This is a note to let you know that I've just added the patch titled

arm64: avoid overflow in VA_START and PAGE_OFFSET

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: arm64-avoid-overflow-in-va_start-and-page_offset.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 82cd588052815eb4146f9f7c5347ca5e32c56360 Mon Sep 17 00:00:00 2001

From: Nick Desaulniers ndesaulniers@google.com Date: Thu, 3 Aug 2017 11:03:58 -0700 Subject: arm64: avoid overflow in VA_START and PAGE_OFFSET

From: Nick Desaulniers ndesaulniers@google.com

commit 82cd588052815eb4146f9f7c5347ca5e32c56360 upstream.

The bitmask used to define these values produces overflow, as seen by this compiler warning:

arch/arm64/kernel/head.S:47:8: warning: integer overflow in preprocessor expression #elif (PAGE_OFFSET & 0x1fffff) != 0 ^~~~~~~~~~~ arch/arm64/include/asm/memory.h:52:46: note: expanded from macro 'PAGE_OFFSET' #define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) ~~~~~~~~~~~~~~~~~~ ^

It would be preferrable to use GENMASK_ULL() instead, but it's not set up to be used from assembly (the UL() macro token pastes UL suffixes when not included in assembly sources).

Suggested-by: Ard Biesheuvel ard.biesheuvel@linaro.org Suggested-by: Yury Norov ynorov@caviumnetworks.com Suggested-by: Matthias Kaehlcke mka@chromium.org Signed-off-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Will Deacon will.deacon@arm.com Cc: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/arm64/include/asm/memory.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -64,8 +64,10 @@ * TASK_UNMAPPED_BASE - the lower boundary of the mmap VM area. */ #define VA_BITS (CONFIG_ARM64_VA_BITS) -#define VA_START (UL(0xffffffffffffffff) << VA_BITS) -#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1)) +#define VA_START (UL(0xffffffffffffffff) - \ + (UL(1) << VA_BITS) + 1) +#define PAGE_OFFSET (UL(0xffffffffffffffff) - \ + (UL(1) << (VA_BITS - 1)) + 1) #define KIMAGE_VADDR (MODULES_END) #define MODULES_END (MODULES_VADDR + MODULES_VSIZE) #define MODULES_VADDR (VA_START + KASAN_SHADOW_SIZE)

Patches currently in stable-queue which might be from ndesaulniers@google.com are

queue-4.9/arm64-avoid-overflow-in-va_start-and-page_offset.patch queue-4.9/netfilter-nf_nat_h323-fix-logical-not-parentheses-warning.patch