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

Pull audit updates from Paul Moore:
 "Four small audit patches for 4.7.

  Two are simple cleanups around the audit thread management code, one
  adds a tty field to AUDIT_LOGIN events, and the final patch makes
  tty_name() usable regardless of CONFIG_TTY.

  Nothing controversial, and it all passes our regression test"

* 'stable-4.7' of git://git.infradead.org/users/pcmoore/audit:
  tty: provide tty_name() even without CONFIG_TTY
  audit: add tty field to LOGIN event
  audit: we don't need to __set_current_state(TASK_RUNNING)
  audit: cleanup prune_tree_thread

include/linux/audit.h

@@ -26,6 +26,7 @@
 #include <linux/sched.h>
 #include <linux/ptrace.h>
 #include <uapi/linux/audit.h>
+#include <linux/tty.h>
 
 #define AUDIT_INO_UNSET ((unsigned long)-1)
 #define AUDIT_DEV_UNSET ((dev_t)-1)
@@ -347,6 +348,23 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 	return tsk->sessionid;
 }
 
+static inline 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;
+}
+
+static inline void audit_put_tty(struct tty_struct *tty)
+{
+	tty_kref_put(tty);
+}
+
 extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp);
 extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode);
 extern void __audit_bprm(struct linux_binprm *bprm);
@@ -504,6 +522,12 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 {
 	return -1;
 }
+static inline struct tty_struct *audit_get_tty(struct task_struct *tsk)
+{
+	return NULL;
+}
+static inline void audit_put_tty(struct tty_struct *tty)
+{ }
 static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
 { }
 static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,

include/linux/tty.h

@@ -371,6 +371,7 @@ extern void proc_clear_tty(struct task_struct *p);
 extern struct tty_struct *get_current_tty(void);
 /* tty_io.c */
 extern int __init tty_init(void);
+extern const char *tty_name(const struct tty_struct *tty);
 #else
 static inline void console_init(void)
 { }
@@ -391,6 +392,8 @@ static inline struct tty_struct *get_current_tty(void)
 /* tty_io.c */
 static inline int __init tty_init(void)
 { return 0; }
+static inline const char *tty_name(const struct tty_struct *tty)
+{ return "(none)"; }
 #endif
 
 extern struct ktermios tty_std_termios;
@@ -415,7 +418,6 @@ static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
 	return tty;
 }
 
-extern const char *tty_name(const struct tty_struct *tty);
 extern const char *tty_driver_name(const struct tty_struct *tty);
 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
 extern int __tty_check_change(struct tty_struct *tty, int sig);

kernel/audit.c

@@ -64,7 +64,6 @@
 #include <linux/security.h>
 #endif
 #include <linux/freezer.h>
-#include <linux/tty.h>
 #include <linux/pid_namespace.h>
 #include <net/netns/generic.h>
 
@@ -430,7 +429,6 @@ restart:
 					attempts, audit_pid);
 				set_current_state(TASK_INTERRUPTIBLE);
 				schedule();
-				__set_current_state(TASK_RUNNING);
 				goto restart;
 			}
 		}
@@ -1341,15 +1339,14 @@ static inline void audit_get_stamp(struct audit_context *ctx,
 static long wait_for_auditd(long sleep_time)
 {
 	DECLARE_WAITQUEUE(wait, current);
-	set_current_state(TASK_UNINTERRUPTIBLE);
-	add_wait_queue_exclusive(&audit_backlog_wait, &wait);
 
 	if (audit_backlog_limit &&
-	    skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
+	    skb_queue_len(&audit_skb_queue) > audit_backlog_limit) {
+		add_wait_queue_exclusive(&audit_backlog_wait, &wait);
+		set_current_state(TASK_UNINTERRUPTIBLE);
 		sleep_time = schedule_timeout(sleep_time);
-
-	__set_current_state(TASK_RUNNING);
 		remove_wait_queue(&audit_backlog_wait, &wait);
+	}
 
 	return sleep_time;
 }
@@ -1890,21 +1887,14 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 {
 	const struct cred *cred;
 	char comm[sizeof(tsk->comm)];
-	char *tty;
+	struct tty_struct *tty;
 
 	if (!ab)
 		return;
 
 	/* tsk == current */
 	cred = current_cred();
-
-	spin_lock_irq(&tsk->sighand->siglock);
-	if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
-		tty = tsk->signal->tty->name;
-	else
-		tty = "(none)";
-	spin_unlock_irq(&tsk->sighand->siglock);
-
+	tty = audit_get_tty(tsk);
 	audit_log_format(ab,
 			 " ppid=%d pid=%d auid=%u uid=%u gid=%u"
 			 " euid=%u suid=%u fsuid=%u"
@@ -1920,11 +1910,11 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
 			 from_kgid(&init_user_ns, cred->egid),
 			 from_kgid(&init_user_ns, cred->sgid),
 			 from_kgid(&init_user_ns, cred->fsgid),
-			 tty, audit_get_sessionid(tsk));
-
+			 tty ? tty_name(tty) : "(none)",
+			 audit_get_sessionid(tsk));
+	audit_put_tty(tty);
 	audit_log_format(ab, " comm=");
 	audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
-
 	audit_log_d_path_exe(ab, tsk->mm);
 	audit_log_task_context(ab);
 }

kernel/audit_tree.c

@@ -661,10 +661,10 @@ static int tag_mount(struct vfsmount *mnt, void *arg)
 static int prune_tree_thread(void *unused)
 {
 	for (;;) {
+		if (list_empty(&prune_list)) {
 			set_current_state(TASK_INTERRUPTIBLE);
-		if (list_empty(&prune_list))
 			schedule();
-		__set_current_state(TASK_RUNNING);
+		}
 
 		mutex_lock(&audit_cmd_mutex);
 		mutex_lock(&audit_filter_mutex);
@@ -693,16 +693,14 @@ static int audit_launch_prune(void)
 {
 	if (prune_thread)
 		return 0;
-	prune_thread = kthread_create(prune_tree_thread, NULL,
+	prune_thread = kthread_run(prune_tree_thread, NULL,
 				"audit_prune_tree");
 	if (IS_ERR(prune_thread)) {
 		pr_err("cannot start thread audit_prune_tree");
 		prune_thread = NULL;
 		return -ENOMEM;
-	} else {
-		wake_up_process(prune_thread);
-		return 0;
 	}
+	return 0;
 }
 
 /* called with audit_filter_mutex */

kernel/auditsc.c

@@ -1980,6 +1980,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 {
 	struct audit_buffer *ab;
 	uid_t uid, oldloginuid, loginuid;
+	struct tty_struct *tty;
 
 	if (!audit_enabled)
 		return;
@@ -1987,14 +1988,17 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
 	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 old-ses=%u ses=%u res=%d",
-			 oldloginuid, loginuid, oldsessionid, sessionid, !rc);
+	audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+			 oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
+			 oldsessionid, sessionid, !rc);
+	audit_put_tty(tty);
 	audit_log_end(ab);
 }