linux-kernel - [PATCH 3.10 124/143] packet: fix heap info leak in PACKET_DIAG_MCLIST sock

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Date:	Sun,  5 Jun 2016 12:20:27 +0200
From:	Willy Tarreau <w@....eu>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Mathias Krause <minipli@...glemail.com>,
	"Eric W . Biederman" <ebiederm@...ssion.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	"David S . Miller" <davem@...emloft.net>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 124/143] packet: fix heap info leak in PACKET_DIAG_MCLIST sock_diag interface

From: Mathias Krause <minipli@...glemail.com>

commit 309cf37fe2a781279b7675d4bb7173198e532867 upstream.

Because we miss to wipe the remainder of i->addr[] in packet_mc_add(),
pdiag_put_mclist() leaks uninitialized heap bytes via the
PACKET_DIAG_MCLIST netlink attribute.

Fix this by explicitly memset(0)ing the remaining bytes in i->addr[].

Fixes: eea68e2f1a00 ("packet: Report socket mclist info via diag module")
Signed-off-by: Mathias Krause <minipli@...glemail.com>
Cc: Eric W. Biederman <ebiederm@...ssion.com>
Cc: Pavel Emelyanov <xemul@...allels.com>
Acked-by: Pavel Emelyanov <xemul@...tuozzo.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Willy Tarreau <w@....eu>
---
 net/packet/af_packet.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 39fa339..2d454a2 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2997,6 +2997,7 @@ static int packet_mc_add(struct sock *sk, struct packet_mreq_max *mreq)
 	i->ifindex = mreq->mr_ifindex;
 	i->alen = mreq->mr_alen;
 	memcpy(i->addr, mreq->mr_address, i->alen);
+	memset(i->addr + i->alen, 0, sizeof(i->addr) - i->alen);
 	i->count = 1;
 	i->next = po->mclist;
 	po->mclist = i;
-- 
2.8.0.rc2.1.gbe9624a