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