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    Subject[31/35] af_packet: prevent information leak
    2.6.32-longterm review patch.  If anyone has any objections, please let us know.

    ------------------


    From: Eric Dumazet <eric.dumazet@gmail.com>

    [ 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 <eric.dumazet@gmail.com>
    CC: Patrick McHardy <kaber@trash.net>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    ---
    include/linux/if_packet.h | 2 ++
    net/packet/af_packet.c | 2 ++
    2 files changed, 4 insertions(+)

    --- a/include/linux/if_packet.h
    +++ b/include/linux/if_packet.h
    @@ -63,6 +63,7 @@ struct tpacket_auxdata
    __u16 tp_mac;
    __u16 tp_net;
    __u16 tp_vlan_tci;
    + __u16 tp_padding;
    };

    /* Rx ring - header status */
    @@ -103,6 +104,7 @@ 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))
    --- a/net/packet/af_packet.c
    +++ b/net/packet/af_packet.c
    @@ -767,6 +767,7 @@ static int tpacket_rcv(struct sk_buff *s
    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:
    @@ -1499,6 +1500,7 @@ static int packet_recvmsg(struct kiocb *
    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);
    }




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