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2020-06-10Merge branch 'rwonce/rework' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/will/linux Pull READ/WRITE_ONCE rework from Will Deacon: "This the READ_ONCE rework I've been working on for a while, which bumps the minimum GCC version and improves code-gen on arm64 when stack protector is enabled" [ Side note: I'm _really_ tempted to raise the minimum gcc version to 4.9, so that we can just say that we require _Generic() support. That would allow us to more cleanly handle a lot of the cases where we depend on very complex macros with 'sizeof' or __builtin_choose_expr() with __builtin_types_compatible_p() etc. This branch has a workaround for sparse not handling _Generic(), either, but that was already fixed in the sparse development branch, so it's really just gcc-4.9 that we'd require. - Linus ] * 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux: compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse compiler_types.h: Optimize __unqual_scalar_typeof compilation time compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long) compiler-types.h: Include naked type in __pick_integer_type() match READ_ONCE: Fix comment describing 2x32-bit atomicity gcov: Remove old GCC 3.4 support arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros READ_ONCE: Drop pointer qualifiers when reading from scalar types READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() arm64: csum: Disable KASAN for do_csum() fault_inject: Don't rely on "return value" from WRITE_ONCE() net: tls: Avoid assigning 'const' pointer to non-const pointer netfilter: Avoid assigning 'const' pointer to non-const pointer compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
2020-05-26gcc-plugins: remove always-false $(if ...) in MakefileMasahiro Yamada1-1/+1
This is the remnant of commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR"). The conditional $(if $(findstring /,$(p)),...) is always false because none of plugins contains '/' in the file name. Clean up the code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
2020-04-15compiler/gcc: Raise minimum GCC version for kernel builds to 4.8Will Deacon1-1/+1
It is very rare to see versions of GCC prior to 4.8 being used to build the mainline kernel. These old compilers are also know to have codegen issues which can lead to silent miscompilation: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Raise the minimum GCC version for kernel build to 4.8 and remove some tautological Kconfig dependencies as a consequence. Cc: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
2020-04-13gcc-common.h: Update for GCC 10Frédéric Pierret (fepitre)2-0/+5
Remove "params.h" include, which has been dropped in GCC 10. Remove is_a_helper() macro, which is now defined in gimple.h, as seen when running './scripts/gcc-plugin.sh g++ g++ gcc': In file included from <stdin>:1: ./gcc-plugins/gcc-common.h:852:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ 852 | inline bool is_a_helper<const ggoto *>::test(const_gimple gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./gcc-plugins/gcc-common.h:125, from <stdin>:1: /usr/lib/gcc/x86_64-redhat-linux/10/plugin/include/gimple.h:1037:1: note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here 1037 | is_a_helper <const ggoto *>::test (const gimple *gs) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ Add -Wno-format-diag to scripts/gcc-plugins/Makefile to avoid meaningless warnings from error() formats used by plugins: scripts/gcc-plugins/structleak_plugin.c: In function ‘int plugin_init(plugin_name_args*, plugin_gcc_version*)’: scripts/gcc-plugins/structleak_plugin.c:253:12: warning: unquoted sequence of 2 consecutive punctuation characters ‘'-’ in format [-Wformat-diag] 253 | error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Frédéric Pierret (fepitre) <frederic.pierret@qubes-os.org> Link: https://lore.kernel.org/r/20200407113259.270172-1-frederic.pierret@qubes-os.org [kees: include -Wno-format-diag for plugin builds] Signed-off-by: Kees Cook <keescook@chromium.org>
2020-04-13gcc-plugins/stackleak: Avoid assignment for unused macro argumentKees Cook1-3/+2
With GCC version >= 8, the cgraph_create_edge() macro argument using "frequency" goes unused. Instead of assigning a temporary variable for the argument, pass the compute_call_stmt_bb_frequency() call directly as the macro argument so that it will just not be called when it is not wanted by the macros. Silences the warning: scripts/gcc-plugins/stackleak_plugin.c:54:6: warning: variable ‘frequency’ set but not used [-Wunused-but-set-variable] Now builds cleanly with gcc-7 and gcc-9. Both boot and pass STACKLEAK_ERASING LKDTM test. Signed-off-by: Kees Cook <keescook@chromium.org>
