xref: /linux/include/linux/ipc_namespace.h (revision e1eb26fa)
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 
14 struct user_namespace;
15 
16 struct 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 
29 struct ipc_namespace {
30 	refcount_t	count;
31 	struct ipc_ids	ids[3];
32 
33 	int		sem_ctls[4];
34 	int		used_sems;
35 
36 	unsigned int	msg_ctlmax;
37 	unsigned int	msg_ctlmnb;
38 	unsigned int	msg_ctlmni;
39 	atomic_t	msg_bytes;
40 	atomic_t	msg_hdrs;
41 
42 	size_t		shm_ctlmax;
43 	size_t		shm_ctlall;
44 	unsigned long	shm_tot;
45 	int		shm_ctlmni;
46 	/*
47 	 * Defines whether IPC_RMID is forced for _all_ shm segments regardless
48 	 * of shmctl()
49 	 */
50 	int		shm_rmid_forced;
51 
52 	struct notifier_block ipcns_nb;
53 
54 	/* The kern_mount of the mqueuefs sb.  We take a ref on it */
55 	struct vfsmount	*mq_mnt;
56 
57 	/* # queues in this ns, protected by mq_lock */
58 	unsigned int    mq_queues_count;
59 
60 	/* next fields are set through sysctl */
61 	unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
62 	unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
63 	unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
64 	unsigned int    mq_msg_default;
65 	unsigned int    mq_msgsize_default;
66 
67 	/* user_ns which owns the ipc ns */
68 	struct user_namespace *user_ns;
69 	struct ucounts *ucounts;
70 
71 	struct llist_node mnt_llist;
72 
73 	struct ns_common ns;
74 } __randomize_layout;
75 
76 extern struct ipc_namespace init_ipc_ns;
77 extern spinlock_t mq_lock;
78 
79 #ifdef CONFIG_SYSVIPC
80 extern void shm_destroy_orphaned(struct ipc_namespace *ns);
81 #else /* CONFIG_SYSVIPC */
shm_destroy_orphaned(struct ipc_namespace * ns)82 static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
83 #endif /* CONFIG_SYSVIPC */
84 
85 #ifdef CONFIG_POSIX_MQUEUE
86 extern int mq_init_ns(struct ipc_namespace *ns);
87 /*
88  * POSIX Message Queue default values:
89  *
90  * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
91  * DFLT_*MAX: Default values for the maximum unprivileged limits
92  * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
93  *   an attribute to the open call and the queue must be created
94  * HARD_*: Highest value the maximums can be set to.  These are enforced
95  *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
96  *   suitably high)
97  *
98  * POSIX Requirements:
99  *   Per app minimum openable message queues - 8.  This does not map well
100  *     to the fact that we limit the number of queues on a per namespace
101  *     basis instead of a per app basis.  So, make the default high enough
102  *     that no given app should have a hard time opening 8 queues.
103  *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
104  *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
105  *     we have run into a situation where running applications in the wild
106  *     require this to be at least 5MB, and preferably 10MB, so I set the
107  *     value to 16MB in hopes that this user is the worst of the bunch and
108  *     the new maximum will handle anyone else.  I may have to revisit this
109  *     in the future.
110  */
111 #define DFLT_QUEUESMAX		      256
112 #define MIN_MSGMAX			1
113 #define DFLT_MSG		       10U
114 #define DFLT_MSGMAX		       10
115 #define HARD_MSGMAX		    65536
116 #define MIN_MSGSIZEMAX		      128
117 #define DFLT_MSGSIZE		     8192U
118 #define DFLT_MSGSIZEMAX		     8192
119 #define HARD_MSGSIZEMAX	    (16*1024*1024)
120 #else
mq_init_ns(struct ipc_namespace * ns)121 static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
122 #endif
123 
124 #if defined(CONFIG_IPC_NS)
125 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
126 	struct user_namespace *user_ns, struct ipc_namespace *ns);
127 
get_ipc_ns(struct ipc_namespace * ns)128 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
129 {
130 	if (ns)
131 		refcount_inc(&ns->count);
132 	return ns;
133 }
134 
135 extern void put_ipc_ns(struct ipc_namespace *ns);
136 #else
copy_ipcs(unsigned long flags,struct user_namespace * user_ns,struct ipc_namespace * ns)137 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
138 	struct user_namespace *user_ns, struct ipc_namespace *ns)
139 {
140 	if (flags & CLONE_NEWIPC)
141 		return ERR_PTR(-EINVAL);
142 
143 	return ns;
144 }
145 
get_ipc_ns(struct ipc_namespace * ns)146 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
147 {
148 	return ns;
149 }
150 
put_ipc_ns(struct ipc_namespace * ns)151 static inline void put_ipc_ns(struct ipc_namespace *ns)
152 {
153 }
154 #endif
155 
156 #ifdef CONFIG_POSIX_MQUEUE_SYSCTL
157 
158 struct ctl_table_header;
159 extern struct ctl_table_header *mq_register_sysctl_table(void);
160 
161 #else /* CONFIG_POSIX_MQUEUE_SYSCTL */
162 
mq_register_sysctl_table(void)163 static inline struct ctl_table_header *mq_register_sysctl_table(void)
164 {
165 	return NULL;
166 }
167 
168 #endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
169 #endif
170