diff options
author | Sascha Hauer <s.hauer@pengutronix.de> | 2020-09-17 09:39:17 +0200 |
---|---|---|
committer | Sascha Hauer <s.hauer@pengutronix.de> | 2020-09-22 20:40:12 +0200 |
commit | 6cd9d2d600f3764a4c51d1a735e36397d91334f3 (patch) | |
tree | a48e89e6a91fe8f3f1009a0982a8a65cc6384ba5 /Makefile | |
parent | 2b7b0cd8d9f71bdf2d6623ead66ef2510095aa0f (diff) | |
download | barebox-6cd9d2d600f3764a4c51d1a735e36397d91334f3.tar.gz barebox-6cd9d2d600f3764a4c51d1a735e36397d91334f3.tar.xz |
Add KASan support
KernelAddressSANitizer (KASAN) is a dynamic memory error detector. It
provides a fast and comprehensive solution for finding use-after-free
and out-of-bounds bugs.
This adds support for KASan to barebox. It is basically a stripped down
version taken from the Linux Kernel as of v5.9-rc1.
Quoting the initial Linux commit 0b24becc810d ("kasan: add kernel address
sanitizer infrastructure") describes what KASan does:
| KASAN uses compile-time instrumentation for checking every memory access,
| therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with
| putting symbol aliases into the wrong section, which breaks kasan
| instrumentation of globals.
|
| Basic idea:
|
| The main idea of KASAN is to use shadow memory to record whether each byte
| of memory is safe to access or not, and use compiler's instrumentation to
| check the shadow memory on each memory access.
|
| Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
| memory and uses direct mapping with a scale and offset to translate a
| memory address to its corresponding shadow address.
|
| For every 8 bytes there is one corresponding byte of shadow memory.
| The following encoding used for each shadow byte: 0 means that all 8 bytes
| of the corresponding memory region are valid for access; k (1 <= k <= 7)
| means that the first k bytes are valid for access, and other (8 - k) bytes
| are not; Any negative value indicates that the entire 8-bytes are
| inaccessible. Different negative values used to distinguish between
| different kinds of inaccessible memory (redzones, freed memory) (see
| mm/kasan/kasan.h).
|
| To be able to detect accesses to bad memory we need a special compiler.
| Such compiler inserts a specific function calls (__asan_load*(addr),
| __asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.
|
| These functions check whether memory region is valid to access or not by
| checking corresponding shadow memory. If access is not valid an error
| printed.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'Makefile')
-rw-r--r-- | Makefile | 6 |
1 files changed, 5 insertions, 1 deletions
@@ -448,6 +448,7 @@ export LDFLAGS_barebox export LDFLAGS_pbl export CFLAGS_UBSAN +export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE # Files to ignore in find ... statements @@ -636,7 +637,10 @@ KBUILD_CFLAGS += $(call cc-option,-Wno-pointer-sign,) # change __FILE__ to the relative path from the srctree KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) -include $(srctree)/scripts/Makefile.ubsan +include-y +=scripts/Makefile.ubsan +include-$(CONFIG_KASAN) += scripts/Makefile.kasan + +include $(addprefix $(srctree)/, $(include-y)) # KBUILD_IMAGE: Default barebox image to build # Depending on the architecture, this can be either compressed or not. |