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1 | /* |
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 | |
26 | struct skcipher_sg_list { |
27 | struct list_head list; |
28 | |
29 | int cur; |
30 | |
31 | struct scatterlist sg[0]; |
32 | }; |
33 | |
34 | struct 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 | |
52 | #define MAX_SGL_ENTS ((PAGE_SIZE - sizeof(struct skcipher_sg_list)) / \ |
53 | sizeof(struct scatterlist) - 1) |
54 | |
55 | static inline int skcipher_sndbuf(struct sock *sk) |
56 | { |
57 | struct alg_sock *ask = alg_sk(sk); |
58 | struct skcipher_ctx *ctx = ask->private; |
59 | |
60 | return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) - |
61 | ctx->used, 0); |
62 | } |
63 | |
64 | static inline bool skcipher_writable(struct sock *sk) |
65 | { |
66 | return PAGE_SIZE <= skcipher_sndbuf(sk); |
67 | } |
68 | |
69 | static 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 | |
99 | static 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 | |
141 | static 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 | |
149 | static 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 | |
175 | static 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 | |
192 | static 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 | |
223 | static 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 | |
242 | static 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; |
254 | int err; |
255 | int i; |
256 | |
257 | if (msg->msg_controllen) { |
258 | err = af_alg_cmsg_send(msg, &con); |
259 | if (err) |
260 | return err; |
261 | |
262 | switch (con.op) { |
263 | case ALG_OP_ENCRYPT: |
264 | enc = 1; |
265 | break; |
266 | case ALG_OP_DECRYPT: |
267 | enc = 0; |
268 | break; |
269 | default: |
270 | return -EINVAL; |
271 | } |
272 | |
273 | if (con.iv && con.iv->ivlen != ivsize) |
274 | return -EINVAL; |
275 | } |
276 | |
277 | err = -EINVAL; |
278 | |
279 | lock_sock(sk); |
280 | if (!ctx->more && ctx->used) |
281 | goto unlock; |
282 | |
283 | if (!ctx->used) { |
284 | ctx->enc = enc; |
285 | if (con.iv) |
286 | memcpy(ctx->iv, con.iv->iv, ivsize); |
287 | } |
288 | |
289 | while (size) { |
290 | struct scatterlist *sg; |
291 | unsigned long len = size; |
292 | int plen; |
293 | |
294 | if (ctx->merge) { |
295 | sgl = list_entry(ctx->tsgl.prev, |
296 | struct skcipher_sg_list, list); |
297 | sg = sgl->sg + sgl->cur - 1; |
298 | len = min_t(unsigned long, len, |
299 | PAGE_SIZE - sg->offset - sg->length); |
300 | |
301 | err = memcpy_fromiovec(page_address(sg_page(sg)) + |
302 | sg->offset + sg->length, |
303 | msg->msg_iov, len); |
304 | if (err) |
305 | goto unlock; |
306 | |
307 | sg->length += len; |
308 | ctx->merge = (sg->offset + sg->length) & |
309 | (PAGE_SIZE - 1); |
310 | |
311 | ctx->used += len; |
312 | copied += len; |
313 | size -= len; |
314 | continue; |
315 | } |
316 | |
317 | if (!skcipher_writable(sk)) { |
318 | err = skcipher_wait_for_wmem(sk, msg->msg_flags); |
319 | if (err) |
320 | goto unlock; |
321 | } |
322 | |
323 | len = min_t(unsigned long, len, skcipher_sndbuf(sk)); |
324 | |
325 | err = skcipher_alloc_sgl(sk); |
326 | if (err) |
327 | goto unlock; |
328 | |
329 | sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); |
330 | sg = sgl->sg; |
331 | do { |
332 | i = sgl->cur; |
333 | plen = min_t(int, len, PAGE_SIZE); |
334 | |
335 | sg_assign_page(sg + i, alloc_page(GFP_KERNEL)); |
336 | err = -ENOMEM; |
337 | if (!sg_page(sg + i)) |
338 | goto unlock; |
339 | |
340 | err = memcpy_fromiovec(page_address(sg_page(sg + i)), |
341 | msg->msg_iov, plen); |
342 | if (err) { |
343 | __free_page(sg_page(sg + i)); |
344 | sg_assign_page(sg + i, NULL); |
345 | goto unlock; |
346 | } |
347 | |
348 | sg[i].length = plen; |
349 | len -= plen; |
350 | ctx->used += plen; |
351 | copied += plen; |
352 | size -= plen; |
353 | sgl->cur++; |
354 | } while (len && sgl->cur < MAX_SGL_ENTS); |
355 | |
