econet: 4 byte infoleak to the network

BugLink: http://bugs.launchpad.net/bugs/761134

commit 67c5c6cb8129c595f21e88254a3fc6b3b841ae8e upstream.

struct aunhdr has 4 padding bytes between 'pad' and 'handle' fields on
x86_64.  These bytes are not initialized in the variable 'ah' before
sending 'ah' to the network.  This leads to 4 bytes kernel stack
infoleak.

This bug was introduced before the git epoch.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Acked-by: Phil Blundell <philb@gnu.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index 0c28263..116d3fd 100644 (file)
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -435,10 +435,10 @@ static int econet_sendmsg(struct kiocb *iocb, struct socket *sock,
                udpdest.sin_addr.s_addr = htonl(network | addr.station);
        }
 
+       memset(&ah, 0, sizeof(ah));
        ah.port = port;
        ah.cb = cb & 0x7f;
        ah.code = 2;            /* magic */
-       ah.pad = 0;
 
        /* tack our header on the front of the iovec */
        size = sizeof(struct aunhdr);