| 1 | |
| 2 | |
| 3 | * linux/ipc/util.c
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| 4 | * Copyright (C) 1992 Krishna Balasubramanian
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| 5 | *
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| 6 | * Sep 1997 - Call suser() last after "normal" permission checks so we
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| 7 | * get BSD style process accounting right.
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| 8 | * Occurs in several places in the IPC code.
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| 9 | * Chris Evans, <[email protected]>
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| 10 | * Nov 1999 - ipc helper functions, unified SMP locking
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| 11 | * Manfred Spraul <[email protected]>
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| 12 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
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| 13 | * Mingming Cao <[email protected]>
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| 14 | * Mar 2006 - support for audit of ipc object properties
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| 15 | * Dustin Kirkland <[email protected]>
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| 16 | * Jun 2006 - namespaces ssupport
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| 17 | * OpenVZ, SWsoft Inc.
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| 18 | * Pavel Emelianov <[email protected]>
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| 19 | *
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| 20 | * General sysv ipc locking scheme:
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| 21 | * rcu_read_lock()
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| 22 | * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr
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| 23 | * tree.
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| 24 | * - perform initial checks (capabilities, auditing and permission,
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| 25 | * etc).
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| 26 | * - perform read-only operations, such as INFO command, that
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| 27 | * do not demand atomicity
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| 28 | * acquire the ipc lock (kern_ipc_perm.lock) through
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| 29 | * ipc_lock_object()
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| 30 | * - perform read-only operations that demand atomicity,
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| 31 | * such as STAT command.
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| 32 | * - perform data updates, such as SET, RMID commands and
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| 33 | * mechanism-specific operations (semop/semtimedop,
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| 34 | * msgsnd/msgrcv, shmat/shmdt).
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| 35 | * drop the ipc lock, through ipc_unlock_object().
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| 36 | * rcu_read_unlock()
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| 37 | *
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| 38 | * The ids->rwsem must be taken when:
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| 39 | * - creating, removing and iterating the existing entries in ipc
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| 40 | * identifier sets.
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| 41 | * - iterating through files under /proc/sysvipc/
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| 42 | *
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| 43 | * Note that sems have a special fast path that avoids kern_ipc_perm.lock -
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| 44 | * see sem_lock().
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| 45 |
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| 46 |
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| 47 | #include <linux/mm.h>
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| 48 | #include <linux/shm.h>
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| 49 | #include <linux/init.h>
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| 50 | #include <linux/msg.h>
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| 51 | #include <linux/vmalloc.h>
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| 52 | #include <linux/slab.h>
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| 53 | #include <linux/notifier.h>
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| 54 | #include <linux/capability.h>
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| 55 | #include <linux/highuid.h>
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| 56 | #include <linux/security.h>
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| 57 | #include <linux/rcupdate.h>
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| 58 | #include <linux/workqueue.h>
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| 59 | #include <linux/seq_file.h>
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| 60 | #include <linux/proc_fs.h>
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| 61 | #include <linux/audit.h>
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| 62 | #include <linux/nsproxy.h>
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| 63 | #include <linux/rwsem.h>
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| 64 | #include <linux/memory.h>
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| 65 | #include <linux/ipc_namespace.h>
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| 66 | #include <linux/rhashtable.h>
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| 67 | #include <linux/log2.h>
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| 68 |
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| 69 | #include <asm/unistd.h>
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| 70 |
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| 71 | #include "util.h"
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| 72 |
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| 73 | struct ipc_proc_iface {
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| 74 | const char *path;
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| 75 | const char *header;
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| 76 | int ids;
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| 77 | int (*show)(struct seq_file *, void *);
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| 78 | };
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| 79 |
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| 80 | |
| 81 | * ipc_init - initialise ipc subsystem
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| 82 | *
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| 83 | * The various sysv ipc resources (semaphores, messages and shared
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| 84 | * memory) are initialised.
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| 85 | *
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| 86 | * A callback routine is registered into the memory hotplug notifier
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| 87 | * chain: since msgmni scales to lowmem this callback routine will be
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| 88 | * called upon successful memory add / remove to recompute msmgni.
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| 89 |
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| 90 | static int __init ipc_init(void)
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| 91 | {
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| 92 | proc_mkdir("sysvipc", NULL);
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| 93 | sem_init();
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| 94 | msg_init();
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| 95 | shm_init();
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| 96 |
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| 97 | return 0;
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| 98 | }
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| 99 | device_initcall(ipc_init);
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| 100 |
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| 101 | static const struct rhashtable_params ipc_kht_params = {
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| 102 | .head_offset = offsetof(struct kern_ipc_perm, khtnode),
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| 103 | .key_offset = offsetof(struct kern_ipc_perm, key),
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| 104 | .key_len = sizeof_field(struct kern_ipc_perm, key),
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| 105 | .automatic_shrinking = true,
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| 106 | };
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| 107 |
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| 108 | |
| 109 | * ipc_init_ids - initialise ipc identifiers
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| 110 | * @ids: ipc identifier set
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| 111 | *
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| 112 | * Set up the sequence range to use for the ipc identifier range (limited
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| 113 | * below ipc_mni) then initialise the keys hashtable and ids idr.
