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![Pierre Peiffer](/assets/img/avatar_default.png)
With the use of idr to store the ipc, the case where the idr cache is empty, when idr_get_new is called (this may happen even if we call idr_pre_get() before), is not well handled: it lets semget()/shmget()/msgget() return ENOSPC when this cache is empty, what 1. does not reflect the facts and 2. does not conform to the man(s). This patch fixes this by retrying the whole process of allocation in this case. Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
952 lines
21 KiB
C
952 lines
21 KiB
C
/*
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* linux/ipc/util.c
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* Copyright (C) 1992 Krishna Balasubramanian
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*
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* Sep 1997 - Call suser() last after "normal" permission checks so we
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* get BSD style process accounting right.
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* Occurs in several places in the IPC code.
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* Chris Evans, <chris@ferret.lmh.ox.ac.uk>
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* Nov 1999 - ipc helper functions, unified SMP locking
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* Manfred Spraul <manfred@colorfullife.com>
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* Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
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* Mingming Cao <cmm@us.ibm.com>
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* Mar 2006 - support for audit of ipc object properties
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* Dustin Kirkland <dustin.kirkland@us.ibm.com>
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* Jun 2006 - namespaces ssupport
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* OpenVZ, SWsoft Inc.
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* Pavel Emelianov <xemul@openvz.org>
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*/
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#include <linux/mm.h>
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#include <linux/shm.h>
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#include <linux/init.h>
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#include <linux/msg.h>
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#include <linux/vmalloc.h>
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#include <linux/slab.h>
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#include <linux/capability.h>
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#include <linux/highuid.h>
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#include <linux/security.h>
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#include <linux/rcupdate.h>
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#include <linux/workqueue.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <linux/audit.h>
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#include <linux/nsproxy.h>
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#include <linux/rwsem.h>
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#include <asm/unistd.h>
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#include "util.h"
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struct ipc_proc_iface {
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const char *path;
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const char *header;
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int ids;
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int (*show)(struct seq_file *, void *);
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};
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struct ipc_namespace init_ipc_ns = {
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.kref = {
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.refcount = ATOMIC_INIT(2),
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},
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};
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static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
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{
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int err;
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struct ipc_namespace *ns;
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err = -ENOMEM;
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ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
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if (ns == NULL)
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goto err_mem;
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err = sem_init_ns(ns);
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if (err)
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goto err_sem;
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err = msg_init_ns(ns);
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if (err)
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goto err_msg;
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err = shm_init_ns(ns);
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if (err)
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goto err_shm;
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kref_init(&ns->kref);
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return ns;
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err_shm:
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msg_exit_ns(ns);
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err_msg:
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sem_exit_ns(ns);
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err_sem:
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kfree(ns);
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err_mem:
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return ERR_PTR(err);
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}
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struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
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{
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struct ipc_namespace *new_ns;
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BUG_ON(!ns);
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get_ipc_ns(ns);
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if (!(flags & CLONE_NEWIPC))
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return ns;
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new_ns = clone_ipc_ns(ns);
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put_ipc_ns(ns);
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return new_ns;
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}
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void free_ipc_ns(struct kref *kref)
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{
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struct ipc_namespace *ns;
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ns = container_of(kref, struct ipc_namespace, kref);
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sem_exit_ns(ns);
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msg_exit_ns(ns);
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shm_exit_ns(ns);
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kfree(ns);
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}
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/**
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* ipc_init - initialise IPC subsystem
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*
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* The various system5 IPC resources (semaphores, messages and shared
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* memory) are initialised
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*/
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static int __init ipc_init(void)
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{
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sem_init();
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msg_init();
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shm_init();
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return 0;
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}
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__initcall(ipc_init);
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/**
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* ipc_init_ids - initialise IPC identifiers
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* @ids: Identifier set
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*
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* Set up the sequence range to use for the ipc identifier range (limited
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* below IPCMNI) then initialise the ids idr.
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*/
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void ipc_init_ids(struct ipc_ids *ids)
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{
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init_rwsem(&ids->rw_mutex);
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ids->in_use = 0;
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ids->seq = 0;
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{
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int seq_limit = INT_MAX/SEQ_MULTIPLIER;
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if(seq_limit > USHRT_MAX)
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ids->seq_max = USHRT_MAX;
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else
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ids->seq_max = seq_limit;
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}
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idr_init(&ids->ipcs_idr);
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}
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#ifdef CONFIG_PROC_FS
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static const struct file_operations sysvipc_proc_fops;
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/**
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* ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
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* @path: Path in procfs
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* @header: Banner to be printed at the beginning of the file.