2020-04-09gcc-plugins: drop support for GCC <= 4.7Masahiro Yamada2-25/+8
Nobody was opposed to raising minimum GCC version to 4.8 [1] So, we will drop GCC <= 4.7 support sooner or later. We always use C++ compiler for building plugins for GCC >= 4.8. This commit drops the plugin support for GCC <= 4.7 a bit earlier, which allows us to dump lots of code. [1] https://lkml.org/lkml/2020/1/23/545 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
2020-04-03Merge tag 'spdx-5.7-rc1' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments
2020-03-31Merge tag 'kbuild-v5.7' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "Build system: - add CONFIG_UNUSED_KSYMS_WHITELIST, which will be useful to define a fixed set of export symbols for Generic Kernel Image (GKI) - allow to run 'make dt_binding_check' without .config - use full schema for checking DT examples in *.yaml files - make modpost fail for missing MODULE_IMPORT_NS(), which makes more sense because we know the produced modules are never loadable - Remove unused 'AS' variable Kconfig: - sanitize DEFCONFIG_LIST, and remove ARCH_DEFCONFIG from Kconfig files - relax the 'imply' behavior so that symbols implied by 'y' can become 'm' - make 'imply' obey 'depends on' in order to make 'imply' really weak Misc: - add documentation on building the kernel with Clang/LLVM - revive __HAVE_ARCH_STRLEN for 32bit sparc to use optimized strlen() - fix warning from deb-pkg builds when CONFIG_DEBUG_INFO=n - various script and Makefile cleanups" * tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) Makefile: Update kselftest help information kbuild: deb-pkg: fix warning when CONFIG_DEBUG_INFO is unset kbuild: add outputmakefile to no-dot-config-targets kbuild: remove AS variable net: wan: wanxl: refactor the firmware rebuild rule net: wan: wanxl: use $(M68KCC) instead of $(M68KAS) for rebuilding firmware net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware kbuild: add comment about grouped target kbuild: add -Wall to KBUILD_HOSTCXXFLAGS kconfig: remove unused variable in qconf.cc sparc: revive __HAVE_ARCH_STRLEN for 32bit sparc kbuild: refactor Makefile.dtbinst more kbuild: compute the dtbs_install destination more simply Makefile: disallow data races on gcc-10 as well kconfig: make 'imply' obey the direct dependency kconfig: allow symbols implied by y to become m net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report() modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n modpost: rework and consolidate logging interface kbuild: allow to run dt_binding_check without kernel configuration ...
2020-03-29kbuild: add -Wall to KBUILD_HOSTCXXFLAGSMasahiro Yamada1-1/+1
Add -Wall to catch more warnings for C++ host programs. When I submitted the previous version, the 0-day bot reported -Wc++11-compat warnings for old GCC: HOSTCXX -fPIC scripts/gcc-plugins/latent_entropy_plugin.o In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/tm.h:28:0, from scripts/gcc-plugins/gcc-common.h:15, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/config/elfos.h:102:21: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\ ^ /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/config/elfos.h:170:24: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/tm.h:42:0, from scripts/gcc-plugins/gcc-common.h:15, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/defaults.h:126:24: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ The source of the warnings is in the plugin headers, so we have no control of it. I just suppressed them by adding -Wno-c++11-compat to scripts/gcc-plugins/Makefile. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
2020-03-25.gitignore: add SPDX License IdentifierMasahiro Yamada1-0/+1
Add SPDX License Identifier to all .gitignore files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-10docs: move gcc-plugins to the kbuild manualJonathan Corbet1-1/+1
Information about GCC plugins is relevant to kernel building, so move this document to the kbuild manual. Acked-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-02-04kbuild: rename hostprogs-y/always to hostprogs/always-yMasahiro Yamada1-1/+1
In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-01-02gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS againArnd Bergmann1-5/+4
