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
26struct alg_type_list {
27	const struct af_alg_type *type;
28	struct list_head list;
29};
30
31static atomic_long_t alg_memory_allocated;
32
33static 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
40static LIST_HEAD(alg_types);
41static DECLARE_RWSEM(alg_types_sem);
42
43static 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
62int 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
85unlock:
86	up_write(&alg_types_sem);
87
88	return err;
89}
90EXPORT_SYMBOL_GPL(af_alg_register_type);
91
92int 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}
111EXPORT_SYMBOL_GPL(af_alg_unregister_type);
112
113static 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
122int af_alg_release(struct socket *sock)
123{
124	if (sock->sk)
125		sock_put(sock->sk);
126	return 0;
127}
128EXPORT_SYMBOL_GPL(af_alg_release);
129
130void 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}
148EXPORT_SYMBOL_GPL(af_alg_release_parent);
149
150static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
151{
152	const u32 forbidden = CRYPTO_ALG_INTERNAL;
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 (sock->state == SS_CONNECTED)
161		return -EINVAL;
162
163	if (addr_len != sizeof(*sa))
164		return -EINVAL;
165
166	sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
167	sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
168
169	type = alg_get_type(sa->salg_type);
170	if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
171		request_module("algif-%s", sa->salg_type);
172		type = alg_get_type(sa->salg_type);
173	}
174
175	if (IS_ERR(type))
176		return PTR_ERR(type);
177
178	private = type->bind(sa->salg_name,
179			     sa->salg_feat & ~forbidden,
180			     sa->salg_mask & ~forbidden);
181	if (IS_ERR(private)) {
182		module_put(type->owner);
183		return PTR_ERR(private);
184	}
185
186	err = -EBUSY;
187	lock_sock(sk);
188	if (ask->refcnt | ask->nokey_refcnt)
189		goto unlock;
190
191	swap(ask->type, type);
192	swap(ask->private, private);
193
194	err = 0;
195
196unlock:
197	release_sock(sk);
198
199	alg_do_release(type, private);
200
201	return err;
202}
203
204static int alg_setkey(struct sock *sk, char __user *ukey,
205		      unsigned int keylen)
206{
207	struct alg_sock *ask = alg_sk(sk);
208	const struct af_alg_type *type = ask->type;
209	u8 *key;
210	int err;
211
212	key = sock_kmalloc(sk, keylen, GFP_KERNEL);
213	if (!key)
214		return -ENOMEM;
215
216	err = -EFAULT;
217	if (copy_from_user(key, ukey, keylen))
218		goto out;
219
220	err = type->setkey(ask->private, key, keylen);
221
222out:
223	sock_kzfree_s(sk, key, keylen);
224
225	return err;
226}
227
228static int alg_setsockopt(struct socket *sock, int level, int optname,
229			  char __user *optval, unsigned int optlen)
230{
231	struct sock *sk = sock->sk;
232	struct alg_sock *ask = alg_sk(sk);
233	const struct af_alg_type *type;
234	int err = -EBUSY;
235
236	lock_sock(sk);
237	if (ask->refcnt)
238		goto unlock;
239
240	type = ask->type;
241
242	err = -ENOPROTOOPT;
243	if (level != SOL_ALG || !type)
244		goto unlock;
245
246	switch (optname) {
247	case ALG_SET_KEY:
248		if (sock->state == SS_CONNECTED)
249			goto unlock;
250		if (!type->setkey)
251			goto unlock;
252
253		err = alg_setkey(sk, optval, optlen);
254		break;
255	case ALG_SET_AEAD_AUTHSIZE:
256		if (sock->state == SS_CONNECTED)
257			goto unlock;
258		if (!type->setauthsize)
259			goto unlock;
260		err = type->setauthsize(ask->private, optlen);
261	}
262
263unlock:
264	release_sock(sk);
265
266	return err;
267}
268
269int af_alg_accept(struct sock *sk, struct socket *newsock)
270{
271	struct alg_sock *ask = alg_sk(sk);
272	const struct af_alg_type *type;
273	struct sock *sk2;
274	unsigned int nokey;
275	int err;
276
277	lock_sock(sk);
278	type = ask->type;
279
280	err = -EINVAL;
281	if (!type)
282		goto unlock;
283
284	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, 0);
285	err = -ENOMEM;
286	if (!sk2)
287		goto unlock;
288
289	sock_init_data(newsock, sk2);
290	sock_graft(sk2, newsock);
291	security_sk_clone(sk, sk2);
292
293	err = type->accept(ask->private, sk2);
294
295	nokey = err == -ENOKEY;
296	if (nokey && type->accept_nokey)
297		err = type->accept_nokey(ask->private, sk2);
298
299	if (err)
300		goto unlock;
301
302	sk2->sk_family = PF_ALG;
303
304	if (nokey || !ask->refcnt++)
305		sock_hold(sk);
306	ask->nokey_refcnt += nokey;
307	alg_sk(sk2)->parent = sk;
308	alg_sk(sk2)->type = type;
309	alg_sk(sk2)->nokey_refcnt = nokey;
310
311	newsock->ops = type->ops;
312	newsock->state = SS_CONNECTED;
313
314	if (nokey)
