c0f4be8303
[ Upstream commit abec3d015fdfb7c63105c7e1c956188bf381aa55 ] Since userfaultfd doesn't implement a write operation, it is more appropriate to open it read-only. When userfaultfds are opened read-write like it is now, and such fd is passed from one process to another, SELinux will check both read and write permissions for the target process, even though it can't actually do any write operation on the fd later. Inspired by the following bug report, which has hit the SELinux scenario described above: https://bugzilla.redhat.com/show_bug.cgi?id=1974559 Reported-by: Robert O'Callahan <roc@ocallahan.org> Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Sasha Levin <sashal@kernel.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.