linux-kernel - [PATCH 0/2] fs: fix capable() call in simple_xattr

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Message-Id: <20220901152632.970018-1-omosnace@redhat.com>
Date:   Thu,  1 Sep 2022 17:26:30 +0200
From:   Ondrej Mosnacek <omosnace@...hat.com>
To:     Alexander Viro <viro@...iv.linux.org.uk>
Cc:     linux-fsdevel@...r.kernel.org,
        linux-security-module@...r.kernel.org, selinux@...r.kernel.org,
        rcu@...r.kernel.org, linux-kernel@...r.kernel.org,
        Martin Pitt <mpitt@...hat.com>
Subject: [PATCH 0/2] fs: fix capable() call in simple_xattr_list()

The goal of these patches is to avoid calling capable() unconditionally
in simple_xattr_list(), which causes issues under SELinux (see
explanation in the second patch).

The first patch tries to make this change safer by converting
simple_xattrs to use the RCU mechanism, so that capable() is not called
while the xattrs->lock is held. I didn't find evidence that this is an
issue in the current code, but it can't hurt to make that change
either way (and it was quite straightforward).

Ondrej Mosnacek (2):
  fs: convert simple_xattrs to RCU list
  fs: don't call capable() prematurely in simple_xattr_list()

 fs/xattr.c            | 39 +++++++++++++++++++++++----------------
 include/linux/xattr.h |  1 +
 2 files changed, 24 insertions(+), 16 deletions(-)

-- 
2.37.2