build: Add option KERNEL_KASAN

The kernel kernel address sanitizer is able to detect some memory
bugs in the kernel like out of range array accesses.

Signed-off-by: Hauke Mehrtens <hauke.mehrtens@intel.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>

diff --git a/config/Config-kernel.in b/config/Config-kernel.in
index e8bcf1970fd31cb375f370651918acaca66bc30d..ed75dd585355abfb07da5970ef7aeda2fa764265 100644 (file)
--- a/config/Config-kernel.in
+++ b/config/Config-kernel.in
@@ -120,6 +120,58 @@ config KERNEL_UBSAN_NULL
          This option enables detection of memory accesses via a
          null pointer.
 
+config KERNEL_KASAN
+       bool "Compile the kernel with KASan: runtime memory debugger"
+       select KERNEL_SLUB_DEBUG
+       depends on (x86_64 || aarch64)
+       help
+         Enables kernel address sanitizer - runtime memory debugger,
+         designed to find out-of-bounds accesses and use-after-free bugs.
+         This is strictly a debugging feature and it requires a gcc version
+         of 4.9.2 or later. Detection of out of bounds accesses to stack or
+         global variables requires gcc 5.0 or later.
+         This feature consumes about 1/8 of available memory and brings about
+         ~x3 performance slowdown.
+         For better error detection enable CONFIG_STACKTRACE.
+         Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
+         (the resulting kernel does not boot).
+
+config KERNEL_KASAN_EXTRA
+       bool "KAsan: extra checks"
+       depends on KERNEL_KASAN && KERNEL_DEBUG_KERNEL
+       help
+         This enables further checks in the kernel address sanitizer, for now
+         it only includes the address-use-after-scope check that can lead
+         to excessive kernel stack usage, frame size warnings and longer
+         compile time.
+         https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
+
+
+choice
+       prompt "Instrumentation type"
+       depends on KERNEL_KASAN
+       default KERNEL_KASAN_OUTLINE
+
+config KERNEL_KASAN_OUTLINE
+       bool "Outline instrumentation"
+       help
+         Before every memory access compiler insert function call
+         __asan_load*/__asan_store*. These functions performs check
+         of shadow memory. This is slower than inline instrumentation,
+         however it doesn't bloat size of kernel's .text section so
+         much as inline does.
+
+config KERNEL_KASAN_INLINE
+       bool "Inline instrumentation"
+       help
+         Compiler directly inserts code checking shadow memory before
+         memory accesses. This is faster than outline (in some workloads
+         it gives about x2 boost over outline instrumentation), but
+         make kernel's .text size much bigger.
+         This requires a gcc version of 5.0 or later.
+
+endchoice
+
 config KERNEL_TASKSTATS
        bool "Compile the kernel with task resource/io statistics and accounting"
        default n

diff --git a/target/linux/generic/config-4.14 b/target/linux/generic/config-4.14
index 73b0d77155e958d8beccc46c9c36ef8a26b4808c..5a9b82db80979807c90705f6557a251565a32e89 100644 (file)
--- a/target/linux/generic/config-4.14
+++ b/target/linux/generic/config-4.14
@@ -4927,6 +4927,7 @@ CONFIG_TCP_CONG_CUBIC=y
 # CONFIG_TEST_FIRMWARE is not set
 # CONFIG_TEST_HASH is not set
 # CONFIG_TEST_HEXDUMP is not set
+# CONFIG_TEST_KASAN is not set
 # CONFIG_TEST_KMOD is not set
 # CONFIG_TEST_KSTRTOX is not set
 # CONFIG_TEST_LIST_SORT is not set

diff --git a/target/linux/generic/config-4.19 b/target/linux/generic/config-4.19
index aba7bccaf62baecf7d4c47d3ca52510b51295369..372cad70a6e89dfc85638e3ffb8ad6af64ae6c17 100644 (file)
--- a/target/linux/generic/config-4.19
+++ b/target/linux/generic/config-4.19
@@ -5187,6 +5187,7 @@ CONFIG_TCP_CONG_CUBIC=y
 # CONFIG_TEST_HASH is not set
 # CONFIG_TEST_HEXDUMP is not set
 # CONFIG_TEST_IDA is not set
+# CONFIG_TEST_KASAN is not set
 # CONFIG_TEST_KMOD is not set
 # CONFIG_TEST_KSTRTOX is not set
 # CONFIG_TEST_LIST_SORT is not set