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| -rw-r--r-- | lib/Kconfig.ubsan | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan new file mode 100644 index 000000000..58f8d03d0 --- /dev/null +++ b/lib/Kconfig.ubsan @@ -0,0 +1,104 @@ +# 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 |