It looks like this series got quite a few Reviewed-by now. What should be the next steps to have it merged ? On Mon, Aug 28, 2023 at 5:09 PM Florent Revest <revest@xxxxxxxxxxxx> wrote: > > Joey recently introduced a Memory-Deny-Write-Executable (MDWE) prctl which tags > current with a flag that prevents pages that were previously not executable from > becoming executable. > This tag always gets inherited by children tasks. (it's in MMF_INIT_MASK) > > At Google, we've been using a somewhat similar downstream patch for a few years > now. To make the adoption of this feature easier, we've had it support a mode in > which the W^X flag does not propagate to children. For example, this is handy if > a C process which wants W^X protection suspects it could start children > processes that would use a JIT. > > I'd like to align our features with the upstream prctl. This series proposes a > new NO_INHERIT flag to the MDWE prctl to make this kind of adoption easier. It > sets a different flag in current that is not in MMF_INIT_MASK and which does not > propagate. > > As part of looking into MDWE, I also fixed a couple of things in the MDWE test. > > This series applies on the mm-everything-2023-08-25-20-06 tag of the mm tree: > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/ > > Diff since v3: > - Added a bunch of Reviewed-by, Acked-by and Tested-by. Thanks everyone! > - Reworded patch 2's description for clarity > - Removed an unnecessary int cast > - Added test coverage for errnos of invalid prctls (EPERM/EINVAL) > - Added test coverage for can_keep_no_flags and can_keep_both_flags > > Diff since v2: > - Turned the MMF_INIT_FLAGS macro into a mmf_init_flags function as suggested by > David Hildenbrand > - Removed the ability to transition from to PR_MDWE_REFUSE_EXEC_GAIN from > (PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT) which also significantly > simplifies the prctl_set_mdwe logic > - Cc-ed -stable on patch 3 as suggested by Alexey Izbyshev > - Added a handful of Reviewed-by/Acked-by trailers > > Diff since v1: > - MMF_HAS_MDWE_NO_INHERIT clears MMF_HAS_MDWE in the fork path as part of a > MMF_INIT_FLAGS macro (suggested by Catalin) > - PR_MDWE_* are defined as unsigned long rather than int (suggested by Andrey) > > Florent Revest (6): > kselftest: vm: Fix tabs/spaces inconsistency in the mdwe test > kselftest: vm: Fix mdwe's mmap_FIXED test case > kselftest: vm: Check errnos in mdwe_test > mm: Make PR_MDWE_REFUSE_EXEC_GAIN an unsigned long > mm: Add a NO_INHERIT flag to the PR_SET_MDWE prctl > kselftest: vm: Add tests for no-inherit memory-deny-write-execute > > include/linux/sched/coredump.h | 10 ++ > include/uapi/linux/prctl.h | 3 +- > kernel/fork.c | 2 +- > kernel/sys.c | 32 ++++-- > tools/include/uapi/linux/prctl.h | 3 +- > tools/testing/selftests/mm/mdwe_test.c | 137 ++++++++++++++++++++++--- > 6 files changed, 163 insertions(+), 24 deletions(-) > > -- > 2.42.0.rc2.253.gd59a3bf2b4-goog >
