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