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| 114 |
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| 115 | void ipc_init_ids(struct ipc_ids *ids)
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| 116 | {
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| 117 | ids->in_use = 0;
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| 118 | ids->seq = 0;
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| 119 | init_rwsem(&ids->rwsem);
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| 120 | rhashtable_init(&ids->key_ht, &ipc_kht_params);
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| 121 | idr_init(&ids->ipcs_idr);
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| 122 | ids->max_idx = -1;
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| 123 | ids->last_idx = -1;
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| 124 | #ifdef CONFIG_CHECKPOINT_RESTORE
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| 125 | ids->next_id = -1;
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| 126 | #endif
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| 127 | }
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| 128 |
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| 129 | #ifdef CONFIG_PROC_FS
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| 130 | static const struct proc_ops sysvipc_proc_ops;
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| 131 | |
| 132 | * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
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| 133 | * @path: Path in procfs
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| 134 | * @header: Banner to be printed at the beginning of the file.
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| 135 | * @ids: ipc id table to iterate.
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| 136 | * @show: show routine.
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| 137 |
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| 138 | void __init ipc_init_proc_interface(const char *path, const char *header,
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| 139 | int ids, int (*show)(struct seq_file *, void *))
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| 140 | {
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| 141 | struct proc_dir_entry *pde;
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| 142 | struct ipc_proc_iface *iface;
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| 143 |
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| 144 | iface = kmalloc_obj(*iface);
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| 145 | if (!iface)
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| 146 | return;
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| 147 | iface->path = path;
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| 148 | iface->header = header;
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| 149 | iface->ids = ids;
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| 150 | iface->show = show;
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| 151 |
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| 152 | pde = proc_create_data(path,
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| 153 | S_IRUGO,
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| 154 | NULL,
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| 155 | &sysvipc_proc_ops,
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| 156 | iface);
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| 157 | if (!pde)
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| 158 | kfree(iface);
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| 159 | }
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| 160 | #endif
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| 161 |
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| 162 | |
| 163 | * ipc_findkey - find a key in an ipc identifier set
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| 164 | * @ids: ipc identifier set
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| 165 | * @key: key to find
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| 166 | *
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| 167 | * Returns the locked pointer to the ipc structure if found or NULL
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| 168 | * otherwise. If key is found ipc points to the owning ipc structure
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| 169 | *
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| 170 | * Called with writer ipc_ids.rwsem held.
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| 171 |
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| 172 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
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| 173 | {
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| 174 | struct kern_ipc_perm *ipcp;
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| 175 |
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| 176 | ipcp = rhashtable_lookup_fast(&ids->key_ht, &key,
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| 177 | ipc_kht_params);
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| 178 | if (!ipcp)
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| 179 | return NULL;
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| 180 |
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| 181 | rcu_read_lock();
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| 182 | ipc_lock_object(ipcp);
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| 183 | return ipcp;
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| 184 | }
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| 185 |
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| 186 | |
| 187 | * Insert new IPC object into idr tree, and set sequence number and id
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| 188 | * in the correct order.
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| 189 | * Especially:
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| 190 | * - the sequence number must be set before inserting the object into the idr,
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| 191 | * because the sequence number is accessed without a lock.
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| 192 | * - the id can/must be set after inserting the object into the idr.
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| 193 | * All accesses must be done after getting kern_ipc_perm.lock.
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| 194 | *
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| 195 | * The caller must own kern_ipc_perm.lock.of the new object.
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| 196 | * On error, the function returns a (negative) error code.
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| 197 | *
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| 198 | * To conserve sequence number space, especially with extended ipc_mni,
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| 199 | * the sequence number is incremented only when the returned ID is less than
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| 200 | * the last one.
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| 201 |
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| 202 | static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
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| 203 | {
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| 204 | int idx, next_id = -1;
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| 205 |
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| 206 | #ifdef CONFIG_CHECKPOINT_RESTORE
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| 207 | next_id = ids->next_id;
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| 208 | ids->next_id = -1;
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| 209 | #endif
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| 210 |
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| 211 | |
| 212 | * As soon as a new object is inserted into the idr,
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| 213 | * ipc_obtain_object_idr() or ipc_obtain_object_check() can find it,
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| 214 | * and the lockless preparations for ipc operations can start.
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| 215 | * This means especially: permission checks, audit calls, allocation
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| 216 | * of undo structures, ...
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| 217 | *
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| 218 | * Thus the object must be fully initialized, and if something fails,
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| 219 | * then the full tear-down sequence must be followed.