I noticed that randconfig builds with gcc no longer produce a lot of ccache hits, unlike with clang, and traced this back to plugins now being enabled unconditionally if they are supported. I am now working around this by adding export CCACHE_COMPILERCHECK=/usr/bin/size -A %compiler% to my top-level Makefile. This changes the heuristic that ccache uses to determine whether the plugins are the same after a 'make clean'. However, it also seems that being able to just turn off the plugins is generally useful, at least for build testing it adds noticeable overhead but does not find a lot of bugs additional bugs, and may be easier for ccache users than my workaround. Fixes: 9f671e58159a ("security: Create "kernel hardening" config area") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20191211133951.401933-1-arnd@arndb.de Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2019-07-31randstruct: Check member structs in is_pure_ops_struct()Joonwon Kang1-5/+5
While no uses in the kernel triggered this case, it was possible to have a false negative where a struct contains other structs which contain only function pointers because of unreachable code in is_pure_ops_struct(). Signed-off-by: Joonwon Kang <kjw1627@gmail.com> Link: https://lore.kernel.org/r/20190727155841.GA13586@host Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2019-07-15docs: move gcc_plugins.txt to core-api and rename to .rstMauro Carvalho Chehab1-1/+1
The gcc_plugins.txt file is already a ReST file. Move it to the core-api book while renaming it. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
2019-05-31Merge tag 'gcc-plugins-v5.2-rc3' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc-plugins fix from Kees Cook: "Handle unusual header environment, fixing a redefined macro error under a Darwin build host" * tag 'gcc-plugins-v5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: Fix build failures under Darwin host
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner1-0/+1
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-20gcc-plugins: Fix build failures under Darwin hostKees Cook1-0/+4
The gcc-common.h file did not take into account certain macros that might have already been defined in the build environment. This updates the header to avoid redefining the macros, as seen on a Darwin host using gcc 4.9.2: HOSTCXX -fPIC scripts/gcc-plugins/arm_ssp_per_task_plugin.o - due to: scripts/gcc-plugins/gcc-common.h In file included from scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3:0: scripts/gcc-plugins/gcc-common.h:153:0: warning: "__unused" redefined ^ In file included from /usr/include/stdio.h:64:0, from /Users/hns/Documents/Projects/QuantumSTEP/System/Library/Frameworks/System.framework/Versions-jessie/x86_64-apple-darwin15.0.0/gcc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.2/plugin/include/system.h:40, from /Users/hns/Documents/Projects/QuantumSTEP/System/Library/Frameworks/System.framework/Versions-jessie/x86_64-apple-darwin15.0.0/gcc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.2/plugin/include/gcc-plugin.h:28, from /Users/hns/Documents/Projects/QuantumSTEP/System/Library/Frameworks/System.framework/Versions-jessie/x86_64-apple-darwin15.0.0/gcc/arm-linux-gnueabi/bin/../lib/gcc/arm-linux-gnueabi/4.9.2/plugin/include/plugin.h:23, from scripts/gcc-plugins/gcc-common.h:9, from scripts/gcc-plugins/arm_ssp_per_task_plugin.c:3: /usr/include/sys/cdefs.h:161:0: note: this is the location of the previous definition ^ Reported-and-tested-by: "H. Nikolaus Schaller" <hns@goldelico.com> Fixes: 189af4657186 ("ARM: smp: add support for per-task stack canaries") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2019-05-13Merge tag 'gcc-plugins-v5.2-rc1' of ↵Linus Torvalds1-1/+1
ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugin fix from Kees Cook: "Fix ARM stack-protector-per-task plugin build for older GCC < 6 (Chris Packham)" * tag 'gcc-plugins-v5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: arm_ssp_per_task_plugin: Fix for older GCC < 6
2019-05-10gcc-plugins: arm_ssp_per_task_plugin: Fix for older GCC < 6Chris Packham1-1/+1
Use gen_rtx_set instead of gen_rtx_SET. The former is a wrapper macro that handles the difference between GCC versions implementing the latter. This fixes the following error on my system with g++ 5.4.0 as the host compiler HOSTCXX -fPIC scripts/gcc-plugins/arm_ssp_per_task_plugin.o scripts/gcc-plugins/arm_ssp_per_task_plugin.c:42:14: error: macro "gen_rtx_SET" requires 3 arguments, but only 2 given mask)), ^ scripts/gcc-plugins/arm_ssp_per_task_plugin.c: In function ‘unsigned int arm_pertask_ssp_rtl_execute()’: scripts/gcc-plugins/arm_ssp_per_task_plugin.c:39:20: error: ‘gen_rtx_SET’ was not declared in this scope emit_insn_before(gen_rtx_SET Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Fixes: 189af4657186 ("ARM: smp: add support for per-task stack canaries") Cc: stable@vger.kernel.org Tested-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-04-24security: Move stackleak config to Kconfig.hardeningKees Cook1-51/+0
