commit db86da7cb76f797a1a8b445166a15cb922c6ff85 upstream.
A security fix in caused the way the unprivileged remount tests were
using user namespaces to break. Tweak the way user namespaces are
being used so the test works again.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4a44a19b470a886997d6647a77bb3e38dcbfa8c5 upstream.
- MNT_NODEV should be irrelevant except when reading back mount flags,
no longer specify MNT_NODEV on remount.
- Test MNT_NODEV on devpts where it is meaningful even for unprivileged mounts.
- Add a test to verify that remount of a prexisting mount with the same flags
is allowed and does not change those flags.
- Cleanup up the definitions of MS_REC, MS_RELATIME, MS_STRICTATIME that are used
when the code is built in an environment without them.
- Correct the test error messages when tests fail. There were not 5 tests
that tested MS_RELATIME.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit db181ce011e3c033328608299cd6fac06ea50130 upstream.
Kenton Varda <kenton@sandstorm.io> discovered that by remounting a
read-only bind mount read-only in a user namespace the
MNT_LOCK_READONLY bit would be cleared, allowing an unprivileged user
to the remount a read-only mount read-write.
Upon review of the code in remount it was discovered that the code allowed
nosuid, noexec, and nodev to be cleared. It was also discovered that
the code was allowing the per mount atime flags to be changed.
The first naive patch to fix these issues contained the flaw that using
default atime settings when remounting a filesystem could be disallowed.
To avoid this problems in the future add tests to ensure unprivileged
remounts are succeeding and failing at the appropriate times.
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
