[linux-block.git] / net / sysctl_net.c

// SPDX-License-Identifier: GPL-2.0-only
/* -*- linux-c -*-
 * sysctl_net.c: sysctl interface to net subsystem.
 *
 * Begun April 1, 1996, Mike Shaver.
 * Added /proc/sys/net directories for each protocol family. [MS]
 *
 * Revision 1.2  1996/05/08  20:24:40  shaver
 * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
 * NET_IPV4_IP_FORWARD.
 *
 *
 */

#include <linux/mm.h>
#include <linux/export.h>
#include <linux/sysctl.h>
#include <linux/nsproxy.h>

#include <net/sock.h>

#ifdef CONFIG_INET
#include <net/ip.h>
#endif

#ifdef CONFIG_NET
#include <linux/if_ether.h>
#endif

static struct ctl_table_set *
net_ctl_header_lookup(struct ctl_table_root *root)
{
	return &current->nsproxy->net_ns->sysctls;
}

static int is_seen(struct ctl_table_set *set)
{
	return &current->nsproxy->net_ns->sysctls == set;
}

/* Return standard mode bits for table entry. */
static int net_ctl_permissions(struct ctl_table_header *head,
			       struct ctl_table *table)
{
	struct net *net = container_of(head->set, struct net, sysctls);

	/* Allow network administrator to have same access as root. */
	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
		int mode = (table->mode >> 6) & 7;
		return (mode << 6) | (mode << 3) | mode;
	}

	return table->mode;
}

static void net_ctl_set_ownership(struct ctl_table_header *head,
				  struct ctl_table *table,
				  kuid_t *uid, kgid_t *gid)
{
	struct net *net = container_of(head->set, struct net, sysctls);
	kuid_t ns_root_uid;
	kgid_t ns_root_gid;

	ns_root_uid = make_kuid(net->user_ns, 0);
	if (uid_valid(ns_root_uid))
		*uid = ns_root_uid;

	ns_root_gid = make_kgid(net->user_ns, 0);
	if (gid_valid(ns_root_gid))
		*gid = ns_root_gid;
}

static struct ctl_table_root net_sysctl_root = {
	.lookup = net_ctl_header_lookup,
	.permissions = net_ctl_permissions,
	.set_ownership = net_ctl_set_ownership,
};

static int __net_init sysctl_net_init(struct net *net)
{
	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
	return 0;
}

static void __net_exit sysctl_net_exit(struct net *net)
{
	retire_sysctl_set(&net->sysctls);
}

static struct pernet_operations sysctl_pernet_ops = {
	.init = sysctl_net_init,
	.exit = sysctl_net_exit,
};

static struct ctl_table_header *net_header;
__init int net_sysctl_init(void)
{
	static struct ctl_table empty[1];
	int ret = -ENOMEM;
	/* Avoid limitations in the sysctl implementation by
	 * registering "/proc/sys/net" as an empty directory not in a
	 * network namespace.
	 */
	net_header = register_sysctl("net", empty);
	if (!net_header)
		goto out;
	ret = register_pernet_subsys(&sysctl_pernet_ops);
	if (ret)
		goto out1;
out:
	return ret;
out1:
	unregister_sysctl_table(net_header);
	net_header = NULL;
	goto out;
}

struct ctl_table_header *register_net_sysctl(struct net *net,
	const char *path, struct ctl_table *table)
{
	return __register_sysctl_table(&net->sysctls, path, table);
}
EXPORT_SYMBOL_GPL(register_net_sysctl);