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| 220 | * (i.e.: set new->deleted, reduce refcount, call_rcu())
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| 221 |
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| 222 |
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| 223 | if (next_id < 0) {
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| 224 | int max_idx;
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| 225 |
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| 226 | max_idx = max(ids->in_use*3/2, ipc_min_cycle);
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| 227 | max_idx = min(max_idx, ipc_mni);
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| 228 |
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| 229 |
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| 230 | idx = idr_alloc_cyclic(&ids->ipcs_idr, NULL, 0, max_idx,
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| 231 | GFP_NOWAIT);
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| 232 |
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| 233 | if (idx >= 0) {
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| 234 | |
| 235 | * idx got allocated successfully.
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| 236 | * Now calculate the sequence number and set the
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| 237 | * pointer for real.
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| 238 |
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| 239 | if (idx <= ids->last_idx) {
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| 240 | ids->seq++;
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| 241 | if (ids->seq >= ipcid_seq_max())
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| 242 | ids->seq = 0;
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| 243 | }
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| 244 | ids->last_idx = idx;
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| 245 |
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| 246 | new->seq = ids->seq;
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| 247 | |
| 248 | * inside idr_replace, as part of
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| 249 | * rcu_assign_pointer
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| 250 |
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| 251 | idr_replace(&ids->ipcs_idr, new, idx);
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| 252 | }
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| 253 | } else {
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| 254 | new->seq = ipcid_to_seqx(next_id);
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| 255 | idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id),
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| 256 | 0, GFP_NOWAIT);
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| 257 | }
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| 258 | if (idx >= 0)
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| 259 | new->id = (new->seq << ipcmni_seq_shift()) + idx;
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| 260 | return idx;
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| 261 | }
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| 262 |
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| 263 | |
| 264 | * ipc_addid - add an ipc identifier
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| 265 | * @ids: ipc identifier set
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| 266 | * @new: new ipc permission set
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| 267 | * @limit: limit for the number of used ids
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| 268 | *
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| 269 | * Add an entry 'new' to the ipc ids idr. The permissions object is
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| 270 | * initialised and the first free entry is set up and the index assigned
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| 271 | * is returned. The 'new' entry is returned in a locked state on success.
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| 272 | *
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| 273 | * On failure the entry is not locked and a negative err-code is returned.
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| 274 | * The caller must use ipc_rcu_putref() to free the identifier.
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| 275 | *
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| 276 | * Called with writer ipc_ids.rwsem held.
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| 277 |
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| 278 | int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
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| 279 | {
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| 280 | kuid_t euid;
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| 281 | kgid_t egid;
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| 282 | int idx, err;
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| 283 |
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| 284 |
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| 285 | refcount_set(&new->refcount, 1);
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| 286 |
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| 287 | if (limit > ipc_mni)
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| 288 | limit = ipc_mni;
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| 289 |
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| 290 | if (ids->in_use >= limit)
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| 291 | return -ENOSPC;
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| 292 |
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| 293 | idr_preload(GFP_KERNEL);
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| 294 |
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| 295 | spin_lock_init(&new->lock);
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| 296 | rcu_read_lock();
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| 297 | spin_lock(&new->lock);
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| 298 |
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| 299 | current_euid_egid(&euid, &egid);
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| 300 | new->cuid = new->uid = euid;
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| 301 | new->gid = new->cgid = egid;
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| 302 |
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| 303 | new->deleted = false;
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| 304 |
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| 305 | idx = ipc_idr_alloc(ids, new);
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| 306 | idr_preload_end();
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| 307 |
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| 308 | if (idx >= 0 && new->key != IPC_PRIVATE) {
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| 309 | err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode,
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| 310 | ipc_kht_params);
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| 311 | if (err < 0) {
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| 312 | idr_remove(&ids->ipcs_idr, idx);
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| 313 | idx = err;
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| 314 | }
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| 315 | }
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| 316 | if (idx < 0) {
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| 317 | new->deleted = true;
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| 318 | spin_unlock(&new->lock);
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| 319 | rcu_read_unlock();
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| 320 | return idx;
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| 321 | }
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| 322 |
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| 323 | ids->in_use++;
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| 324 | if (idx > ids->max_idx)
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| 325 | ids->max_idx = idx;
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| 326 | return idx;
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| 327 | }
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| 328 |
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| 329 | |
| 330 | * ipcget_new - create a new ipc object
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| 331 | * @ns: ipc namespace
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| 332 | * @ids: ipc identifier set
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| 333 | * @ops: the actual creation routine to call
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| 334 | * @params: its parameters
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| 335 | *
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| 336 | * This routine is called by sys_msgget, sys_semget() and sys_shmget()
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| 337 | * when the key is IPC_PRIVATE.
