1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __IPC_NAMESPACE_H__
3#define __IPC_NAMESPACE_H__
4
5#include <linux/err.h>
6#include <linux/idr.h>
7#include <linux/rwsem.h>
8#include <linux/notifier.h>
9#include <linux/nsproxy.h>
10#include <linux/ns_common.h>
11#include <linux/refcount.h>
12#include <linux/rhashtable-types.h>
13
14struct user_namespace;
15
16struct ipc_ids {
17	int in_use;
18	unsigned short seq;
19	struct rw_semaphore rwsem;
20	struct idr ipcs_idr;
21	int max_idx;
22	int last_idx;	/* For wrap around detection */
23#ifdef CONFIG_CHECKPOINT_RESTORE
24	int next_id;
25#endif
26	struct rhashtable key_ht;
27};
28
29struct ipc_namespace {
30	struct ipc_ids	ids[3];
31
32	int		sem_ctls[4];
33	int		used_sems;
34
35	unsigned int	msg_ctlmax;
36	unsigned int	msg_ctlmnb;
37	unsigned int	msg_ctlmni;
38	atomic_t	msg_bytes;
39	atomic_t	msg_hdrs;
40
41	size_t		shm_ctlmax;
42	size_t		shm_ctlall;
43	unsigned long	shm_tot;
44	int		shm_ctlmni;
45	/*
46	 * Defines whether IPC_RMID is forced for _all_ shm segments regardless
47	 * of shmctl()
48	 */
49	int		shm_rmid_forced;
50
51	struct notifier_block ipcns_nb;
52
53	/* The kern_mount of the mqueuefs sb.  We take a ref on it */
54	struct vfsmount	*mq_mnt;
55
56	/* # queues in this ns, protected by mq_lock */
57	unsigned int    mq_queues_count;
58
59	/* next fields are set through sysctl */
60	unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
61	unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
62	unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
63	unsigned int    mq_msg_default;
64	unsigned int    mq_msgsize_default;
65
66	/* user_ns which owns the ipc ns */
67	struct user_namespace *user_ns;
68	struct ucounts *ucounts;
69
70	struct llist_node mnt_llist;
71
72	struct ns_common ns;
73} __randomize_layout;
74
75extern struct ipc_namespace init_ipc_ns;
76extern spinlock_t mq_lock;
77
78#ifdef CONFIG_SYSVIPC
79extern void shm_destroy_orphaned(struct ipc_namespace *ns);
80#else /* CONFIG_SYSVIPC */
81static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
82#endif /* CONFIG_SYSVIPC */
83
84#ifdef CONFIG_POSIX_MQUEUE
85extern int mq_init_ns(struct ipc_namespace *ns);
86/*
87 * POSIX Message Queue default values:
88 *
89 * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
90 * DFLT_*MAX: Default values for the maximum unprivileged limits
91 * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
92 *   an attribute to the open call and the queue must be created
93 * HARD_*: Highest value the maximums can be set to.  These are enforced
94 *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
95 *   suitably high)
96 *
97 * POSIX Requirements:
98 *   Per app minimum openable message queues - 8.  This does not map well
99 *     to the fact that we limit the number of queues on a per namespace
100 *     basis instead of a per app basis.  So, make the default high enough
101 *     that no given app should have a hard time opening 8 queues.
102 *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
103 *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
104 *     we have run into a situation where running applications in the wild
105 *     require this to be at least 5MB, and preferably 10MB, so I set the
106 *     value to 16MB in hopes that this user is the worst of the bunch and
107 *     the new maximum will handle anyone else.  I may have to revisit this
108 *     in the future.
109 */
110#define DFLT_QUEUESMAX		      256
111#define MIN_MSGMAX			1
112#define DFLT_MSG		       10U
113#define DFLT_MSGMAX		       10
114#define HARD_MSGMAX		    65536
115#define MIN_MSGSIZEMAX		      128
116#define DFLT_MSGSIZE		     8192U
117#define DFLT_MSGSIZEMAX		     8192
118#define HARD_MSGSIZEMAX	    (16*1024*1024)
119#else
120static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
121#endif
122
123#if defined(CONFIG_IPC_NS)
124extern struct ipc_namespace *copy_ipcs(unsigned long flags,
125	struct user_namespace *user_ns, struct ipc_namespace *ns);
126
127static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
128{
129	if (ns)
130		refcount_inc(&ns->ns.count);
131	return ns;
132}
133
134static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
135{
136	if (ns) {
137		if (refcount_inc_not_zero(&ns->ns.count))
138			return ns;
139	}
140
141	return NULL;
142}
143
144extern void put_ipc_ns(struct ipc_namespace *ns);
145#else
146static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
147	struct user_namespace *user_ns, struct ipc_namespace *ns)
148{
149	if (flags & CLONE_NEWIPC)
150		return ERR_PTR(-EINVAL);
151
152	return ns;
153}
154
155static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
156{
157	return ns;
158}
159
160static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
161{
162	return ns;
163}
164
165static inline void put_ipc_ns(struct ipc_namespace *ns)
166{
167}
168#endif
169
170#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
171
172struct ctl_table_header;
173extern struct ctl_table_header *mq_register_sysctl_table(void);
174
175#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
176
177static inline struct ctl_table_header *mq_register_sysctl_table(void)
178{
179	return NULL;
180}
181
182#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
183#endif
184