Merge branch 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit

Pull audit fixes from Paul Moore:
 "Two small patches to fix audit problems in 4.7-rcX: the first fixes a
  potential kref leak, the second removes some header file noise.

  The first is an important bug fix that really should go in before 4.7
  is released, the second is not critical, but falls into the very-nice-
  to-have category so I'm including in the pull request.

  Both patches are straightforward, self-contained, and pass our
  testsuite without problem"

* 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit:
  audit: move audit_get_tty to reduce scope and kabi changes
  audit: move calcs after alloc and check when logging set loginuid

3 files changed, 25 insertions, 4 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 22bb4f24f071..8d528f9930da 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1883,6 +1883,23 @@ out_null:
 	audit_log_format(ab, " exe=(null)");
 }
 
+struct tty_struct *audit_get_tty(struct task_struct *tsk)
+{
+	struct tty_struct *tty = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsk->sighand->siglock, flags);
+	if (tsk->signal)
+		tty = tty_kref_get(tsk->signal->tty);
+	spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+	return tty;
+}
+
+void audit_put_tty(struct tty_struct *tty)
+{
+	tty_kref_put(tty);
+}
+
 void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 {
 	const struct cred *cred;
diff --git a/kernel/audit.h b/kernel/audit.h
index cbbe6bb6496e..a492f4c4e710 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -23,6 +23,7 @@
 #include <linux/audit.h>
 #include <linux/skbuff.h>
 #include <uapi/linux/mqueue.h>
+#include <linux/tty.h>
 
 /* AUDIT_NAMES is the number of slots we reserve in the audit_context
  * for saving names from getname().  If we get more names we will allocate
@@ -262,6 +263,9 @@ extern struct audit_entry *audit_dupe_rule(struct audit_krule *old);
 extern void audit_log_d_path_exe(struct audit_buffer *ab,
 				 struct mm_struct *mm);
 
+extern struct tty_struct *audit_get_tty(struct task_struct *tsk);
+extern void audit_put_tty(struct tty_struct *tty);
+
 /* audit watch functions */
 #ifdef CONFIG_AUDIT_WATCH
 extern void audit_put_watch(struct audit_watch *watch);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 62ab53d7619c..2672d105cffc 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -63,7 +63,6 @@
 #include <asm/unistd.h>
 #include <linux/security.h>
 #include <linux/list.h>
-#include <linux/tty.h>
 #include <linux/binfmts.h>
 #include <linux/highmem.h>
 #include <linux/syscalls.h>
@@ -1985,14 +1984,15 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	if (!audit_enabled)
 		return;
 
+	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
+	if (!ab)
+		return;
+
 	uid = from_kuid(&init_user_ns, task_uid(current));
 	oldloginuid = from_kuid(&init_user_ns, koldloginuid);
 	loginuid = from_kuid(&init_user_ns, kloginuid),
 	tty = audit_get_tty(current);
 
-	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
-	if (!ab)
-		return;
 	audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
 	audit_log_task_context(ab);
 	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",