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* gcc-plugins/stackleak: Ignore .noinstr.text and .entry.textKees Cook2022-02-061-0/+4
| | | | | | | | | | | | | | | | | | The .noinstr.text section functions may not have "current()" sanely available. Similarly true for .entry.text, though such a check is currently redundant. Add a check for both. In an x86_64 defconfig build, the following functions no longer receive stackleak instrumentation: __do_fast_syscall_32() do_int80_syscall_32() do_machine_check() do_syscall_64() exc_general_protection() fixup_bad_iret() Suggested-by: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
* gcc-plugins/stackleak: Exactly match strings instead of prefixesKees Cook2022-02-061-4/+21
| | | | | | | | | | Since STRING_CST may not be NUL terminated, strncmp() was used for check for equality. However, this may lead to mismatches for longer section names where the start matches the tested-for string. Test for exact equality by checking for the presences of NUL termination. Cc: Alexander Popov <alex.popov@linux.com> Signed-off-by: Kees Cook <keescook@chromium.org>
* Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2021-11-021-21/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: - Rejig task/thread info to place thread info in task struct - Amba bus cleanups (removing unused functions) - Handle Amba device probe without IRQ domains - Parse linux,usable-memory-range in decompressor - Mark OCRAM as read-only after initialisation - Refactor page fault handling - Fix PXN handling with LPAE kernels - Warning and build fixes from Arnd * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (32 commits) ARM: 9151/1: Thumb2: avoid __builtin_thread_pointer() on Clang ARM: 9150/1: Fix PID_IN_CONTEXTIDR regression when THREAD_INFO_IN_TASK=y ARM: 9147/1: add printf format attribute to early_print() ARM: 9146/1: RiscPC needs older gcc version ARM: 9145/1: patch: fix BE32 compilation ARM: 9144/1: forbid ftrace with clang and thumb2_kernel ARM: 9143/1: add CONFIG_PHYS_OFFSET default values ARM: 9142/1: kasan: work around LPAE build warning ARM: 9140/1: allow compile-testing without machine record ARM: 9137/1: disallow CONFIG_THUMB with ARMv4 ARM: 9136/1: ARMv7-M uses BE-8, not BE-32 ARM: 9135/1: kprobes: address gcc -Wempty-body warning ARM: 9101/1: sa1100/assabet: convert LEDs to gpiod APIs ARM: 9131/1: mm: Fix PXN process with LPAE feature ARM: 9130/1: mm: Provide die_kernel_fault() helper ARM: 9126/1: mm: Kill page table base print in show_pte() ARM: 9127/1: mm: Cleanup access_error() ARM: 9129/1: mm: Kill task_struct argument for __do_page_fault() ARM: 9128/1: mm: Refactor the __do_page_fault() ARM: imx6: mark OCRAM mapping read-only ...
| * gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK supportArd Biesheuvel2021-09-271-21/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We will be enabling THREAD_INFO_IN_TASK support for ARM, which means that we can no longer load the stack canary value by masking the stack pointer and taking the copy that lives in thread_info. Instead, we will be able to load it from the task_struct directly, by using the TPIDRURO register which will hold the current task pointer when THREAD_INFO_IN_TASK is in effect. This is much more straight-forward, and allows us to declutter this code a bit while at it. Note that this means that ARMv6 (non-v6K) SMP systems can no longer use this feature, but those are quite rare to begin with, so this is a reasonable trade off. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
* | gcc-plugins: remove duplicate include in gcc-common.hYe Guojin2021-10-211-1/+0
| | | | | | | | | | | | | | | | | | | | 'tree-ssa-operands.h' included in 'gcc-common.h' is duplicated. it's also included at line 56. Reported-by: Zeal Robot <zealci@zte.com.cn> Signed-off-by: Ye Guojin <ye.guojin@zte.com.cn> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20211019082910.998257-1-ye.guojin@zte.com.cn
* | gcc-plugins: Remove cyc_complexityKees Cook2021-10-212-85/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This plugin has no impact on the resulting binary, is disabled under COMPILE_TEST, and is not enabled on any builds I'm aware of. Additionally, given the clarified purpose of GCC plugins in the kernel, remove cyc_complexity. 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: linux-hardening@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: linux-doc@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20211020173554.38122-3-keescook@chromium.org
