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Miklos Szeredi authored
If st_uid/st_gid doesn't have a mapping in the mounter's user_ns, then copy-up should fail, just like it would fail if the mounter task was doing the copy using "cp -a". There's a corner case where the "cp -a" would succeed but copy up fail: if there's a mapping of the invalid uid/gid (65534 by default) in the user namespace. This is because stat(2) will return this value if the mapping doesn't exist in the current user_ns and "cp -a" will in turn be able to create a file with this uid/gid. This behavior would be inconsistent with POSIX ACL's, which return -1 for invalid uid/gid which result in a failed copy. For consistency and simplicity fail the copy of the st_uid/st_gid are invalid. Fixes: 459c7c56 ("ovl: unprivieged mounts") Cc: <stable@vger.kernel.org> # v5.11 Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:
Christian Brauner <brauner@kernel.org> Reviewed-by:
Seth Forshee <sforshee@kernel.org>
4f11ada1