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authorEric Paris <eparis@redhat.com>2008-10-31 17:40:00 -0400
committerJames Morris <jmorris@namei.org>2008-11-01 09:38:48 +1100
commit37dd0bd04a3240d2922786d501e2f12cec858fbf (patch)
treed4fa5a124a95d33bf22276429a82822ec8d4810a /security/selinux
parent721d5dfe7e516954c501d5e9d0dfab379cf4241a (diff)
downloadlinux-2.6.38-lt-ux500-37dd0bd04a3240d2922786d501e2f12cec858fbf.tar.gz
SELinux: properly handle empty tty_files list
SELinux has wrongly (since 2004) had an incorrect test for an empty tty->tty_files list. With an empty list selinux would be pointing to part of the tty struct itself and would then proceed to dereference that value and again dereference that result. An F10 change to plymouth on a ppc64 system is actually currently triggering this bug. This patch uses list_empty() to handle empty lists rather than looking at a meaningless location. [note, this fixes the oops reported in https://bugzilla.redhat.com/show_bug.cgi?id=469079] Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/selinux')
-rw-r--r--security/selinux/hooks.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3e3fde7c1d2..f85597a4d73 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;