[linux-block.git] / net / ax25 / ax25_uid.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */

#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/sysctl.h>
#include <linux/export.h>
#include <net/ip.h>
#include <net/arp.h>

/*
 *	Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
 */

static HLIST_HEAD(ax25_uid_list);
static DEFINE_RWLOCK(ax25_uid_lock);

int ax25_uid_policy;

EXPORT_SYMBOL(ax25_uid_policy);

ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
{
	ax25_uid_assoc *ax25_uid, *res = NULL;

	read_lock(&ax25_uid_lock);
	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
		if (uid_eq(ax25_uid->uid, uid)) {
			ax25_uid_hold(ax25_uid);
			res = ax25_uid;
			break;
		}
	}
	read_unlock(&ax25_uid_lock);

	return res;
}

EXPORT_SYMBOL(ax25_findbyuid);

int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
{
	ax25_uid_assoc *ax25_uid;
	ax25_uid_assoc *user;
	unsigned long res;

	switch (cmd) {
	case SIOCAX25GETUID:
		res = -ENOENT;
		read_lock(&ax25_uid_lock);
		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
				res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
				break;
			}
		}
		read_unlock(&ax25_uid_lock);

		return res;

	case SIOCAX25ADDUID:
	{
		kuid_t sax25_kuid;
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
		if (!uid_valid(sax25_kuid))
			return -EINVAL;
		user = ax25_findbyuid(sax25_kuid);
		if (user) {
			ax25_uid_put(user);
			return -EEXIST;
		}
		if (sax->sax25_uid == 0)
			return -EINVAL;
		if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
			return -ENOMEM;

		refcount_set(&ax25_uid->refcount, 1);
		ax25_uid->uid  = sax25_kuid;
		ax25_uid->call = sax->sax25_call;

		write_lock(&ax25_uid_lock);
		hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
		write_unlock(&ax25_uid_lock);

		return 0;
	}
	case SIOCAX25DELUID:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		ax25_uid = NULL;
		write_lock(&ax25_uid_lock);
		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
				break;
		}
		if (ax25_uid == NULL) {
			write_unlock(&ax25_uid_lock);
			return -ENOENT;
		}
		hlist_del_init(&ax25_uid->uid_node);
		ax25_uid_put(ax25_uid);
		write_unlock(&ax25_uid_lock);

		return 0;

	default:
		return -EINVAL;
	}

	return -EINVAL;	/*NOTREACHED */
}

#ifdef CONFIG_PROC_FS

static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(ax25_uid_lock)
{
	read_lock(&ax25_uid_lock);
	return seq_hlist_start_head(&ax25_uid_list, *pos);
}

static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	return seq_hlist_next(v, &ax25_uid_list, pos);
}

static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
	__releases(ax25_uid_lock)
{
	read_unlock(&ax25_uid_lock);
}

static int ax25_uid_seq_show(struct seq_file *seq, void *v)
{
	char buf[11];

	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
	else {
		struct ax25_uid_assoc *pt;

		pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
		seq_printf(seq, "%6d %s\n",
			from_kuid_munged(seq_user_ns(seq), pt->uid),
			ax2asc(buf, &pt->call));
	}
	return 0;
}

const struct seq_operations ax25_uid_seqops = {
	.start = ax25_uid_seq_start,
	.next = ax25_uid_seq_next,
	.stop = ax25_uid_seq_stop,
	.show = ax25_uid_seq_show,
};
#endif

