Messages in this thread |  | | Date | Sun, 30 Jun 1996 23:34:17 +0200 | From | JF Martinez <> | Subject | Re: Network performance |
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Date: Sat, 29 Jun 1996 17:04:06 -0700 From: "Leonard N. Zubkoff" <lnz@dandelion.com> Cc: bruce@otherother.com, linux-kernel@vger.rutgers.edu Sender: owner-linux-kernel@vger.rutgers.edu Precedence: bulk
Date: Sat, 29 Jun 1996 16:18:02 -0600 (CST) From: Aaron Ucko <UCKO@vax1.rockhurst.edu>
Interesting...how was this made secure? The OS must have implemented shared libs in such a way that library code was privileged but user code wasn't... I don't even want to THINK about statically linked binaries! :-) Reminds me of Hurd, though.
Why does the library code need to be privileged? Read and write can be built out of memory mapping primitives without security problems so long as the kernel implements the proper access rights on the underlying mapped object. Naturally, installing a new type manager required the appropriate access rights itself. As for static linking, the global libraries were *never* statically linked into anything. It just wasn't possible or necessary.
Leonard
The system of privileged libraries is used in IBM's MVS (don't shoot, please) it would be nice to have it for SVGAlib games. Running suid root too much programs and specially games makes me nervous: it is an open door to virusses. With privileged libraries the program would be suid root only when executing library code (got from a secure source) and not the entire game you don't know where it comes from.
But in Linux we could get protection for EXT2FS filesystems even from suid root programs by running in secure mode and having all the binaries marked not modifiable. I don't know if that protects against using the block special file however.
--
Jean Francois Martinez
Join the Free World side in the holy war against Microsoft's Evil Empire. (Ronald Reagan)
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