netdev - Re: [PATCH] Multicast packet reassembly can fail

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: <4AE780CB.8070401@hp.com>
Date:	Tue, 27 Oct 2009 16:22:51 -0700
From:	Rick Jones <rick.jones2@...com>
To:	Steve Chen <schen@...sta.com>
CC:	netdev@...r.kernel.org
Subject: Re: [PATCH] Multicast packet reassembly can fail

Steve Chen wrote:
> Multicast packet reassembly can fail
> 
> When multicast connections with multiple fragments are received by the same
> node from more than one Ethernet ports, race condition between fragments
> from each Ethernet port can cause fragment reassembly to fail leading to
> packet drop.  This is because packets from each Ethernet port appears identical
> to the the code that reassembles the Ethernet packet.
> 
> The solution is evaluate the Ethernet interface number in addition to all other
> parameters so that every packet can be uniquely identified.  The existing
> iif field in struct ipq is now used to generate the hash key, and iif is also
> used for comparison in case of hash collision.
> 
> Please note that q->saddr ^ (q->iif << 5) is now being passed into
> ipqhashfn to generate the hash key.  This is borrowed from the routing
> code.
> 
> Signed-off-by: Steve Chen <schen@...sta.com>
> Signed-off-by: Mark Huth <mhuth@...sta.com>

It has been hours since my last good Emily Litella moment so I'll ask - isn't 
the combination of source and dest addr, protocol, IP ID and fragment offset 
supposed to take care of this?  How does the ingress interface have anything to 
do with it?

rick jones
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html