user/sven/linux.git/scripts/gcc-plugins, branch v5.1.1

Merge tag 'gcc-plugins-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2019-03-09T17:06:15Z

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

kasan: remove use after scope bugs detection.

2019-03-06T05:07:13Z

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 Acked-by: Will Deacon [arm64] Cc: Qian Cai Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Catalin Marinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

gcc-plugins: structleak: Generalize to all variable types

2019-03-04T17:29:41Z

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 Reviewed-by: Ard Biesheuvel

gcc-plugins: arm_ssp_per_task_plugin: fix for GCC 9+

2019-01-20T22:06:40Z

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 Signed-off-by: Kees Cook

gcc-plugins: arm_ssp_per_task_plugin: sign extend the SP mask

2019-01-20T22:06:40Z

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 Signed-off-by: Ard Biesheuvel Signed-off-by: Kees Cook

Merge tag 'gcc-plugins-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-12-27T19:19:07Z

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

ARM: smp: add support for per-task stack canaries

2018-12-12T21:20:07Z

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 Cc: Kees Cook Cc: Emese Revfy Cc: Arnd Bergmann Cc: Laura Abbott Cc: kernel-hardening@lists.openwall.com Acked-by: Nicolas Pitre Signed-off-by: Ard Biesheuvel Signed-off-by: Kees Cook

stackleak: Register the 'stackleak_cleanup' pass before the '*free_cfg' pass

2018-12-06T17:10:23Z

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 Signed-off-by: Alexander Popov Signed-off-by: Kees Cook

stackleak: Allow runtime disabling of kernel stack erasing

2018-09-04T17:35:48Z

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 Signed-off-by: Alexander Popov Tested-by: Laura Abbott Signed-off-by: Kees Cook

fs/proc: Show STACKLEAK metrics in the /proc file system

2018-09-04T17:35:48Z

Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about tasks via the /proc file system. In particular, /proc//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 Signed-off-by: Alexander Popov Tested-by: Laura Abbott Signed-off-by: Kees Cook