--On Thursday, February 14, 2002 16:51:43 +0100 bert hubert <ahu@ds9a.nl>
wrote:
> When a process first issues setuid() and then goes on to create threads,
> those threads run under the setuid() uid - all is well.
>
> However, once the first thread is created, only the thread calling
> setuid() gets setuid in fact. All new threads continue to be created as
> root.
>
> This behaviour exists under 2.2.18 with glibc 2.1.3 and under 2.4.17 with
> glibc 2.2.5, and is shown using the brief program attached.
>
> Is this by design? It appears that all threads created get the uid of the
> thread manager process.
It's the expected behavior for a task-based model like Linux. Each task is
independent and inherits the uid/gid from whoever called clone(). It's
just one of several resources that are specified as process-wide in POSIX,
but are per-task in Linux.
I've been working on a patch to allow clone() to specify shared
credentials, but it's been on the back burner.
Dave McCracken
======================================================================
Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059
dmccr@us.ibm.com T/L 678-3059
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This archive was generated by hypermail 2b29 : Fri Feb 15 2002 - 21:01:02 EST