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         int last_idx;   /* For wrap around detection */
  23 #ifdef CONFIG_CHECKPOINT_RESTORE
  24         int next_id;
  25 #endif
  26         struct rhashtable key_ht;
  27 };
  28
  29 struct ipc_namespace {
  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 llist_node mnt_llist;
  71
  72         struct ns_common ns;
  73 } __randomize_layout;
  74
  75 extern struct ipc_namespace init_ipc_ns;
  76 extern spinlock_t mq_lock;
  77
  78 #ifdef CONFIG_SYSVIPC
  79 extern void shm_destroy_orphaned(struct ipc_namespace *ns);
  80 #else /* CONFIG_SYSVIPC */
  81 static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
  82 #endif /* CONFIG_SYSVIPC */
  83
  84 #ifdef CONFIG_POSIX_MQUEUE
  85 extern int mq_init_ns(struct ipc_namespace *ns);
  86 /*
  87  * POSIX Message Queue default values:
  88  *
  89  * MIN_*: Lowest value an admin can set the maximum unprivileged limit to
  90  * DFLT_*MAX: Default values for the maximum unprivileged limits
  91  * DFLT_{MSG,MSGSIZE}: Default values used when the user doesn't supply
  92  *   an attribute to the open call and the queue must be created
  93  * HARD_*: Highest value the maximums can be set to.  These are enforced
  94  *   on CAP_SYS_RESOURCE apps as well making them inviolate (so make them
  95  *   suitably high)
  96  *
  97  * POSIX Requirements:
  98  *   Per app minimum openable message queues - 8.  This does not map well
  99  *     to the fact that we limit the number of queues on a per namespace
 100  *     basis instead of a per app basis.  So, make the default high enough
 101  *     that no given app should have a hard time opening 8 queues.
 102  *   Minimum maximum for HARD_MSGMAX - 32767.  I bumped this to 65536.
 103  *   Minimum maximum for HARD_MSGSIZEMAX - POSIX is silent on this.  However,
 104  *     we have run into a situation where running applications in the wild
 105  *     require this to be at least 5MB, and preferably 10MB, so I set the
 106  *     value to 16MB in hopes that this user is the worst of the bunch and
 107  *     the new maximum will handle anyone else.  I may have to revisit this
 108  *     in the future.
 109  */
 110 #define DFLT_QUEUESMAX                256
 111 #define MIN_MSGMAX                      1
 112 #define DFLT_MSG                       10U
 113 #define DFLT_MSGMAX                    10
 114 #define HARD_MSGMAX                 65536
 115 #define MIN_MSGSIZEMAX                128
 116 #define DFLT_MSGSIZE                 8192U
 117 #define DFLT_MSGSIZEMAX              8192
 118 #define HARD_MSGSIZEMAX     (16*1024*1024)
 119 #else
 120 static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 121 #endif
 122
 123 #if defined(CONFIG_IPC_NS)
 124 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
 125         struct user_namespace *user_ns, struct ipc_namespace *ns);
 126
 127 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 128 {
 129         if (ns)
 130                 refcount_inc(&ns->ns.count);
 131         return ns;
 132 }
 133
 134 extern void put_ipc_ns(struct ipc_namespace *ns);
 135 #else
 136 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
 137         struct user_namespace *user_ns, struct ipc_namespace *ns)
 138 {
 139         if (flags & CLONE_NEWIPC)
 140                 return ERR_PTR(-EINVAL);
 141
 142         return ns;
 143 }
 144
 145 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 146 {
 147         return ns;
 148 }
 149
 150 static inline void put_ipc_ns(struct ipc_namespace *ns)
 151 {
 152 }
 153 #endif
 154
 155 #ifdef CONFIG_POSIX_MQUEUE_SYSCTL
 156
 157 struct ctl_table_header;
 158 extern struct ctl_table_header *mq_register_sysctl_table(void);
 159
 160 #else /* CONFIG_POSIX_MQUEUE_SYSCTL */
 161
 162 static inline struct ctl_table_header *mq_register_sysctl_table(void)
 163 {
 164         return NULL;
 165 }
 166
 167 #endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
 168 #endif