From 947d2e0a70d4b93eda4b9fe229ad2bf0bfc79251 Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Wed, 12 Feb 2020 11:49:01 +0100 Subject: [PATCH] build: Add KCOV kernel code coverage for fuzzing The adds an option to activate KCOV (Code coverage for fuzzing). Signed-off-by: Hauke Mehrtens Reviewed-by: Alexandru Ardelean --- config/Config-kernel.in | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/config/Config-kernel.in b/config/Config-kernel.in index ed75dd5853..5e677e6afd 100644 --- a/config/Config-kernel.in +++ b/config/Config-kernel.in @@ -172,6 +172,39 @@ config KERNEL_KASAN_INLINE endchoice +config KERNEL_KCOV + bool "Compile the kernel with code coverage for fuzzing" + select KERNEL_DEBUG_FS + help + KCOV exposes kernel code coverage information in a form suitable + for coverage-guided fuzzing (randomized testing). + + If RANDOMIZE_BASE is enabled, PC values will not be stable across + different machines and across reboots. If you need stable PC values, + disable RANDOMIZE_BASE. + + For more details, see Documentation/kcov.txt. + +config KERNEL_KCOV_ENABLE_COMPARISONS + bool "Enable comparison operands collection by KCOV" + depends on KERNEL_KCOV + help + KCOV also exposes operands of every comparison in the instrumented + code along with operand sizes and PCs of the comparison instructions. + These operands can be used by fuzzing engines to improve the quality + of fuzzing coverage. + +config KERNEL_KCOV_INSTRUMENT_ALL + bool "Instrument all code by default" + depends on KERNEL_KCOV + default y if KERNEL_KCOV + help + If you are doing generic system call fuzzing (like e.g. syzkaller), + then you will want to instrument the whole kernel and you should + say y here. If you are doing more targeted fuzzing (like e.g. + filesystem fuzzing with AFL) then you will want to enable coverage + for more specific subsets of files, and should say n here. + config KERNEL_TASKSTATS bool "Compile the kernel with task resource/io statistics and accounting" default n -- 2.30.2