Ben Laurie wrote:
>
> Holger Reif wrote:
> >
> > Dr Stephen Henson schrieb:
> > >
> > > Hmmm. A similar could happen with the PKCS#7 and certificate routines:
> > > some PKCS#7 implementations don't correctly sort authenticated
> > > attributes and some certificates are filled with horrible stuff like
> > > indefinite length encoding. The usual workaround is to verify the
> > > signature on the original data or order rather than a re-encoded version
> > > of it: this is done in a few places already.
> >
> > This discussion has a long history. There has been a
> > discussion with eric on this behalf long ago. But
> > AFAIR Eric was not convinced to make signature
> > verification on the original data. Perhaps he
> > believed that eventually the correct solution (tm)
> > only will survive ;-)
>
> I agree with Eric, though an ability to enable buggy behaviour is also
> acceptable.
>
Well ideally you shouldn't have to verify signatures on the original
data.
In practice if you completely re-encode certificates a large proportion
of them will fail a signature: including those made with previous
version of SSLeay itself! So many in fact that it would render such
"correct" software useless.
The only reason this doesn't happpen at present and hasn't in the past
is because not all of a certificate is decoded: some things like
certificate extensions are kept as a "blob". So it could be argued that
it partially verifies signatures on the original data already.
To give one example...
The BIT STRING should not have any trailing zeros in its encoding unless
it is used to contain another structure (e.g. legacy cases like public
keys and digital signatures in certificates). Lots of certificates don't
follow this rule with things like netscape-certificate-type and
keyUsage. SSLeay didn't follow this either: OpenSSL does.
Steve.
--
Dr Stephen N. Henson. http://www.drh-consultancy.demon.co.uk/
Personal Email: [EMAIL PROTECTED]
Senior crypto engineer, Celo Communications: http://www.celocom.com/
Core developer of the OpenSSL project: http://www.openssl.org/
Business Email: [EMAIL PROTECTED] PGP key: via homepage.
______________________________________________________________________
OpenSSL Project http://www.openssl.org
Development Mailing List [EMAIL PROTECTED]
Automated List Manager [EMAIL PROTECTED]
