Re: CLONE_PID (was Re: Potential Threads security bug with LinuxThreads)

Andi Kleen (ak@muc.de)
26 Aug 1998 11:08:41 +0200


In article <19980825175126.B1221@dot.cygnus.com>,
Richard Henderson <rth@cygnus.com> writes:
> On Mon, Aug 24, 1998 at 01:51:20AM +0000, David Wragg wrote:
>> 2. The obvious deviations from POSIX threads: signal handling, wait etc.
> [...]
>> The reason I'm not tackling CLONE_PID is that I don't see what problem
>> it is supposed to solve.

> Primarily your point 2, that is, CLONE_PID is supposed to be the flag
> that indicates when a set of tasks (at least) share a common signal
> delivery queue.

> It may imply other things, such as the effect of exit. Currently this
> is handled with some particularly ugly atexit hooks; it would be nice
> for things to be done cleaner.

Another thing it should do is to broadcast all uid/gid/euid etc. changes
to all other threads that share the pid. Currently Linux has "per thread
permissions", that differs from all other Unixes I know and it is a
potential security problem.

-Andi

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