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 5.15-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-5.15 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/pkru.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/pkru.h
+++ b/arch/x86/include/asm/pkru.h
@@ -4,8 +4,8 @@
#include <asm/fpu/xstate.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
Patches currently in stable-queue which might be from andrew.cooper3@xxxxxxxxxx are
queue-5.15/x86-pkey-fix-undefined-behaviour-with-pkru_wd_bit.patch