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* @ids: ipc id table to iterate.
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* @show: show routine.
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*/
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void __init ipc_init_proc_interface(const char *path, const char *header,
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int ids, int (*show)(struct seq_file *, void *))
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{
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struct proc_dir_entry *pde;
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struct ipc_proc_iface *iface;
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iface = kmalloc(sizeof(*iface), GFP_KERNEL);
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if (!iface)
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return;
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iface->path = path;
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iface->header = header;
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iface->ids = ids;
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iface->show = show;
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pde = create_proc_entry(path,
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S_IRUGO, /* world readable */
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NULL /* parent dir */);
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if (pde) {
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pde->data = iface;
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pde->proc_fops = &sysvipc_proc_fops;
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} else {
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kfree(iface);
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}
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}
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#endif
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/**
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* ipc_findkey - find a key in an ipc identifier set
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* @ids: Identifier set
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* @key: The key to find
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*
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* Requires ipc_ids.rw_mutex locked.
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* Returns the LOCKED pointer to the ipc structure if found or NULL
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* if not.
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* If key is found ipc points to the owning ipc structure
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*/
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static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
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{
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struct kern_ipc_perm *ipc;
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int next_id;
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int total;
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for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
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ipc = idr_find(&ids->ipcs_idr, next_id);
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if (ipc == NULL)
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continue;
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if (ipc->key != key) {
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total++;
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continue;
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}
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ipc_lock_by_ptr(ipc);
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return ipc;
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}
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return NULL;
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}
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/**
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* ipc_get_maxid - get the last assigned id
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* @ids: IPC identifier set
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*
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* Called with ipc_ids.rw_mutex held.
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*/
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int ipc_get_maxid(struct ipc_ids *ids)
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{
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struct kern_ipc_perm *ipc;
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int max_id = -1;
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int total, id;
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if (ids->in_use == 0)
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return -1;
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if (ids->in_use == IPCMNI)
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return IPCMNI - 1;
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/* Look for the last assigned id */
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total = 0;
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for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
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ipc = idr_find(&ids->ipcs_idr, id);
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if (ipc != NULL) {
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max_id = id;
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total++;
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}
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}
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return max_id;
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}
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/**
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* ipc_addid - add an IPC identifier
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* @ids: IPC identifier set
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* @new: new IPC permission set
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* @size: limit for the number of used ids
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*
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* Add an entry 'new' to the IPC ids idr. The permissions object is
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* initialised and the first free entry is set up and the id assigned
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* is returned. The 'new' entry is returned in a locked state on success.
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* On failure the entry is not locked and a negative err-code is returned.
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*
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* Called with ipc_ids.rw_mutex held as a writer.
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*/
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int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
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{
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int id, err;
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if (size > IPCMNI)
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size = IPCMNI;
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if (ids->in_use >= size)
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return -ENOSPC;
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err = idr_get_new(&ids->ipcs_idr, new, &id);
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if (err)
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return err;
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ids->in_use++;
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new->cuid = new->uid = current->euid;
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new->gid = new->cgid = current->egid;
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new->seq = ids->seq++;
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if(ids->seq > ids->seq_max)
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ids->seq = 0;
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spin_lock_init(&new->lock);
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new->deleted = 0;
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rcu_read_lock();
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spin_lock(&new->lock);
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return id;
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}
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/**
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* ipcget_new - create a new ipc object
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* @ns: namespace
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* @ids: IPC identifer set
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* @ops: the actual creation routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget, sys_semget() and sys_shmget()
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* when the key is IPC_PRIVATE.
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*/
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int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
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struct ipc_ops *ops, struct ipc_params *params)
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{
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int err;
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retry:
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err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
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if (!err)
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return -ENOMEM;
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down_write(&ids->rw_mutex);
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err = ops->getnew(ns, params);
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up_write(&ids->rw_mutex);
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if (err == -EAGAIN)
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goto retry;
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return err;
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}
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/**
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* ipc_check_perms - check security and permissions for an IPC
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* @ipcp: ipc permission set
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* @ops: the actual security routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget(), sys_semget() and sys_shmget()
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* when the key is not IPC_PRIVATE and that key already exists in the
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* ids IDR.
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*
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* On success, the IPC id is returned.
