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treewide: Add SPDX license identifier - Makefile/Kconfig 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>
2019-05-19 12:07:45 +00:00
# SPDX-License-Identifier: GPL-2.0-only
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
config HAVE_GCC_PLUGINS
bool
help
An arch should select this symbol if it supports building with
GCC plugins.
gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again 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>
2019-12-11 13:39:28 +00:00
menuconfig GCC_PLUGINS
bool "GCC plugins"
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
depends on HAVE_GCC_PLUGINS
compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 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>
2020-01-22 19:38:21 +00:00
depends on CC_IS_GCC
gcc-plugins: simplify GCC plugin-dev capability test Linus pointed out a third of the time in the Kconfig parse stage comes from the single invocation of cc1plus in scripts/gcc-plugin.sh [1], and directly testing plugin-version.h for existence cuts down the overhead a lot. [2] This commit takes one step further to kill the build test entirely. The small piece of code was probably intended to test the C++ designated initializer, which was not supported until C++20. In fact, with -pedantic option given, both GCC and Clang emit a warning. $ echo 'class test { public: int test; } test = { .test = 1 };' | g++ -x c++ -pedantic - -fsyntax-only <stdin>:1:43: warning: C++ designated initializers only available with '-std=c++2a' or '-std=gnu++2a' [-Wpedantic] $ echo 'class test { public: int test; } test = { .test = 1 };' | clang++ -x c++ -pedantic - -fsyntax-only <stdin>:1:43: warning: designated initializers are a C++20 extension [-Wc++20-designator] class test { public: int test; } test = { .test = 1 }; ^ 1 warning generated. Otherwise, modern C++ compilers should be able to build the code, and hopefully skipping this test should not make any practical problem. Checking the existence of plugin-version.h is still needed to ensure the plugin-dev package is installed. The test code is now small enough to be embedded in scripts/gcc-plugins/Kconfig. [1] https://lore.kernel.org/lkml/CAHk-=wjU4DCuwQ4pXshRbwDCUQB31ScaeuDo1tjoZ0_PjhLHzQ@mail.gmail.com/ [2] https://lore.kernel.org/lkml/CAHk-=whK0aQxs6Q5ijJmYF1n2ch8cVFSUzU5yUM_HOjig=+vnw@mail.gmail.com/ Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201203125700.161354-1-masahiroy@kernel.org
2020-12-03 12:57:00 +00:00
depends on $(success,test -e $(shell,$(CC) -print-file-name=plugin)/include/plugin-version.h)
security: Create "kernel hardening" config area 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>
2019-04-10 15:23:44 +00:00
default y
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
help
GCC plugins are loadable modules that provide extra features to the
compiler. They are useful for runtime instrumentation and static analysis.
docs: move gcc-plugins to the kbuild manual 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>
2020-03-02 22:24:04 +00:00
See Documentation/kbuild/gcc-plugins.rst for details.
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again 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>
2019-12-11 13:39:28 +00:00
if GCC_PLUGINS
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
config GCC_PLUGIN_SANCOV
bool
gcc-plugins: Explicitly document purpose and deprecation schedule GCC plugins should only exist when some compiler feature needs to be proven but does not exist in either GCC nor Clang. For example, if a desired feature is already in Clang, it should be added to GCC upstream. Document this explicitly. Additionally, mark the plugins with matching upstream GCC features as removable past their respective GCC versions. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-security-module@vger.kernel.org Cc: llvm@lists.linux.dev Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211020173554.38122-2-keescook@chromium.org
2021-10-20 17:35:53 +00:00
# Plugin can be removed once the kernel only supports GCC 6+
depends on !CC_HAS_SANCOV_TRACE_PC
gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig 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>
2018-07-05 06:24:12 +00:00
help
This plugin inserts a __sanitizer_cov_trace_pc() call at the start of
basic blocks. It supports all gcc versions with plugin support (from
gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"
by Dmitry Vyukov <dvyukov@google.com>.
config GCC_PLUGIN_LATENT_ENTROPY
bool "Generate some entropy during boot and runtime"
help
By saying Y here the kernel will instrument some kernel code to
extract some entropy from both original and artificially created
program state. This will help especially embedded systems where
there is little 'natural' source of entropy normally. The cost
is some slowdown of the boot process (about 0.5%) and fork and
irq processing.
Note that entropy extracted this way is not cryptographically
secure!
This plugin was ported from grsecurity/PaX. More information at:
* https://grsecurity.net/
* https://pax.grsecurity.net/
ARM: smp: add support for per-task stack canaries 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>
2018-12-06 08:32:57 +00:00
config GCC_PLUGIN_ARM_SSP_PER_TASK
bool
depends on GCC_PLUGINS && ARM
gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS again 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>
2019-12-11 13:39:28 +00:00
endif