netdev - RE: [net-next-2.6 PATCH 6/9] vxge: Check if FCS stripping is disabled by the firmware.

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]

Date:	Tue, 6 Oct 2009 02:41:26 -0400
From:	"Ramkrishna Vepa" <Ramkrishna.Vepa@...erion.com>
To:	"Eric Dumazet" <eric.dumazet@...il.com>,
	"Sreenivasa Honnur" <Sreenivasa.Honnur@...erion.com>
Cc:	<davem@...emloft.net>, <netdev@...r.kernel.org>
Subject: RE: [net-next-2.6 PATCH 6/9] vxge: Check if FCS stripping is disabled by the firmware.

> > - Added a function to check if FCS stripping is disabled by the
> firmware, if
> >   it is not disabled fail driver load.
> >
> > - By default FCS stripping is disabled by the firmware. With this
> assumption
> >   driver decrements the indicated packet length by 4 bytes(FCS
length).
> >
> > - This patch ensures that FCS stripping is disabled during driver
load
> time.
> >
> > Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@...erion.com>
> 
> What the big deal about FCS not being stripped ?
[Ram] The minimum frame size that can be received by the hardware is 57
Bytes. A 64 Byte Ethernet frame with the vlan tag and fcs stripped will
result in a 56 Byte frame which will lock up the receive engine. The
work around is to disable fcs stripping in the hardware which is a
privileged operation done with a firmware version that the driver checks
for currently.

Ram
--
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