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*
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* It is called with ipc_ids.rw_mutex and ipcp->lock held.
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*/
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static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
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struct ipc_params *params)
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{
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int err;
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if (ipcperms(ipcp, params->flg))
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err = -EACCES;
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else {
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err = ops->associate(ipcp, params->flg);
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if (!err)
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err = ipcp->id;
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}
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return err;
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}
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/**
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* ipcget_public - get an ipc object or create a new one
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* @ns: namespace
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* @ids: IPC identifer set
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* @ops: the actual creation routine to call
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* @params: its parameters
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*
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* This routine is called by sys_msgget, sys_semget() and sys_shmget()
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* when the key is not IPC_PRIVATE.
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* It adds a new entry if the key is not found and does some permission
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* / security checkings if the key is found.
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*
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* On success, the ipc id is returned.
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*/
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int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
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struct ipc_ops *ops, struct ipc_params *params)
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{
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struct kern_ipc_perm *ipcp;
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int flg = params->flg;
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int err;
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retry:
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err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
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/*
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* Take the lock as a writer since we are potentially going to add
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* a new entry + read locks are not "upgradable"
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*/
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down_write(&ids->rw_mutex);
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ipcp = ipc_findkey(ids, params->key);
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if (ipcp == NULL) {
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/* key not used */
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if (!(flg & IPC_CREAT))
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err = -ENOENT;
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else if (!err)
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err = -ENOMEM;
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else
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err = ops->getnew(ns, params);
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} else {
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/* ipc object has been locked by ipc_findkey() */
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if (flg & IPC_CREAT && flg & IPC_EXCL)
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err = -EEXIST;
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else {
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err = 0;
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if (ops->more_checks)
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err = ops->more_checks(ipcp, params);
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if (!err)
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/*
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* ipc_check_perms returns the IPC id on
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* success
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*/
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err = ipc_check_perms(ipcp, ops, params);
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}
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ipc_unlock(ipcp);
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}
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up_write(&ids->rw_mutex);
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if (err == -EAGAIN)
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goto retry;
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return err;
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}
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/**
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* ipc_rmid - remove an IPC identifier
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* @ids: IPC identifier set
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* @ipcp: ipc perm structure containing the identifier to remove
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*
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* ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
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* before this function is called, and remain locked on the exit.
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*/
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void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
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{
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int lid = ipcid_to_idx(ipcp->id);
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idr_remove(&ids->ipcs_idr, lid);
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ids->in_use--;
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ipcp->deleted = 1;
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return;
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}
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/**
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* ipc_alloc - allocate ipc space
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* @size: size desired
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*
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* Allocate memory from the appropriate pools and return a pointer to it.
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* NULL is returned if the allocation fails
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*/
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void* ipc_alloc(int size)
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{
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void* out;
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if(size > PAGE_SIZE)
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out = vmalloc(size);
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else
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out = kmalloc(size, GFP_KERNEL);
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return out;
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}
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/**
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* ipc_free - free ipc space
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* @ptr: pointer returned by ipc_alloc
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* @size: size of block
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*
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* Free a block created with ipc_alloc(). The caller must know the size
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* used in the allocation call.
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*/
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void ipc_free(void* ptr, int size)
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{
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if(size > PAGE_SIZE)
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vfree(ptr);
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else
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kfree(ptr);
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}
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/*
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* rcu allocations:
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* There are three headers that are prepended to the actual allocation:
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* - during use: ipc_rcu_hdr.
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* - during the rcu grace period: ipc_rcu_grace.
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* - [only if vmalloc]: ipc_rcu_sched.
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* Their lifetime doesn't overlap, thus the headers share the same memory.
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* Unlike a normal union, they are right-aligned, thus some container_of
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* forward/backward casting is necessary:
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*/
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struct ipc_rcu_hdr
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{
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int refcount;
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int is_vmalloc;
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void *data[0];
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};
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struct ipc_rcu_grace
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{
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struct rcu_head rcu;
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/* "void *" makes sure alignment of following data is sane. */
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void *data[0];
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};
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struct ipc_rcu_sched
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{
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struct work_struct work;
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/* "void *" makes sure alignment of following data is sane. */
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void *data[0];
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};
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#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
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sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
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#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
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sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
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static inline int rcu_use_vmalloc(int size)
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{
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/* Too big for a single page? */
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if (HDRLEN_KMALLOC + size > PAGE_SIZE)
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return 1;
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return 0;
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}
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/**
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* ipc_rcu_alloc - allocate ipc and rcu space
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* @size: size desired
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*
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* Allocate memory for the rcu header structure + the object.
