On 12/31/05, Stewart Stremler <[EMAIL PROTECTED]> wrote:
> begin quoting Carl Lowenstein as of Sat, Dec 31, 2005 at 08:35:07AM -0800:
> [snip]
> > As a side thought, consider the difficulty of including the checksum
> > value itself in the data to be checksummed. You can't change one
> > without the other.
>
> Depending on the algorithm, it isn't _that_ hard.
>
> MD5 or SHA hashes, yes, that would be a problem.
>
> -Stewart "Easier yet if you give yourself a scratch space" Stremler
You can learn a lot if you look in the right place. But it takes a
while to find the place. Also requires that you install the
anaconda-runtime package.
- - - - - - - -
$ cat /usr/share/doc/anaconda-10.1.0.2/mediacheck.txt
Mediacheck documentation
August, 2002
Mediacheck is a tool we use to test the integrity of ISO images. The
ISO9660 specification allows for a 512 byte region which is for
application use. We use it to store a checksum of the ISO image. Of
couse putting the checksum into this region will change the checksum
of the final ISO image, so when we verify the checksum later we have
to fill in this 512 region with the original contents before the
implantation. It is set to all ASCII 32 decimal spaces.
If you have a set of ISO images you can implant the checksum data with
this command:
implantmd5iso <isoname>
NOTE: You cannot re-implant an ISO once its been implanted.
To check a ISO image you can use this command line:
checkisomd5 <isoname>
The tools are in the anaconda-runtime package, currently in the
/usr/lib/anaconda-runtime/ directory.
- - - - - - - -
carl
--
carl lowenstein marine physical lab u.c. san diego
[EMAIL PROTECTED]
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