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| 338 |
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| 339 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
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| 340 | const struct ipc_ops *ops, struct ipc_params *params)
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| 341 | {
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| 342 | int err;
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| 343 |
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| 344 | down_write(&ids->rwsem);
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| 345 | err = ops->getnew(ns, params);
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| 346 | up_write(&ids->rwsem);
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| 347 | return err;
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| 348 | }
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| 349 |
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| 350 | |
| 351 | * ipc_check_perms - check security and permissions for an ipc object
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| 352 | * @ns: ipc namespace
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| 353 | * @ipcp: ipc permission set
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| 354 | * @ops: the actual security routine to call
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| 355 | * @params: its parameters
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| 356 | *
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| 357 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
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| 358 | * when the key is not IPC_PRIVATE and that key already exists in the
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| 359 | * ds IDR.
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| 360 | *
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| 361 | * On success, the ipc id is returned.
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| 362 | *
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| 363 | * It is called with ipc_ids.rwsem and ipcp->lock held.
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| 364 |
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| 365 | static int ipc_check_perms(struct ipc_namespace *ns,
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| 366 | struct kern_ipc_perm *ipcp,
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| 367 | const struct ipc_ops *ops,
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| 368 | struct ipc_params *params)
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| 369 | {
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| 370 | int err;
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| 371 |
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| 372 | if (ipcperms(ns, ipcp, params->flg))
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| 373 | err = -EACCES;
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| 374 | else {
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| 375 | err = ops->associate(ipcp, params->flg);
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| 376 | if (!err)
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| 377 | err = ipcp->id;
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| 378 | }
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| 379 |
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| 380 | return err;
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| 381 | }
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| 382 |
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| 383 | |
| 384 | * ipcget_public - get an ipc object or create a new one
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| 385 | * @ns: ipc namespace
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| 386 | * @ids: ipc identifier set
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| 387 | * @ops: the actual creation routine to call
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| 388 | * @params: its parameters
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| 389 | *
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| 390 | * This routine is called by sys_msgget, sys_semget() and sys_shmget()
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| 391 | * when the key is not IPC_PRIVATE.
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| 392 | * It adds a new entry if the key is not found and does some permission
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| 393 | * / security checkings if the key is found.
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| 394 | *
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| 395 | * On success, the ipc id is returned.
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| 396 |
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| 397 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
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| 398 | const struct ipc_ops *ops, struct ipc_params *params)
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| 399 | {
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| 400 | struct kern_ipc_perm *ipcp;
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| 401 | int flg = params->flg;
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| 402 | int err;
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| 403 |
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| 404 | |
| 405 | * Take the lock as a writer since we are potentially going to add
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| 406 | * a new entry + read locks are not "upgradable"
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| 407 |
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| 408 | down_write(&ids->rwsem);
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| 409 | ipcp = ipc_findkey(ids, params->key);
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| 410 | if (ipcp == NULL) {
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| 411 |
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| 412 | if (!(flg & IPC_CREAT))
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| 413 | err = -ENOENT;
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| 414 | else
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| 415 | err = ops->getnew(ns, params);
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| 416 | } else {
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| 417 |
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| 418 |
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| 419 | if (flg & IPC_CREAT && flg & IPC_EXCL)
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| 420 | err = -EEXIST;
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| 421 | else {
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| 422 | err = 0;
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| 423 | if (ops->more_checks)
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| 424 | err = ops->more_checks(ipcp, params);
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| 425 | if (!err)
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| 426 | |
| 427 | * ipc_check_perms returns the IPC id on
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| 428 | * success
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| 429 |
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| 430 | err = ipc_check_perms(ns, ipcp, ops, params);
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| 431 | }
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| 432 | ipc_unlock(ipcp);
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| 433 | }
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| 434 | up_write(&ids->rwsem);
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| 435 |
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| 436 | return err;
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| 437 | }
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| 438 |
|
| 439 | |
| 440 | * ipc_kht_remove - remove an ipc from the key hashtable
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| 441 | * @ids: ipc identifier set
|
| 442 | * @ipcp: ipc perm structure containing the key to remove
|
| 443 | *
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| 444 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
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| 445 | * before this function is called, and remain locked on the exit.
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| 446 |
|
| 447 | static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
|
| 448 | {
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| 449 | if (ipcp->key != IPC_PRIVATE)
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| 450 | WARN_ON_ONCE(rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
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| 451 | ipc_kht_params));
|
| 452 | }
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| 453 |
|
| 454 | |
| 455 | * ipc_search_maxidx - search for the highest assigned index
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| 456 | * @ids: ipc identifier set
|
| 457 | * @limit: known upper limit for highest assigned index
|
| 458 | *
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| 459 | * The function determines the highest assigned index in @ids. It is intended
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| 460 | * to be called when ids->max_idx needs to be updated.
|
| 461 | * Updating ids->max_idx is necessary when the current highest index ipc
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| 462 | * object is deleted.