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* Returns the pointer to the object.
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* NULL is returned if the allocation fails.
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*/
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void* ipc_rcu_alloc(int size)
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{
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void* out;
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/*
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* We prepend the allocation with the rcu struct, and
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* workqueue if necessary (for vmalloc).
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*/
|
|
if (rcu_use_vmalloc(size)) {
|
|
out = vmalloc(HDRLEN_VMALLOC + size);
|
|
if (out) {
|
|
out += HDRLEN_VMALLOC;
|
|
container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
|
|
container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
|
}
|
|
} else {
|
|
out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
|
|
if (out) {
|
|
out += HDRLEN_KMALLOC;
|
|
container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
|
|
container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
|
}
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
void ipc_rcu_getref(void *ptr)
|
|
{
|
|
container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
|
|
}
|
|
|
|
static void ipc_do_vfree(struct work_struct *work)
|
|
{
|
|
vfree(container_of(work, struct ipc_rcu_sched, work));
|
|
}
|
|
|
|
/**
|
|
* ipc_schedule_free - free ipc + rcu space
|
|
* @head: RCU callback structure for queued work
|
|
*
|
|
* Since RCU callback function is called in bh,
|
|
* we need to defer the vfree to schedule_work().
|
|
*/
|
|
static void ipc_schedule_free(struct rcu_head *head)
|
|
{
|
|
struct ipc_rcu_grace *grace;
|
|
struct ipc_rcu_sched *sched;
|
|
|
|
grace = container_of(head, struct ipc_rcu_grace, rcu);
|
|
sched = container_of(&(grace->data[0]), struct ipc_rcu_sched,
|
|
data[0]);
|
|
|
|
INIT_WORK(&sched->work, ipc_do_vfree);
|
|
schedule_work(&sched->work);
|
|
}
|
|
|
|
/**
|
|
* ipc_immediate_free - free ipc + rcu space
|
|
* @head: RCU callback structure that contains pointer to be freed
|
|
*
|
|
* Free from the RCU callback context.
|
|
*/
|
|
static void ipc_immediate_free(struct rcu_head *head)
|
|
{
|
|
struct ipc_rcu_grace *free =
|
|
container_of(head, struct ipc_rcu_grace, rcu);
|
|
kfree(free);
|
|
}
|
|
|
|
void ipc_rcu_putref(void *ptr)
|
|
{
|
|
if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
|
|
return;
|
|
|
|
if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
|
|
call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
|
|
ipc_schedule_free);
|
|
} else {
|
|
call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
|
|
ipc_immediate_free);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* ipcperms - check IPC permissions
|
|
* @ipcp: IPC permission set
|
|
* @flag: desired permission set.
|
|
*
|
|
* Check user, group, other permissions for access
|
|
* to ipc resources. return 0 if allowed
|
|
*/
|
|
|
|
int ipcperms (struct kern_ipc_perm *ipcp, short flag)
|
|
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
|
|
int requested_mode, granted_mode, err;
|
|
|
|
if (unlikely((err = audit_ipc_obj(ipcp))))
|
|
return err;
|
|
requested_mode = (flag >> 6) | (flag >> 3) | flag;
|
|
granted_mode = ipcp->mode;
|
|
if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
|
|
granted_mode >>= 6;
|
|
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
|
|
granted_mode >>= 3;
|
|
/* is there some bit set in requested_mode but not in granted_mode? */
|
|
if ((requested_mode & ~granted_mode & 0007) &&
|
|
!capable(CAP_IPC_OWNER))
|
|
return -1;
|
|
|
|
return security_ipc_permission(ipcp, flag);
|
|
}
|
|
|
|
/*
|
|
* Functions to convert between the kern_ipc_perm structure and the
|
|
* old/new ipc_perm structures
|
|
*/
|
|
|
|
/**
|
|
* kernel_to_ipc64_perm - convert kernel ipc permissions to user
|
|
* @in: kernel permissions
|
|
* @out: new style IPC permissions
|
|
*
|
|
* Turn the kernel object @in into a set of permissions descriptions
|
|
* for returning to userspace (@out).
