This is a note to let you know that I've just added the patch titled x86/pkey: Fix undefined behaviour with PKRU_WD_BIT to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-pkey-fix-undefined-behaviour-with-pkru_wd_bit.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 57690554abe135fee81d6ac33cc94d75a7e224bb Mon Sep 17 00:00:00 2001 From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Date: Thu, 16 Dec 2021 00:08:56 +0000 Subject: x86/pkey: Fix undefined behaviour with PKRU_WD_BIT From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> 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@xxxxxxxxxx> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20211216000856.4480-1-andrew.cooper3@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/pgtable.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1356,8 +1356,8 @@ static inline pmd_t pmd_swp_clear_soft_d #endif #endif -#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 static inline bool __pkru_allows_read(u32 pkru, u16 pkey) Patches currently in stable-queue which might be from andrew.cooper3@xxxxxxxxxx are queue-4.19/x86-pkey-fix-undefined-behaviour-with-pkru_wd_bit.patch