[PATCH 1/1] Correct OSPF checksum validation

Ondrej Zajicek santiago at crfreenet.org
Tue Apr 28 13:47:31 CEST 2015


On Sun, Apr 26, 2015 at 05:10:11PM +0100, Chris Boot wrote:
> Prior to this patch, BIRD validates the OSPF LSA checksum by calculating
> a new checksum and comparing it with the checksum in the header. Due to
> the specifics of the Fletcher checksum used in OSPF, this is not
> necessarily correct as the checkbytes in the header may be calculated
> via a different means and end up with a different value that is
> nonetheless still correct.
> 
> The documented means of validating the checksum as specified in RFC 905
> B.4 is to calculate c0 and c1 from the unchanged contents of the packet,
> which must result in a zero value to be considered valid.
> 
> Signed-off-by: Chris Boot <bootc at bootc.net>

Thanks, merged.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: Digital signature
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20150428/cc8bfa40/attachment.asc>


More information about the Bird-users mailing list