 release_sock(sk);
496
497 return copied ?: err;
498}
499
500
501static unsigned int skcipher_poll(struct file *file, struct socket *sock,
502 poll_table *wait)
503{
504 struct sock *sk = sock->sk;
505 struct alg_sock *ask = alg_sk(sk);
506 struct skcipher_ctx *ctx = ask->private;
507 unsigned int mask;
508
509 sock_poll_wait(file, sk_sleep(sk), wait);
510 mask = 0;
511
512 if (ctx->used)
513 mask |= POLLIN | POLLRDNORM;
514
515 if (skcipher_writable(sk))
516 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
517
518 return mask;
519}
520
521static struct proto_ops algif_skcipher_ops = {
522 .family = PF_ALG,
523
524 .connect = sock_no_connect,
525 .socketpair = sock_no_socketpair,
526 .getname = sock_no_getname,
527 .ioctl = sock_no_ioctl,
528 .listen = sock_no_listen,
529 .shutdown = sock_no_shutdown,
530 .getsockopt = sock_no_getsockopt,
531 .mmap = sock_no_mmap,
532 .bind = sock_no_bind,
533 .accept = sock_no_accept,
534 .setsockopt = sock_no_setsockopt,
535
536 .release = af_alg_release,
537 .sendmsg = skcipher_sendmsg,
538 .sendpage = skcipher_sendpage,
539 .recvmsg = skcipher_recvmsg,
540 .poll = skcipher_poll,
541};
542
543static void *skcipher_bind(const char *name, u32 type, u32 mask)
544{
545 return crypto_alloc_ablkcipher(name, type, mask);
546}
547
548static void skcipher_release(void *private)
549{
550 crypto_free_ablkcipher(private);
551}
552
553static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
554{
555 return crypto_ablkcipher_setkey(private, key, keylen);
556}
557
558static void skcipher_sock_destruct(struct sock *sk)
559{
560 struct alg_sock *ask = alg_sk(sk);
561 struct skcipher_ctx *ctx = ask->private;
562 struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
563
564 skcipher_free_sgl(sk);
Daniel Borkmann79e88652014-11-19 17:13:11 +0100565 sock_kzfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
Herbert Xu8ff59092010-10-19 21:31:55 +0800566 sock_kfree_s(sk, ctx, ctx->len);
567 af_alg_release_parent(sk);
568}
569
570static int skcipher_accept_parent(void *private, struct sock *sk)
571{
572 struct skcipher_ctx *ctx;
573 struct alg_sock *ask = alg_sk(sk);
574 unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);
575
576 ctx = sock_kmalloc(sk, len, GFP_KERNEL);
577 if (!ctx)
578 return -ENOMEM;
579
580 ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
581 GFP_KERNEL);
582 if (!ctx->iv) {
583 sock_kfree_s(sk, ctx, len);
584 return -ENOMEM;
585 }
586
587 memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));
588
589 INIT_LIST_HEAD(&ctx->tsgl);
590 ctx->len = len;
591 ctx->used = 0;
592 ctx->more = 0;
593 ctx->merge = 0;
594 ctx->enc = 0;
595 af_alg_init_completion(&ctx->completion);
596
597 ask->private = ctx;
598
599 ablkcipher_request_set_tfm(&ctx->req, private);
600 ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
601 af_alg_complete, &ctx->completion);
602
603 sk->sk_destruct = skcipher_sock_destruct;
604
605 return 0;
606}
607
608static const struct af_alg_type algif_type_skcipher = {
609 .bind = skcipher_bind,
610 .release = skcipher_release,
611 .setkey = skcipher_setkey,
612 .accept = skcipher_accept_parent,
613 .ops = &algif_skcipher_ops,
614 .name = "skcipher",
615 .owner = THIS_MODULE
616};
617
618static int __init algif_skcipher_init(void)
619{
620 return af_alg_register_type(&algif_type_skcipher);
621}
622
623static void __exit algif_skcipher_exit(void)
624{
625 int err = af_alg_unregister_type(&algif_type_skcipher);
626 BUG_ON(err);
627}
628
629module_init(algif_skcipher_init);
630module_exit(algif_skcipher_exit);
631MODULE_LICENSE("GPL");