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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51F2DC4361B for ; Mon, 14 Dec 2020 22:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 207BD22507 for ; Mon, 14 Dec 2020 22:23:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388476AbgLNWXH (ORCPT ); Mon, 14 Dec 2020 17:23:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:33748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407337AbgLNWXH (ORCPT ); Mon, 14 Dec 2020 17:23:07 -0500 Date: Mon, 14 Dec 2020 14:22:26 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1607984547; bh=2bh2j7PxTLr9YKpVDQpJKyYu2ZcKa/MysFXjgxFyOtE=; h=From:To:Subject:From; b=tcPL/W9N3Al0myGnGwnG4mPcI0qZClC7EmRAZIZekRaNZjDOJ/k3539Vjl/8k3DzN nrTKfWuUzU0UuNRhsjglYhoxR/fAfr4inu0VU32FTVrYevD60LUtnUzdStjOO95yRA PL7tjQ85iIn5YhHLjYHGC9/LFBKKca8lxCRMx/Rk= From: akpm@linux-foundation.org To: andreyknvl@google.com, arnd@arndb.de, dvyukov@google.com, elver@google.com, gregkh@linuxfoundation.org, keescook@chromium.org, mm-commits@vger.kernel.org Subject: + lkdtm-disable-kasan-for-rodatao.patch added to -mm tree Message-ID: <20201214222226.k13eGkZdc%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: lkdtm: disable KASAN for rodata.o has been added to the -mm tree. Its filename is lkdtm-disable-kasan-for-rodatao.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/lkdtm-disable-kasan-for-rodatao.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/lkdtm-disable-kasan-for-rodatao.patch 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Marco Elver Subject: lkdtm: disable KASAN for rodata.o Building lkdtm with KASAN and Clang 11 or later results in the following error when attempting to load the module: kernel tried to execute NX-protected page - exploit attempt? (uid: 0) BUG: unable to handle page fault for address: ffffffffc019cd70 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0011) - permissions violation ... RIP: 0010:asan.module_ctor+0x0/0xffffffffffffa290 [lkdtm] ... Call Trace: do_init_module+0x17c/0x570 load_module+0xadee/0xd0b0 __x64_sys_finit_module+0x16c/0x1a0 do_syscall_64+0x34/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The reason is that rodata.o generates a dummy function that lives in .rodata to validate that .rodata can't be executed; however, Clang 11 adds KASAN globals support by generating module constructors to initialize globals redzones. When Clang 11 adds a module constructor to rodata.o, it is also added to .rodata: any attempt to call it on initialization results in the above error. Therefore, disable KASAN instrumentation for rodata.o. Link: https://lkml.kernel.org/r/20201214191413.3164796-1-elver@google.com Signed-off-by: Marco Elver Cc: Kees Cook Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Andrey Konovalov Cc: Dmitry Vyukov Signed-off-by: Andrew Morton --- drivers/misc/lkdtm/Makefile | 1 + 1 file changed, 1 insertion(+) --- a/drivers/misc/lkdtm/Makefile~lkdtm-disable-kasan-for-rodatao +++ a/drivers/misc/lkdtm/Makefile @@ -11,6 +11,7 @@ lkdtm-$(CONFIG_LKDTM) += usercopy.o lkdtm-$(CONFIG_LKDTM) += stackleak.o lkdtm-$(CONFIG_LKDTM) += cfi.o +KASAN_SANITIZE_rodata.o := n KASAN_SANITIZE_stackleak.o := n KCOV_INSTRUMENT_rodata.o := n _ Patches currently in -mm which might be from elver@google.com are lkdtm-disable-kasan-for-rodatao.patch mm-add-kernel-electric-fence-infrastructure-fix.patch mm-add-kernel-electric-fence-infrastructure-fix-2.patch arm64-kfence-enable-kfence-for-arm64.patch kfence-use-pt_regs-to-generate-stack-trace-on-faults.patch kfence-documentation-add-kfence-documentation.patch kfence-add-test-suite.patch maintainers-add-entry-for-kfence.patch