[Lucid CVE-2012-6544 2/2] Bluetooth: HCI - Fix info leak in getsockopt(HCI_FILTER)

[Luis Henriques]

From: Mathias Krause <minipli at googlemail.com>

CVE-2012-6544

BugLink: http://bugs.launchpad.net/bugs/1156751

The HCI code fails to initialize the two padding bytes of struct
hci_ufilter before copying it to userland -- that for leaking two
bytes kernel stack. Add an explicit memset(0) before filling the
structure to avoid the info leak.

Signed-off-by: Mathias Krause <minipli at googlemail.com>
Cc: Marcel Holtmann <marcel at holtmann.org>
Cc: Gustavo Padovan <gustavo at padovan.org>
Cc: Johan Hedberg <johan.hedberg at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit e15ca9a0ef9a86f0477530b0f44a725d67f889ee)

Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/bluetooth/hci_sock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 4b48a25..7e1ea29 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -577,6 +577,7 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname, char
 		{
 			struct hci_filter *f = &hci_pi(sk)->filter;
 
+			memset(&uf, 0, sizeof(uf));
 			uf.type_mask = f->type_mask;
 			uf.opcode    = f->opcode;
 			uf.event_mask[0] = *((u32 *) f->event_mask + 0);
-- 
1.8.1.2