This moves the stackleak plugin options to Kconfig.hardening's memory initialization menu. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Alexander Popov <alex.popov@linux.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-04-24security: Create "kernel hardening" config areaKees Cook1-69/+6
Right now kernel hardening options are scattered around various Kconfig files. This can be a central place to collect these kinds of options going forward. This is initially populated with the memory initialization options from the gcc-plugins. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-03-09Merge tag 'gcc-plugins-v5.1-rc1' of ↵Linus Torvalds2-22/+72
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc-plugins updates from Kees Cook: "This adds additional type coverage to the existing structleak plugin and adds a large set of selftests to help evaluate stack variable zero-initialization coverage. That can be used to test whatever instrumentation might be performing zero-initialization: either with the structleak plugin or with Clang's coming "-ftrivial-auto-var-init=zero" option. Summary: - Add scalar and array initialization coverage - Refactor Kconfig to make options more clear - Add self-test module for testing automatic initialization" * tag 'gcc-plugins-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lib: Introduce test_stackinit module gcc-plugins: structleak: Generalize to all variable types
2019-03-05kasan: remove use after scope bugs detection.Andrey Ryabinin1-4/+0
Use after scope bugs detector seems to be almost entirely useless for the linux kernel. It exists over two years, but I've seen only one valid bug so far [1]. And the bug was fixed before it has been reported. There were some other use-after-scope reports, but they were false-positives due to different reasons like incompatibility with structleak plugin. This feature significantly increases stack usage, especially with GCC < 9 version, and causes a 32K stack overflow. It probably adds performance penalty too. Given all that, let's remove use-after-scope detector entirely. While preparing this patch I've noticed that we mistakenly enable use-after-scope detection for clang compiler regardless of CONFIG_KASAN_EXTRA setting. This is also fixed now. [1] http://lkml.kernel.org/r/<20171129052106.rhgbjhhis53hkgfn@wfg-t540p.sh.intel.com> Link: http://lkml.kernel.org/r/20190111185842.13978-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Will Deacon <will.deacon@arm.com> [arm64] Cc: Qian Cai <cai@lca.pw> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-04gcc-plugins: structleak: Generalize to all variable typesKees Cook2-22/+72
This adjusts structleak to also work with non-struct types when they are passed by reference, since those variables may leak just like anything else. This is exposed via an improved set of Kconfig options. (This does mean structleak is slightly misnamed now.) Building with CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL should give the kernel complete initialization coverage of all stack variables passed by reference, including padding (see lib/test_stackinit.c). Using CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE to count added initializations under defconfig: ..._BYREF: 5945 added initializations ..._BYREF_ALL: 16606 added initializations There is virtually no change to text+data size (both have less than 0.05% growth): text data bss dec hex filename 19502103 5051456 1917000 26470559 193e89f vmlinux.stock 19513412 5051456 1908808 26473676 193f4cc vmlinux.byref 19516974 5047360 1900616 26464950 193d2b6 vmlinux.byref_all The measured performance difference is in the noise for hackbench and kernel build benchmarks: Stock: 5x hackbench -g 20 -l 1000 Mean: 10.649s Std Dev: 0.339 5x kernel build (4-way parallel) Mean: 261.98s Std Dev: 1.53 CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF: 5x hackbench -g 20 -l 1000 Mean: 10.540s Std Dev: 0.233 5x kernel build (4-way parallel) Mean: 260.52s Std Dev: 1.31 CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL: 5x hackbench -g 20 -l 1000 Mean: 10.320 Std Dev: 0.413 5x kernel build (4-way parallel) Mean: 260.10 Std Dev: 0.86 This does not yet solve missing padding initialization for structures on the stack that are never passed by reference (which should be a tiny minority). Hopefully this will be more easily addressed by upstream compiler fixes after clarifying the C11 padding initialization specification. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2019-01-20gcc-plugins: arm_ssp_per_task_plugin: fix for GCC 9+Ard Biesheuvel1-0/+18
