From: Eric Dumazet Date: Tue, 7 Jun 2011 05:42:06 +0000 (-0700) Subject: af_packet: prevent information leak X-Git-Tag: v2.6.27.60~12 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6e4e58898f4bb7e512f939fd89c0f5ad9b4939ae;p=thirdparty%2Fkernel%2Fstable.git af_packet: prevent information leak [ Upstream commit 13fcb7bd322164c67926ffe272846d4860196dc6 ] 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 CC: Patrick McHardy Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h index 18db0668065a6..025ec33fbc82b 100644 --- a/include/linux/if_packet.h +++ b/include/linux/if_packet.h @@ -61,6 +61,7 @@ struct tpacket_auxdata __u16 tp_mac; __u16 tp_net; __u16 tp_vlan_tci; + __u16 tp_padding; }; struct tpacket_hdr @@ -93,6 +94,7 @@ struct tpacket2_hdr __u32 tp_sec; __u32 tp_nsec; __u16 tp_vlan_tci; + __u16 tp_padding; }; #define TPACKET2_HDRLEN (TPACKET_ALIGN(sizeof(struct tpacket2_hdr)) + sizeof(struct sockaddr_ll)) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 45dfb9476295d..150dd52b7e32e 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -708,6 +708,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe h.h2->tp_sec = ts.tv_sec; h.h2->tp_nsec = ts.tv_nsec; h.h2->tp_vlan_tci = skb->vlan_tci; + h.h2->tp_padding = 0; hdrlen = sizeof(*h.h2); break; default: @@ -1181,6 +1182,7 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, aux.tp_net = skb_network_offset(skb); aux.tp_vlan_tci = skb->vlan_tci; + aux.tp_padding = 0; put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux); }