1 /*
2 * af_alg: User-space algorithm interface
3 *
4 * This file provides the user-space API for algorithms.
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 <linux/atomic.h>
16 #include <crypto/if_alg.h>
17 #include <linux/crypto.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/list.h>
21 #include <linux/module.h>
22 #include <linux/net.h>
23 #include <linux/rwsem.h>
24 #include <linux/security.h>
25
26 struct alg_type_list {
27 const struct af_alg_type *type;
28 struct list_head list;
29 };
30
31 static atomic_long_t alg_memory_allocated;
32
33 static struct proto alg_proto = {
34 .name = "ALG",
35 .owner = THIS_MODULE,
36 .memory_allocated = &alg_memory_allocated,
37 .obj_size = sizeof(struct alg_sock),
38 };
39
40 static LIST_HEAD(alg_types);
41 static DECLARE_RWSEM(alg_types_sem);
42
alg_get_type(const char * name)43 static const struct af_alg_type *alg_get_type(const char *name)
44 {
45 const struct af_alg_type *type = ERR_PTR(-ENOENT);
46 struct alg_type_list *node;
47
48 down_read(&alg_types_sem);
49 list_for_each_entry(node, &alg_types, list) {
50 if (strcmp(node->type->name, name))
51 continue;
52
53 if (try_module_get(node->type->owner))
54 type = node->type;
55 break;
56 }
57 up_read(&alg_types_sem);
58
59 return type;
60 }
61
af_alg_register_type(const struct af_alg_type * type)62 int af_alg_register_type(const struct af_alg_type *type)
63 {
64 struct alg_type_list *node;
65 int err = -EEXIST;
66
67 down_write(&alg_types_sem);
68 list_for_each_entry(node, &alg_types, list) {
69 if (!strcmp(node->type->name, type->name))
70 goto unlock;
71 }
72
73 node = kmalloc(sizeof(*node), GFP_KERNEL);
74 err = -ENOMEM;
75 if (!node)
76 goto unlock;
77
78 type->ops->owner = THIS_MODULE;
79 if (type->ops_nokey)
80 type->ops_nokey->owner = THIS_MODULE;
81 node->type = type;
82 list_add(&node->list, &alg_types);
83 err = 0;
84
85 unlock:
86 up_write(&alg_types_sem);
87
88 return err;
89 }
90 EXPORT_SYMBOL_GPL(af_alg_register_type);
91
af_alg_unregister_type(const struct af_alg_type * type)92 int af_alg_unregister_type(const struct af_alg_type *type)
93 {
94 struct alg_type_list *node;
95 int err = -ENOENT;
96
97 down_write(&alg_types_sem);
98 list_for_each_entry(node, &alg_types, list) {
99 if (strcmp(node->type->name, type->name))
100 continue;
101
102 list_del(&node->list);
103 kfree(node);
104 err = 0;
105 break;
106 }
107 up_write(&alg_types_sem);
108
109 return err;
110 }
111 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
112
alg_do_release(const struct af_alg_type * type,void * private)113 static void alg_do_release(const struct af_alg_type *type, void *private)
114 {
115 if (!type)
116 return;
117
118 type->release(private);
119 module_put(type->owner);
120 }
121
af_alg_release(struct socket * sock)122 int af_alg_release(struct socket *sock)
123 {
124 if (sock->sk)
125 sock_put(sock->sk);
126 return 0;
127 }
128 EXPORT_SYMBOL_GPL(af_alg_release);
129
af_alg_release_parent(struct sock * sk)130 void af_alg_release_parent(struct sock *sk)
131 {
132 struct alg_sock *ask = alg_sk(sk);
133 unsigned int nokey = ask->nokey_refcnt;
134 bool last = nokey && !ask->refcnt;
135
136 sk = ask->parent;
137 ask = alg_sk(sk);
138
139 lock_sock(sk);
140 ask->nokey_refcnt -= nokey;
141 if (!last)
142 last = !--ask->refcnt;
143 release_sock(sk);
144
145 if (last)
146 sock_put(sk);
147 }
148 EXPORT_SYMBOL_GPL(af_alg_release_parent);
149
alg_bind(struct socket * sock,struct sockaddr * uaddr,int addr_len)150 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
151 {
152 struct sock *sk = sock->sk;
153 struct alg_sock *ask = alg_sk(sk);
154 struct sockaddr_alg *sa = (void *)uaddr;
155 const struct af_alg_type *type;
156 void *private;
157 int err;
158
159 if (sock->state == SS_CONNECTED)
160 return -EINVAL;
161
162 if (addr_len != sizeof(*sa))
163 return -EINVAL;
164
165 sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
166 sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
167
168 type = alg_get_type(sa->salg_type);
169 if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
170 request_module("algif-%s", sa->salg_type);
171 type = alg_get_type(sa->salg_type);
172 }
173
174 if (IS_ERR(type))
175 return PTR_ERR(type);
