Date: Thu, 26 Mar 1998 16:25:34 -0800 (PST) From: David Wolfskill <dhw@whistle.com> To: freebsd-questions@FreeBSD.ORG Subject: amd, NFS, & set[GU]ID flags (2.2.6-BETA) Message-ID: <199803270025.QAA01598@pau-amma.whistle.com>
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OK; I'm running 2.2.6-BETA as of about a week ago.
I have a filesystem mounted (via NFS & amd); the amd spec says "nosuid,
grpid".
I built a program (top) on that filesystem as a setGID, owned by
root.kmem, which matches the permissions for /dev/mem.
I try running the program; get "Permission denied" for /dev/mem.
I try runing the program under "sudo"; it works fine.
I try copying the file ("cp -p") to /tmp & running it (normally --
no "sudo") from there; it works fine. (/tmp is *not* mounted via
NFS.)
I fired up a dumb little hack of a program that I cobbled up a while
back (to list mounted filesystems & the mount flags); the relevant
"flags" field for the filesystem in question reads 00000008,
which (according to /usr/include/sys/mount.h) is MNT_NOSUID; the
associated comment reads "/* don't honor setuid bits on fs */"
Here's where things get "interesting": I don't see a flag for "do
[not] honor setgid bits on fs". And the empirical evidence at hand
suggests that quite possibly, the MNT_NOSUID flag is being used
for both setuid & setgid.... I will prowl around a bit... but
since I'm still rather new to the FreeBSD world, I would appreciate any
"course corrections" that might be appropriate.
(BTW: I had earlier inquired as to a way to determine the "NFS mount
option flags" empirically. Never did find a way to do this, but I did
finally(!) discover the "nfsvs" option for the amd spec, and since I
implemented that, my machine seems significantly more stable....)
Thanks,
david
--
David Wolfskill dhw@whistle.com (650) 577-7158 pager: (650) 401-0168
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