lkml.org 
[lkml]   [2011]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRe: [held lock freed] Re: [GIT] Networking
Date
On Monday 21 March 2011, Eric Dumazet wrote:
> > diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
> > index 4680b1e..b2cf1db 100644
> > --- a/net/x25/af_x25.c
> > +++ b/net/x25/af_x25.c
> > @@ -669,8 +669,8 @@ static int x25_release(struct socket *sock)
> >
> > sock_orphan(sk);
> > out:
> > - release_sock(sk);
> > sock_put(sk);
> > + release_sock(sk);
> > return 0;
> > }
> >
>
> Hmm, x25_release() looks fine, I believe no fix is needed.
>

D'oh. You're right of course. My patch would introduce the bug,
not fix it. Updated patch below.

Arnd
8<-------------------------
net/appletalk: fix atalk_release use after free

The BKL removal in appletalk introduced a use-after-free problem,
where atalk_destroy_socket frees a sock, but we still release
the socket lock on it.

An easy fix is to take an extra reference on the sock and sock_put
it when returning from atalk_release.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

index 3d4f4b0..206e771 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1051,6 +1051,7 @@ static int atalk_release(struct socket *sock)
{
struct sock *sk = sock->sk;

+ sock_hold(sk);
lock_sock(sk);
if (sk) {
sock_orphan(sk);
@@ -1058,6 +1059,8 @@ static int atalk_release(struct socket *sock)
atalk_destroy_socket(sk);
}
release_sock(sk);
+ sock_put(sk);
+
return 0;
}


\
 
 \ /
  Last update: 2011-03-21 16:25    [W:0.065 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site