/*
 * 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);
}
ers/usb/serial/keyspan_usa28msg.h?id=c74454fadd5ea6fc866ffe2c417a0dba56b2bf1c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-27 12:36:39 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-27 12:36:39 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/tipc/bcast.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>2fb78e89405f4321b86274a0c24b30896dd50529</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/tipc/bcast.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=2fb78e89405f4321b86274a0c24b30896dd50529'>4de241e242441b80bd3f0022fc546bb07374571f</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/tipc/bcast.h?id=2fb78e89405f4321b86274a0c24b30896dd50529'>net/tipc/bcast.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/tipc/bcast.h?id=dd3b9f25c867cb2507a45e436d6ede8eb08e7b05'>dd3b9f25c867cb2507a45e436d6ede8eb08e7b05</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/tipc/bcast.h?id=2fb78e89405f4321b86274a0c24b30896dd50529&amp;id2=dd3b9f25c867cb2507a45e436d6ede8eb08e7b05'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/tipc/bcast.h?id=c14024dbb156c8392908aaa822097d27c6af8ec8'>c14024dbb156c8392908aaa822097d27c6af8ec8</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/tipc/bcast.h?id=2fb78e89405f4321b86274a0c24b30896dd50529&amp;id2=c14024dbb156c8392908aaa822097d27c6af8ec8'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'for-linus' of git://git.kernel.dk/linux-block</div><div class='commit-msg'>Pull block fixes from Jens Axboe:
 "A set of fixes for this series. This contains:

   - Set of fixes for the nvme target code

   - A revert of patch from this merge window, causing a regression with
     WRITE_SAME on iSCSI targets at least.

   - A fix for a use-after-free in the new O_DIRECT bdev code.

   - Two fixes for the xen-blkfront driver"

* 'for-linus' of git://git.kernel.dk/linux-block:
  Revert "sd: remove __data_len hack for WRITE SAME"
  nvme-fc: use blk_rq_nr_phys_segments
  nvmet-rdma: Fix missing dma sync to nvme data structures
  nvmet: Call fatal_error from keep-alive timout expiration
  nvmet: cancel fatal error and flush async work before free controller
  nvmet: delete controllers deletion upon subsystem release
  nvmet_fc: correct logic in disconnect queue LS handling
  block: fix use after free in __blkdev_direct_IO
  xen-blkfront: correct maximum segment accounting
  xen-blkfront: feature flags handling adjustments
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=2fb78e89405f4321b86274a0c24b30896dd50529'>Diffstat</a> (limited to 'net/tipc/bcast.h')</div><table summary='diffstat' class='diffstat'>