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Postings from October 2003
For some reason I haven't been able to fathom,
$) = $EGID;
$> = $EUID;
is NOT the equivalelent of
($), $>) = ($EUID, $EGID);
when running a setuid-root script, at least on Solaris and I suspect on all
platforms which support setreuid/setregid. In the list assignment case,
perl uses setreuid/setregid instead of serial calls to seteuid/setegid and
it gets the first parameter wrong:
setreuid(37845, 37845) = 0
:
setregid(10, 10) = 0
In this case, by specifying the uid of the invoking user as the first
parameter, perl is giving up root privilege, and therefore the ability to
set the euid/egid back to root at some future point. Am I going mad, or is
this broken? I can't see why a list assignment should result in different
system calls to a serial assignment.
According to the setreuid/setregid manpages, the first parameter (real
uid/gid) should be -1 to specify 'no change'. Either that, or perl should
use seteuid/setegid instead of setreuid/setregid, which is what is does in
the serial assignment case.
--
Alan Burlison
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