The quilt patch titled Subject: mseal: fix is_madv_discard() has been removed from the -mm tree. Its filename was mseal-fix-is_madv_discard.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Pedro Falcato pedro.falcato@gmail.com Subject: mseal: fix is_madv_discard() Date: Wed, 7 Aug 2024 18:33:35 +0100

is_madv_discard did its check wrong. MADV_ flags are not bitwise, they're normal sequential numbers. So, for instance: behavior & (/* ... */ | MADV_REMOVE)

tagged both MADV_REMOVE and MADV_RANDOM (bit 0 set) as discard operations.

As a result the kernel could erroneously block certain madvises (e.g MADV_RANDOM or MADV_HUGEPAGE) on sealed VMAs due to them sharing bits with blocked MADV operations (e.g REMOVE or WIPEONFORK).

This is obviously incorrect, so use a switch statement instead.

Link: https://lkml.kernel.org/r/20240807173336.2523757-1-pedro.falcato@gmail.com Link: https://lkml.kernel.org/r/20240807173336.2523757-2-pedro.falcato@gmail.com Fixes: 8be7258aad44 ("mseal: add mseal syscall") Signed-off-by: Pedro Falcato pedro.falcato@gmail.com Tested-by: Jeff Xu jeffxu@chromium.org Reviewed-by: Jeff Xu jeffxu@chromium.org Cc: Kees Cook kees@kernel.org Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/mseal.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/mm/mseal.c~mseal-fix-is_madv_discard +++ a/mm/mseal.c @@ -40,9 +40,17 @@ static bool can_modify_vma(struct vm_are

static bool is_madv_discard(int behavior) { - return behavior & - (MADV_FREE | MADV_DONTNEED | MADV_DONTNEED_LOCKED | - MADV_REMOVE | MADV_DONTFORK | MADV_WIPEONFORK); + switch (behavior) { + case MADV_FREE: + case MADV_DONTNEED: + case MADV_DONTNEED_LOCKED: + case MADV_REMOVE: + case MADV_DONTFORK: + case MADV_WIPEONFORK: + return true; + } + + return false; }

static bool is_ro_anon(struct vm_area_struct *vma) _

Patches currently in -mm which might be from pedro.falcato@gmail.com are

selftests-mm-add-mseal-test-for-no-discard-madvise.patch selftests-mm-add-mseal-test-for-no-discard-madvise-fix.patch