The patch titled
Subject: mseal: fix is_madv_discard()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mseal-fix-is_madv_discard.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mseal-fix-is_madv_discard.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Pedro Falcato <pedro.falcato@xxxxxxxxx>
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. This is obviously incorrect, so use
a switch statement instead.
Link: https://lkml.kernel.org/r/20240807173336.2523757-1-pedro.falcato@xxxxxxxxx
Link: https://lkml.kernel.org/r/20240807173336.2523757-2-pedro.falcato@xxxxxxxxx
Fixes: 8be7258aad44 ("mseal: add mseal syscall")
Signed-off-by: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Cc: Jeff Xu <jeffxu@xxxxxxxxxxxx>
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxx are
mseal-fix-is_madv_discard.patch
selftests-mm-add-mseal-test-for-no-discard-madvise.patch