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| 463 | * If no ipc object is allocated, then -1 is returned.
|
| 464 | *
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| 465 | * ipc_ids.rwsem needs to be held by the caller.
|
| 466 |
|
| 467 | static int ipc_search_maxidx(struct ipc_ids *ids, int limit)
|
| 468 | {
|
| 469 | int tmpidx;
|
| 470 | int i;
|
| 471 | int retval;
|
| 472 |
|
| 473 | i = ilog2(limit+1);
|
| 474 |
|
| 475 | retval = 0;
|
| 476 | for (; i >= 0; i--) {
|
| 477 | tmpidx = retval | (1<<i);
|
| 478 | |
| 479 | * "0" is a possible index value, thus search using
|
| 480 | * e.g. 15,7,3,1,0 instead of 16,8,4,2,1.
|
| 481 |
|
| 482 | tmpidx = tmpidx-1;
|
| 483 | if (idr_get_next(&ids->ipcs_idr, &tmpidx))
|
| 484 | retval |= (1<<i);
|
| 485 | }
|
| 486 | return retval - 1;
|
| 487 | }
|
| 488 |
|
| 489 | |
| 490 | * ipc_rmid - remove an ipc identifier
|
| 491 | * @ids: ipc identifier set
|
| 492 | * @ipcp: ipc perm structure containing the identifier to remove
|
| 493 | *
|
| 494 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
|
| 495 | * before this function is called, and remain locked on the exit.
|
| 496 |
|
| 497 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
|
| 498 | {
|
| 499 | int idx = ipcid_to_idx(ipcp->id);
|
| 500 |
|
| 501 | WARN_ON_ONCE(idr_remove(&ids->ipcs_idr, idx) != ipcp);
|
| 502 | ipc_kht_remove(ids, ipcp);
|
| 503 | ids->in_use--;
|
| 504 | ipcp->deleted = true;
|
| 505 |
|
| 506 | if (unlikely(idx == ids->max_idx)) {
|
| 507 | idx = ids->max_idx-1;
|
| 508 | if (idx >= 0)
|
| 509 | idx = ipc_search_maxidx(ids, idx);
|
| 510 | ids->max_idx = idx;
|
| 511 | }
|
| 512 | }
|
| 513 |
|
| 514 | |
| 515 | * ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE
|
| 516 | * @ids: ipc identifier set
|
| 517 | * @ipcp: ipc perm structure containing the key to modify
|
| 518 | *
|
| 519 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
|
| 520 | * before this function is called, and remain locked on the exit.
|
| 521 |
|
| 522 | void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
|
| 523 | {
|
| 524 | ipc_kht_remove(ids, ipcp);
|
| 525 | ipcp->key = IPC_PRIVATE;
|
| 526 | }
|
| 527 |
|
| 528 | bool ipc_rcu_getref(struct kern_ipc_perm *ptr)
|
| 529 | {
|
| 530 | return refcount_inc_not_zero(&ptr->refcount);
|
| 531 | }
|
| 532 |
|
| 533 | void ipc_rcu_putref(struct kern_ipc_perm *ptr,
|
| 534 | void (*func)(struct rcu_head *head))
|
| 535 | {
|
| 536 | if (!refcount_dec_and_test(&ptr->refcount))
|
| 537 | return;
|
| 538 |
|
| 539 | call_rcu(&ptr->rcu, func);
|
| 540 | }
|
| 541 |
|
| 542 | |
| 543 | * ipcperms - check ipc permissions
|
| 544 | * @ns: ipc namespace
|
| 545 | * @ipcp: ipc permission set
|
| 546 | * @flag: desired permission set
|
| 547 | *
|
| 548 | * Check user, group, other permissions for access
|
| 549 | * to ipc resources. return 0 if allowed
|
| 550 | *
|
| 551 | * @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h>
|
| 552 |
|
| 553 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
|
| 554 | {
|
| 555 | kuid_t euid = current_euid();
|
| 556 | int requested_mode, granted_mode;
|
| 557 |
|
| 558 | audit_ipc_obj(ipcp);
|
| 559 | requested_mode = (flag >> 6) | (flag >> 3) | flag;
|
| 560 | granted_mode = ipcp->mode;
|
| 561 | if (uid_eq(euid, ipcp->cuid) ||
|
| 562 | uid_eq(euid, ipcp->uid))
|
| 563 | granted_mode >>= 6;
|
| 564 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
|
| 565 | granted_mode >>= 3;
|
| 566 |
|
| 567 | if ((requested_mode & ~granted_mode & 0007) &&
|
| 568 | !ns_capable(ns->user_ns, CAP_IPC_OWNER))
|
| 569 | return -1;
|
| 570 |
|
| 571 | return security_ipc_permission(ipcp, flag);
|
| 572 | }
|
| 573 |
|
| 574 | |
| 575 | * Functions to convert between the kern_ipc_perm structure and the
|
| 576 | * old/new ipc_perm structures
|
| 577 |
|
| 578 |
|
| 579 | |
| 580 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user
|
| 581 | * @in: kernel permissions
|
| 582 | * @out: new style ipc permissions
|
| 583 | *
|
| 584 | * Turn the kernel object @in into a set of permissions descriptions
|
| 585 | * for returning to userspace (@out).
