posix/wordexp-tst.sh

[Joseph S. Myers]

I wrote:

> posix/wordexp-tst.sh leaves its output files behind in TMPDIR after
> running, if TMPDIR is set.  If TMPDIR were set to a shared directory for
> some reason (e.g. set to /var/tmp because of /tmp being full), the usual
> symlink attacks also apply.

Grepping for /tmp|TMPDIR shows several more /tmp symlink holes that are
open during a glibc make check.  Suggestion: always use the build
directory for temporary files during testing, irrespective of TMPDIR.

One runtime issue: the ld.so profiling output file might be opened through
a symlink in /var/tmp; it's probably best to use O_NOFOLLOW if available.

-- 
Joseph S. Myers
jsm28@cam.ac.uk