packet: fix heap info leak in PACKET_DIAG_MCLIST sock_diag interface

[ Upstream commit 309cf37fe2a781279b7675d4bb7173198e532867 ]

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@googlemail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index da1ae0e13cb5b413ddc627a2c841b2fbc1820823..9cc7b512b4722ad300b887644022ef0fdcf25b64 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3436,6 +3436,7 @@ 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;