|
| 586 |
|
| 587 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out)
|
| 588 | {
|
| 589 | out->key = in->key;
|
| 590 | out->uid = from_kuid_munged(current_user_ns(), in->uid);
|
| 591 | out->gid = from_kgid_munged(current_user_ns(), in->gid);
|
| 592 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
|
| 593 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
|
| 594 | out->mode = in->mode;
|
| 595 | out->seq = in->seq;
|
| 596 | }
|
| 597 |
|
| 598 | |
| 599 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
|
| 600 | * @in: new style ipc permissions
|
| 601 | * @out: old style ipc permissions
|
| 602 | *
|
| 603 | * Turn the new style permissions object @in into a compatibility
|
| 604 | * object and store it into the @out pointer.
|
| 605 |
|
| 606 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
|
| 607 | {
|
| 608 | out->key = in->key;
|
| 609 | SET_UID(out->uid, in->uid);
|
| 610 | SET_GID(out->gid, in->gid);
|
| 611 | SET_UID(out->cuid, in->cuid);
|
| 612 | SET_GID(out->cgid, in->cgid);
|
| 613 | out->mode = in->mode;
|
| 614 | out->seq = in->seq;
|
| 615 | }
|
| 616 |
|
| 617 | |
| 618 | * ipc_obtain_object_idr - Look for an id in the ipc ids idr and
|
| 619 | * return associated ipc object.
|
| 620 | * @ids: ipc identifier set
|
| 621 | * @id: ipc id to look for
|
| 622 | *
|
| 623 | * Call inside the RCU critical section.
|
| 624 | * The ipc object is *not* locked on exit.
|
| 625 |
|
| 626 | struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id)
|
| 627 | {
|
| 628 | struct kern_ipc_perm *out;
|
| 629 | int idx = ipcid_to_idx(id);
|
| 630 |
|
| 631 | out = idr_find(&ids->ipcs_idr, idx);
|
| 632 | if (!out)
|
| 633 | return ERR_PTR(-EINVAL);
|
| 634 |
|
| 635 | return out;
|
| 636 | }
|
| 637 |
|
| 638 | |
| 639 | * ipc_obtain_object_check - Similar to ipc_obtain_object_idr() but
|
| 640 | * also checks the ipc object sequence number.
|
| 641 | * @ids: ipc identifier set
|
| 642 | * @id: ipc id to look for
|
| 643 | *
|
| 644 | * Call inside the RCU critical section.
|
| 645 | * The ipc object is *not* locked on exit.
|
| 646 |
|
| 647 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
|
| 648 | {
|
| 649 | struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id);
|
| 650 |
|
| 651 | if (IS_ERR(out))
|
| 652 | goto out;
|
| 653 |
|
| 654 | if (ipc_checkid(out, id))
|
| 655 | return ERR_PTR(-EINVAL);
|
| 656 | out:
|
| 657 | return out;
|
| 658 | }
|
| 659 |
|
| 660 | |
| 661 | * ipcget - Common sys_*get() code
|
| 662 | * @ns: namespace
|
| 663 | * @ids: ipc identifier set
|
| 664 | * @ops: operations to be called on ipc object creation, permission checks
|
| 665 | * and further checks
|
| 666 | * @params: the parameters needed by the previous operations.
|
| 667 | *
|
| 668 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
|
| 669 |
|
| 670 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
|
| 671 | const struct ipc_ops *ops, struct ipc_params *params)
|
| 672 | {
|
| 673 | if (params->key == IPC_PRIVATE)
|
| 674 | return ipcget_new(ns, ids, ops, params);
|
| 675 | else
|
| 676 | return ipcget_public(ns, ids, ops, params);
|
| 677 | }
|
| 678 |
|
| 679 | |
| 680 | * ipc_update_perm - update the permissions of an ipc object
|
| 681 | * @in: the permission given as input.
|
| 682 | * @out: the permission of the ipc to set.
|
| 683 |
|
| 684 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
|
| 685 | {
|
| 686 | kuid_t uid = make_kuid(current_user_ns(), in->uid);
|
| 687 | kgid_t gid = make_kgid(current_user_ns(), in->gid);
|
| 688 | if (!uid_valid(uid) || !gid_valid(gid))
|
| 689 | return -EINVAL;
|
| 690 |
|
| 691 | out->uid = uid;
|
| 692 | out->gid = gid;
|
| 693 | out->mode = (out->mode & ~S_IRWXUGO)
|
| 694 | | (in->mode & S_IRWXUGO);
|
| 695 |
|
| 696 | return 0;
|
| 697 | }
|
| 698 |
|
| 699 | |
| 700 | * ipcctl_obtain_check - retrieve an ipc object and check permissions
|
| 701 | * @ns: ipc namespace
|
| 702 | * @ids: the table of ids where to look for the ipc
|
| 703 | * @id: the id of the ipc to retrieve
|
| 704 | * @cmd: the cmd to check
|
| 705 | * @perm: the permission to set
|
| 706 | * @extra_perm: one extra permission parameter used by msq
|
| 707 | *
|
| 708 | * This function does some common audit and permissions check for some IPC_XXX
|
| 709 | * cmd and is called from semctl_down, shmctl_down and msgctl_down.
