tree da3c7514877f6881b8be76e203614917227be52a
parent 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8
author Miklos Szeredi <miklos@szeredi.hu> 1449253128 +0100
committer Al Viro <viro@zeniv.linux.org.uk> 1449422903 -0500

ovl: fix permission checking for setattr

[Al Viro] The bug is in being too enthusiastic about optimizing ->setattr()
away - instead of "copy verbatim with metadata" + "chmod/chown/utimes"
(with the former being always safe and the latter failing in case of
insufficient permissions) it tries to combine these two.  Note that copyup
itself will have to do ->setattr() anyway; _that_ is where the elevated
capabilities are right.  Having these two ->setattr() (one to set verbatim
copy of metadata, another to do what overlayfs ->setattr() had been asked
to do in the first place) combined is where it breaks.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>