linux security - Mar 1998 - Re: Re: Re: Towards a solution of tmp-file problems (fwd)

Forwarding a message from Steve \"Stevers!\"
Coile:
> This is already possible.  Create the file then unlink it.  The file
> contents aren''t deleted and i-node isn''t released until
the file is
> closed.
Without kernel support, unlinking the file at creation time requires
a code change in the process which creates the file. And this doesn''t
protect scripts which use temp files for communication between their
subprocesses, e.g.

#!/bin/sh

cat > /tmp/a.$$
awk '' { print $1 } '' < /tmp.a.$$ | sort -o /tmp/field1.$$
awk '' { print $2 } '' < /tmp.a.$$ | sort -o /tmp/field2.$$
paste /tmp/field1.$$ /tmp/field2.$$
rm -f /tmp/a.$$ /tmp/field1.$$ /tmp/field2.$$
exit 0

A private namespace protects this script and its subprocesses by making the
files _totally_ inaccessible to unrelated processes. The private namespace
can be imposed from above or the script can define its own.

Nick.
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