[tz] [PROPOSED PATCH 2/2] Use lz format for new tarball

Clive D.W. Feather clive at davros.org
Sat Aug 27 20:36:26 UTC 2016


Random832 said:
> "Not only data at a random position are interpreted as the CRC. Whatever
> data that follow the bogus CRC will be interpreted as the beginning of
> the following field, preventing the successful decoding of any remaining
> data in the stream. "
> 
> What are the odds that the bytes found there will coincidentally match
> the CRC of the short data? And won't a corrupted length field always
> prevent the successful decoding of any remaining data, regardless of how
> the CRC is stored relative to it?

Not necessarily.

There's a situation with Bluetooth where a 1-bit corruption of the length
field results in the wrong bytes being examined for the CRC *but* only one
byte of the CRC is actually independent. If that has the right value, it
doesn't matter what the rest of the "CRC" is; the CRC calculation comes out
right.

-- 
Clive D.W. Feather          | If you lie to the compiler,
Email: clive at davros.org     | it will get its revenge.
Web: http://www.davros.org  |   - Henry Spencer
Mobile: +44 7973 377646


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