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