mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-19 02:04:19 +08:00
36f7f28416
This patch fixes up coding-style problem at this commit: 4f27a7d49789b04404eca26ccde5f527231d01d5 selinux: fast status update interface (/selinux/status) Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com> Signed-off-by: James Morris <jmorris@namei.org>
127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/*
|
|
* mmap based event notifications for SELinux
|
|
*
|
|
* Author: KaiGai Kohei <kaigai@ak.jp.nec.com>
|
|
*
|
|
* Copyright (C) 2010 NEC corporation
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2,
|
|
* as published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mutex.h>
|
|
#include "avc.h"
|
|
#include "services.h"
|
|
|
|
/*
|
|
* The selinux_status_page shall be exposed to userspace applications
|
|
* using mmap interface on /selinux/status.
|
|
* It enables to notify applications a few events that will cause reset
|
|
* of userspace access vector without context switching.
|
|
*
|
|
* The selinux_kernel_status structure on the head of status page is
|
|
* protected from concurrent accesses using seqlock logic, so userspace
|
|
* application should reference the status page according to the seqlock
|
|
* logic.
|
|
*
|
|
* Typically, application checks status->sequence at the head of access
|
|
* control routine. If it is odd-number, kernel is updating the status,
|
|
* so please wait for a moment. If it is changed from the last sequence
|
|
* number, it means something happen, so application will reset userspace
|
|
* avc, if needed.
|
|
* In most cases, application shall confirm the kernel status is not
|
|
* changed without any system call invocations.
|
|
*/
|
|
static struct page *selinux_status_page;
|
|
static DEFINE_MUTEX(selinux_status_lock);
|
|
|
|
/*
|
|
* selinux_kernel_status_page
|
|
*
|
|
* It returns a reference to selinux_status_page. If the status page is
|
|
* not allocated yet, it also tries to allocate it at the first time.
|
|
*/
|
|
struct page *selinux_kernel_status_page(void)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
struct page *result = NULL;
|
|
|
|
mutex_lock(&selinux_status_lock);
|
|
if (!selinux_status_page) {
|
|
selinux_status_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
|
|
|
|
if (selinux_status_page) {
|
|
status = page_address(selinux_status_page);
|
|
|
|
status->version = SELINUX_KERNEL_STATUS_VERSION;
|
|
status->sequence = 0;
|
|
status->enforcing = selinux_enforcing;
|
|
/*
|
|
* NOTE: the next policyload event shall set
|
|
* a positive value on the status->policyload,
|
|
* although it may not be 1, but never zero.
|
|
* So, application can know it was updated.
|
|
*/
|
|
status->policyload = 0;
|
|
status->deny_unknown = !security_get_allow_unknown();
|
|
}
|
|
}
|
|
result = selinux_status_page;
|
|
mutex_unlock(&selinux_status_lock);
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* selinux_status_update_setenforce
|
|
*
|
|
* It updates status of the current enforcing/permissive mode.
|
|
*/
|
|
void selinux_status_update_setenforce(int enforcing)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
|
|
mutex_lock(&selinux_status_lock);
|
|
if (selinux_status_page) {
|
|
status = page_address(selinux_status_page);
|
|
|
|
status->sequence++;
|
|
smp_wmb();
|
|
|
|
status->enforcing = enforcing;
|
|
|
|
smp_wmb();
|
|
status->sequence++;
|
|
}
|
|
mutex_unlock(&selinux_status_lock);
|
|
}
|
|
|
|
/*
|
|
* selinux_status_update_policyload
|
|
*
|
|
* It updates status of the times of policy reloaded, and current
|
|
* setting of deny_unknown.
|
|
*/
|
|
void selinux_status_update_policyload(int seqno)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
|
|
mutex_lock(&selinux_status_lock);
|
|
if (selinux_status_page) {
|
|
status = page_address(selinux_status_page);
|
|
|
|
status->sequence++;
|
|
smp_wmb();
|
|
|
|
status->policyload = seqno;
|
|
status->deny_unknown = !security_get_allow_unknown();
|
|
|
|
smp_wmb();
|
|
status->sequence++;
|
|
}
|
|
mutex_unlock(&selinux_status_lock);
|
|
}
|