text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   *  Copyright (C) 2007
   *
   *  Author: Eric Biederman <ebiederm@xmision.com>
   */
  
  #include <linux/module.h>
  #include <linux/ipc.h>
  #include <linux/nsproxy.h>
  #include <linux/sysctl.h>
  #include <linux/uaccess.h>
  #include <linux/ipc_namespace.h>
  #include <linux/msg.h>
  #include "util.h"
  
  static void *get_ipc(struct ctl_table *table)
  {
  	char *which = table->data;
  	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
  	which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
  	return which;
  }
  
  #ifdef CONFIG_PROC_SYSCTL
  static int proc_ipc_dointvec(struct ctl_table *table, int write,
  		void *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct ctl_table ipc_table;
  
  	memcpy(&ipc_table, table, sizeof(ipc_table));
  	ipc_table.data = get_ipc(table);
  
  	return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
  }
  
  static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
  		void *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct ctl_table ipc_table;
  
  	memcpy(&ipc_table, table, sizeof(ipc_table));
  	ipc_table.data = get_ipc(table);
  
  	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  }
  
  static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
  		void *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  	int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
  
  	if (err < 0)
  		return err;
  	if (ns->shm_rmid_forced)
  		shm_destroy_orphaned(ns);
  	return err;
  }
  
  static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
  		void *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct ctl_table ipc_table;
  	memcpy(&ipc_table, table, sizeof(ipc_table));
  	ipc_table.data = get_ipc(table);
  
  	return proc_doulongvec_minmax(&ipc_table, write, buffer,
  					lenp, ppos);
  }
  
  static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
  		void *buffer, size_t *lenp, loff_t *ppos)
  {
  	struct ctl_table ipc_table;
  	int dummy = 0;
  
  	memcpy(&ipc_table, table, sizeof(ipc_table));
  	ipc_table.data = &dummy;
  
  	if (write)
  		pr_info_once("writing to auto_msgmni has no effect");
  
  	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  }
  
  static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
  	void __user *buffer, size_t *lenp, loff_t *ppos)
  {
  	int ret, semmni;
  	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  
  	semmni = ns->sem_ctls[3];
  	ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
  
  	if (!ret)
  		ret = sem_check_semmni(current->nsproxy->ipc_ns);
  
  	/*
  	 * Reset the semmni value if an error happens.
  	 */
  	if (ret)
  		ns->sem_ctls[3] = semmni;
  	return ret;
  }
  
  #else
  #define proc_ipc_doulongvec_minmax NULL
  #define proc_ipc_dointvec	   NULL
  #define proc_ipc_dointvec_minmax   NULL
  #define proc_ipc_dointvec_minmax_orphans   NULL
  #define proc_ipc_auto_msgmni	   NULL
  #define proc_ipc_sem_dointvec	   NULL
  #endif
  
  int ipc_mni = IPCMNI;
  int ipc_mni_shift = IPCMNI_SHIFT;
  int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
  
  static struct ctl_table ipc_kern_table[] = {
  	{
  		.procname	= "shmmax",
  		.data		= &init_ipc_ns.shm_ctlmax,
  		.maxlen		= sizeof(init_ipc_ns.shm_ctlmax),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_doulongvec_minmax,
  	},
  	{
  		.procname	= "shmall",
  		.data		= &init_ipc_ns.shm_ctlall,
  		.maxlen		= sizeof(init_ipc_ns.shm_ctlall),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_doulongvec_minmax,
  	},
  	{
  		.procname	= "shmmni",
  		.data		= &init_ipc_ns.shm_ctlmni,
  		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= &ipc_mni,
  	},
  	{
  		.procname	= "shm_rmid_forced",
  		.data		= &init_ipc_ns.shm_rmid_forced,
  		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_ONE,
  	},
  	{
  		.procname	= "msgmax",
  		.data		= &init_ipc_ns.msg_ctlmax,
  		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_INT_MAX,
  	},
  	{
  		.procname	= "msgmni",
  		.data		= &init_ipc_ns.msg_ctlmni,
  		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= &ipc_mni,
  	},
  	{
  		.procname	= "auto_msgmni",
  		.data		= NULL,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_auto_msgmni,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_ONE,
  	},
  	{
  		.procname	=  "msgmnb",
  		.data		= &init_ipc_ns.msg_ctlmnb,
  		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_INT_MAX,
  	},
  	{
  		.procname	= "sem",
  		.data		= &init_ipc_ns.sem_ctls,
  		.maxlen		= 4*sizeof(int),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_sem_dointvec,
  	},
  #ifdef CONFIG_CHECKPOINT_RESTORE
  	{
  		.procname	= "sem_next_id",
  		.data		= &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
  		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_INT_MAX,
  	},
  	{
  		.procname	= "msg_next_id",
  		.data		= &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
  		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_INT_MAX,
  	},
  	{
  		.procname	= "shm_next_id",
  		.data		= &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
  		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
  		.mode		= 0644,
  		.proc_handler	= proc_ipc_dointvec_minmax,
  		.extra1		= SYSCTL_ZERO,
  		.extra2		= SYSCTL_INT_MAX,
  	},
  #endif
  	{}
  };
  
  static struct ctl_table ipc_root_table[] = {
  	{
  		.procname	= "kernel",
  		.mode		= 0555,
  		.child		= ipc_kern_table,
  	},
  	{}
  };
  
  static int __init ipc_sysctl_init(void)
  {
  	register_sysctl_table(ipc_root_table);
  	return 0;
  }
  
  device_initcall(ipc_sysctl_init);
  
  static int __init ipc_mni_extend(char *str)
  {
  	ipc_mni = IPCMNI_EXTEND;
  	ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
  	ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
  	pr_info("IPCMNI extended to %d.\n", ipc_mni);
  	return 0;
  }
  early_param("ipcmni_extend", ipc_mni_extend);
  