2006-08-24 13:11:40

by Stephen Smalley

Subject: [patch 1/1] 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 <[email protected]>

---

security/selinux/hooks.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5d1b8c7..4b0f904 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1711,10 +1711,12 @@ static inline void flush_unauthorized_fi
{
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);
@@ -1734,6 +1736,7 @@ static inline void flush_unauthorized_fi
}
file_list_unlock();
}
+ mutex_unlock(&tty_mutex);

/* Revalidate access to inherited open files. */


--
Stephen Smalley
National Security Agency

2006-08-24 13:47:25

by Alan

Subject: Re: [patch 1/1] selinux: fix tty locking

Ar Iau, 2006-08-24 am 09:13 -0400, ysgrifennodd Stephen Smalley:
> 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 <[email protected]>

Acked-by: Alan Cox <[email protected]>

2006-08-24 15:02:10

by James Morris

Subject: Re: [patch 1/1] selinux: fix tty locking

On Thu, 24 Aug 2006, Stephen Smalley wrote:

> 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 <[email protected]>

Acked-by: James Morris <[email protected]>




--
James Morris
<[email protected]>