|
| 710 | *
|
| 711 | * It:
|
| 712 | * - retrieves the ipc object with the given id in the given table.
|
| 713 | * - performs some audit and permission check, depending on the given cmd
|
| 714 | * - returns a pointer to the ipc object or otherwise, the corresponding
|
| 715 | * error.
|
| 716 | *
|
| 717 | * Call holding the both the rwsem and the rcu read lock.
|
| 718 |
|
| 719 | struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
|
| 720 | struct ipc_ids *ids, int id, int cmd,
|
| 721 | struct ipc64_perm *perm, int extra_perm)
|
| 722 | {
|
| 723 | kuid_t euid;
|
| 724 | int err = -EPERM;
|
| 725 | struct kern_ipc_perm *ipcp;
|
| 726 |
|
| 727 | ipcp = ipc_obtain_object_check(ids, id);
|
| 728 | if (IS_ERR(ipcp)) {
|
| 729 | err = PTR_ERR(ipcp);
|
| 730 | goto err;
|
| 731 | }
|
| 732 |
|
| 733 | audit_ipc_obj(ipcp);
|
| 734 | if (cmd == IPC_SET)
|
| 735 | audit_ipc_set_perm(extra_perm, perm->uid,
|
| 736 | perm->gid, perm->mode);
|
| 737 |
|
| 738 | euid = current_euid();
|
| 739 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
|
| 740 | ns_capable(ns->user_ns, CAP_SYS_ADMIN))
|
| 741 | return ipcp;
|
| 742 | err:
|
| 743 | return ERR_PTR(err);
|
| 744 | }
|
| 745 |
|
| 746 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
|
| 747 |
|
| 748 |
|
| 749 | |
| 750 | * ipc_parse_version - ipc call version
|
| 751 | * @cmd: pointer to command
|
| 752 | *
|
| 753 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
|
| 754 | * The @cmd value is turned from an encoding command and version into
|
| 755 | * just the command code.
|
| 756 |
|
| 757 | int ipc_parse_version(int *cmd)
|
| 758 | {
|
| 759 | if (*cmd & IPC_64) {
|
| 760 | *cmd ^= IPC_64;
|
| 761 | return IPC_64;
|
| 762 | } else {
|
| 763 | return IPC_OLD;
|
| 764 | }
|
| 765 | }
|
| 766 |
|
| 767 | #endif
|
| 768 |
|
| 769 | #ifdef CONFIG_PROC_FS
|
| 770 | struct ipc_proc_iter {
|
| 771 | struct ipc_namespace *ns;
|
| 772 | struct pid_namespace *pid_ns;
|
| 773 | struct ipc_proc_iface *iface;
|
| 774 | };
|
| 775 |
|
| 776 | struct pid_namespace *ipc_seq_pid_ns(struct seq_file *s)
|
| 777 | {
|
| 778 | struct ipc_proc_iter *iter = s->private;
|
| 779 | return iter->pid_ns;
|
| 780 | }
|
| 781 |
|
| 782 | |
| 783 | * sysvipc_find_ipc - Find and lock the ipc structure based on seq pos
|
| 784 | * @ids: ipc identifier set
|
| 785 | * @pos: expected position
|
| 786 | *
|
| 787 | * The function finds an ipc structure, based on the sequence file
|
| 788 | * position @pos. If there is no ipc structure at position @pos, then
|
| 789 | * the successor is selected.
|
| 790 | * If a structure is found, then it is locked (both rcu_read_lock() and
|
| 791 | * ipc_lock_object()) and @pos is set to the position needed to locate
|
| 792 | * the found ipc structure.
|
| 793 | * If nothing is found (i.e. EOF), @pos is not modified.
|
| 794 | *
|
| 795 | * The function returns the found ipc structure, or NULL at EOF.
