This is the v2 of the patch series with various improvements of the stackleak gcc plugin. The first three patches disable unneeded gcc plugin instrumentation for some files. The fourth patch is the main improvement. It eliminates an unwanted side-effect of kernel code instrumentation performed by stackleak gcc plugin. This patch is a deep reengineering of the idea described on grsecurity blog: https://grsecurity.net/resolving_an_unfortunate_stackleak_interaction The final patch adds 'verbose' stackleak parameter for printing additional info about the kernel code instrumentation during kernel building. I would like to thank Alexander Monakov <amonakov@xxxxxxxxx> for his advisory on gcc internals. This patch series was tested for gcc version 4.8, 5, 6, 7, 8, 9, and 10 on x86_64, i386 and arm64. That was done using the project 'kernel-build-containers': https://github.com/a13xp0p0v/kernel-build-containers Changes from v1: - rebase onto 5.8.0-rc2; - don't exclude alloca() from the instrumentation logic, because it will be used in kernel stack offset randomization; - reorder patches in the series; - don't use gcc plugins for building vgettimeofday.c in arm and arm64 vDSO; - follow alphabetic order in include/linux/compiler_attributes.h. Link to v1: https://lore.kernel.org/lkml/20200604134957.505389-1-alex.popov@xxxxxxxxx/ Alexander Popov (5): gcc-plugins/stackleak: Don't instrument itself ARM: vdso: Don't use gcc plugins for building vgettimeofday.c arm64: vdso: Don't use gcc plugins for building vgettimeofday.c gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving gcc-plugins/stackleak: Add 'verbose' plugin parameter arch/arm/vdso/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 2 +- include/linux/compiler_attributes.h | 13 ++ kernel/Makefile | 1 + kernel/stackleak.c | 16 +- scripts/Makefile.gcc-plugins | 2 + scripts/gcc-plugins/stackleak_plugin.c | 248 +++++++++++++++++++++---- 7 files changed, 239 insertions(+), 45 deletions(-) -- 2.25.4
