Commit 260a459d authored Jan 20, 2014 by Eric W. Biederman Committed by Al Viro Jan 26, 2014

vfs: Is mounted should be testing mnt_ns for NULL or error.



A bug was introduced with the is_mounted helper function in
commit f7a99c5b
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sat Jun 9 00:59:08 2012 -0400

    get rid of ->mnt_longterm

    it's enough to set ->mnt_ns of internal vfsmounts to something
    distinct from all struct mnt_namespace out there; then we can
    just use the check for ->mnt_ns != NULL in the fast path of
    mntput_no_expire()

    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The intent was to test if the real_mount(vfsmount)->mnt_ns was
NULL_OR_ERR but the code is actually testing real_mount(vfsmount)
and always returning true.

The result is d_absolute_path returning paths it should be hiding.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 9fe55eea

fs/mount.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -74,7 +74,7 @@ static inline int mnt_has_parent(struct mount *mnt)
		static inline int is_mounted(struct vfsmount *mnt)
		{
		/* neither detached nor internal? */
		return !IS_ERR_OR_NULL(real_mount(mnt));
		return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
		}

		extern struct mount __lookup_mnt(struct vfsmount , struct dentry *);

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