af_packet: prevent information leak
In 2.6.27, commit 393e52e33c6c2 (packet: deliver VLAN TCI to userspace)
added a small information leak.
Add padding field and make sure its zeroed before copy to user.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ba248d9..c0c3cda 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -804,6 +804,7 @@
} else {
h.h2->tp_vlan_tci = 0;
}
+ h.h2->tp_padding = 0;
hdrlen = sizeof(*h.h2);
break;
default:
@@ -1736,6 +1737,7 @@
} else {
aux.tp_vlan_tci = 0;
}
+ aux.tp_padding = 0;
put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
}