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![Alexey Gladkov](/assets/img/avatar_default.png)
The problem that Dmitry Vyukov pointed out is that if setup_ipc_sysctls fails, mq_sysctls must be freed before return. executing program BUG: memory leak unreferenced object 0xffff888112fc9200 (size 512): comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s) hex dump (first 32 bytes): ef d3 60 85 ff ff ff ff 0c 9b d2 12 81 88 ff ff ..`............. 04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff814b6eb3>] kmemdup+0x23/0x50 mm/util.c:129 [<ffffffff82219a9b>] kmemdup include/linux/fortify-string.h:456 [inline] [<ffffffff82219a9b>] setup_mq_sysctls+0x4b/0x1c0 ipc/mq_sysctl.c:89 [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline] [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91 [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90 [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226 [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165 [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline] [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline] [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234 [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff888112fd5f00 (size 256): comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s) hex dump (first 32 bytes): 00 92 fc 12 81 88 ff ff 00 00 00 00 01 00 00 00 ................ 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff816fea1b>] kmalloc include/linux/slab.h:605 [inline] [<ffffffff816fea1b>] kzalloc include/linux/slab.h:733 [inline] [<ffffffff816fea1b>] __register_sysctl_table+0x7b/0x7f0 fs/proc/proc_sysctl.c:1344 [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112 [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline] [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91 [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90 [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226 [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165 [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline] [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline] [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234 [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff888112fbba00 (size 256): comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s) hex dump (first 32 bytes): 78 ba fb 12 81 88 ff ff 00 00 00 00 01 00 00 00 x............... 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff816fef49>] kmalloc include/linux/slab.h:605 [inline] [<ffffffff816fef49>] kzalloc include/linux/slab.h:733 [inline] [<ffffffff816fef49>] new_dir fs/proc/proc_sysctl.c:978 [inline] [<ffffffff816fef49>] get_subdir fs/proc/proc_sysctl.c:1022 [inline] [<ffffffff816fef49>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373 [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112 [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline] [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91 [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90 [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226 [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165 [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline] [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline] [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234 [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 BUG: memory leak unreferenced object 0xffff888112fbb900 (size 256): comm "syz-executor237", pid 3648, jiffies 4294970469 (age 12.270s) hex dump (first 32 bytes): 78 b9 fb 12 81 88 ff ff 00 00 00 00 01 00 00 00 x............... 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff816fef49>] kmalloc include/linux/slab.h:605 [inline] [<ffffffff816fef49>] kzalloc include/linux/slab.h:733 [inline] [<ffffffff816fef49>] new_dir fs/proc/proc_sysctl.c:978 [inline] [<ffffffff816fef49>] get_subdir fs/proc/proc_sysctl.c:1022 [inline] [<ffffffff816fef49>] __register_sysctl_table+0x5a9/0x7f0 fs/proc/proc_sysctl.c:1373 [<ffffffff82219b7a>] setup_mq_sysctls+0x12a/0x1c0 ipc/mq_sysctl.c:112 [<ffffffff822197f2>] create_ipc_ns ipc/namespace.c:63 [inline] [<ffffffff822197f2>] copy_ipcs+0x292/0x390 ipc/namespace.c:91 [<ffffffff8127de7c>] create_new_namespaces+0xdc/0x4f0 kernel/nsproxy.c:90 [<ffffffff8127e89b>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226 [<ffffffff8123f92e>] ksys_unshare+0x2fe/0x600 kernel/fork.c:3165 [<ffffffff8123fc42>] __do_sys_unshare kernel/fork.c:3236 [inline] [<ffffffff8123fc42>] __se_sys_unshare kernel/fork.c:3234 [inline] [<ffffffff8123fc42>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3234 [<ffffffff845aab45>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845aab45>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 Reported-by: syzbot+b4b0d1b35442afbf6fd2@syzkaller.appspotmail.com Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/000000000000f5004705e1db8bad@google.com Link: https://lkml.kernel.org/r/20220622200729.2639663-1-legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
238 lines
5.3 KiB
C
238 lines
5.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/ipc/namespace.c
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* Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
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*/
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#include <linux/ipc.h>
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#include <linux/msg.h>
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#include <linux/ipc_namespace.h>
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#include <linux/rcupdate.h>
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#include <linux/nsproxy.h>
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#include <linux/slab.h>
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#include <linux/cred.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/user_namespace.h>
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#include <linux/proc_ns.h>
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#include <linux/sched/task.h>
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#include "util.h"
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static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
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{
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return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
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}
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static void dec_ipc_namespaces(struct ucounts *ucounts)
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{
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dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
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}
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static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
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struct ipc_namespace *old_ns)
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{
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struct ipc_namespace *ns;
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struct ucounts *ucounts;
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int err;
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err = -ENOSPC;
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ucounts = inc_ipc_namespaces(user_ns);
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if (!ucounts)
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goto fail;
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err = -ENOMEM;
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ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT);
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if (ns == NULL)
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goto fail_dec;
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err = ns_alloc_inum(&ns->ns);
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if (err)
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goto fail_free;
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ns->ns.ops = &ipcns_operations;
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refcount_set(&ns->ns.count, 1);
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ns->user_ns = get_user_ns(user_ns);
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ns->ucounts = ucounts;
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err = mq_init_ns(ns);
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if (err)
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goto fail_put;
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err = -ENOMEM;
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if (!setup_mq_sysctls(ns))
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goto fail_put;
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if (!setup_ipc_sysctls(ns))
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goto fail_mq;
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sem_init_ns(ns);
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msg_init_ns(ns);
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shm_init_ns(ns);
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return ns;
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fail_mq:
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retire_mq_sysctls(ns);
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fail_put:
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put_user_ns(ns->user_ns);
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ns_free_inum(&ns->ns);
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fail_free:
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kfree(ns);
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fail_dec:
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dec_ipc_namespaces(ucounts);
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fail:
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return ERR_PTR(err);
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}
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struct ipc_namespace *copy_ipcs(unsigned long flags,
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struct user_namespace *user_ns, struct ipc_namespace *ns)
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{
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if (!(flags & CLONE_NEWIPC))
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return get_ipc_ns(ns);
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return create_ipc_ns(user_ns, ns);
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}
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/*
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* free_ipcs - free all ipcs of one type
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* @ns: the namespace to remove the ipcs from
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* @ids: the table of ipcs to free
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* @free: the function called to free each individual ipc
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*
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* Called for each kind of ipc when an ipc_namespace exits.