* | gcc-plugins: Explicitly document purpose and deprecation scheduleKees Cook2021-10-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* | gcc-plugins: remove support for GCC 4.9 and olderArd Biesheuvel2021-10-046-208/+1
|/ | | | | | | | | The minimum GCC version has been bumped to 5.1, so we can get rid of all the compatibility code for anything older than that. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210922182632.633394-1-ardb@kernel.org
* scripts: make some scripts executableMasahiro Yamada2021-08-101-0/+0
| | | | | | | | | | | | | | | | Set the x bit to some scripts to make them directly executable. Especially, scripts/checkdeclares.pl is not hooked by anyone. It should be executable since it is tedious to type 'perl scripts/checkdeclares.pl'. The original patch [1] set the x bit properly, but it was lost when it was merged as commit 21917bded72c ("scripts: a new script for checking duplicate struct declaration"). [1] https://lore.kernel.org/lkml/20210401110943.1010796-1-wanjiabing@vivo.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* .gitignore: prefix local generated files with a slashMasahiro Yamada2021-05-021-1/+1
| | | | | | | | | | | | The pattern prefixed with '/' matches files in the same directory, but not ones in sub-directories. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Andra Paraschiv <andraprs@amazon.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Gabriel Krisman Bertazi <krisman@collabora.com>
* kbuild: rebuild GCC plugins when the compiler is upgradedMasahiro Yamada2021-03-111-0/+1
| | | | | | | | | | | | | | | | | | | | | Linus reported a build error due to the GCC plugin incompatibility when the compiler is upgraded. [1] GCC plugins are tied to a particular GCC version. So, they must be rebuilt when the compiler is upgraded. This seems to be a long-standing flaw since the initial support of GCC plugins. Extend commit 8b59cd81dc5e ("kbuild: ensure full rebuild when the compiler is updated"), so that GCC plugins are covered by the compiler upgrade detection. [1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/ Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org>
* gcc-plugins: latent_entropy: remove unneeded semicolonJason Yan2021-03-011-1/+1
| | | | | | | | | | | Fix the following coccicheck warning: scripts/gcc-plugins/latent_entropy_plugin.c:539:2-3: Unneeded semicolon Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200418070521.10931-1-yanaijie@huawei.com
* gcc-plugins: structleak: remove unneeded variable 'ret'Jason Yan2021-03-011-2/+1
| | | | | | | | | | | | Fix the following coccicheck warning: scripts/gcc-plugins/structleak_plugin.c:177:14-17: Unneeded variable: "ret". Return "0" on line 207 Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200418070505.10715-1-yanaijie@huawei.com
* gcc-plugins: fix gcc 11 indigestion with plugins...Valdis Klētnieks2021-01-061-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Fedora Rawhide has started including gcc 11,and the g++ compiler throws a wobbly when it hits scripts/gcc-plugins: HOSTCXX scripts/gcc-plugins/latent_entropy_plugin.so In file included from /usr/include/c++/11/type_traits:35, from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/system.h:244, from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/gcc-plugin.h:28, from scripts/gcc-plugins/gcc-common.h:7, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/include/c++/11/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options. 32 | #error This file requires compiler and library support \ In fact, it works just fine with c++11, which has been in gcc since 4.8, and we now require 4.9 as a minimum. Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/82487.1609006918@turing-police
* gcc-plugins: simplify GCC plugin-dev capability testMasahiro Yamada2020-12-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* gcc-plugins: remove code for GCC versions older than 4.9Masahiro Yamada2020-12-0410-505/+1
| | | | | | | | | Documentation/process/changes.rst says the minimal GCC version is 4.9. Hence, BUILDING_GCC_VERSION is greater than or equal to 4009. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201202134929.99883-1-masahiroy@kernel.org
* Merge tag 'kbuild-v5.9' of ↵Linus Torvalds2020-08-091-11/+50
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