GCC 9 reworks the way the references to the stack canary are emitted, to prevent the value from being spilled to the stack before the final comparison in the epilogue, defeating the purpose, given that the spill slot is under control of the attacker that we are protecting ourselves from. Since our canary value address is obtained without accessing memory (as opposed to pre-v7 code that will obtain it from a literal pool), it is unlikely (although not guaranteed) that the compiler will spill the canary value in the same way, so let's just disable this improvement when building with GCC9+. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-20gcc-plugins: arm_ssp_per_task_plugin: sign extend the SP maskArd Biesheuvel1-2/+3
The ARM per-task stack protector GCC plugin hits an assert in the compiler in some case, due to the fact the the SP mask expression is not sign-extended as it should be. So fix that. Suggested-by: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-12-27Merge tag 'gcc-plugins-v4.21-rc1' of ↵Linus Torvalds2-0/+107
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc-plugins update from Kees Cook: "Both arm and arm64 are gaining per-task stack canaries (to match x86), but arm is being done with a gcc plugin, hence it going through the gcc-plugins tree. New gcc-plugin: - Enable per-task stack protector for ARM (Ard Biesheuvel)" * tag 'gcc-plugins-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: ARM: smp: add support for per-task stack canaries
2018-12-12ARM: smp: add support for per-task stack canariesArd Biesheuvel2-0/+107
On ARM, we currently only change the value of the stack canary when switching tasks if the kernel was built for UP. On SMP kernels, this is impossible since the stack canary value is obtained via a global symbol reference, which means a) all running tasks on all CPUs must use the same value b) we can only modify the value when no kernel stack frames are live on any CPU, which is effectively never. So instead, use a GCC plugin to add a RTL pass that replaces each reference to the address of the __stack_chk_guard symbol with an expression that produces the address of the 'stack_canary' field that is added to struct thread_info. This way, each task will use its own randomized value. Cc: Russell King <linux@armlinux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Emese Revfy <re.emese@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Laura Abbott <labbott@redhat.com> Cc: kernel-hardening@lists.openwall.com Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-12-06stackleak: Register the 'stackleak_cleanup' pass before the '*free_cfg' passAlexander Popov1-3/+5
Currently the 'stackleak_cleanup' pass deleting a CALL insn is executed after the 'reload' pass. That allows gcc to do some weird optimization in function prologues and epilogues, which are generated later [1]. Let's avoid that by registering the 'stackleak_cleanup' pass before the '*free_cfg' pass. It's the moment when the stack frame size is already final, function prologues and epilogues are generated, and the machine-dependent code transformations are not done. [1] https://www.openwall.com/lists/kernel-hardening/2018/11/23/2 Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-09-04stackleak: Allow runtime disabling of kernel stack erasingAlexander Popov1-0/+8
Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides 'stack_erasing' sysctl. It can be used in runtime to control kernel stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Alexander Popov <alex.popov@linux.com> Tested-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-09-04fs/proc: Show STACKLEAK metrics in the /proc file systemAlexander Popov1-0/+12
Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about tasks via the /proc file system. In particular, /proc/<pid>/stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it can be useful for estimating the STACKLEAK performance impact for your workloads. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Alexander Popov <alex.popov@linux.com> Tested-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-09-04gcc-plugins: Add STACKLEAK plugin for tracking the kernel stackAlexander Popov2-0/+439
