Andrew Cooper 9ede07c4af x86/pkey: Fix undefined behaviour with PKRU_WD_BIT
commit 57690554abe135fee81d6ac33cc94d75a7e224bb upstream.

Both __pkru_allows_write() and arch_set_user_pkey_access() shift
PKRU_WD_BIT (a signed constant) by up to 30 bits, hitting the
sign bit.

Use unsigned constants instead.

Clearly pkey 15 has not been used in combination with UBSAN yet.

Noticed by code inspection only.  I can't actually provoke the
compiler into generating incorrect logic as far as this shift is
concerned.

[
  dhansen: add stable@ tag, plus minor changelog massaging,

           For anyone doing backports, these #defines were in
	   arch/x86/include/asm/pgtable.h before 784a46618f6.
]

Fixes: 33a709b25a76 ("mm/gup, x86/mm/pkeys: Check VMAs and PTEs for protection keys")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20211216000856.4480-1-andrew.cooper3@citrix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-29 12:28:54 +01:00
2021-10-18 20:22:03 -10:00
2021-10-28 12:17:01 -07:00
2021-12-22 09:32:52 +01:00

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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