[PATCH] caching daemon release and nsswitch patches

Jilles Tjoelker jilles at stack.nl
Wed Aug 31 19:48:17 GMT 2005

On Wed, Aug 31, 2005 at 11:18:19PM +0400, Michael Bushkov wrote:
> >On Tue, Aug 30, 2005 at 05:32:52PM +0400, Michael Bushkov wrote:
> >>We can't ensure that, I guess. In the upcoming version (before the 1st of
> >>September), the cache would be per-user. This would solve all the security
> >>problems. In a little while, I'll implement the ability for cached to act
> >>as nscd. So you'll be able to choose the behaviour.

> >What about setuid/setgid programs then?

> >setuid root programs can use root's cache, perhaps a similar thing could
> >be done for other setuid programs, but what about setgid?

> >perhaps don't cache at all for set*id programs (issetugid(2))?
> Per-user cache uses euid as the user identifier. So every setuid program
> will use the cache, which corresponds to its euid.
> But how can setgid affect the cache operations? Do you see some potential 
> issue?

User X puts some garbled information in the cache for his uid, then
starts a setgid program. That setgid program will use the bad data
in the cache which is potentially exploitable.

Jilles Tjoelker

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