Merge tag 'selinux-pr-20200330' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:
 "We've got twenty SELinux patches for the v5.7 merge window, the
  highlights are below:

   - Deprecate setting /sys/fs/selinux/checkreqprot to 1.

     This flag was originally created to deal with legacy userspace and
     the READ_IMPLIES_EXEC personality flag. We changed the default from
     1 to 0 back in Linux v4.4 and now we are taking the next step of
     deprecating it, at some point in the future we will take the final
     step of rejecting 1.

   - Allow kernfs symlinks to inherit the SELinux label of the parent
     directory. In order to preserve backwards compatibility this is
     protected by the genfs_seclabel_symlinks SELinux policy capability.

   - Optimize how we store filename transitions in the kernel, resulting
     in some significant improvements to policy load times.

   - Do a better job calculating our internal hash table sizes which
     resulted in additional policy load improvements and likely general
     SELinux performance improvements as well.

   - Remove the unused initial SIDs (labels) and improve how we handle
     initial SIDs.

   - Enable per-file labeling for the bpf filesystem.

   - Ensure that we properly label NFS v4.2 filesystems to avoid a
     temporary unlabeled condition.

   - Add some missing XFS quota command types to the SELinux quota
     access controls.

   - Fix a problem where we were not updating the seq_file position
     index correctly in selinuxfs.

   - We consolidate some duplicated code into helper functions.

   - A number of list to array conversions.

   - Update Stephen Smalley's email address in MAINTAINERS"

* tag 'selinux-pr-20200330' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: clean up indentation issue with assignment statement
  NFS: Ensure security label is set for root inode
  MAINTAINERS: Update my email address
  selinux: avtab_init() and cond_policydb_init() return void
  selinux: clean up error path in policydb_init()
  selinux: remove unused initial SIDs and improve handling
  selinux: reduce the use of hard-coded hash sizes
  selinux: Add xfs quota command types
  selinux: optimize storage of filename transitions
  selinux: factor out loop body from filename_trans_read()
  security: selinux: allow per-file labeling for bpffs
  selinux: generalize evaluate_cond_node()
  selinux: convert cond_expr to array
  selinux: convert cond_av_list to array
  selinux: convert cond_list to array
  selinux: sel_avc_get_stat_idx should increase position index
  selinux: allow kernfs symlinks to inherit parent directory context
  selinux: simplify evaluate_cond_node()
  Documentation,selinux: deprecate setting checkreqprot to 1
  selinux: move status variables out of selinux_ss

1 files changed, 124 insertions, 0 deletions

diff --git a/security/selinux/status.c b/security/selinux/status.c
new file mode 100644
index 000000000000..4bc8f809934c
--- /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);
+}