Bugtraq mailing list archives

Re: Race conditions - patch.


From: deraadt () CVS OPENBSD ORG (Theo de Raadt)
Date: Mon, 23 Feb 1998 00:42:50 -0700


Here's my kernel patch. This one should finally (?) stop typical
race conditions, including pipe attacks and regular file races.
This solution is radical (disallows writing to not-your pipes and
files in +t directories), but works fine. Even if any program
fails, it may be easily patched to store it's files in eg. /tmp
subdir. It's much easier to change one path than to fix a lot
of vunerable utilities.

I must say this, though I suspect Aleph1 will be starting to get
annoyed at both sides of this silly discussion:

I am quite fascinated at the extent to which people will go to avoid
fixing the /tmp races in the programs in question.

To me it is quite clear that your patches are breaking the
expectations which regular code has in a POSIX/UNIX environment,
ie. expectations that /tmp works.

Perhaps your next patch will make it impossible to create directories
or files in /tmp.

Because, as I am sure you do realize, it is very easy to effect denial
of service attacks by creating a directory where a program expects a
file, or a file where a program expects to create a directory.

So... how much longer is this futile slashing going to continue?



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