ipc_namespace.h

  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
 16struct user_namespace;
 17
 18struct 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
 31struct 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
 83extern struct ipc_namespace init_ipc_ns;
 84extern spinlock_t mq_lock;
 85
 86#ifdef CONFIG_SYSVIPC
 87extern void shm_destroy_orphaned(struct ipc_namespace *ns);
 88#else /* CONFIG_SYSVIPC */
 89static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
 90#endif /* CONFIG_SYSVIPC */
 91
 92#ifdef CONFIG_POSIX_MQUEUE
 93extern 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
128static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
129#endif
130
131#if defined(CONFIG_IPC_NS)
132static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
133{
134	return container_of(ns, struct ipc_namespace, ns);
135}
136
137extern struct ipc_namespace *copy_ipcs(u64 flags,
138	struct user_namespace *user_ns, struct ipc_namespace *ns);
139
140static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
141{
142	if (ns)
143		ns_ref_inc(ns);
144	return ns;
145}
146
147static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
148{
149	if (ns) {
150		if (ns_ref_get(ns))
151			return ns;
152	}
153
154	return NULL;
155}
156
157extern void put_ipc_ns(struct ipc_namespace *ns);
158#else
159static inline struct ipc_namespace *copy_ipcs(u64 flags,
160	struct user_namespace *user_ns, struct ipc_namespace *ns)
161{
162	if (flags & CLONE_NEWIPC)
163		return ERR_PTR(-EINVAL);
164
165	return ns;
166}
167
168static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
169{
170	return ns;
171}
172
173static inline struct ipc_namespace *get_ipc_ns_not_zero(struct ipc_namespace *ns)
174{
175	return ns;
176}
177
178static inline void put_ipc_ns(struct ipc_namespace *ns)
179{
180}
181#endif
182
183#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
184
185void retire_mq_sysctls(struct ipc_namespace *ns);
186bool setup_mq_sysctls(struct ipc_namespace *ns);
187
188#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
189
190static inline void retire_mq_sysctls(struct ipc_namespace *ns)
191{
192}
193
194static inline bool setup_mq_sysctls(struct ipc_namespace *ns)
195{
196	return true;
197}
198
199#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
200
201#ifdef CONFIG_SYSVIPC_SYSCTL
202
203bool setup_ipc_sysctls(struct ipc_namespace *ns);
204void retire_ipc_sysctls(struct ipc_namespace *ns);
205
206#else /* CONFIG_SYSVIPC_SYSCTL */
207
208static inline void retire_ipc_sysctls(struct ipc_namespace *ns)
209{
210}
211
212static inline bool setup_ipc_sysctls(struct ipc_namespace *ns)
213{
214	return true;
215}
216
217#endif /* CONFIG_SYSVIPC_SYSCTL */
218#endif