The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: aa1701e20a847dba6c406545dcba6a8755fa6406 Gitweb: https://git.kernel.org/tip/aa1701e20a847dba6c406545dcba6a8755fa6406 Author: Andrew Cooper andrew.cooper3@citrix.com AuthorDate: Thu, 16 Dec 2021 00:08:56 Committer: Borislav Petkov bp@suse.de CommitterDate: Sun, 19 Dec 2021 14:09:41 +01:00

x86/pkey: Fix undefined behaviour with PKRU_WD_BIT

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 Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20211216000856.4480-1-andrew.cooper3@citrix.com --- arch/x86/include/asm/pkru.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h index 4cd49af..74f0a2d 100644 --- a/arch/x86/include/asm/pkru.h +++ b/arch/x86/include/asm/pkru.h @@ -4,8 +4,8 @@

#include <asm/cpufeature.h>

-#define PKRU_AD_BIT 0x1 -#define PKRU_WD_BIT 0x2 +#define PKRU_AD_BIT 0x1u +#define PKRU_WD_BIT 0x2u #define PKRU_BITS_PER_PKEY 2

#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS