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 const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
153 struct sock *sk = sock->sk;
154 struct alg_sock *ask = alg_sk(sk);
155 struct sockaddr_alg *sa = (void *)uaddr;
156 const struct af_alg_type *type;
157 void *private;
158 int err;
159
160 /* If caller uses non-allowed flag, return error. */
161 if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
162 return -EINVAL;
163
164 if (sock->state == SS_CONNECTED)
165 return -EINVAL;
166
167 if (addr_len != sizeof(*sa))
168 return -EINVAL;
169
170 sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
171 sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
172
173 type = alg_get_type(sa->salg_type);
174 if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
175 request_module("algif-%s", sa->salg_type);
176 type = alg_get_type(sa->salg_type);
177 }
178
179 if (IS_ERR(type))
180 return PTR_ERR(type);
181
182 private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
183 if (IS_ERR(private)) {
184 module_put(type->owner);
185 return PTR_ERR(private);
186 }
187
188 err = -EBUSY;
189 lock_sock(sk);
190 if (ask->refcnt | ask->nokey_refcnt)
191 goto unlock;
192
193 swap(ask->type, type);
194 swap(ask->private, private);
195
196 err = 0;
197
198 unlock:
199 release_sock(sk);
200
201 alg_do_release(type, private);
202
203 return err;
204 }
205
alg_setkey(struct sock * sk,char __user * ukey,unsigned int keylen)206 static int alg_setkey(struct sock *sk, char __user *ukey,
207 unsigned int keylen)
208 {
209 struct alg_sock *ask = alg_sk(sk);
210 const struct af_alg_type *type = ask->type;
211 u8 *key;
212 int err;
213
214 key = sock_kmalloc(sk, keylen, GFP_KERNEL);
215 if (!key)
216 return -ENOMEM;
217
218 err = -EFAULT;
219 if (copy_from_user(key, ukey, keylen))
220 goto out;
221
222 err = type->setkey(ask->private, key, keylen);
223
224 out:
225 sock_kzfree_s(sk, key, keylen);
226
227 return err;
228 }
229
alg_setsockopt(struct socket * sock,int level,int optname,char __user * optval,unsigned int optlen)230 static int alg_setsockopt(struct socket *sock, int level, int optname,
231 char __user *optval, unsigned int optlen)
232 {
233 struct sock *sk = sock->sk;
234 struct alg_sock *ask = alg_sk(sk);
235 const struct af_alg_type *type;
236 int err = -EBUSY;
237
238 lock_sock(sk);
239 if (ask->refcnt)
240 goto unlock;
241
242 type = ask->type;
243
244 err = -ENOPROTOOPT;
245 if (level != SOL_ALG || !type)
246 goto unlock;
247
248 switch (optname) {
249 case ALG_SET_KEY:
250 if (sock->state == SS_CONNECTED)
251 goto unlock;
252 if (!type->setkey)
253 goto unlock;
254
255 err = alg_setkey(sk, optval, optlen);
256 break;
257 case ALG_SET_AEAD_AUTHSIZE:
258 if (sock->state == SS_CONNECTED)
259 goto unlock;
260 if (!type->setauthsize)
261 goto unlock;
262 err = type->setauthsize(ask->private, optlen);
263 }
264
265 unlock:
266 release_sock(sk);
267
268 return err;
269 }
270
af_alg_accept(struct sock * sk,struct socket * newsock)271 int af_alg_accept(struct sock *sk, struct socket *newsock)
272 {
273 struct alg_sock *ask = alg_sk(sk);
274 const struct af_alg_type *type;
275 struct sock *sk2;
276 unsigned int nokey;
277 int err;
278
279 lock_sock(sk);
280 type = ask->type;
281
282 err = -EINVAL;
283 if (!type)
284 goto unlock;
285
286 sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, 0);
287 err = -ENOMEM;
288 if (!sk2)
289 goto unlock;
290
291 sock_init_data(newsock, sk2);
292 sock_graft(sk2, newsock);
293 security_sk_clone(sk, sk2);
294
295 err = type->accept(ask->private, sk2);
296
297 nokey = err == -ENOKEY;
298 if (nokey && type->accept_nokey)
299 err = type->accept_nokey(ask->private, sk2);
300
301 if (err)
302 goto unlock;
303
304 sk2->sk_family = PF_ALG;
305
306 if (nokey || !ask->refcnt++)
307 sock_hold(sk);
308 ask->nokey_refcnt += nokey;
309 alg_sk(sk2)->parent = sk;
310 alg_sk(sk2)->type = type;
311 alg_sk(sk2)->nokey_refcnt = nokey;
312
313 newsock->ops = type->ops;
314 newsock->state = SS_CONNECTED;
315
316 if (nokey)
317 newsock->ops = type->ops_nokey;
318
319 err = 0;
320
321 unlock:
322 release_sock(sk);
323
324 return err;
325 }
326 EXPORT_SYMBOL_GPL(af_alg_accept);
327
alg_accept(struct socket * sock,struct socket * newsock,int flags)328 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
329 {
330 return af_alg_accept(sock->sk, newsock);
331 }
332
333 static const struct proto_ops alg_proto_ops = {
334 .family = PF_ALG,
335 .owner = THIS_MODULE,
336
337 .connect = sock_no_connect,
338 .socketpair = sock_no_socketpair,
339 .getname = sock_no_getname,
340 .ioctl = sock_no_ioctl,
341 .listen = sock_no_listen,
342 .shutdown = sock_no_shutdown,
343 .getsockopt = sock_no_getsockopt,
344 .mmap = sock_no_mmap,
345 .sendpage = sock_no_sendpage,
346 .sendmsg = sock_no_sendmsg,
347 .recvmsg = sock_no_recvmsg,
348 .poll = sock_no_poll,
349
