include/linux/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.h>
  13
  14 struct user_namespace;
  15
  16 struct ipc_ids {
  17         int in_use;
  18         unsigned short seq;
  19         bool tables_initialized;
  20         struct rw_semaphore rwsem;
  21         struct idr ipcs_idr;
  22         int max_id;
  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 ns_common ns;
  72 } __randomize_layout;
  73
  74 extern struct ipc_namespace init_ipc_ns;
  75 extern spinlock_t mq_lock;
  76
  77 #ifdef CONFIG_SYSVIPC
  78 extern void shm_destroy_orphaned(struct ipc_namespace *ns);
  79 #else /* CONFIG_SYSVIPC */
  80 static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
  81 #endif /* CONFIG_SYSVIPC */
  82
  83 #ifdef CONFIG_POSIX_MQUEUE
  84 extern int mq_init_ns(struct ipc_namespace *ns);
  85 /*
  86  * POSIX Message Queue default values:
  87  *
  88  * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
  89  * DFLT_*MAX: Default values for the maximum unprivileged limits
  90  * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
  91  *   an attribute to the open call and the queue must be created
  92  * HARD_*: Highest value the maximums can be set to.  These are enforced
  93  *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
  94  *   suitably high)
  95  *
  96  * POSIX Requirements:
  97  *   Per app minimum openable message queues - 8.  This does not map well
  98  *     to the fact that we limit the number of queues on a per namespace
  99  *     basis instead of a per app basis.  So, make the default high enough
 100  *     that no given app should have a hard time opening 8 queues.
 101  *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
 102  *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
 103  *     we have run into a situation where running applications in the wild
 104  *     require this to be at least 5MB, and preferably 10MB, so I set the
 105  *     value to 16MB in hopes that this user is the worst of the bunch and
 106  *     the new maximum will handle anyone else.  I may have to revisit this
 107  *     in the future.
 108  */
 109 #define DFLT_QUEUESMAX                256
 110 #define MIN_MSGMAX                      1
 111 #define DFLT_MSG                       10U
 112 #define DFLT_MSGMAX                    10
 113 #define HARD_MSGMAX                 65536
 114 #define MIN_MSGSIZEMAX                128
 115 #define DFLT_MSGSIZE                 8192U
 116 #define DFLT_MSGSIZEMAX              8192
 117 #define HARD_MSGSIZEMAX     (16*1024*1024)
 118 #else
 119 static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 120 #endif
 121
 122 #if defined(CONFIG_IPC_NS)
 123 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
 124         struct user_namespace *user_ns, struct ipc_namespace *ns);
 125
 126 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 127 {
 128         if (ns)
 129                 refcount_inc(&ns->count);
 130         return ns;
 131 }
 132
 133 extern void put_ipc_ns(struct ipc_namespace *ns);
 134 #else
 135 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
 136         struct user_namespace *user_ns, struct ipc_namespace *ns)
 137 {
 138         if (flags & CLONE_NEWIPC)
 139                 return ERR_PTR(-EINVAL);
 140
 141         return ns;
 142 }
 143
 144 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 145 {
 146         return ns;
 147 }
 148
 149 static inline void put_ipc_ns(struct ipc_namespace *ns)
 150 {
 151 }
 152 #endif
 153
 154 #ifdef CONFIG_POSIX_MQUEUE_SYSCTL
 155
 156 struct ctl_table_header;
 157 extern struct ctl_table_header *mq_register_sysctl_table(void);
 158
 159 #else /* CONFIG_POSIX_MQUEUE_SYSCTL */
 160
 161 static inline struct ctl_table_header *mq_register_sysctl_table(void)
 162 {
 163         return NULL;
 164 }
 165
 166 #endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
 167 #endif