From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 76F0E8E0001 for ; Wed, 23 Jan 2019 06:04:16 -0500 (EST) Received: by mail-pf1-f200.google.com with SMTP id x67so1455094pfk.16 for ; Wed, 23 Jan 2019 03:04:16 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 88sor25619039plb.63.2019.01.23.03.04.15 for (Google Transport Security); Wed, 23 Jan 2019 03:04:15 -0800 (PST) From: Kees Cook Subject: [PATCH 0/3] gcc-plugins: Introduce stackinit plugin Date: Wed, 23 Jan 2019 03:03:46 -0800 Message-Id: <20190123110349.35882-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Kees Cook , Ard Biesheuvel , Laura Abbott , Alexander Popov , xen-devel@lists.xenproject.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, dev@openvswitch.org, linux-kbuild@vger.kernel.org, linux-security-module@vger.kernel.org, kernel-hardening@lists.openwall.com This adds a new plugin "stackinit" that attempts to perform unconditional initialization of all stack variables[1]. It has wider effects than GCC_PLUGIN_STRUCTLEAK_BYREF_ALL=y since BYREF_ALL does not consider non-structures. A notable weakness is that padding bytes in many cases remain uninitialized since GCC treats these bytes as "undefined". I'm hoping we can improve the compiler (or the plugin) to cover that too. (It's worth noting that BYREF_ALL actually does handle the padding -- I think this is due to the different method of detecting if initialization is needed.) Included is a tree-wide change to move switch variables up and out of their switch and into the top-level variable declarations. Included is a set of test cases for evaluating stack initialization, which checks for padding, different types, etc. Feedback welcome! :) -Kees [1] https://lkml.kernel.org/r/CA+55aFykZL+cSBJjBBts7ebEFfyGPdMzTmLSxKnT_29=j942dA@mail.gmail.com Kees Cook (3): treewide: Lift switch variables out of switches gcc-plugins: Introduce stackinit plugin lib: Introduce test_stackinit module arch/x86/xen/enlighten_pv.c | 7 +- drivers/char/pcmcia/cm4000_cs.c | 2 +- drivers/char/ppdev.c | 20 +- drivers/gpu/drm/drm_edid.c | 4 +- drivers/gpu/drm/i915/intel_display.c | 2 +- drivers/gpu/drm/i915/intel_pm.c | 4 +- drivers/net/ethernet/intel/e1000/e1000_main.c | 3 +- drivers/tty/n_tty.c | 3 +- drivers/usb/gadget/udc/net2280.c | 5 +- fs/fcntl.c | 3 +- lib/Kconfig.debug | 9 + lib/Makefile | 1 + lib/test_stackinit.c | 327 ++++++++++++++++++ mm/shmem.c | 5 +- net/core/skbuff.c | 4 +- net/ipv6/ip6_gre.c | 4 +- net/ipv6/ip6_tunnel.c | 4 +- net/openvswitch/flow_netlink.c | 7 +- scripts/Makefile.gcc-plugins | 6 + scripts/gcc-plugins/Kconfig | 9 + scripts/gcc-plugins/gcc-common.h | 11 +- scripts/gcc-plugins/stackinit_plugin.c | 79 +++++ security/tomoyo/common.c | 3 +- security/tomoyo/condition.c | 7 +- security/tomoyo/util.c | 4 +- 25 files changed, 484 insertions(+), 49 deletions(-) create mode 100644 lib/test_stackinit.c create mode 100644 scripts/gcc-plugins/stackinit_plugin.c -- 2.17.1