From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C238C7619A for ; Wed, 12 Apr 2023 19:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229520AbjDLT6w (ORCPT ); Wed, 12 Apr 2023 15:58:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229546AbjDLT6v (ORCPT ); Wed, 12 Apr 2023 15:58:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 135851FFC; Wed, 12 Apr 2023 12:58:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 844EE612E1; Wed, 12 Apr 2023 19:58:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DC27EC433D2; Wed, 12 Apr 2023 19:58:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1681329525; bh=sLZEPWLSVLdeU+Eb7MKyMvJihbfk+a1JsVmuIoR7nCA=; h=Date:To:From:Subject:From; b=YVbbVxuEgDp37S5/kpfQhDSDCsMJ+RR1al0jll5MbH4vhy0mGSLnJB95x2vSNiSpC YW5UFTAQDRwUKTzqCnNIUNyP8eP6gN0SaLiSNk2nannAQgoEosbmxfbdJF2On2hd+R o9t27t+hhxWYe8sOr5qYyk4iZ6v3aooVxOvhXNpg= Date: Wed, 12 Apr 2023 12:58:45 -0700 To: mm-commits@vger.kernel.org, zokeefe@google.com, stable@vger.kernel.org, rppt@kernel.org, mike.kravetz@oracle.com, david@redhat.com, axelrasmussen@google.com, 0x7f454c46@gmail.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: + revert-userfaultfd-dont-fail-on-unrecognized-features.patch added to mm-hotfixes-unstable branch Message-Id: <20230412195845.DC27EC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: Revert "userfaultfd: don't fail on unrecognized features" has been added to the -mm mm-hotfixes-unstable branch. Its filename is revert-userfaultfd-dont-fail-on-unrecognized-features.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-userfaultfd-dont-fail-on-unrecognized-features.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: Peter Xu Subject: Revert "userfaultfd: don't fail on unrecognized features" Date: Wed, 12 Apr 2023 12:38:52 -0400 This is a proposal to revert commit 914eedcb9ba0ff53c33808. I found this when writing a simple UFFDIO_API test to be the first unit test in this set. Two things breaks with the commit: - UFFDIO_API check was lost and missing. According to man page, the kernel should reject ioctl(UFFDIO_API) if uffdio_api.api != 0xaa. This check is needed if the api version will be extended in the future, or user app won't be able to identify which is a new kernel. - Feature flags checks were removed, which means UFFDIO_API with a feature that does not exist will also succeed. According to the man page, we should (and it makes sense) to reject ioctl(UFFDIO_API) if unknown features passed in. Link: https://lore.kernel.org/r/20220722201513.1624158-1-axelrasmussen@google.com Link: https://lkml.kernel.org/r/20230412163922.327282-2-peterx@redhat.com Fixes: 914eedcb9ba0 ("userfaultfd: don't fail on unrecognized features") Signed-off-by: Peter Xu Acked-by: David Hildenbrand Cc: Axel Rasmussen Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Zach O'Keefe Cc: Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/fs/userfaultfd.c~revert-userfaultfd-dont-fail-on-unrecognized-features +++ a/fs/userfaultfd.c @@ -1955,8 +1955,10 @@ static int userfaultfd_api(struct userfa ret = -EFAULT; if (copy_from_user(&uffdio_api, buf, sizeof(uffdio_api))) goto out; - /* Ignore unsupported features (userspace built against newer kernel) */ - features = uffdio_api.features & UFFD_API_FEATURES; + features = uffdio_api.features; + ret = -EINVAL; + if (uffdio_api.api != UFFD_API || (features & ~UFFD_API_FEATURES)) + goto err_out; ret = -EPERM; if ((features & UFFD_FEATURE_EVENT_FORK) && !capable(CAP_SYS_PTRACE)) goto err_out; _ Patches currently in -mm which might be from peterx@redhat.com are mm-khugepaged-check-again-on-anon-uffd-wp-during-isolation.patch revert-userfaultfd-dont-fail-on-unrecognized-features.patch selftests-mm-update-gitignore-with-two-missing-tests.patch selftests-mm-dump-a-summary-in-run_vmtestssh.patch selftests-mm-merge-utilh-into-vm_utilh.patch selftests-mm-use-test_gen_progs-where-proper.patch selftests-mm-link-vm_utilc-always.patch selftests-mm-merge-default_huge_page_size-into-one.patch selftests-mm-use-pm_-macros-in-vm_utilsh.patch selftests-mm-reuse-pagemap_get_entry-in-vm_utilh.patch selftests-mm-test-uffdio_zeropage-only-when-hugetlb.patch selftests-mm-drop-test_uffdio_zeropage_eexist.patch selftests-mm-create-uffd-common.patch selftests-mm-split-uffd-tests-into-uffd-stress-and-uffd-unit-tests.patch selftests-mm-uffd_register.patch selftests-mm-uffd_open_devsys.patch selftests-mm-uffdio_api-test.patch selftests-mm-drop-global-mem_fd-in-uffd-tests.patch selftests-mm-drop-global-hpage_size-in-uffd-tests.patch selftests-mm-rename-uffd_stats-to-uffd_args.patch selftests-mm-let-uffd_handle_page_fault-take-wp-parameter.patch selftests-mm-allow-allocate_area-to-fail-properly.patch selftests-mm-add-framework-for-uffd-unit-test.patch selftests-mm-move-uffd-pagemap-test-to-unit-test.patch selftests-mm-move-uffd-minor-test-to-unit-test.patch selftests-mm-move-uffd-sig-events-tests-into-uffd-unit-tests.patch selftests-mm-move-zeropage-test-into-uffd-unit-tests.patch selftests-mm-workaround-no-way-to-detect-uffd-minor-wp.patch selftests-mm-allow-uffd-test-to-skip-properly-with-no-privilege.patch selftests-mm-drop-sys-dev-test-in-uffd-stress-test.patch selftests-mm-add-shmem-private-test-to-uffd-stress.patch selftests-mm-add-uffdio-register-ioctls-test.patch