350 .bind = alg_bind,
351 .release = af_alg_release,
352 .setsockopt = alg_setsockopt,
353 .accept = alg_accept,
354 };
355
alg_sock_destruct(struct sock * sk)356 static void alg_sock_destruct(struct sock *sk)
357 {
358 struct alg_sock *ask = alg_sk(sk);
359
360 alg_do_release(ask->type, ask->private);
361 }
362
alg_create(struct net * net,struct socket * sock,int protocol,int kern)363 static int alg_create(struct net *net, struct socket *sock, int protocol,
364 int kern)
365 {
366 struct sock *sk;
367 int err;
368
369 if (sock->type != SOCK_SEQPACKET)
370 return -ESOCKTNOSUPPORT;
371 if (protocol != 0)
372 return -EPROTONOSUPPORT;
373
374 err = -ENOMEM;
375 sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
376 if (!sk)
377 goto out;
378
379 sock->ops = &alg_proto_ops;
380 sock_init_data(sock, sk);
381
382 sk->sk_family = PF_ALG;
383 sk->sk_destruct = alg_sock_destruct;
384
385 return 0;
386 out:
387 return err;
388 }
389
390 static const struct net_proto_family alg_family = {
391 .family = PF_ALG,
392 .create = alg_create,
393 .owner = THIS_MODULE,
394 };
395
af_alg_make_sg(struct af_alg_sgl * sgl,struct iov_iter * iter,int len)396 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
397 {
398 size_t off;
399 ssize_t n;
400 int npages, i;
401
402 n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
403 if (n < 0)
404 return n;
405
406 npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
407 if (WARN_ON(npages == 0))
408 return -EINVAL;
409 /* Add one extra for linking */
410 sg_init_table(sgl->sg, npages + 1);
411
412 for (i = 0, len = n; i < npages; i++) {
413 int plen = min_t(int, len, PAGE_SIZE - off);
414
415 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
416
417 off = 0;
418 len -= plen;
419 }
420 sg_mark_end(sgl->sg + npages - 1);
421 sgl->npages = npages;
422
423 return n;
424 }
425 EXPORT_SYMBOL_GPL(af_alg_make_sg);
426
af_alg_link_sg(struct af_alg_sgl * sgl_prev,struct af_alg_sgl * sgl_new)427 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
428 {
429 sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
430 sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
431 }
432 EXPORT_SYMBOL_GPL(af_alg_link_sg);
433
af_alg_free_sg(struct af_alg_sgl * sgl)434 void af_alg_free_sg(struct af_alg_sgl *sgl)
435 {
436 int i;
437
438 for (i = 0; i < sgl->npages; i++)
439 put_page(sgl->pages[i]);
440 }
441 EXPORT_SYMBOL_GPL(af_alg_free_sg);
442
af_alg_cmsg_send(struct msghdr * msg,struct af_alg_control * con)443 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
444 {
445 struct cmsghdr *cmsg;
446
447 for_each_cmsghdr(cmsg, msg) {
448 if (!CMSG_OK(msg, cmsg))
449 return -EINVAL;
450 if (cmsg->cmsg_level != SOL_ALG)
451 continue;
452
453 switch (cmsg->cmsg_type) {
454 case ALG_SET_IV:
455 if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
456 return -EINVAL;
457 con->iv = (void *)CMSG_DATA(cmsg);
458 if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
459 sizeof(*con->iv)))
460 return -EINVAL;
461 break;
462
463 case ALG_SET_OP:
464 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
465 return -EINVAL;
466 con->op = *(u32 *)CMSG_DATA(cmsg);
467 break;
468
469 case ALG_SET_AEAD_ASSOCLEN:
470 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
471 return -EINVAL;
472 con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
473 break;
474
475 default:
476 return -EINVAL;
477 }
478 }
479
480 return 0;
481 }
482 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
483
af_alg_wait_for_completion(int err,struct af_alg_completion * completion)484 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
485 {
486 switch (err) {
487 case -EINPROGRESS:
488 case -EBUSY:
489 wait_for_completion(&completion->completion);
490 reinit_completion(&completion->completion);
491 err = completion->err;
492 break;
493 };
494
495 return err;
496 }
497 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
498
af_alg_complete(struct crypto_async_request * req,int err)499 void af_alg_complete(struct crypto_async_request *req, int err)
500 {
501 struct af_alg_completion *completion = req->data;
502
503 if (err == -EINPROGRESS)
504 return;
505
506 completion->err = err;
507 complete(&completion->completion);
508 }
509 EXPORT_SYMBOL_GPL(af_alg_complete);
510
af_alg_init(void)511 static int __init af_alg_init(void)
512 {
513 int err = proto_register(&alg_proto, 0);
514
515 if (err)
516 goto out;
517
518 err = sock_register(&alg_family);
519 if (err != 0)
520 goto out_unregister_proto;
521
522 out:
523 return err;
524
525 out_unregister_proto:
526 proto_unregister(&alg_proto);
527 goto out;
528 }
529
af_alg_exit(void)530 static void __exit af_alg_exit(void)
531 {
532 sock_unregister(PF_ALG);
533 proto_unregister(&alg_proto);
534 }
535
536 module_init(af_alg_init);
537 module_exit(af_alg_exit);
538 MODULE_LICENSE("GPL");
539 MODULE_ALIAS_NETPROTO(AF_ALG);
540