mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 12:44:11 +08:00
6a6155f664
When the kernel is compiled with Clang, -fsanitize=bounds expands to -fsanitize=array-bounds and -fsanitize=local-bounds. Enabling -fsanitize=local-bounds with Clang has the unfortunate side-effect of inserting traps; this goes back to its original intent, which was as a hardening and not a debugging feature [1]. The same feature made its way into -fsanitize=bounds, but the traps remained. For that reason, -fsanitize=bounds was split into 'array-bounds' and 'local-bounds' [2]. Since 'local-bounds' doesn't behave like a normal sanitizer, enable it with Clang only if trapping behaviour was requested by CONFIG_UBSAN_TRAP=y. Add the UBSAN_BOUNDS_LOCAL config to Kconfig.ubsan to enable the 'local-bounds' option by default when UBSAN_TRAP is enabled. [1] http://lists.llvm.org/pipermail/llvm-dev/2012-May/049972.html [2] http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20131021/091536.html Suggested-by: Marco Elver <elver@google.com> Signed-off-by: George Popescu <georgepope@android.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Brazdil <dbrazdil@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: https://lkml.kernel.org/r/20200922074330.2549523-1-georgepope@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
105 lines
3.7 KiB
Plaintext
105 lines
3.7 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
|
|
config ARCH_HAS_UBSAN_SANITIZE_ALL
|
|
bool
|
|
|
|
menuconfig 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
|
|
|
|
if UBSAN
|
|
|
|
config UBSAN_TRAP
|
|
bool "On Sanitizer warnings, abort the running kernel code"
|
|
depends on $(cc-option, -fsanitize-undefined-trap-on-error)
|
|
help
|
|
Building kernels with Sanitizer features enabled tends to grow
|
|
the kernel size by around 5%, due to adding all the debugging
|
|
text on failure paths. To avoid this, Sanitizer instrumentation
|
|
can just issue a trap. This reduces the kernel size overhead but
|
|
turns all warnings (including potentially harmless conditions)
|
|
into full exceptions that abort the running kernel code
|
|
(regardless of context, locks held, etc), which may destabilize
|
|
the system. For some system builders this is an acceptable
|
|
trade-off.
|
|
|
|
config UBSAN_KCOV_BROKEN
|
|
def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
|
|
depends on CC_IS_CLANG
|
|
depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=bounds -fsanitize-coverage=trace-pc)
|
|
help
|
|
Some versions of clang support either UBSAN or KCOV but not the
|
|
combination of the two.
|
|
See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
|
|
in newer releases.
|
|
|
|
config UBSAN_BOUNDS
|
|
bool "Perform array index bounds checking"
|
|
default UBSAN
|
|
depends on !UBSAN_KCOV_BROKEN
|
|
help
|
|
This option enables detection of directly indexed out of bounds
|
|
array accesses, where the array size is known at compile time.
|
|
Note that this does not protect array overflows via bad calls
|
|
to the {str,mem}*cpy() family of functions (that is addressed
|
|
by CONFIG_FORTIFY_SOURCE).
|
|
|
|
config UBSAN_LOCAL_BOUNDS
|
|
bool "Perform array local bounds checking"
|
|
depends on UBSAN_TRAP
|
|
depends on CC_IS_CLANG
|
|
depends on !UBSAN_KCOV_BROKEN
|
|
help
|
|
This option enables -fsanitize=local-bounds which traps when an
|
|
exception/error is detected. Therefore, it should be enabled only
|
|
if trapping is expected.
|
|
Enabling this option detects errors due to accesses through a
|
|
pointer that is derived from an object of a statically-known size,
|
|
where an added offset (which may not be known statically) is
|
|
out-of-bounds.
|
|
|
|
config UBSAN_MISC
|
|
bool "Enable all other Undefined Behavior sanity checks"
|
|
default UBSAN
|
|
help
|
|
This option enables all sanity checks that don't have their
|
|
own Kconfig options. Disable this if you only want to have
|
|
individually selected checks.
|
|
|
|
config UBSAN_SANITIZE_ALL
|
|
bool "Enable instrumentation for the entire kernel"
|
|
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_ALIGNMENT
|
|
bool "Enable checks for pointers alignment"
|
|
default !HAVE_EFFICIENT_UNALIGNED_ACCESS
|
|
depends on !UBSAN_TRAP
|
|
help
|
|
This option enables the check of unaligned memory accesses.
|
|
Enabling this option on architectures that support unaligned
|
|
accesses may produce a lot of false positives.
|
|
|
|
config TEST_UBSAN
|
|
tristate "Module for testing for undefined behavior detection"
|
|
depends on m
|
|
help
|
|
This is a test module for UBSAN.
|
|
It triggers various undefined behavior, and detect it.
|
|
|
|
endif # if UBSAN
|