Aleksa Sarai 7345a19c1a namei: only return -ECHILD from follow_dotdot_rcu()
commit 2b98149c2377bff12be5dd3ce02ae0506e2dd613 upstream.

It's over-zealous to return hard errors under RCU-walk here, given that
a REF-walk will be triggered for all other cases handling ".." under
RCU.

The original purpose of this check was to ensure that if a rename occurs
such that a directory is moved outside of the bind-mount which the
resolution started in, it would be detected and blocked to avoid being
able to mess with paths outside of the bind-mount. However, triggering a
new REF-walk is just as effective a solution.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-11 18:02:53 +01:00
..
2020-01-27 14:46:51 +01:00
2019-08-06 19:05:23 +02:00
2019-12-17 20:38:33 +01:00
2020-02-28 16:36:05 +01:00
2019-12-17 20:38:44 +01:00
2019-12-17 20:38:15 +01:00
2018-12-21 14:13:04 +01:00
2017-09-04 19:05:15 -04:00
2020-03-11 18:02:43 +01:00
2019-12-05 15:38:25 +01:00