|
| 796 |
|
| 797 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t *pos)
|
| 798 | {
|
| 799 | int tmpidx;
|
| 800 | struct kern_ipc_perm *ipc;
|
| 801 |
|
| 802 |
|
| 803 | tmpidx = *pos - 1;
|
| 804 |
|
| 805 | ipc = idr_get_next(&ids->ipcs_idr, &tmpidx);
|
| 806 | if (ipc != NULL) {
|
| 807 | rcu_read_lock();
|
| 808 | ipc_lock_object(ipc);
|
| 809 |
|
| 810 |
|
| 811 | *pos = tmpidx + 1;
|
| 812 | }
|
| 813 | return ipc;
|
| 814 | }
|
| 815 |
|
| 816 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
|
| 817 | {
|
| 818 | struct ipc_proc_iter *iter = s->private;
|
| 819 | struct ipc_proc_iface *iface = iter->iface;
|
| 820 | struct kern_ipc_perm *ipc = it;
|
| 821 |
|
| 822 |
|
| 823 | if (ipc && ipc != SEQ_START_TOKEN)
|
| 824 | ipc_unlock(ipc);
|
| 825 |
|
| 826 |
|
| 827 | (*pos)++;
|
| 828 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], pos);
|
| 829 | }
|
| 830 |
|
| 831 | |
| 832 | * File positions: pos 0 -> header, pos n -> ipc idx = n - 1.
|
| 833 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
|
| 834 |
|
| 835 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
|
| 836 | {
|
| 837 | struct ipc_proc_iter *iter = s->private;
|
| 838 | struct ipc_proc_iface *iface = iter->iface;
|
| 839 | struct ipc_ids *ids;
|
| 840 |
|
| 841 | ids = &iter->ns->ids[iface->ids];
|
| 842 |
|
| 843 | |
| 844 | * Take the lock - this will be released by the corresponding
|
| 845 | * call to stop().
|
| 846 |
|
| 847 | down_read(&ids->rwsem);
|
| 848 |
|
| 849 |
|
| 850 | if (*pos < 0)
|
| 851 | return NULL;
|
| 852 |
|
| 853 |
|
| 854 | if (*pos == 0)
|
| 855 | return SEQ_START_TOKEN;
|
| 856 |
|
| 857 |
|
| 858 | return sysvipc_find_ipc(ids, pos);
|
| 859 | }
|
| 860 |
|
| 861 | static void sysvipc_proc_stop(struct seq_file *s, void *it)
|
| 862 | {
|
| 863 | struct kern_ipc_perm *ipc = it;
|
| 864 | struct ipc_proc_iter *iter = s->private;
|
| 865 | struct ipc_proc_iface *iface = iter->iface;
|
| 866 | struct ipc_ids *ids;
|
| 867 |
|
| 868 |
|
| 869 | if (ipc && ipc != SEQ_START_TOKEN)
|
| 870 | ipc_unlock(ipc);
|
| 871 |
|
| 872 | ids = &iter->ns->ids[iface->ids];
|
| 873 |
|
| 874 | up_read(&ids->rwsem);
|
| 875 | }
|
| 876 |
|
| 877 | static int sysvipc_proc_show(struct seq_file *s, void *it)
|
| 878 | {
|
| 879 | struct ipc_proc_iter *iter = s->private;
|
| 880 | struct ipc_proc_iface *iface = iter->iface;
|
| 881 |
|
| 882 | if (it == SEQ_START_TOKEN) {
|
| 883 | seq_puts(s, iface->header);
|
| 884 | return 0;
|
| 885 | }
|
| 886 |
|
| 887 | return iface->show(s, it);
|
| 888 | }
|
| 889 |
|
| 890 | static const struct seq_operations sysvipc_proc_seqops = {
|
| 891 | .start = sysvipc_proc_start,
|
| 892 | .stop = sysvipc_proc_stop,
|
| 893 | .next = sysvipc_proc_next,
|
| 894 | .show = sysvipc_proc_show,
|
| 895 | };
|
| 896 |
|
| 897 | static int sysvipc_proc_open(struct inode *inode, struct file *file)
|
| 898 | {
|
| 899 | struct ipc_proc_iter *iter;
|
| 900 |
|
| 901 | iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter));
|
| 902 | if (!iter)
|
| 903 | return -ENOMEM;
|
| 904 |
|
| 905 | iter->iface = pde_data(inode);
|
| 906 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
|
| 907 | iter->pid_ns = get_pid_ns(task_active_pid_ns(current));
|
| 908 |
|
| 909 | return 0;
|
| 910 | }
|
| 911 |
|
| 912 | static int sysvipc_proc_release(struct inode *inode, struct file *file)
|
| 913 | {
|
| 914 | struct seq_file *seq = file->private_data;
|
| 915 | struct ipc_proc_iter *iter = seq->private;
|
| 916 | put_ipc_ns(iter->ns);
|
| 917 | put_pid_ns(iter->pid_ns);
|
| 918 | return seq_release_private(inode, file);
|
| 919 | }
|
| 920 |
|
| 921 | static const struct proc_ops sysvipc_proc_ops = {
|
| 922 | .proc_flags = PROC_ENTRY_PERMANENT,
|
| 923 | .proc_open = sysvipc_proc_open,
|
| 924 | .proc_read = seq_read,
|
| 925 | .proc_lseek = seq_lseek,
|
| 926 | .proc_release = sysvipc_proc_release,
|
| 927 | };
|
| 928 | #endif
|