/*
 *	Free all memory associated with UID/Callsign structures.
 */
void __exit ax25_uid_free(void)
{
	ax25_uid_assoc *ax25_uid;

	write_lock(&ax25_uid_lock);
again:
	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
		hlist_del_init(&ax25_uid->uid_node);
		ax25_uid_put(ax25_uid);
		goto again;
	}
	write_unlock(&ax25_uid_lock);
}
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
1da177e4 LT	3	*
	4	* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
	5	*/
4fc268d2 RD	6
4fc268d2 RD	7	#include <linux/capability.h>
1da177e4 LT	8	#include <linux/errno.h>
	9	#include <linux/types.h>
	10	#include <linux/socket.h>
	11	#include <linux/in.h>
	12	#include <linux/kernel.h>
1da177e4 LT	13	#include <linux/timer.h>
	14	#include <linux/string.h>
	15	#include <linux/sockios.h>
	16	#include <linux/net.h>
	17	#include <linux/spinlock.h>
5a0e3ad6	18	#include <linux/slab.h>
1da177e4 LT	19	#include <net/ax25.h>
	20	#include <linux/inet.h>
	21	#include <linux/netdevice.h>
	22	#include <linux/if_arp.h>
	23	#include <linux/skbuff.h>
	24	#include <net/sock.h>
7c0f6ba6	25	#include <linux/uaccess.h>
1da177e4 LT	26	#include <linux/fcntl.h>
	27	#include <linux/mm.h>
	28	#include <linux/interrupt.h>
01d7dd0e	29	#include <linux/list.h>
1da177e4 LT	30	#include <linux/notifier.h>
	31	#include <linux/proc_fs.h>
	32	#include <linux/seq_file.h>
	33	#include <linux/stat.h>
1da177e4	34	#include <linux/sysctl.h>
bc3b2d7f	35	#include <linux/export.h>
1da177e4 LT	36	#include <net/ip.h>
	37	#include <net/arp.h>
	38
	39	/*
	40	* Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
	41	*/
	42
f16f3026	43	static HLIST_HEAD(ax25_uid_list);
1da177e4 LT	44	static DEFINE_RWLOCK(ax25_uid_lock);
1da177e4 LT	45
f16f3026	46	int ax25_uid_policy;
1da177e4	47
70868eac RB	48	EXPORT_SYMBOL(ax25_uid_policy);
70868eac RB	49
d13fda85	50	ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
1da177e4	51	{
01d7dd0e	52	ax25_uid_assoc ax25_uid, res = NULL;
1da177e4 LT	53
1da177e4 LT	54	read_lock(&ax25_uid_lock);
b67bfe0d	55	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
d13fda85	56	if (uid_eq(ax25_uid->uid, uid)) {
01d7dd0e RB	57	ax25_uid_hold(ax25_uid);
01d7dd0e RB	58	res = ax25_uid;
1da177e4 LT	59	break;
	60	}
	61	}
	62	read_unlock(&ax25_uid_lock);
	63
01d7dd0e	64	return res;
1da177e4 LT	65	}
1da177e4 LT	66
70868eac RB	67	EXPORT_SYMBOL(ax25_findbyuid);
70868eac RB	68
1da177e4 LT	69	int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
1da177e4 LT	70	{
01d7dd0e	71	ax25_uid_assoc *ax25_uid;
01d7dd0e	72	ax25_uid_assoc *user;
1da177e4 LT	73	unsigned long res;
	74
	75	switch (cmd) {
	76	case SIOCAX25GETUID:
	77	res = -ENOENT;
	78	read_lock(&ax25_uid_lock);
b67bfe0d	79	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
1da177e4	80	if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
d13fda85	81	res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
1da177e4 LT	82	break;
	83	}
	84	}
	85	read_unlock(&ax25_uid_lock);
	86
	87	return res;
	88
	89	case SIOCAX25ADDUID:
d13fda85 EB	90	{
d13fda85 EB	91	kuid_t sax25_kuid;
1da177e4 LT	92	if (!capable(CAP_NET_ADMIN))
1da177e4 LT	93	return -EPERM;
d13fda85 EB	94	sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
	95	if (!uid_valid(sax25_kuid))
	96	return -EINVAL;
