On Wed, Aug 7, 2024 at 11:59 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > 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> Tested-by: Jeff Xu <jeffxu@xxxxxxxxxxxx> Reviewed-by: Jeff Xu <jeffxu@xxxxxxxxxxxx> In case needed. Thanks -Jeff > --- > > 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 >
