Sorry for the long delay.
Pavel Raiskup <prais...@redhat.com> writes:
> Ensure that nobody can cross privilege boundaries by pre-creating
> symlink on '$tmpdir' path.
> Just testing 'mkdir -p' by creating '/tmp/ins$RANDOM-$$/d' is not
> safe because '/tmp' directory is usually world-writeable and
> '/tmp/ins$RANDOM-$$' content could be pretty easily guessed by
> attacker (at least for shells where $RANDOM is not supported).
> So, as the first step, create the '/tmp/ins$RANDOM-$$' without -p.
> This step would fail early if somebody wanted catch us.
> Note that systems that implement (and have enabled)
> fs.protected_symlinks kernel feature are not affected even without
> this commit.
> * lib/install-sh: Implement safer 'mkdir -p' test by running
> '$mkdirprog $mkdir_mode "$tmpdir"' first.
> (scriptversion): Bump.
> lib/install-sh | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
Applied in commit 968bf9f66e3966d1975295b97539876518ebd2a0.
Thank you for the patch.
GPG: F2A3 8D7E EB2B 6640 5761 070D 0ADE E100 9460 4D37