Hanno Böck <[email protected]> writes:
> I did a quick fuzzing test of the command line tools coming with nettle.
Fixes checked in now.
> echo "{MiM}"|sexp-conv
> causes an assert:
> sexp-conv:
> /var/tmp/portage/dev-libs/nettle-3.2/work/nettle-3.2/tools/input.c:128:
> sexp_input_start_coding: Assertion `!input->coding' failed.
This one was interesting. {} indicates "transport syntax", which is
canonical syntax wrapped in base64 encoding. MiM is not a valid base64
encoding, but it nevertheless decodes to the two characters "2#" before
the truncation is detected. And "2#" is the start of hex string in
advanced syntax, but invalid in canonical syntax.
The code used to improperly accept it as a hex string and configure the
input for base16 decoding. And then triggered an assertion failure
because the code wasn't prepared to handle several layers of decoding,
with base16 inside base64.
This case (and other uses of advanced syntax in this context) should now
be rejected with an error message.
Regards,
/Niels
--
Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26.
Internet email is subject to wholesale government surveillance.
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