/tmp races in gcc.c [Fwd]

[Marc Lehmann]

On Thu, Jan 22, 1998 at 10:29:55PM -0800, Joe Buck wrote:
> 
> > >If the temporary filenames are essentially unpredictable (e.g.  pid plus a
> > >sequence of randomly generated characters), it should defeat this hack and
> > >reduce the probability of collision to an arbitrarily low value.  In the
> > >meantime paranoid folks can set TMPDIR to a directory only they can read
> > >or write (e.g. /root/tmp).  This defeats the hack.
> > 
> > Please don't do this! there are sooo many bad programs out there
> > using this (bogus!) kind of "fix"...
> 
> Yeah, like most public-key cryptosystems.  You think they are all broken?

yes... do you want to make an implementation for gcc? look at how pgp does
it, or other programs...

it's so difficult to get this right, and a compiler is definitely not
the place to implement it.

> Remember, good crypto means open algorithms, so if you do it right the
> fact that the bad guy has the source code does not help.  The trick is
> to get enough entropy that can't be observed.

yes.. please implement it.. do it portably, though.

> > there is no such thing as a random character sequence (which is accaptable
> > for implementation in gcc), and you can be sure the exploit for any scheme
> > you might device is available within hours/days of it's creation..
> 
> If you are so convinced that these types of schemes can always be quickly
> defeated, then I'll assume you are a world-class cryptanalyst, and
> defeating SSL connections is no challenge for you.

no, the point was that no such algorithm (which are complex, btw)
should go into gcc.

> Anything that slows gcc down is not acceptable.  It is already much
> slower than many competing compilers.  Making a directory is a very
> expensive operation in many situations.

as is making cryptographically strong random numbers.

again, I was not saying it's impossible.. I just said most implementations
are either broken, or very expensive.

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