Re: As 2.0 looms

Miquel van Smoorenburg (
Wed, 22 May 1996 20:36:54 +0200 (MET DST)

In article <>,
Alan Cox <> wrote:
>> Nope, there is no window, because the read() actually checks the same
>> things that "ptrace" checks. Notably, in order to be able to read the
>> process memory map, we must have the PF_PTRACED bit set, and then a suid
>> execve wouldn't succeed anyway.
>It depends when the read tests, we could start the read have PF_TRACED turn off
>and then exec a setuid program. If the read tests per byte we should be ok.

How Alan? The only process that can turn off the trace bit
_is_ the process doing the reading/mmaping...


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