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1f5c135ee5
The ipc sysctls are not available for modification inside the user namespace. Following the mqueue sysctls, we changed the implementation to be more userns friendly. So far, the changes do not provide additional access to files. This will be done in a future patch. Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/be6f9d014276f4dddd0c3aa05a86052856c1c555.1644862280.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
313 lines
7.5 KiB
C
313 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2007
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*
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* Author: Eric Biederman <ebiederm@xmision.com>
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*/
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#include <linux/module.h>
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#include <linux/ipc.h>
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#include <linux/nsproxy.h>
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#include <linux/sysctl.h>
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#include <linux/uaccess.h>
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#include <linux/capability.h>
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#include <linux/ipc_namespace.h>
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#include <linux/msg.h>
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#include <linux/slab.h>
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#include "util.h"
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static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ipc_namespace *ns = table->extra1;
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struct ctl_table ipc_table;
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int err;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.extra1 = SYSCTL_ZERO;
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ipc_table.extra2 = SYSCTL_ONE;
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err = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
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if (err < 0)
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return err;
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if (ns->shm_rmid_forced)
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shm_destroy_orphaned(ns);
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return err;
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}
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static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ctl_table ipc_table;
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int dummy = 0;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.data = &dummy;
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if (write)
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pr_info_once("writing to auto_msgmni has no effect");
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return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
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}
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static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ipc_namespace *ns = table->extra1;
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struct ctl_table ipc_table;
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int ret, semmni;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.extra1 = NULL;
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ipc_table.extra2 = NULL;
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semmni = ns->sem_ctls[3];
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ret = proc_dointvec(table, write, buffer, lenp, ppos);
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if (!ret)
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ret = sem_check_semmni(current->nsproxy->ipc_ns);
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/*
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* Reset the semmni value if an error happens.
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*/
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if (ret)
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ns->sem_ctls[3] = semmni;
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return ret;
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}
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#ifdef CONFIG_CHECKPOINT_RESTORE
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static int proc_ipc_dointvec_minmax_checkpoint_restore(struct ctl_table *table,
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int write, void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ipc_namespace *ns = table->extra1;
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struct ctl_table ipc_table;
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if (write && !checkpoint_restore_ns_capable(ns->user_ns))
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return -EPERM;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.extra1 = SYSCTL_ZERO;
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ipc_table.extra2 = SYSCTL_INT_MAX;
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return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
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}
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#endif
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int ipc_mni = IPCMNI;
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int ipc_mni_shift = IPCMNI_SHIFT;
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int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
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static struct ctl_table ipc_sysctls[] = {
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{
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.procname = "shmmax",
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.data = &init_ipc_ns.shm_ctlmax,
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.maxlen = sizeof(init_ipc_ns.shm_ctlmax),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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},
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{
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.procname = "shmall",
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.data = &init_ipc_ns.shm_ctlall,
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.maxlen = sizeof(init_ipc_ns.shm_ctlall),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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},
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{
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.procname = "shmmni",
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.data = &init_ipc_ns.shm_ctlmni,
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.maxlen = sizeof(init_ipc_ns.shm_ctlmni),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &ipc_mni,
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},
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{
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.procname = "shm_rmid_forced",
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.data = &init_ipc_ns.shm_rmid_forced,
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.maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec_minmax_orphans,
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},
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{
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.procname = "msgmax",
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.data = &init_ipc_ns.msg_ctlmax,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmax),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "msgmni",
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.data = &init_ipc_ns.msg_ctlmni,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmni),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &ipc_mni,
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},
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{
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.procname = "auto_msgmni",
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.data = NULL,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_ipc_auto_msgmni,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_ONE,
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},
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{
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.procname = "msgmnb",
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.data = &init_ipc_ns.msg_ctlmnb,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "sem",
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.data = &init_ipc_ns.sem_ctls,
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.maxlen = 4*sizeof(int),
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.mode = 0644,
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.proc_handler = proc_ipc_sem_dointvec,
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},
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#ifdef CONFIG_CHECKPOINT_RESTORE
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{
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.procname = "sem_next_id",
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.data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
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.mode = 0666,
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.proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore,
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},
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{
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.procname = "msg_next_id",
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.data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
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.mode = 0666,
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.proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore,
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},
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{
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.procname = "shm_next_id",
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.data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
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.mode = 0666,
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.proc_handler = proc_ipc_dointvec_minmax_checkpoint_restore,
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},
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#endif
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{}
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};
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static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
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{
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return ¤t->nsproxy->ipc_ns->ipc_set;
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}
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static int set_is_seen(struct ctl_table_set *set)
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{
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return ¤t->nsproxy->ipc_ns->ipc_set == set;
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}
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static struct ctl_table_root set_root = {
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.lookup = set_lookup,
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};
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bool setup_ipc_sysctls(struct ipc_namespace *ns)
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{
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struct ctl_table *tbl;
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setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);
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tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
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if (tbl) {
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int i;
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for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
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if (tbl[i].data == &init_ipc_ns.shm_ctlmax) {
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tbl[i].data = &ns->shm_ctlmax;
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} else if (tbl[i].data == &init_ipc_ns.shm_ctlall) {
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tbl[i].data = &ns->shm_ctlall;
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} else if (tbl[i].data == &init_ipc_ns.shm_ctlmni) {
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tbl[i].data = &ns->shm_ctlmni;
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} else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced) {
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tbl[i].data = &ns->shm_rmid_forced;
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tbl[i].extra1 = ns;
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} else if (tbl[i].data == &init_ipc_ns.msg_ctlmax) {
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tbl[i].data = &ns->msg_ctlmax;
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} else if (tbl[i].data == &init_ipc_ns.msg_ctlmni) {
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tbl[i].data = &ns->msg_ctlmni;
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} else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb) {
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tbl[i].data = &ns->msg_ctlmnb;
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} else if (tbl[i].data == &init_ipc_ns.sem_ctls) {
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tbl[i].data = &ns->sem_ctls;
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tbl[i].extra1 = ns;
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#ifdef CONFIG_CHECKPOINT_RESTORE
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} else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id) {
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tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;
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tbl[i].extra1 = ns;
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} else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id) {
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tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;
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tbl[i].extra1 = ns;
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} else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id) {
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tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
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tbl[i].extra1 = ns;
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#endif
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} else {
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tbl[i].data = NULL;
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}
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}
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ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set, "kernel", tbl);
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}
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if (!ns->ipc_sysctls) {
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kfree(tbl);
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retire_sysctl_set(&ns->ipc_set);
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return false;
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}
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return true;
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}
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void retire_ipc_sysctls(struct ipc_namespace *ns)
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{
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struct ctl_table *tbl;
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tbl = ns->ipc_sysctls->ctl_table_arg;
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unregister_sysctl_table(ns->ipc_sysctls);
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retire_sysctl_set(&ns->ipc_set);
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kfree(tbl);
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}
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static int __init ipc_sysctl_init(void)
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{
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if (!setup_ipc_sysctls(&init_ipc_ns)) {
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pr_warn("ipc sysctl registration failed\n");
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return -ENOMEM;
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}
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return 0;
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}
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device_initcall(ipc_sysctl_init);
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static int __init ipc_mni_extend(char *str)
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{
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ipc_mni = IPCMNI_EXTEND;
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ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
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ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
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pr_info("IPCMNI extended to %d.\n", ipc_mni);
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return 0;
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}
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early_param("ipcmni_extend", ipc_mni_extend);
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