Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/security/selinux/status.c b/security/selinux/status.c
new file mode 100644
index 0000000..4bc8f80
--- /dev/null
+++ b/security/selinux/status.c
@@ -0,0 +1,124 @@
+// 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);
+}