The STACKLEAK feature erases the kernel stack before returning from syscalls. That reduces the information which kernel stack leak bugs can reveal and blocks some uninitialized stack variable attacks. This commit introduces the STACKLEAK gcc plugin. It is needed for tracking the lowest border of the kernel stack, which is important for the code erasing the used part of the kernel stack at the end of syscalls (comes in a separate commit). The STACKLEAK feature is ported from grsecurity/PaX. More information at: https://grsecurity.net/ https://pax.grsecurity.net/ This code is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on our understanding of the code. Changes or omissions from the original code are ours and don't reflect the original grsecurity/PaX code. Signed-off-by: Alexander Popov <alex.popov@linux.com> Tested-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-09-04x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscallsAlexander Popov1-0/+19
The STACKLEAK feature (initially developed by PaX Team) has the following benefits: 1. Reduces the information that can be revealed through kernel stack leak bugs. The idea of erasing the thread stack at the end of syscalls is similar to CONFIG_PAGE_POISONING and memzero_explicit() in kernel crypto, which all comply with FDP_RIP.2 (Full Residual Information Protection) of the Common Criteria standard. 2. Blocks some uninitialized stack variable attacks (e.g. CVE-2017-17712, CVE-2010-2963). That kind of bugs should be killed by improving C compilers in future, which might take a long time. This commit introduces the code filling the used part of the kernel stack with a poison value before returning to userspace. Full STACKLEAK feature also contains the gcc plugin which comes in a separate commit. The STACKLEAK feature is ported from grsecurity/PaX. More information at: https://grsecurity.net/ https://pax.grsecurity.net/ This code is modified from Brad Spengler/PaX Team's code in the last public patch of grsecurity/PaX based on our understanding of the code. Changes or omissions from the original code are ours and don't reflect the original grsecurity/PaX code. Performance impact: Hardware: Intel Core i7-4770, 16 GB RAM Test #1: building the Linux kernel on a single core 0.91% slowdown Test #2: hackbench -s 4096 -l 2000 -g 15 -f 25 -P 4.2% slowdown So the STACKLEAK description in Kconfig includes: "The tradeoff is the performance impact: on a single CPU system kernel compilation sees a 1% slowdown, other systems and workloads may vary and you are advised to test this feature on your expected workload before deploying it". Signed-off-by: Alexander Popov <alex.popov@linux.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-08-26Merge tag 'gcc-plugins-v4.19-rc1-fix' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugin fix from Kees Cook: "Lift gcc test into Kconfig. This is for better behavior when the kernel is built with Clang, reported by Stefan Agner" * tag 'gcc-plugins-v4.19-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: Disable when building under Clang
2018-08-23gcc-plugins: Disable when building under ClangKees Cook1-1/+1
Prior to doing compiler feature detection in Kconfig, attempts to build GCC plugins with Clang would fail the build, much in the same way missing GCC plugin headers would fail the build. However, now that this logic has been lifted into Kconfig, add an explicit test for GCC (instead of duplicating it in the feature-test script). Reported-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-24gcc-plugins: Clean up the cgraph_create_edge* macrosAlexander Popov1-10/+16
Drop useless redefinitions of cgraph_create_edge* macros. Drop the unused nest argument. Also support gcc-8, which doesn't have freq argument. Signed-off-by: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-07-24gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/KconfigMasahiro Yamada1-0/+142
Collect relevant code into the scripts/gcc-plugins directory. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-07-02gcc-plugins: remove unused GCC_PLUGIN_SUBDIRMasahiro Yamada1-5/+0
GCC_PLUGIN_SUBDIR has never been used. If you really need this in the future, please re-add it then. For now, the code is unused. Remove. 'export HOSTLIBS' is not necessary either. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-11gcc-plugins: test plugin support in Kconfig and clean up MakefileMasahiro Yamada1-0/+1
Run scripts/gcc-plugin.sh from Kconfig so that users can enable GCC_PLUGINS only when the compiler supports building plugins. Kconfig defines a new symbol, PLUGIN_HOSTCC. This will contain the compiler (g++ or gcc) used for building plugins, or empty if the plugin can not be supported at all. This allows us to remove all ugly testing in Makefile.gcc-plugins. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org>
2018-06-11kcov: test compiler capability in Kconfig and correct dependencyMasahiro Yamada1-4/+0
