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dc6a664089
commit c28f922c9dcee0e4876a2c095939d77fe7e15116 upstream.
What we want is to verify there is that clone won't expose something
hidden by a mount we wouldn't be able to undo. "Wouldn't be able to undo"
may be a result of MNT_LOCKED on a child, but it may also come from
lacking admin rights in the userns of the namespace mount belongs to.
clone_private_mnt() checks the former, but not the latter.
There's a number of rather confusing CAP_SYS_ADMIN checks in various
userns during the mount, especially with the new mount API; they serve
different purposes and in case of clone_private_mnt() they usually,
but not always end up covering the missing check mentioned above.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reported-by: "Orlando, Noah" <Noah.Orlando@deshaw.com>
Fixes: 427215d85e ("ovl: prevent private clone if bind mount is not allowed")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ merge conflict resolution: clone_private_mount() was reworked in
db04662e2f4f ("fs: allow detached mounts in clone_private_mount()").
Tweak the relevant ns_capable check so that it works on older kernels ]
Signed-off-by: Noah Orlando <Noah.Orlando@deshaw.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.