From b20c8122a3204496fca8b5343c93b60fe11dad04 Mon Sep 17 00:00:00 2001
From: Stephen Smalley <sds@tycho.nsa.gov>
Date: Mon, 25 Sep 2006 23:32:03 -0700
Subject: [PATCH] [PATCH] selinux: fix tty locking
Take tty_mutex when accessing ->signal->tty in selinux code. Noted by Alan
Cox. Longer term, we are looking at refactoring the code to provide better
encapsulation of the tty layer, but this is a simple fix that addresses the
immediate bug.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
security/selinux/hooks.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 55cec4d6f1174..e4d81a42fca42 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1689,10 +1689,12 @@ static inline void flush_unauthorized_files(struct files_struct * files)
{
struct avc_audit_data ad;
struct file *file, *devnull = NULL;
- struct tty_struct *tty = current->signal->tty;
+ struct tty_struct *tty;
struct fdtable *fdt;
long j = -1;
+ mutex_lock(&tty_mutex);
+ tty = current->signal->tty;
if (tty) {
file_list_lock();
file = list_entry(tty->tty_files.next, typeof(*file), f_u.fu_list);
@@ -1712,6 +1714,7 @@ static inline void flush_unauthorized_files(struct files_struct * files)
}
file_list_unlock();
}
+ mutex_unlock(&tty_mutex);
/* Revalidate access to inherited open files. */
--
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