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*/
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void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
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void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
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{
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struct kern_ipc_perm *perm;
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int next_id;
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int total, in_use;
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down_write(&ids->rwsem);
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in_use = ids->in_use;
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for (total = 0, next_id = 0; total < in_use; next_id++) {
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perm = idr_find(&ids->ipcs_idr, next_id);
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if (perm == NULL)
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continue;
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rcu_read_lock();
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ipc_lock_object(perm);
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free(ns, perm);
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total++;
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}
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up_write(&ids->rwsem);
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}
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static void free_ipc_ns(struct ipc_namespace *ns)
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{
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/* mq_put_mnt() waits for a grace period as kern_unmount()
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* uses synchronize_rcu().
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*/
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mq_put_mnt(ns);
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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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retire_mq_sysctls(ns);
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retire_ipc_sysctls(ns);
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dec_ipc_namespaces(ns->ucounts);
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put_user_ns(ns->user_ns);
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ns_free_inum(&ns->ns);
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kfree(ns);
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}
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static LLIST_HEAD(free_ipc_list);
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static void free_ipc(struct work_struct *unused)
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{
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struct llist_node *node = llist_del_all(&free_ipc_list);
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struct ipc_namespace *n, *t;
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llist_for_each_entry_safe(n, t, node, mnt_llist)
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free_ipc_ns(n);
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}
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/*
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* The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
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*/
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static DECLARE_WORK(free_ipc_work, free_ipc);
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/*
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* put_ipc_ns - drop a reference to an ipc namespace.
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* @ns: the namespace to put
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*
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* If this is the last task in the namespace exiting, and
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* it is dropping the refcount to 0, then it can race with
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* a task in another ipc namespace but in a mounts namespace
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* which has this ipcns's mqueuefs mounted, doing some action
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* with one of the mqueuefs files. That can raise the refcount.
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* So dropping the refcount, and raising the refcount when
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* accessing it through the VFS, are protected with mq_lock.
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*
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* (Clearly, a task raising the refcount on its own ipc_ns
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* needn't take mq_lock since it can't race with the last task
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* in the ipcns exiting).
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*/
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void put_ipc_ns(struct ipc_namespace *ns)
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{
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if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) {
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mq_clear_sbinfo(ns);
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spin_unlock(&mq_lock);
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if (llist_add(&ns->mnt_llist, &free_ipc_list))
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schedule_work(&free_ipc_work);
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}
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}
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static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
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{
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return container_of(ns, struct ipc_namespace, ns);
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}
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static struct ns_common *ipcns_get(struct task_struct *task)
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{
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struct ipc_namespace *ns = NULL;
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struct nsproxy *nsproxy;
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task_lock(task);
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nsproxy = task->nsproxy;
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if (nsproxy)
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ns = get_ipc_ns(nsproxy->ipc_ns);
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task_unlock(task);
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return ns ? &ns->ns : NULL;
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}
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static void ipcns_put(struct ns_common *ns)
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{
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return put_ipc_ns(to_ipc_ns(ns));
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}
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static int ipcns_install(struct nsset *nsset, struct ns_common *new)
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{
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struct nsproxy *nsproxy = nsset->nsproxy;
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struct ipc_namespace *ns = to_ipc_ns(new);
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if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
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!ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
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return -EPERM;
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put_ipc_ns(nsproxy->ipc_ns);
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nsproxy->ipc_ns = get_ipc_ns(ns);
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return 0;
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}
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static struct user_namespace *ipcns_owner(struct ns_common *ns)
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{
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return to_ipc_ns(ns)->user_ns;
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}
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const struct proc_ns_operations ipcns_operations = {
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.name = "ipc",
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.type = CLONE_NEWIPC,
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.get = ipcns_get,
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.put = ipcns_put,
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.install = ipcns_install,
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.owner = ipcns_owner,
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};
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