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 #include <linux/sysctl.h>
14 #include <linux/percpu_counter.h>
15 
16 struct user_namespace;
17 
18 struct ipc_ids {
19 	int in_use;
20 	unsigned short seq;
21 	struct rw_semaphore rwsem;
22 	struct idr ipcs_idr;
23 	int max_idx;
24 	int last_idx;	/* For wrap around detection */
25 #ifdef CONFIG_CHECKPOINT_RESTORE
26 	int next_id;
27 #endif
28 	struct rhashtable key_ht;
29 };
30 
31 struct ipc_namespace {
32 	struct ipc_ids	ids[3];
33 
34 	int		sem_ctls[4];
35 	int		used_sems;
36 
37 	unsigned int	msg_ctlmax;
38 	unsigned int	msg_ctlmnb;
39 	unsigned int	msg_ctlmni;
40 	struct percpu_counter percpu_msg_bytes;
41 	struct percpu_counter percpu_msg_hdrs;
42 
43 	size_t		shm_ctlmax;
44 	size_t		shm_ctlall;
45 	unsigned long	shm_tot;
46 	int		shm_ctlmni;
47 	/*
48 	 * Defines whether IPC_RMID is forced for _all_ shm segments regardless
49 	 * of shmctl()
50 	 */
51 	int		shm_rmid_forced;
52 
53 	struct notifier_block ipcns_nb;
54 
55 	/* The kern_mount of the mqueuefs sb.  We take a ref on it */
56 	struct vfsmount	*mq_mnt;
57 
58 	/* # queues in this ns, protected by mq_lock */
59 	unsigned int    mq_queues_count;
60 
61 	/* next fields are set through sysctl */
62 	unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
63 	unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
64 	unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
65 	unsigned int    mq_msg_default;
66 	unsigned int    mq_msgsize_default;
67 
68 	struct ctl_table_set	mq_set;
69 	struct ctl_table_header	*mq_sysctls;
70 
71 	struct ctl_table_set	ipc_set;
72 	struct ctl_table_header	*ipc_sysctls;
73 
74 	/* user_ns which owns the ipc ns */
75 	struct user_namespace *user_ns;
76 	struct ucounts *ucounts;
77 
78 	struct llist_node mnt_llist;
79 
80 	struct ns_common ns;
81 } __randomize_layout;
82 
83 extern struct ipc_namespace init_ipc_ns;
84 extern spinlock_t mq_lock;
85 
86 #ifdef CONFIG_SYSVIPC
87 extern void shm_destroy_orphaned(struct ipc_namespace *ns);
88 #else /* CONFIG_SYSVIPC */
shm_destroy_orphaned(struct ipc_namespace * ns)89 static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
90 #endif /* CONFIG_SYSVIPC */
91 
92 #ifdef CONFIG_POSIX_MQUEUE
93 extern int mq_init_ns(struct ipc_namespace *ns);
94 /*
95  * POSIX Message Queue default values:
96  *
97  * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
98  * DFLT_*MAX: Default values for the maximum unprivileged limits
99  * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
100  *   an attribute to the open call and the queue must be created
101  * HARD_*: Highest value the maximums can be set to.  These are enforced
102  *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
103  *   suitably high)
104  *
105  * POSIX Requirements:
106  *   Per app minimum openable message queues - 8.  This does not map well
107  *     to the fact that we limit the number of queues on a per namespace
108  *     basis instead of a per app basis.  So, make the default high enough
109  *     that no given app should have a hard time opening 8 queues.
110  *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
111  *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
112  *     we have run into a situation where running applications in the wild
113  *     require this to be at least 5MB, and preferably 10MB, so I set the
114  *     value to 16MB in hopes that this user is the worst of the bunch and
115  *     the new maximum will handle anyone else.  I may have to revisit this
116  *     in the future.
117  */
118 #define DFLT_QUEUESMAX		      256
119 #define MIN_MSGMAX			1
120 #define DFLT_MSG		       10U
121 #define DFLT_MSGMAX		       10
122 #define HARD_MSGMAX		    65536
123 #define MIN_MSGSIZEMAX		      128
124 #define DFLT_MSGSIZE		     8192U
125 #define DFLT_MSGSIZEMAX		     8192
126 #define HARD_MSGSIZEMAX	    (16*1024*1024)
127 #else
mq_init_ns(struct ipc_namespace * ns)128 static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
129 #endif
130 
131 #if defined(CONFIG_IPC_NS)
132 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
133 	struct user_namespace *user_ns, struct ipc_namespace *ns);
134 
get_ipc_ns(struct ipc_namespace * ns)135 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
136 {
137 	if (ns)
138 		refcount_inc(&ns->ns.count);
139 	return ns;
140 }
141 
get_ipc_ns_not_zero(struct ipc_namespace * ns)142 static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
143 {
144 	if (ns) {
145 		if (refcount_inc_not_zero(&ns->ns.count))
146 			return ns;
147 	}
148 
149 	return NULL;
150 }
151 
152 extern void put_ipc_ns(struct ipc_namespace *ns);
153 #else
copy_ipcs(unsigned long flags,struct user_namespace * user_ns,struct ipc_namespace * ns)154 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
155 	struct user_namespace *user_ns, struct ipc_namespace *ns)
156 {
157 	if (flags & CLONE_NEWIPC)
158 		return ERR_PTR(-EINVAL);
159 
160 	return ns;
161 }
162 
get_ipc_ns(struct ipc_namespace * ns)163 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
164 {
165 	return ns;
166 }
167 
get_ipc_ns_not_zero(struct ipc_namespace * ns)168 static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
169 {
170 	return ns;
171 }
172 
put_ipc_ns(struct ipc_namespace * ns)173 static inline void put_ipc_ns(struct ipc_namespace *ns)
174 {
175 }
176 #endif
177 
178 #ifdef CONFIG_POSIX_MQUEUE_SYSCTL
179 
180 void retire_mq_sysctls(struct ipc_namespace *ns);
181 bool setup_mq_sysctls(struct ipc_namespace *ns);
182 
183 #else /* CONFIG_POSIX_MQUEUE_SYSCTL */
184 
retire_mq_sysctls(struct ipc_namespace * ns)185 static inline void retire_mq_sysctls(struct ipc_namespace *ns)
186 {
187 }
188 
setup_mq_sysctls(struct ipc_namespace * ns)189 static inline bool setup_mq_sysctls(struct ipc_namespace *ns)
190 {
191 	return true;
192 }
193 
194 #endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
195 
196 #ifdef CONFIG_SYSVIPC_SYSCTL
197 
198 bool setup_ipc_sysctls(struct ipc_namespace *ns);
199 void retire_ipc_sysctls(struct ipc_namespace *ns);
200 
201 #else /* CONFIG_SYSVIPC_SYSCTL */
202 
retire_ipc_sysctls(struct ipc_namespace * ns)203 static inline void retire_ipc_sysctls(struct ipc_namespace *ns)
204 {
205 }
206 
setup_ipc_sysctls(struct ipc_namespace * ns)207 static inline bool setup_ipc_sysctls(struct ipc_namespace *ns)
208 {
209 	return true;
210 }
211 
212 #endif /* CONFIG_SYSVIPC_SYSCTL */
213 #endif
214