|
|
*/
|
|
|
|
|
|
void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
|
|
{
|
|
out->key = in->key;
|
|
out->uid = in->uid;
|
|
out->gid = in->gid;
|
|
out->cuid = in->cuid;
|
|
out->cgid = in->cgid;
|
|
out->mode = in->mode;
|
|
out->seq = in->seq;
|
|
}
|
|
|
|
/**
|
|
* ipc64_perm_to_ipc_perm - convert new ipc permissions to old
|
|
* @in: new style IPC permissions
|
|
* @out: old style IPC permissions
|
|
*
|
|
* Turn the new style permissions object @in into a compatibility
|
|
* object and store it into the @out pointer.
|
|
*/
|
|
|
|
void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
|
|
{
|
|
out->key = in->key;
|
|
SET_UID(out->uid, in->uid);
|
|
SET_GID(out->gid, in->gid);
|
|
SET_UID(out->cuid, in->cuid);
|
|
SET_GID(out->cgid, in->cgid);
|
|
out->mode = in->mode;
|
|
out->seq = in->seq;
|
|
}
|
|
|
|
/**
|
|
* ipc_lock - Lock an ipc structure without rw_mutex held
|
|
* @ids: IPC identifier set
|
|
* @id: ipc id to look for
|
|
*
|
|
* Look for an id in the ipc ids idr and lock the associated ipc object.
|
|
*
|
|
* The ipc object is locked on exit.
|
|
*
|
|
* This is the routine that should be called when the rw_mutex is not already
|
|
* held, i.e. idr tree not protected: it protects the idr tree in read mode
|
|
* during the idr_find().
|
|
*/
|
|
|
|
struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
|
|
{
|
|
struct kern_ipc_perm *out;
|
|
int lid = ipcid_to_idx(id);
|
|
|
|
down_read(&ids->rw_mutex);
|
|
|
|
rcu_read_lock();
|
|
out = idr_find(&ids->ipcs_idr, lid);
|
|
if (out == NULL) {
|
|
rcu_read_unlock();
|
|
up_read(&ids->rw_mutex);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
up_read(&ids->rw_mutex);
|
|
|
|
spin_lock(&out->lock);
|
|
|
|
/* ipc_rmid() may have already freed the ID while ipc_lock
|
|
* was spinning: here verify that the structure is still valid
|
|
*/
|
|
if (out->deleted) {
|
|
spin_unlock(&out->lock);
|
|
rcu_read_unlock();
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
/**
|
|
* ipc_lock_down - Lock an ipc structure with rw_sem held
|
|
* @ids: IPC identifier set
|
|
* @id: ipc id to look for
|
|
*
|
|
* Look for an id in the ipc ids idr and lock the associated ipc object.
|
|
*
|
|
* The ipc object is locked on exit.
|
|
*
|
|
* This is the routine that should be called when the rw_mutex is already
|
|
* held, i.e. idr tree protected.
|
|
*/
|
|
|
|
struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *ids, int id)
|
|
{
|
|
struct kern_ipc_perm *out;
|
|
int lid = ipcid_to_idx(id);
|
|
|
|
rcu_read_lock();
|
|
out = idr_find(&ids->ipcs_idr, lid);
|
|
if (out == NULL) {
|
|
rcu_read_unlock();
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
spin_lock(&out->lock);
|
|
|
|
/*
|
|
* No need to verify that the structure is still valid since the
|
|
* rw_mutex is held.
|
|
*/
|
|
return out;
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_IPC_PARSE_VERSION
|
|
|
|
|
|
/**
|
|
* ipc_parse_version - IPC call version
|
|
* @cmd: pointer to command
|
|
*
|
|
* Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
|
|
* The @cmd value is turned from an encoding command and version into
|
|
* just the command code.
|
|
*/
|
|
|
|
int ipc_parse_version (int *cmd)
|
|
{
|
|
if (*cmd & IPC_64) {
|
|
*cmd ^= IPC_64;
|
|
return IPC_64;
|
|
} else {
|
|
return IPC_OLD;
|
|
}
|
|
}
|
|
|
|
#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
|
|
|
|
#ifdef CONFIG_PROC_FS
|
|
struct ipc_proc_iter {
|
|
struct ipc_namespace *ns;
|
|
struct ipc_proc_iface *iface;
|
|
};
|
|
|
|
/*
|
|
* This routine locks the ipc structure found at least at position pos.