| * kbuild: move host .so build rules to scripts/gcc-plugins/MakefileMasahiro Yamada2020-08-101-11/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The host shared library rules are currently implemented in scripts/Makefile.host, but actually GCC-plugin is the only user of them. (The VDSO .so files are built for the target by different build rules) Hence, they do not need to be treewide available. Move all the relevant build rules to scripts/gcc-plugins/Makefile. I also optimized the build steps so *.so is directly built from .c because every upstream plugin is compiled from a single source file. I am still keeping the multi-file plugin support, which Kees Cook mentioned might be needed by out-of-tree plugins. (https://lkml.org/lkml/2019/1/11/1107) If the plugin, foo.so, is compiled from two files foo.c and foo2.c, then you can do like follows: foo-objs := foo.o foo2.o Single-file plugins do not need the *-objs notation. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
* | Merge tag 'gcc-plugins-v5.9-rc1' of ↵Linus Torvalds2020-08-044-34/+220
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugin updates from Kees Cook: "Primarily improvements to STACKLEAK from Alexander Popov, along with some additional cleanups. - Update URLs for HTTPS scheme where available (Alexander A. Klimov) - Improve STACKLEAK code generation on x86 (Alexander Popov)" * tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: Replace HTTP links with HTTPS ones gcc-plugins/stackleak: Add 'verbose' plugin parameter gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving ARM: vdso: Don't use gcc plugins for building vgettimeofday.c gcc-plugins/stackleak: Don't instrument itself
| * gcc-plugins: Replace HTTP links with HTTPS onesAlexander A. Klimov2020-07-133-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Link: https://lore.kernel.org/r/20200713135018.34708-1-grandmaster@al2klimov.de Signed-off-by: Kees Cook <keescook@chromium.org>
| * gcc-plugins/stackleak: Add 'verbose' plugin parameterAlexander Popov2020-06-241-5/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add 'verbose' plugin parameter for stackleak gcc plugin. It can be used for printing additional info about the kernel code instrumentation. For using it add the following to scripts/Makefile.gcc-plugins: gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \ += -fplugin-arg-stackleak_plugin-verbose Signed-off-by: Alexander Popov <alex.popov@linux.com> Link: https://lore.kernel.org/r/20200624123330.83226-6-alex.popov@linux.com Signed-off-by: Kees Cook <keescook@chromium.org>
| * gcc-plugins/stackleak: Use asm instrumentation to avoid useless register savingAlexander Popov2020-06-241-28/+177
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel code instrumentation in stackleak gcc plugin works in two stages. At first, stack tracking is added to GIMPLE representation of every function (except some special cases). And later, when stack frame size info is available, stack tracking is removed from the RTL representation of the functions with small stack frame. There is an unwanted side-effect for these functions: some of them do useless work with caller-saved registers. As an example of such case, proc_sys_write without() instrumentation: 55 push %rbp 41 b8 01 00 00 00 mov $0x1,%r8d 48 89 e5 mov %rsp,%rbp e8 11 ff ff ff callq ffffffff81284610 <proc_sys_call_handler> 5d pop %rbp c3 retq 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 00 00 00 proc_sys_write() with instrumentation: 55 push %rbp 48 89 e5 mov %rsp,%rbp 41 56 push %r14 41 55 push %r13 41 54 push %r12 53 push %rbx 49 89 f4 mov %rsi,%r12 48 89 fb mov %rdi,%rbx 49 89 d5 mov %rdx,%r13 49 89 ce mov %rcx,%r14 4c 89 f1 mov %r14,%rcx 4c 89 ea mov %r13,%rdx 4c 89 e6 mov %r12,%rsi 48 89 df mov %rbx,%rdi 41 b8 01 00 00 00 mov $0x1,%r8d e8 f2 fe ff ff callq ffffffff81298e80 <proc_sys_call_handler> 5b pop %rbx 41 5c pop %r12 41 5d pop %r13 41 5e pop %r14 5d pop %rbp c3 retq 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1) 00 00 Let's improve the instrumentation to avoid this: 1. Make stackleak_track_stack() save all register that it works with. Use no_caller_saved_registers attribute for that function. This attribute is available for x86_64 and i386 starting from gcc-7. 2. Insert calling stackleak_track_stack() in asm: asm volatile("call stackleak_track_stack" :: "r" (current_stack_pointer)) Here we use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h. The input constraint is taken into account during gcc shrink-wrapping optimization. It is needed to be sure that stackleak_track_stack() call is inserted after the prologue of the containing function, when the stack frame is prepared. This work is a deep reengineering of the idea described on grsecurity blog https://grsecurity.net/resolving_an_unfortunate_stackleak_interaction Signed-off-by: Alexander Popov <alex.popov@linux.com> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Link: https://lore.kernel.org/r/20200624123330.83226-5-alex.popov@linux.com Signed-off-by: Kees Cook <keescook@chromium.org>