315		newsock->ops = type->ops_nokey;
316
317	err = 0;
318
319unlock:
320	release_sock(sk);
321
322	return err;
323}
324EXPORT_SYMBOL_GPL(af_alg_accept);
325
326static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
327{
328	return af_alg_accept(sock->sk, newsock);
329}
330
331static const struct proto_ops alg_proto_ops = {
332	.family		=	PF_ALG,
333	.owner		=	THIS_MODULE,
334
335	.connect	=	sock_no_connect,
336	.socketpair	=	sock_no_socketpair,
337	.getname	=	sock_no_getname,
338	.ioctl		=	sock_no_ioctl,
339	.listen		=	sock_no_listen,
340	.shutdown	=	sock_no_shutdown,
341	.getsockopt	=	sock_no_getsockopt,
342	.mmap		=	sock_no_mmap,
343	.sendpage	=	sock_no_sendpage,
344	.sendmsg	=	sock_no_sendmsg,
345	.recvmsg	=	sock_no_recvmsg,
346	.poll		=	sock_no_poll,
347
348	.bind		=	alg_bind,
349	.release	=	af_alg_release,
350	.setsockopt	=	alg_setsockopt,
351	.accept		=	alg_accept,
352};
353
354static void alg_sock_destruct(struct sock *sk)
355{
356	struct alg_sock *ask = alg_sk(sk);
357
358	alg_do_release(ask->type, ask->private);
359}
360
361static int alg_create(struct net *net, struct socket *sock, int protocol,
362		      int kern)
363{
364	struct sock *sk;
365	int err;
366
367	if (sock->type != SOCK_SEQPACKET)
368		return -ESOCKTNOSUPPORT;
369	if (protocol != 0)
370		return -EPROTONOSUPPORT;
371
372	err = -ENOMEM;
373	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
374	if (!sk)
375		goto out;
376
377	sock->ops = &alg_proto_ops;
378	sock_init_data(sock, sk);
379
380	sk->sk_family = PF_ALG;
381	sk->sk_destruct = alg_sock_destruct;
382
383	return 0;
384out:
385	return err;
386}
387
388static const struct net_proto_family alg_family = {
389	.family	=	PF_ALG,
390	.create	=	alg_create,
391	.owner	=	THIS_MODULE,
392};
393
394int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
395{
396	size_t off;
397	ssize_t n;
398	int npages, i;
399
400	n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
401	if (n < 0)
402		return n;
403
404	npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
405	if (WARN_ON(npages == 0))
406		return -EINVAL;
407	/* Add one extra for linking */
408	sg_init_table(sgl->sg, npages + 1);
409
410	for (i = 0, len = n; i < npages; i++) {
411		int plen = min_t(int, len, PAGE_SIZE - off);
412
413		sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
414
415		off = 0;
416		len -= plen;
417	}
418	sg_mark_end(sgl->sg + npages - 1);
419	sgl->npages = npages;
420
421	return n;
422}
423EXPORT_SYMBOL_GPL(af_alg_make_sg);
424
425void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
426{
427	sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
428	sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
429}
430EXPORT_SYMBOL_GPL(af_alg_link_sg);
431
432void af_alg_free_sg(struct af_alg_sgl *sgl)
433{
434	int i;
435
436	for (i = 0; i < sgl->npages; i++)
437		put_page(sgl->pages[i]);
438}
439EXPORT_SYMBOL_GPL(af_alg_free_sg);
440
441int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
442{
443	struct cmsghdr *cmsg;
444
445	for_each_cmsghdr(cmsg, msg) {
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		case ALG_SET_AEAD_ASSOCLEN:
468			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
469				return -EINVAL;
470			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
471			break;
472
473		default:
474			return -EINVAL;
475		}
476	}
477
478	return 0;
479}
480EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
481
482int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
483{
484	switch (err) {
485	case -EINPROGRESS:
486	case -EBUSY:
487		wait_for_completion(&completion->completion);
488		reinit_completion(&completion->completion);
489		err = completion->err;
490		break;
491	};
492
493	return err;
494}
495EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
496
497void af_alg_complete(struct crypto_async_request *req, int err)
498{
499	struct af_alg_completion *completion = req->data;
500
501	if (err == -EINPROGRESS)
502		return;
503
504	completion->err = err;
505	complete(&completion->completion);
506}
507EXPORT_SYMBOL_GPL(af_alg_complete);
508
509static int __init af_alg_init(void)
510{
511	int err = proto_register(&alg_proto, 0);
512
513	if (err)
514		goto out;
515
516	err = sock_register(&alg_family);
517	if (err != 0)
518		goto out_unregister_proto;
519
520out:
521	return err;
522
523out_unregister_proto:
524	proto_unregister(&alg_proto);
525	goto out;
526}
527
528static void __exit af_alg_exit(void)
529{
530	sock_unregister(PF_ALG);
531	proto_unregister(&alg_proto);
532}
533
534module_init(af_alg_init);
535module_exit(af_alg_exit);
536MODULE_LICENSE("GPL");
537MODULE_ALIAS_NETPROTO(AF_ALG);
538