[quagga-dev 11563] Re: MD5 packet validation tool

Paul Jakma paul at jakma.org
Wed Oct 8 10:51:21 BST 2014


Fancy slapping some kind of suitable licence header on it, and we could 
stick it in tools/? :)



On Fri, 28 Mar 2014, Daniel Walton wrote:

> I spent some time fighting a MD5 bug recently and needed a way to determine if the sender was actually generating a bad MD5 signature or if the receiver was just intrepreting it incorrectly.  I wrote a little python tool that will calculate the MD5 signature of a packet.  I couldn't find anything like this online so here it is (attached) in case anyone else has to debug MD5 signatures.
> dwalton at hydra-06[~]# ./md5-sanity.py --help
> usage: md5-sanity.py [-h] packet signature password
> positional arguments:
>  packet      A hex dump of the entire packet
>  signature   A hex dump of the MD5 signature in the packet
>  password    The password for the TCP session
> optional arguments:
>  -h, --help  show this help message and exit
> dwalton at hydra-06[~]#
> dwalton at hydra-06[~]# ./md5-sanity.py 00020000000400020000000b080045c0004f547540000106e46f1e0102011e0102028b6e00b3d3678760009393a0a018003ef5a3000001011312c54024f52dcfcc96aa36b737d09d7fd3ffffffffffffffffffffffffffffffff001304 c54024f52dcfcc96aa36b737d09d7fd3 FOO
> IP Header Length: 20
> IP Source Address:
> IP Destination Address:
> Protocol: 6
> TCP Total Length: 59
> TCP Header Length: 40
> TCP Payload Length: 19
> Generate the MD5 signature for the following payload:
> 1E010201 1E010202 0006003B 8B6E00B3
> D3678760 009393A0 A018003E 00000000
> 00130446 4F4F
> This packet contains a valid MD5 signature:
> MD5 In Payload  : 0xC54024F52DCFCC96AA36B737D09D7FD3
> MD5 Calculated  : 0xC54024F52DCFCC96AA36B737D09D7FD3
> dwalton at hydra-06[~]#
> Daniel

Paul Jakma	paul at jakma.org	@pjakma	Key ID: 64A2FF6A
 	"If he learns from his mistakes, pretty soon he'll know everything."

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