Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  SELinux: properly handle empty tty_files list

1 files changed, 5 insertions, 3 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3e3fde7c1d2b..f85597a4d733 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2126,14 +2126,16 @@ static inline void flush_unauthorized_files(struct files_struct *files)
         tty = get_current_tty();
         if (tty) {
                 file_list_lock();
-                file = list_entry(tty->tty_files.next, typeof(*file), f_u.fu_list);
-                if (file) {
+                if (!list_empty(&tty->tty_files)) {
+                        struct inode *inode;
+
                         /* Revalidate access to controlling tty.
                            Use inode_has_perm on the tty inode directly rather
                            than using file_has_perm, as this particular open
                            file may belong to another process and we are only
                            interested in the inode-based check here. */
-                        struct inode *inode = file->f_path.dentry->d_inode;
+                        file = list_first_entry(&tty->tty_files, struct file, f_u.fu_list);
+                        inode = file->f_path.dentry->d_inode;
                         if (inode_has_perm(current, inode,
                                            FILE__READ | FILE__WRITE, NULL)) {
                                 drop_tty = 1;