356 | ctx->merge = plen & (PAGE_SIZE - 1); |
357 | } |
358 | |
359 | err = 0; |
360 | |
361 | ctx->more = msg->msg_flags & MSG_MORE; |
362 | if (!ctx->more && !list_empty(&ctx->tsgl)) |
363 | sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); |
364 | |
365 | unlock: |
366 | skcipher_data_wakeup(sk); |
367 | release_sock(sk); |
368 | |
369 | return copied ?: err; |
370 | } |
371 | |
372 | static ssize_t skcipher_sendpage(struct socket *sock, struct page *page, |
373 | int offset, size_t size, int flags) |
374 | { |
375 | struct sock *sk = sock->sk; |
376 | struct alg_sock *ask = alg_sk(sk); |
377 | struct skcipher_ctx *ctx = ask->private; |
378 | struct skcipher_sg_list *sgl; |
379 | int err = -EINVAL; |
380 | |
381 | lock_sock(sk); |
382 | if (!ctx->more && ctx->used) |
383 | goto unlock; |
384 | |
385 | if (!size) |
386 | goto done; |
387 | |
388 | if (!skcipher_writable(sk)) { |
389 | err = skcipher_wait_for_wmem(sk, flags); |
390 | if (err) |
391 | goto unlock; |
392 | } |
393 | |
394 | err = skcipher_alloc_sgl(sk); |
395 | if (err) |
396 | goto unlock; |
397 | |
398 | ctx->merge = 0; |
399 | sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); |
400 | |
401 | get_page(page); |
402 | sg_set_page(sgl->sg + sgl->cur, page, size, offset); |
403 | sgl->cur++; |
404 | ctx->used += size; |
405 | |
406 | done: |
407 | ctx->more = flags & MSG_MORE; |
408 | if (!ctx->more && !list_empty(&ctx->tsgl)) |
409 | sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list); |
410 | |
411 | unlock: |
412 | skcipher_data_wakeup(sk); |
413 | release_sock(sk); |
414 | |
415 | return err ?: size; |
416 | } |
417 | |
418 | static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock, |
419 | struct msghdr *msg, size_t ignored, int flags) |
420 | { |
421 | struct sock *sk = sock->sk; |
422 | struct alg_sock *ask = alg_sk(sk); |
423 | struct skcipher_ctx *ctx = ask->private; |
424 | unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm( |
425 | &ctx->req)); |
426 | struct skcipher_sg_list *sgl; |
427 | struct scatterlist *sg; |
428 | unsigned long iovlen; |
429 | struct iovec *iov; |
430 | int err = -EAGAIN; |
431 | int used; |
432 | long copied = 0; |
433 | |
434 | lock_sock(sk); |
435 | for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0; |
436 | iovlen--, iov++) { |
437 | unsigned long seglen = iov->iov_len; |
438 | char __user *from = iov->iov_base; |
439 | |
440 | while (seglen) { |
441 | sgl = list_first_entry(&ctx->tsgl, |
442 | struct skcipher_sg_list, list); |
443 | sg = sgl->sg; |
444 | |
445 | while (!sg->length) |
446 | sg++; |
447 | |
448 | used = ctx->used; |
449 | if (!used) { |
450 | err = skcipher_wait_for_data(sk, flags); |
451 | if (err) |
452 | goto unlock; |
453 | } |
454 | |
455 | used = min_t(unsigned long, used, seglen); |
456 | |
457 | used = af_alg_make_sg(&ctx->rsgl, from, used, 1); |
458 | err = used; |
459 | if (err < 0) |
460 | goto unlock; |
461 | |
462 | if (ctx->more || used < ctx->used) |
463 | used -= used % bs; |
464 | |
465 | err = -EINVAL; |
466 | if (!used) |
467 | goto free; |
468 | |
469 | ablkcipher_request_set_crypt(&ctx->req, sg, |
470 | ctx->rsgl.sg, used, |
471 | ctx->iv); |
472 | |
473 | err = af_alg_wait_for_completion( |
474 | ctx->enc ? |
475 | crypto_ablkcipher_encrypt(&ctx->req) : |
476 | crypto_ablkcipher_decrypt(&ctx->req), |
477 | &ctx->completion); |
478 | |
479 | free: |
480 | af_alg_free_sg(&ctx->rsgl); |
481 | |
482 | if (err) |
483 | goto unlock; |
484 | |
485 | copied += used; |
486 | from += used; |
487 | seglen -= used; |
488 | skcipher_pull_sgl(sk, used); |
489 | } |
490 | } |
491 | |
492 | err = 0; |
493 | |
494 | unlock: |
495 | skcipher_wmem_wakeup(sk); |
496 | release_sock(sk); |
497 | |
498 | return copied ?: err; |
499 | } |
500 | |
501 | |
502 | static unsigned int skcipher_poll(struct file *file, struct socket *sock, |
503 | poll_table *wait) |
504 | { |
505 | struct sock *sk = sock->sk; |
