mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
synced 2024-12-29 17:22:07 +00:00
0887a7ebc9
Patch series "ubsan: Split out bounds checker", v5.
This splits out the bounds checker so it can be individually used. This
is enabled in Android and hopefully for syzbot. Includes LKDTM tests for
behavioral corner-cases (beyond just the bounds checker), and adjusts
ubsan and kasan slightly for correct panic handling.
This patch (of 6):
The Undefined Behavior Sanitizer can operate in two modes: warning
reporting mode via lib/ubsan.c handler calls, or trap mode, which uses
__builtin_trap() as the handler. Using lib/ubsan.c means the kernel image
is about 5% larger (due to all the debugging text and reporting structures
to capture details about the warning conditions). Using the trap mode,
the image size changes are much smaller, though at the loss of the
"warning only" mode.
In order to give greater flexibility to system builders that want minimal
changes to image size and are prepared to deal with kernel code being
aborted and potentially destabilizing the system, this introduces
CONFIG_UBSAN_TRAP. The resulting image sizes comparison:
text data bss dec hex filename
19533663 6183037 18554956 44271656 2a38828 vmlinux.stock
19991849 7618513 18874448 46484810 2c54d4a vmlinux.ubsan
19712181 6284181 18366540 44362902 2a4ec96 vmlinux.ubsan-trap
CONFIG_UBSAN=y: image +4.8% (text +2.3%, data +18.9%)
CONFIG_UBSAN_TRAP=y: image +0.2% (text +0.9%, data +1.6%)
Additionally adjusts the CONFIG_UBSAN Kconfig help for clarity and removes
the mention of non-existing boot param "ubsan_handle".
Suggested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Link: http://lkml.kernel.org/r/20200227193516.32566-2-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
64 lines
2.3 KiB
Plaintext
64 lines
2.3 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
|
|
config ARCH_HAS_UBSAN_SANITIZE_ALL
|
|
bool
|
|
|
|
config UBSAN
|
|
bool "Undefined behaviour sanity checker"
|
|
help
|
|
This option enables the Undefined Behaviour sanity checker.
|
|
Compile-time instrumentation is used to detect various undefined
|
|
behaviours at runtime. For more details, see:
|
|
Documentation/dev-tools/ubsan.rst
|
|
|
|
config UBSAN_TRAP
|
|
bool "On Sanitizer warnings, abort the running kernel code"
|
|
depends on UBSAN
|
|
depends on $(cc-option, -fsanitize-undefined-trap-on-error)
|
|
help
|
|
Building kernels with Sanitizer features enabled tends to grow
|
|
the kernel size by around 5%, due to adding all the debugging
|
|
text on failure paths. To avoid this, Sanitizer instrumentation
|
|
can just issue a trap. This reduces the kernel size overhead but
|
|
turns all warnings (including potentially harmless conditions)
|
|
into full exceptions that abort the running kernel code
|
|
(regardless of context, locks held, etc), which may destabilize
|
|
the system. For some system builders this is an acceptable
|
|
trade-off.
|
|
|
|
config UBSAN_SANITIZE_ALL
|
|
bool "Enable instrumentation for the entire kernel"
|
|
depends on UBSAN
|
|
depends on ARCH_HAS_UBSAN_SANITIZE_ALL
|
|
|
|
# We build with -Wno-maybe-uninitilzed, but we still want to
|
|
# use -Wmaybe-uninitilized in allmodconfig builds.
|
|
# So dependsy bellow used to disable this option in allmodconfig
|
|
depends on !COMPILE_TEST
|
|
default y
|
|
help
|
|
This option activates instrumentation for the entire kernel.
|
|
If you don't enable this option, you have to explicitly specify
|
|
UBSAN_SANITIZE := y for the files/directories you want to check for UB.
|
|
Enabling this option will get kernel image size increased
|
|
significantly.
|
|
|
|
config UBSAN_NO_ALIGNMENT
|
|
bool "Disable checking of pointers alignment"
|
|
depends on UBSAN
|
|
default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
|
|
help
|
|
This option disables the check of unaligned memory accesses.
|
|
This option should be used when building allmodconfig.
|
|
Disabling this option on architectures that support unaligned
|
|
accesses may produce a lot of false positives.
|
|
|
|
config UBSAN_ALIGNMENT
|
|
def_bool !UBSAN_NO_ALIGNMENT
|
|
|
|
config TEST_UBSAN
|
|
tristate "Module for testing for undefined behavior detection"
|
|
depends on m && UBSAN
|
|
help
|
|
This is a test module for UBSAN.
|
|
It triggers various undefined behavior, and detect it.
|