|
|
*/
|
|
struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
|
|
loff_t *new_pos)
|
|
{
|
|
struct kern_ipc_perm *ipc;
|
|
int total, id;
|
|
|
|
total = 0;
|
|
for (id = 0; id < pos && total < ids->in_use; id++) {
|
|
ipc = idr_find(&ids->ipcs_idr, id);
|
|
if (ipc != NULL)
|
|
total++;
|
|
}
|
|
|
|
if (total >= ids->in_use)
|
|
return NULL;
|
|
|
|
for ( ; pos < IPCMNI; pos++) {
|
|
ipc = idr_find(&ids->ipcs_idr, pos);
|
|
if (ipc != NULL) {
|
|
*new_pos = pos + 1;
|
|
ipc_lock_by_ptr(ipc);
|
|
return ipc;
|
|
}
|
|
}
|
|
|
|
/* Out of range - return NULL to terminate iteration */
|
|
return NULL;
|
|
}
|
|
|
|
static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct kern_ipc_perm *ipc = it;
|
|
|
|
/* If we had an ipc id locked before, unlock it */
|
|
if (ipc && ipc != SEQ_START_TOKEN)
|
|
ipc_unlock(ipc);
|
|
|
|
return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos);
|
|
}
|
|
|
|
/*
|
|
* File positions: pos 0 -> header, pos n -> ipc id = n - 1.
|
|
* SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
|
|
*/
|
|
static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct ipc_ids *ids;
|
|
|
|
ids = iter->ns->ids[iface->ids];
|
|
|
|
/*
|
|
* Take the lock - this will be released by the corresponding
|
|
* call to stop().
|
|
*/
|
|
down_read(&ids->rw_mutex);
|
|
|
|
/* pos < 0 is invalid */
|
|
if (*pos < 0)
|
|
return NULL;
|
|
|
|
/* pos == 0 means header */
|
|
if (*pos == 0)
|
|
return SEQ_START_TOKEN;
|
|
|
|
/* Find the (pos-1)th ipc */
|
|
return sysvipc_find_ipc(ids, *pos - 1, pos);
|
|
}
|
|
|
|
static void sysvipc_proc_stop(struct seq_file *s, void *it)
|
|
{
|
|
struct kern_ipc_perm *ipc = it;
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
struct ipc_ids *ids;
|
|
|
|
/* If we had a locked structure, release it */
|
|
if (ipc && ipc != SEQ_START_TOKEN)
|
|
ipc_unlock(ipc);
|
|
|
|
ids = iter->ns->ids[iface->ids];
|
|
/* Release the lock we took in start() */
|
|
up_read(&ids->rw_mutex);
|
|
}
|
|
|
|
static int sysvipc_proc_show(struct seq_file *s, void *it)
|
|
{
|
|
struct ipc_proc_iter *iter = s->private;
|
|
struct ipc_proc_iface *iface = iter->iface;
|
|
|
|
if (it == SEQ_START_TOKEN)
|
|
return seq_puts(s, iface->header);
|
|
|
|
return iface->show(s, it);
|
|
}
|
|
|
|
static struct seq_operations sysvipc_proc_seqops = {
|
|
.start = sysvipc_proc_start,
|
|
.stop = sysvipc_proc_stop,
|
|
.next = sysvipc_proc_next,
|
|
.show = sysvipc_proc_show,
|
|
};
|
|
|
|
static int sysvipc_proc_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret;
|
|
struct seq_file *seq;
|
|
struct ipc_proc_iter *iter;
|
|
|
|
ret = -ENOMEM;
|
|
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
goto out;
|
|
|
|
ret = seq_open(file, &sysvipc_proc_seqops);
|
|
if (ret)
|
|
goto out_kfree;
|
|
|
|
seq = file->private_data;
|
|
seq->private = iter;
|
|
|
|
iter->iface = PDE(inode)->data;
|
|
iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
|
|
out:
|
|
return ret;
|
|
out_kfree:
|
|
kfree(iter);
|
|
goto out;
|
|
}
|
|
|
|
static int sysvipc_proc_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *seq = file->private_data;
|
|
struct ipc_proc_iter *iter = seq->private;
|
|
put_ipc_ns(iter->ns);
|
|
return seq_release_private(inode, file);
|
|
}
|
|
|
|
static const struct file_operations sysvipc_proc_fops = {
|
|
.open = sysvipc_proc_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = sysvipc_proc_release,
|
|
};
|
|
#endif /* CONFIG_PROC_FS */
|