netdev - Re: net/packet: use-after-free in packet_rcv

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170209151220.GA4843@oracle.com>
Date:   Thu, 9 Feb 2017 07:12:20 -0800
From:   Sowmini Varadhan <sowmini.varadhan@...cle.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     David Miller <davem@...emloft.net>,
        Willem de Bruijn <willemb@...gle.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Daniel Borkmann <daniel@...earbox.net>, jarno@....org,
        philip.pettersson@...il.com, weongyo.linux@...il.com,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        syzkaller <syzkaller@...glegroups.com>
Subject: Re: net/packet: use-after-free in packet_rcv_fanout

On (02/09/17 14:14), Dmitry Vyukov wrote:
> 
> Call Trace:
   :
>  packet_rcv_has_room+0x25/0xb0 net/packet/af_packet.c:1308
>  fanout_demux_rollover+0x3bb/0x6b0 net/packet/af_packet.c:1388
>  packet_rcv_fanout+0x674/0x800 net/packet/af_packet.c:1490
>  dev_queue_xmit_nit+0x73a/0xa90 net/core/dev.c:1898
    :
>  tcp_sendmsg_fastopen net/ipv4/tcp.c:1110 [inline]
    :

looks like a race between a NIT socket (tcpdump, maybe?) that is closing,
and a standard tcp socket.. packet_release() takes the po->bind_lock
to remove the socket from the ptype_all NIT queue. but how does
that sync with the Tx path for other af_inet/af_inet6 sockets? 

--Sowmini