As Documentation/kbuild/kconfig-language.txt notes, 'select' should be be used with care - it forces a lower limit of another symbol, ignoring the dependency. Currently, KCOV can select GCC_PLUGINS even if arch does not select HAVE_GCC_PLUGINS. This could cause the unmet direct dependency. Now that Kconfig can test compiler capability, let's handle this in a more sophisticated way. There are two ways to enable KCOV; use the compiler that natively supports -fsanitize-coverage=trace-pc, or build the SANCOV plugin if the compiler has ability to build GCC plugins. Hence, the correct dependency for KCOV is: depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS You do not need to build the SANCOV plugin if the compiler already supports -fsanitize-coverage=trace-pc. Hence, the select should be: select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC With this, GCC_PLUGIN_SANCOV is selected only when necessary, so scripts/Makefile.gcc-plugins can be cleaner. I also cleaned up Kconfig and scripts/Makefile.kcov as well. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Kees Cook <keescook@chromium.org>
2018-03-31security: convert security hooks to use hlistSargun Dhillon1-2/+2
This changes security_hook_heads to use hlist_heads instead of the circular doubly-linked list heads. This should cut down the size of the struct by about half. In addition, it allows mutation of the hooks at the tail of the callback list without having to modify the head. The longer-term purpose of this is to enable making the heads read only. Signed-off-by: Sargun Dhillon <sargun@sargun.me> Reviewed-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-02-05gcc-plugins: Use dynamic initializersKees Cook3-78/+33
GCC 8 changed the order of some fields and is very picky about ordering in static initializers, so instead just move to dynamic initializers, and drop the redundant already-zero field assignments. Suggested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-02-05gcc-plugins: Add include required by GCC release 8valdis.kletnieks@vt.edu1-0/+4
GCC requires another #include to get the gcc-plugins to build cleanly. Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman7-0/+7
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-07Merge branch 'for-next/gcc-plugin/structleak' into for-next/gcc-pluginsKees Cook1-2/+11
2017-08-07gcc-plugins: structleak: add option to init all vars used as byref argsArd Biesheuvel1-2/+11
In the Linux kernel, struct type variables are rarely passed by-value, and so functions that initialize such variables typically take an input reference to the variable rather than returning a value that can subsequently be used in an assignment. If the initalization function is not part of the same compilation unit, the lack of an assignment operation defeats any analysis the compiler can perform as to whether the variable may be used before having been initialized. This means we may end up passing on such variables uninitialized, resulting in potential information leaks. So extend the existing structleak GCC plugin so it will [optionally] apply to all struct type variables that have their address taken at any point, rather than only to variables of struct types that have a __user annotation. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2017-08-01randstruct: Enable function pointer struct detectionKees Cook1-3/+0
This enables the automatic structure selection logic in the randstruct GCC plugin. The selection logic randomizes all structures that contain only function pointers, unless marked with __no_randomize_layout. Signed-off-by: Kees Cook <keescook@chromium.org>
2017-06-22randstruct: Whitelist NIU struct page overloadingKees Cook1-0/+2
The NIU ethernet driver intentionally stores a page struct pointer on top of the "mapping" field. Whitelist this case: drivers/net/ethernet/sun/niu.c: In function ‘niu_rx_pkt_ignore’: drivers/net/ethernet/sun/niu.c:3402:10: note: found mismatched ssa struct pointer types: ‘struct page’ and ‘struct address_space’ *link = (struct page *) page->mapping; ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cc: David S. Miller <davem@davemloft.net> Signed-off-by: Kees Cook <keescook@chromium.org>
2017-06-22randstruct: Whitelist big_key path struct overloadingKees Cook1-0/+2
The big_key payload structure intentionally stores a struct path in two void pointers to avoid header soup. Whitelist this case: security/keys/big_key.c: In function ‘big_key_read’: security/keys/big_key.c:293:16: note: found mismatched rhs struct pointer types: ‘struct path’ and ‘void *’ struct path *path = (struct path *)&key->payload.data[big_key_path]; ^~~~ Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-04 21:28:44 +0000