Zev Weiss 907efa8839 ARM: prctl: reject PR_SET_MDWE on pre-ARMv6
commit 166ce846dc5974a266f6c2a2896dbef5425a6f21 upstream.

On v5 and lower CPUs we can't provide MDWE protection, so ensure we fail
any attempt to enable it via prctl(PR_SET_MDWE).

Previously such an attempt would misleadingly succeed, leading to any
subsequent mmap(PROT_READ|PROT_WRITE) or execve() failing unconditionally
(the latter somewhat violently via force_fatal_sig(SIGSEGV) due to
READ_IMPLIES_EXEC).

Link: https://lkml.kernel.org/r/20240227013546.15769-6-zev@bewilderbeest.net
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Cc: <stable@vger.kernel.org>	[6.3+]
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sam James <sam@gentoo.org>
Cc: Stefan Roesch <shr@devkernel.io>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-03 15:28:54 +02:00
2024-04-03 15:28:17 +02:00
2024-02-16 19:10:43 +01:00
2022-09-28 09:02:20 +02:00
2024-03-26 18:22:53 -04:00

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.
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