506 | struct alg_sock *ask = alg_sk(sk); |
507 | struct skcipher_ctx *ctx = ask->private; |
508 | unsigned int mask; |
509 | |
510 | sock_poll_wait(file, sk_sleep(sk), wait); |
511 | mask = 0; |
512 | |
513 | if (ctx->used) |
514 | mask |= POLLIN | POLLRDNORM; |
515 | |
516 | if (skcipher_writable(sk)) |
517 | mask |= POLLOUT | POLLWRNORM | POLLWRBAND; |
518 | |
519 | return mask; |
520 | } |
521 | |
522 | static struct proto_ops algif_skcipher_ops = { |
523 | .family = PF_ALG, |
524 | |
525 | .connect = sock_no_connect, |
526 | .socketpair = sock_no_socketpair, |
527 | .getname = sock_no_getname, |
528 | .ioctl = sock_no_ioctl, |
529 | .listen = sock_no_listen, |
530 | .shutdown = sock_no_shutdown, |
531 | .getsockopt = sock_no_getsockopt, |
532 | .mmap = sock_no_mmap, |
533 | .bind = sock_no_bind, |
534 | .accept = sock_no_accept, |
535 | .setsockopt = sock_no_setsockopt, |
536 | |
537 | .release = af_alg_release, |
538 | .sendmsg = skcipher_sendmsg, |
539 | .sendpage = skcipher_sendpage, |
540 | .recvmsg = skcipher_recvmsg, |
541 | .poll = skcipher_poll, |
542 | }; |
543 | |
544 | static void *skcipher_bind(const char *name, u32 type, u32 mask) |
545 | { |
546 | return crypto_alloc_ablkcipher(name, type, mask); |
547 | } |
548 | |
549 | static void skcipher_release(void *private) |
550 | { |
551 | crypto_free_ablkcipher(private); |
552 | } |
553 | |
554 | static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) |
555 | { |
556 | return crypto_ablkcipher_setkey(private, key, keylen); |
557 | } |
558 | |
559 | static void skcipher_sock_destruct(struct sock *sk) |
560 | { |
561 | struct alg_sock *ask = alg_sk(sk); |
562 | struct skcipher_ctx *ctx = ask->private; |
563 | struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req); |
564 | |
565 | skcipher_free_sgl(sk); |
566 | sock_kfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm)); |
567 | sock_kfree_s(sk, ctx, ctx->len); |
568 | af_alg_release_parent(sk); |
569 | } |
570 | |
571 | static int skcipher_accept_parent(void *private, struct sock *sk) |
572 | { |
573 | struct skcipher_ctx *ctx; |
574 | struct alg_sock *ask = alg_sk(sk); |
575 | unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private); |
576 | |
577 | ctx = sock_kmalloc(sk, len, GFP_KERNEL); |
578 | if (!ctx) |
579 | return -ENOMEM; |
580 | |
581 | ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private), |
582 | GFP_KERNEL); |
583 | if (!ctx->iv) { |
584 | sock_kfree_s(sk, ctx, len); |
585 | return -ENOMEM; |
586 | } |
587 | |
588 | memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private)); |
589 | |
590 | INIT_LIST_HEAD(&ctx->tsgl); |
591 | ctx->len = len; |
592 | ctx->used = 0; |
593 | ctx->more = 0; |
594 | ctx->merge = 0; |
595 | ctx->enc = 0; |
596 | af_alg_init_completion(&ctx->completion); |
597 | |
598 | ask->private = ctx; |
599 | |
600 | ablkcipher_request_set_tfm(&ctx->req, private); |
601 | ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, |
602 | af_alg_complete, &ctx->completion); |
603 | |
604 | sk->sk_destruct = skcipher_sock_destruct; |
605 | |
606 | return 0; |
607 | } |
608 | |
609 | static const struct af_alg_type algif_type_skcipher = { |
610 | .bind = skcipher_bind, |
611 | .release = skcipher_release, |
612 | .setkey = skcipher_setkey, |
613 | .accept = skcipher_accept_parent, |
614 | .ops = &algif_skcipher_ops, |
615 | .name = "skcipher", |
616 | .owner = THIS_MODULE |
617 | }; |
618 | |
619 | static int __init algif_skcipher_init(void) |
620 | { |
621 | return af_alg_register_type(&algif_type_skcipher); |
622 | } |
623 | |
624 | static void __exit algif_skcipher_exit(void) |
625 | { |
626 | int err = af_alg_unregister_type(&algif_type_skcipher); |
627 | BUG_ON(err); |
628 | } |
629 | |
630 | module_init(algif_skcipher_init); |
631 | module_exit(algif_skcipher_exit); |
632 | MODULE_LICENSE("GPL"); |
633 |
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