The patch titled Subject: mm: make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long has been added to the -mm mm-unstable branch. Its filename is mm-make-pr_mdwe_refuse_exec_gain-an-unsigned-long.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Florent Revest revest@chromium.org Subject: mm: make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long Date: Mon, 28 Aug 2023 17:08:56 +0200

Defining a prctl flag as an int is a footgun because on a 64 bit machine and with a variadic implementation of prctl (like in musl and glibc), when used directly as a prctl argument, it can get casted to long with garbage upper bits which would result in unexpected behaviors.

This patch changes the constant to an unsigned long to eliminate that possibilities. This does not break UAPI.

Link: https://lkml.kernel.org/r/20230828150858.393570-5-revest@chromium.org Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl") Signed-off-by: Florent Revest revest@chromium.org Suggested-by: Alexey Izbyshev izbyshev@ispras.ru Reviewed-by: David Hildenbrand david@redhat.com Reviewed-by: Kees Cook keescook@chromium.org Acked-by: Catalin Marinas catalin.marinas@arm.com Cc: stable@vger.kernel.org Cc: Anshuman Khandual anshuman.khandual@arm.com Cc: Ayush Jain ayush.jain3@amd.com Cc: Greg Thelen gthelen@google.com Cc: Joey Gouly joey.gouly@arm.com Cc: KP Singh kpsingh@kernel.org Cc: Mark Brown broonie@kernel.org Cc: Michal Hocko mhocko@suse.com Cc: Peter Xu peterx@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Szabolcs Nagy Szabolcs.Nagy@arm.com Cc: Topi Miettinen toiwoton@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

include/uapi/linux/prctl.h | 2 +- tools/include/uapi/linux/prctl.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/include/uapi/linux/prctl.h~mm-make-pr_mdwe_refuse_exec_gain-an-unsigned-long +++ a/include/uapi/linux/prctl.h @@ -283,7 +283,7 @@ struct prctl_mm_map {

/* Memory deny write / execute */ #define PR_SET_MDWE 65 -# define PR_MDWE_REFUSE_EXEC_GAIN 1 +# define PR_MDWE_REFUSE_EXEC_GAIN (1UL << 0)

#define PR_GET_MDWE 66

--- a/tools/include/uapi/linux/prctl.h~mm-make-pr_mdwe_refuse_exec_gain-an-unsigned-long +++ a/tools/include/uapi/linux/prctl.h @@ -283,7 +283,7 @@ struct prctl_mm_map {

/* Memory deny write / execute */ #define PR_SET_MDWE 65 -# define PR_MDWE_REFUSE_EXEC_GAIN 1 +# define PR_MDWE_REFUSE_EXEC_GAIN (1UL << 0)

#define PR_GET_MDWE 66

_

Patches currently in -mm which might be from revest@chromium.org are

kselftest-vm-fix-tabs-spaces-inconsistency-in-the-mdwe-test.patch kselftest-vm-fix-mdwes-mmap_fixed-test-case.patch kselftest-vm-check-errnos-in-mdwe_test.patch mm-make-pr_mdwe_refuse_exec_gain-an-unsigned-long.patch mm-add-a-no_inherit-flag-to-the-pr_set_mdwe-prctl.patch kselftest-vm-add-tests-for-no-inherit-memory-deny-write-execute.patch