void unregister_net_sysctl_table(struct ctl_table_header *header)
{
	unregister_sysctl_table(header);
}
EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/* -- linux-c --
	3	* sysctl_net.c: sysctl interface to net subsystem.
	4	*
	5	* Begun April 1, 1996, Mike Shaver.
	6	* Added /proc/sys/net directories for each protocol family. [MS]
	7	*
	8	* Revision 1.2 1996/05/08 20:24:40 shaver
	9	* Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
	10	* NET_IPV4_IP_FORWARD.
	11	*
	12	*
	13	*/
	14
	15	#include <linux/mm.h>
	16	#include <linux/export.h>
	17	#include <linux/sysctl.h>
	18	#include <linux/nsproxy.h>
	19
	20	#include <net/sock.h>
	21
	22	#ifdef CONFIG_INET
	23	#include <net/ip.h>
	24	#endif
	25
	26	#ifdef CONFIG_NET
	27	#include <linux/if_ether.h>
	28	#endif
	29
	30	static struct ctl_table_set *
	31	net_ctl_header_lookup(struct ctl_table_root *root)
	32	{
	33	return &current->nsproxy->net_ns->sysctls;
	34	}
	35
	36	static int is_seen(struct ctl_table_set *set)
	37	{
	38	return &current->nsproxy->net_ns->sysctls == set;
	39	}
	40
	41	/* Return standard mode bits for table entry. */
	42	static int net_ctl_permissions(struct ctl_table_header *head,
	43	struct ctl_table *table)
	44	{
	45	struct net *net = container_of(head->set, struct net, sysctls);
	46
	47	/* Allow network administrator to have same access as root. */
	48	if (ns_capable_noaudit(net->user_ns, CAP_NET_ADMIN)) {
	49	int mode = (table->mode >> 6) & 7;
	50	return (mode << 6) \| (mode << 3) \| mode;
	51	}
	52
	53	return table->mode;
	54	}
	55
	56	static void net_ctl_set_ownership(struct ctl_table_header *head,
	57	struct ctl_table *table,
	58	kuid_t uid, kgid_t gid)
	59	{
	60	struct net *net = container_of(head->set, struct net, sysctls);
	61	kuid_t ns_root_uid;
	62	kgid_t ns_root_gid;
	63
	64	ns_root_uid = make_kuid(net->user_ns, 0);
	65	if (uid_valid(ns_root_uid))
	66	*uid = ns_root_uid;
	67
	68	ns_root_gid = make_kgid(net->user_ns, 0);
	69	if (gid_valid(ns_root_gid))
	70	*gid = ns_root_gid;
	71	}
	72
	73	static struct ctl_table_root net_sysctl_root = {
	74	.lookup = net_ctl_header_lookup,
	75	.permissions = net_ctl_permissions,
	76	.set_ownership = net_ctl_set_ownership,
	77	};
	78
	79	static int __net_init sysctl_net_init(struct net *net)
	80	{
	81	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
	82	return 0;
	83	}
	84
	85	static void __net_exit sysctl_net_exit(struct net *net)
	86	{
	87	retire_sysctl_set(&net->sysctls);
	88	}
	89
	90	static struct pernet_operations sysctl_pernet_ops = {
	91	.init = sysctl_net_init,
	92	.exit = sysctl_net_exit,
	93	};
	94
	95	static struct ctl_table_header *net_header;
	96	__init int net_sysctl_init(void)
	97	{
	98	static struct ctl_table empty[1];
	99	int ret = -ENOMEM;
	100	/* Avoid limitations in the sysctl implementation by
	101	* registering "/proc/sys/net" as an empty directory not in a
	102	* network namespace.
	103	*/
	104	net_header = register_sysctl("net", empty);
	105	if (!net_header)
	106	goto out;
	107	ret = register_pernet_subsys(&sysctl_pernet_ops);
	108	if (ret)
	109	goto out1;
	110	out:
	111	return ret;
	112	out1:
	113	unregister_sysctl_table(net_header);
	114	net_header = NULL;
	115	goto out;
	116	}
	117
	118	struct ctl_table_header register_net_sysctl(struct net net,
	119	const char path, struct ctl_table table)
	120	{
	121	return __register_sysctl_table(&net->sysctls, path, table);
	122	}
	123	EXPORT_SYMBOL_GPL(register_net_sysctl);
	124
	125	void unregister_net_sysctl_table(struct ctl_table_header *header)
	126	{
	127	unregister_sysctl_table(header);
	128	}
	129	EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);