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Patch series "Clean up UBSAN Makefile", v2.
This series attempts to address the issues seen with UBSAN's object-size
sanitizer causing problems under GCC. In the process, the Kconfig and
Makefile are refactored to do all the cc-option calls in the Kconfig.
Additionally start to detangle -Wno-maybe-uninitialized, disable
UBSAN_TRAP under COMPILE_TEST for wider build coverage, and expand the
libusan tests.
This patch (of 7):
In commit 78a5255ffb ("Stop the ad-hoc games with
-Wno-maybe-initialized") -Wmaybe-uninitialized was disabled globally, so
keeping the disabling logic here too doesn't make sense.
Link: https://lkml.kernel.org/r/20201203004437.389959-1-keescook@chromium.org
Link: https://lkml.kernel.org/r/20201203004437.389959-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
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: Marco Elver <elver@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: George Popescu <georgepope@android.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
101 lines
3.5 KiB
Plaintext
101 lines
3.5 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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config ARCH_HAS_UBSAN_SANITIZE_ALL
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bool
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menuconfig UBSAN
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bool "Undefined behaviour sanity checker"
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help
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This option enables the Undefined Behaviour sanity checker.
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Compile-time instrumentation is used to detect various undefined
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behaviours at runtime. For more details, see:
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Documentation/dev-tools/ubsan.rst
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if UBSAN
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config UBSAN_TRAP
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bool "On Sanitizer warnings, abort the running kernel code"
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depends on $(cc-option, -fsanitize-undefined-trap-on-error)
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help
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Building kernels with Sanitizer features enabled tends to grow
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the kernel size by around 5%, due to adding all the debugging
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text on failure paths. To avoid this, Sanitizer instrumentation
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can just issue a trap. This reduces the kernel size overhead but
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turns all warnings (including potentially harmless conditions)
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into full exceptions that abort the running kernel code
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(regardless of context, locks held, etc), which may destabilize
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the system. For some system builders this is an acceptable
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trade-off.
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config UBSAN_KCOV_BROKEN
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def_bool KCOV && CC_HAS_SANCOV_TRACE_PC
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depends on CC_IS_CLANG
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depends on !$(cc-option,-Werror=unused-command-line-argument -fsanitize=bounds -fsanitize-coverage=trace-pc)
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help
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Some versions of clang support either UBSAN or KCOV but not the
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combination of the two.
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See https://bugs.llvm.org/show_bug.cgi?id=45831 for the status
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in newer releases.
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config UBSAN_BOUNDS
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bool "Perform array index bounds checking"
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default UBSAN
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depends on !UBSAN_KCOV_BROKEN
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help
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This option enables detection of directly indexed out of bounds
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array accesses, where the array size is known at compile time.
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Note that this does not protect array overflows via bad calls
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to the {str,mem}*cpy() family of functions (that is addressed
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by CONFIG_FORTIFY_SOURCE).
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config UBSAN_LOCAL_BOUNDS
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bool "Perform array local bounds checking"
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depends on UBSAN_TRAP
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depends on CC_IS_CLANG
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depends on !UBSAN_KCOV_BROKEN
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help
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This option enables -fsanitize=local-bounds which traps when an
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exception/error is detected. Therefore, it should be enabled only
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if trapping is expected.
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Enabling this option detects errors due to accesses through a
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pointer that is derived from an object of a statically-known size,
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where an added offset (which may not be known statically) is
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out-of-bounds.
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config UBSAN_MISC
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bool "Enable all other Undefined Behavior sanity checks"
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default UBSAN
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help
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This option enables all sanity checks that don't have their
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own Kconfig options. Disable this if you only want to have
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individually selected checks.
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config UBSAN_SANITIZE_ALL
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bool "Enable instrumentation for the entire kernel"
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depends on ARCH_HAS_UBSAN_SANITIZE_ALL
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depends on !COMPILE_TEST
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default y
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help
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This option activates instrumentation for the entire kernel.
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If you don't enable this option, you have to explicitly specify
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UBSAN_SANITIZE := y for the files/directories you want to check for UB.
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Enabling this option will get kernel image size increased
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significantly.
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config UBSAN_ALIGNMENT
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bool "Enable checks for pointers alignment"
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default !HAVE_EFFICIENT_UNALIGNED_ACCESS
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depends on !UBSAN_TRAP
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help
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This option enables the check of unaligned memory accesses.
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Enabling this option on architectures that support unaligned
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accesses may produce a lot of false positives.
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config TEST_UBSAN
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tristate "Module for testing for undefined behavior detection"
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depends on m
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help
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This is a test module for UBSAN.
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It triggers various undefined behavior, and detect it.
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endif # if UBSAN
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