The quilt patch titled
Subject: drivers/misc/open-dice: don't touch VM_MAYSHARE
has been removed from the -mm tree. Its filename was
drivers-misc-open-dice-dont-touch-vm_mayshare.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: drivers/misc/open-dice: don't touch VM_MAYSHARE
Date: Mon, 2 Jan 2023 17:08:56 +0100
A MAP_SHARED mapping always has VM_MAYSHARE set, and writable
(VM_MAYWRITE) MAP_SHARED mappings have VM_SHARED set as well. To identify
a MAP_SHARED mapping, it's sufficient to look at VM_MAYSHARE.
We cannot have VM_MAYSHARE|VM_WRITE mappings without having VM_SHARED set.
Consequently, current code will never actually end up clearing
VM_MAYSHARE and that code is confusing, because nobody is supposed to mess
with VM_MAYWRITE.
Let's clean it up and restructure the code. No functional change intended.
Link: https://lkml.kernel.org/r/20230102160856.500584-4-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Nicolas Pitre <nico@xxxxxxxxxxx>
Cc: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/misc/open-dice.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
--- a/drivers/misc/open-dice.c~drivers-misc-open-dice-dont-touch-vm_mayshare
+++ a/drivers/misc/open-dice.c
@@ -90,15 +90,13 @@ static int open_dice_mmap(struct file *f
{
struct open_dice_drvdata *drvdata = to_open_dice_drvdata(filp);
- /* Do not allow userspace to modify the underlying data. */
- if ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))
- return -EPERM;
-
- /* Ensure userspace cannot acquire VM_WRITE + VM_SHARED later. */
- if (vma->vm_flags & VM_WRITE)
- vma->vm_flags &= ~VM_MAYSHARE;
- else if (vma->vm_flags & VM_SHARED)
+ if (vma->vm_flags & VM_MAYSHARE) {
+ /* Do not allow userspace to modify the underlying data. */
+ if (vma->vm_flags & VM_WRITE)
+ return -EPERM;
+ /* Ensure userspace cannot acquire VM_WRITE later. */
vma->vm_flags &= ~VM_MAYWRITE;
+ }
/* Create write-combine mapping so all clients observe a wipe. */
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks.patch
mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.patch
alpha-mm-support-__have_arch_pte_swp_exclusive.patch
arc-mm-support-__have_arch_pte_swp_exclusive.patch
arm-mm-support-__have_arch_pte_swp_exclusive.patch
csky-mm-support-__have_arch_pte_swp_exclusive.patch
hexagon-mm-support-__have_arch_pte_swp_exclusive.patch
ia64-mm-support-__have_arch_pte_swp_exclusive.patch
loongarch-mm-support-__have_arch_pte_swp_exclusive.patch
m68k-mm-remove-dummy-__swp-definitions-for-nommu.patch
m68k-mm-support-__have_arch_pte_swp_exclusive.patch
microblaze-mm-support-__have_arch_pte_swp_exclusive.patch
mips-mm-support-__have_arch_pte_swp_exclusive.patch
nios2-mm-refactor-swap-pte-layout.patch
nios2-mm-support-__have_arch_pte_swp_exclusive.patch
openrisc-mm-support-__have_arch_pte_swp_exclusive.patch
parisc-mm-support-__have_arch_pte_swp_exclusive.patch
powerpc-mm-support-__have_arch_pte_swp_exclusive-on-32bit-book3s.patch
powerpc-nohash-mm-support-__have_arch_pte_swp_exclusive.patch
riscv-mm-support-__have_arch_pte_swp_exclusive.patch
sh-mm-support-__have_arch_pte_swp_exclusive.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-32bit.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-64bit.patch
um-mm-support-__have_arch_pte_swp_exclusive.patch
x86-mm-support-__have_arch_pte_swp_exclusive-also-on-32bit.patch
xtensa-mm-support-__have_arch_pte_swp_exclusive.patch
mm-remove-__have_arch_pte_swp_exclusive.patch