	97	user = ax25_findbyuid(sax25_kuid);
01d7dd0e RB	98	if (user) {
01d7dd0e RB	99	ax25_uid_put(user);
1da177e4	100	return -EEXIST;
01d7dd0e	101	}
1da177e4 LT	102	if (sax->sax25_uid == 0)
	103	return -EINVAL;
	104	if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
	105	return -ENOMEM;
	106
07f2282f	107	refcount_set(&ax25_uid->refcount, 1);
d13fda85	108	ax25_uid->uid = sax25_kuid;
1da177e4 LT	109	ax25_uid->call = sax->sax25_call;
	110
	111	write_lock(&ax25_uid_lock);
01d7dd0e	112	hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
1da177e4 LT	113	write_unlock(&ax25_uid_lock);
	114
	115	return 0;
d13fda85	116	}
1da177e4 LT	117	case SIOCAX25DELUID:
	118	if (!capable(CAP_NET_ADMIN))
	119	return -EPERM;
	120
01d7dd0e	121	ax25_uid = NULL;
1da177e4	122	write_lock(&ax25_uid_lock);
b67bfe0d	123	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
01d7dd0e	124	if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
1da177e4	125	break;
1da177e4 LT	126	}
	127	if (ax25_uid == NULL) {
	128	write_unlock(&ax25_uid_lock);
	129	return -ENOENT;
	130	}
01d7dd0e RB	131	hlist_del_init(&ax25_uid->uid_node);
01d7dd0e RB	132	ax25_uid_put(ax25_uid);
1da177e4 LT	133	write_unlock(&ax25_uid_lock);
1da177e4 LT	134
01d7dd0e	135	return 0;
1da177e4 LT	136
	137	default:
	138	return -EINVAL;
	139	}
	140
	141	return -EINVAL; /NOTREACHED /
	142	}
	143
	144	#ifdef CONFIG_PROC_FS
	145
	146	static void ax25_uid_seq_start(struct seq_file seq, loff_t *pos)
f16f3026	147	__acquires(ax25_uid_lock)
1da177e4	148	{
1da177e4	149	read_lock(&ax25_uid_lock);
b512f3d8	150	return seq_hlist_start_head(&ax25_uid_list, *pos);
1da177e4 LT	151	}
	152
	153	static void ax25_uid_seq_next(struct seq_file seq, void v, loff_t pos)
	154	{
b512f3d8	155	return seq_hlist_next(v, &ax25_uid_list, pos);
1da177e4 LT	156	}
	157
	158	static void ax25_uid_seq_stop(struct seq_file seq, void v)
f16f3026	159	__releases(ax25_uid_lock)
1da177e4 LT	160	{
	161	read_unlock(&ax25_uid_lock);
	162	}
	163
	164	static int ax25_uid_seq_show(struct seq_file seq, void v)
	165	{
f75268cd RB	166	char buf[11];
f75268cd RB	167
1da177e4 LT	168	if (v == SEQ_START_TOKEN)
	169	seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
	170	else {
b512f3d8	171	struct ax25_uid_assoc *pt;
1da177e4	172
b512f3d8	173	pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
d13fda85 EB	174	seq_printf(seq, "%6d %s\n",
	175	from_kuid_munged(seq_user_ns(seq), pt->uid),
	176	ax2asc(buf, &pt->call));
1da177e4 LT	177	}
	178	return 0;
	179	}
	180
fddda2b7	181	const struct seq_operations ax25_uid_seqops = {
1da177e4 LT	182	.start = ax25_uid_seq_start,
	183	.next = ax25_uid_seq_next,
	184	.stop = ax25_uid_seq_stop,
	185	.show = ax25_uid_seq_show,
	186	};
1da177e4 LT	187	#endif
	188
	189	/*
	190	* Free all memory associated with UID/Callsign structures.
	191	*/
	192	void __exit ax25_uid_free(void)
	193	{
01d7dd0e	194	ax25_uid_assoc *ax25_uid;
1da177e4 LT	195
1da177e4 LT	196	write_lock(&ax25_uid_lock);
ae1b6a31	197	again:
b67bfe0d	198	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
01d7dd0e RB	199	hlist_del_init(&ax25_uid->uid_node);
01d7dd0e RB	200	ax25_uid_put(ax25_uid);
ae1b6a31	201	goto again;
1da177e4	202	}
1da177e4 LT	203	write_unlock(&ax25_uid_lock);
1da177e4 LT	204	}