Messages in this thread | | | Date | Mon, 12 Apr 2004 15:02:52 -0700 | From | Chris Wright <> | Subject | Re: fix must_not_trace_exec() test |
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* Andy Lutomirski (luto@myrealbox.com) wrote: > Olaf Dietsche wrote: > > Although, I'd rather not lump together unrelated tests without > > renaming must_not_trace_exec(). Btw, can someone enlighten me what > > this atomic_read() test is all about. > > I assumed that the test was to check if the caller is a thread, but that > sounds odd -- wouldn't it stop being a thread after the exec anyway? > Maybe that part happens after compute_creds, so this prevents a race? > Although I don't see how it could be triggered if the thread never > entered usermode before getting a new fs/files/sighand.
There's no requirement for CLONE_THREAD when using at least CLONE_FS and CLONE_FILES. And all of the latter are inherited across execve(). These tests are needed to keep a malicious program from controlling the setuid program in ways other than ptrace.
thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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