* | gcc-plugins: fix gcc-plugins directory path in documentationMasahiro Yamada2020-06-281-1/+1
|/ | | | | | | Fix typos "plgins" -> "plugins". Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
* Merge branch 'rwonce/rework' of ↵Linus Torvalds2020-06-101-1/+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
| * compiler/gcc: Raise minimum GCC version for kernel builds to 4.8Will Deacon2020-04-151-1/+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>
* | gcc-plugins: remove always-false $(if ...) in MakefileMasahiro Yamada2020-05-261-1/+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>
* | gcc-common.h: Update for GCC 10Frédéric Pierret (fepitre)2020-04-132-0/+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>
* | gcc-plugins/stackleak: Avoid assignment for unused macro argumentKees Cook2020-04-131-3/+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>
* gcc-plugins: drop support for GCC <= 4.7Masahiro Yamada2020-04-092-25/+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>
* Merge tag 'spdx-5.7-rc1' of ↵Linus Torvalds2020-04-031-0/+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
| * .gitignore: add SPDX License IdentifierMasahiro Yamada2020-03-251-0/+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>
* | Merge tag 'kbuild-v5.7' of ↵Linus Torvalds2020-03-311-1/+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 ...
| * | kbuild: add -Wall to KBUILD_HOSTCXXFLAGSMasahiro Yamada2020-03-291-1/+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>
* | docs: move gcc-plugins to the kbuild manualJonathan Corbet2020-03-101-1/+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>
* kbuild: rename hostprogs-y/always to hostprogs/always-yMasahiro Yamada2020-02-041-1/+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>
* gcc-plugins: make it possible to disable CONFIG_GCC_PLUGINS againArnd Bergmann2020-01-021-5/+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>
* randstruct: Check member structs in is_pure_ops_struct()Joonwon Kang2019-07-311-5/+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>
* docs: move gcc_plugins.txt to core-api and rename to .rstMauro Carvalho Chehab2019-07-151-1/+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>
* Merge tag 'gcc-plugins-v5.2-rc3' of ↵Linus Torvalds2019-05-311-0/+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
| * gcc-plugins: Fix build failures under Darwin hostKees Cook2019-05-201-0/+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>
* | treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-211-0/+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>
* | Merge tag 'gcc-plugins-v5.2-rc1' of ↵Linus Torvalds2019-05-131-1/+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
| * gcc-plugins: arm_ssp_per_task_plugin: Fix for older GCC < 6Chris Packham2019-05-101-1/+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>
* | security: Move stackleak config to Kconfig.hardeningKees Cook2019-04-241-51/+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>
* | security: Create "kernel hardening" config areaKees Cook2019-04-241-69/+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>
* Merge tag 'gcc-plugins-v5.1-rc1' of ↵Linus Torvalds2019-03-092-22/+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
| * gcc-plugins: structleak: Generalize to all variable typesKees Cook2019-03-042-22/+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>
* | kasan: remove use after scope bugs detection.Andrey Ryabinin2019-03-051-4/+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>
* gcc-plugins: arm_ssp_per_task_plugin: fix for GCC 9+Ard Biesheuvel2019-01-201-0/+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>
* gcc-plugins: arm_ssp_per_task_plugin: sign extend the SP maskArd Biesheuvel2019-01-201-2/+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>
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