176
177 private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
178 if (IS_ERR(private)) {
179 module_put(type->owner);
180 return PTR_ERR(private);
181 }
182
183 err = -EBUSY;
184 lock_sock(sk);
185 if (ask->refcnt | ask->nokey_refcnt)
186 goto unlock;
187
188 swap(ask->type, type);
189 swap(ask->private, private);
190
191 err = 0;
192
193 unlock:
194 release_sock(sk);
195
196 alg_do_release(type, private);
197
198 return err;
199 }
200
alg_setkey(struct sock * sk,char __user * ukey,unsigned int keylen)201 static int alg_setkey(struct sock *sk, char __user *ukey,
202 unsigned int keylen)
203 {
204 struct alg_sock *ask = alg_sk(sk);
205 const struct af_alg_type *type = ask->type;
206 u8 *key;
207 int err;
208
209 key = sock_kmalloc(sk, keylen, GFP_KERNEL);
210 if (!key)
211 return -ENOMEM;
212
213 err = -EFAULT;
214 if (copy_from_user(key, ukey, keylen))
215 goto out;
216
217 err = type->setkey(ask->private, key, keylen);
218
219 out:
220 sock_kfree_s(sk, key, keylen);
221
222 return err;
223 }
224
alg_setsockopt(struct socket * sock,int level,int optname,char __user * optval,unsigned int optlen)225 static int alg_setsockopt(struct socket *sock, int level, int optname,
226 char __user *optval, unsigned int optlen)
227 {
228 struct sock *sk = sock->sk;
229 struct alg_sock *ask = alg_sk(sk);
230 const struct af_alg_type *type;
231 int err = -EBUSY;
232
233 lock_sock(sk);
234 if (ask->refcnt)
235 goto unlock;
236
237 type = ask->type;
238
239 err = -ENOPROTOOPT;
240 if (level != SOL_ALG || !type)
241 goto unlock;
242
243 switch (optname) {
244 case ALG_SET_KEY:
245 if (sock->state == SS_CONNECTED)
246 goto unlock;
247 if (!type->setkey)
248 goto unlock;
249
250 err = alg_setkey(sk, optval, optlen);
251 }
252
253 unlock:
254 release_sock(sk);
255
256 return err;
257 }
258
af_alg_accept(struct sock * sk,struct socket * newsock)259 int af_alg_accept(struct sock *sk, struct socket *newsock)
260 {
261 struct alg_sock *ask = alg_sk(sk);
262 const struct af_alg_type *type;
263 struct sock *sk2;
264 unsigned int nokey;
265 int err;
266
267 lock_sock(sk);
268 type = ask->type;
269
270 err = -EINVAL;
271 if (!type)
272 goto unlock;
273
274 sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
275 err = -ENOMEM;
276 if (!sk2)
277 goto unlock;
278
279 sock_init_data(newsock, sk2);
280 sock_graft(sk2, newsock);
281 security_sk_clone(sk, sk2);
282
283 err = type->accept(ask->private, sk2);
284
285 nokey = err == -ENOKEY;
286 if (nokey && type->accept_nokey)
287 err = type->accept_nokey(ask->private, sk2);
288
289 if (err)
290 goto unlock;
291
292 sk2->sk_family = PF_ALG;
293
294 if (nokey || !ask->refcnt++)
295 sock_hold(sk);
296 ask->nokey_refcnt += nokey;
297 alg_sk(sk2)->parent = sk;
298 alg_sk(sk2)->type = type;
299 alg_sk(sk2)->nokey_refcnt = nokey;
300
301 newsock->ops = type->ops;
302 newsock->state = SS_CONNECTED;
303
304 if (nokey)
305 newsock->ops = type->ops_nokey;
306
307 err = 0;
308
309 unlock:
310 release_sock(sk);
311
312 return err;
313 }
314 EXPORT_SYMBOL_GPL(af_alg_accept);
315
alg_accept(struct socket * sock,struct socket * newsock,int flags)316 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
317 {
318 return af_alg_accept(sock->sk, newsock);
319 }
320
321 static const struct proto_ops alg_proto_ops = {
322 .family = PF_ALG,
323 .owner = THIS_MODULE,
324
325 .connect = sock_no_connect,
326 .socketpair = sock_no_socketpair,
327 .getname = sock_no_getname,
328 .ioctl = sock_no_ioctl,
329 .listen = sock_no_listen,
330 .shutdown = sock_no_shutdown,
331 .getsockopt = sock_no_getsockopt,
332 .mmap = sock_no_mmap,
333 .sendpage = sock_no_sendpage,
334 .sendmsg = sock_no_sendmsg,
335 .recvmsg = sock_no_recvmsg,
336 .poll = sock_no_poll,
337
338 .bind = alg_bind,
339 .release = af_alg_release,
340 .setsockopt = alg_setsockopt,
341 .accept = alg_accept,
342 };
343
alg_sock_destruct(struct sock * sk)344 static void alg_sock_destruct(struct sock *sk)
345 {
346 struct alg_sock *ask = alg_sk(sk);
347
348 alg_do_release(ask->type, ask->private);
349 }
350
alg_create(struct net * net,struct socket * sock,int protocol,int kern)351 static int alg_create(struct net *net, struct socket *sock, int protocol,
352 int kern)
353 {
354 struct sock *sk;
355 int err;
356
357 if (sock->type != SOCK_SEQPACKET)
358 return -ESOCKTNOSUPPORT;
359 if (protocol != 0)
360 return -EPROTONOSUPPORT;
361
362 err = -ENOMEM;
363 sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
364 if (!sk)
365 goto out;
366
367 sock->ops = &alg_proto_ops;
368 sock_init_data(sock, sk);
369
370 sk->sk_family = PF_ALG;
371 sk->sk_destruct = alg_sock_destruct;
372
373 return 0;
374 out:
375 return err;
376 }
377
378 static const struct net_proto_family alg_family = {
379 .family = PF_ALG,
380 .create = alg_create,
381 .owner = THIS_MODULE,
382 };
383
af_alg_make_sg(struct af_alg_sgl * sgl,void __user * addr,int len,int write)384 int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
385 int write)
386 {
387 unsigned long from = (unsigned long)addr;
388 unsigned long npages;
389 unsigned off;
390 int err;
391 int i;
392
393 err = -EFAULT;
394 if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
395 goto out;
396
397 off = from & ~PAGE_MASK;
398 npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
399 if (npages > ALG_MAX_PAGES)
400 npages = ALG_MAX_PAGES;
401
402 err = get_user_pages_fast(from, npages, write, sgl->pages);
403 if (err < 0)
404 goto out;
405
406 npages = err;
407 err = -EINVAL;
408 if (WARN_ON(npages == 0))
409 goto out;
410
411 err = 0;
412
413 sg_init_table(sgl->sg, npages);
414
415 for (i = 0; i < npages; i++) {
416 int plen = min_t(int, len, PAGE_SIZE - off);
417
418 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
419
420 off = 0;
421 len -= plen;
422 err += plen;
423 }
424
425 out:
426 return err;
427 }
428 EXPORT_SYMBOL_GPL(af_alg_make_sg);
429
af_alg_free_sg(struct af_alg_sgl * sgl)430 void af_alg_free_sg(struct af_alg_sgl *sgl)
431 {
432 int i;
433
434 i = 0;
435 do {
436 put_page(sgl->pages[i]);
437 } while (!sg_is_last(sgl->sg + (i++)));
438 }
439 EXPORT_SYMBOL_GPL(af_alg_free_sg);
440
af_alg_cmsg_send(struct msghdr * msg,struct af_alg_control * con)441 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
442 {
443 struct cmsghdr *cmsg;
444
445 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
446 if (!CMSG_OK(msg, cmsg))
447 return -EINVAL;
448 if (cmsg->cmsg_level != SOL_ALG)
449 continue;
450
451 switch(cmsg->cmsg_type) {
452 case ALG_SET_IV:
453 if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
454 return -EINVAL;
455 con->iv = (void *)CMSG_DATA(cmsg);
456 if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
457 sizeof(*con->iv)))
458 return -EINVAL;
459 break;
460
461 case ALG_SET_OP:
462 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
463 return -EINVAL;
464 con->op = *(u32 *)CMSG_DATA(cmsg);
465 break;
466
467 default:
468 return -EINVAL;
469 }
470 }
471
472 return 0;
473 }
474 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
475
af_alg_wait_for_completion(int err,struct af_alg_completion * completion)476 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
477 {
478 switch (err) {
479 case -EINPROGRESS:
480 case -EBUSY:
481 wait_for_completion(&completion->completion);
482 reinit_completion(&completion->completion);
483 err = completion->err;
484 break;
485 };
486
487 return err;
488 }
489 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
490
af_alg_complete(struct crypto_async_request * req,int err)491 void af_alg_complete(struct crypto_async_request *req, int err)
492 {
493 struct af_alg_completion *completion = req->data;
494
495 if (err == -EINPROGRESS)
496 return;
497
498 completion->err = err;
499 complete(&completion->completion);
500 }
501 EXPORT_SYMBOL_GPL(af_alg_complete);
502
af_alg_init(void)503 static int __init af_alg_init(void)
504 {
505 int err = proto_register(&alg_proto, 0);
506
507 if (err)
508 goto out;
509
510 err = sock_register(&alg_family);
511 if (err != 0)
512 goto out_unregister_proto;
513
514 out:
515 return err;
516
517 out_unregister_proto:
518 proto_unregister(&alg_proto);
519 goto out;
520 }
521
af_alg_exit(void)522 static void __exit af_alg_exit(void)
523 {
524 sock_unregister(PF_ALG);
525 proto_unregister(&alg_proto);
526 }
527
528 module_init(af_alg_init);
529 module_exit(af_alg_exit);
530 MODULE_LICENSE("GPL");
531 MODULE_ALIAS_NETPROTO(AF_ALG);
532