mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-29 23:53:32 +00:00
4b36cb773a
It fits more naturally in selinux_state, since it reflects also global state (the enforcing and policyload fields). Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* mmap based event notifications for SELinux
|
|
*
|
|
* Author: KaiGai Kohei <kaigai@ak.jp.nec.com>
|
|
*
|
|
* Copyright (C) 2010 NEC corporation
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mutex.h>
|
|
#include "avc.h"
|
|
#include "security.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.
|
|
*/
|
|
|
|
/*
|
|
* 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(struct selinux_state *state)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
struct page *result = NULL;
|
|
|
|
mutex_lock(&state->status_lock);
|
|
if (!state->status_page) {
|
|
state->status_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
|
|
|
|
if (state->status_page) {
|
|
status = page_address(state->status_page);
|
|
|
|
status->version = SELINUX_KERNEL_STATUS_VERSION;
|
|
status->sequence = 0;
|
|
status->enforcing = enforcing_enabled(state);
|
|
/*
|
|
* 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(state);
|
|
}
|
|
}
|
|
result = state->status_page;
|
|
mutex_unlock(&state->status_lock);
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* selinux_status_update_setenforce
|
|
*
|
|
* It updates status of the current enforcing/permissive mode.
|
|
*/
|
|
void selinux_status_update_setenforce(struct selinux_state *state,
|
|
int enforcing)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
|
|
mutex_lock(&state->status_lock);
|
|
if (state->status_page) {
|
|
status = page_address(state->status_page);
|
|
|
|
status->sequence++;
|
|
smp_wmb();
|
|
|
|
status->enforcing = enforcing;
|
|
|
|
smp_wmb();
|
|
status->sequence++;
|
|
}
|
|
mutex_unlock(&state->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(struct selinux_state *state,
|
|
int seqno)
|
|
{
|
|
struct selinux_kernel_status *status;
|
|
|
|
mutex_lock(&state->status_lock);
|
|
if (state->status_page) {
|
|
status = page_address(state->status_page);
|
|
|
|
status->sequence++;
|
|
smp_wmb();
|
|
|
|
status->policyload = seqno;
|
|
status->deny_unknown = !security_get_allow_unknown(state);
|
|
|
|
smp_wmb();
|
|
status->sequence++;
|
|
}
|
|
mutex_unlock(&state->status_lock);
|
|
}
|