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| -rw-r--r-- | lib/Kconfig.ubsan | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan new file mode 100644 index 000000000..fd15230a7 --- /dev/null +++ b/lib/Kconfig.ubsan @@ -0,0 +1,150 @@ +# 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 !COMPILE_TEST + 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 CC_HAS_UBSAN_BOUNDS + def_bool $(cc-option,-fsanitize=bounds) + +config CC_HAS_UBSAN_ARRAY_BOUNDS + def_bool $(cc-option,-fsanitize=array-bounds) + +config UBSAN_BOUNDS + bool "Perform array index bounds checking" + default UBSAN + depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS + 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_ONLY_BOUNDS + def_bool CC_HAS_UBSAN_BOUNDS && !CC_HAS_UBSAN_ARRAY_BOUNDS + depends on UBSAN_BOUNDS + help + This is a weird case: Clang's -fsanitize=bounds includes + -fsanitize=local-bounds, but it's trapping-only, so for + Clang, we must use -fsanitize=array-bounds when we want + traditional array bounds checking enabled. For GCC, we + want -fsanitize=bounds. + +config UBSAN_ARRAY_BOUNDS + def_bool CC_HAS_UBSAN_ARRAY_BOUNDS + depends on UBSAN_BOUNDS + +config UBSAN_LOCAL_BOUNDS + bool "Perform array local bounds checking" + depends on UBSAN_TRAP + depends on $(cc-option,-fsanitize=local-bounds) + help + This option enables -fsanitize=local-bounds which traps when an + exception/error is detected. Therefore, it may only be enabled + with CONFIG_UBSAN_TRAP. + + 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_SHIFT + bool "Perform checking for bit-shift overflows" + default UBSAN + depends on $(cc-option,-fsanitize=shift) + help + This option enables -fsanitize=shift which checks for bit-shift + operations that overflow to the left or go switch to negative + for signed types. + +config UBSAN_DIV_ZERO + bool "Perform checking for integer divide-by-zero" + depends on $(cc-option,-fsanitize=integer-divide-by-zero) + # https://github.com/ClangBuiltLinux/linux/issues/1657 + # https://github.com/llvm/llvm-project/issues/56289 + depends on !CC_IS_CLANG + help + This option enables -fsanitize=integer-divide-by-zero which checks + for integer division by zero. This is effectively redundant with the + kernel's existing exception handling, though it can provide greater + debugging information under CONFIG_UBSAN_REPORT_FULL. + +config UBSAN_UNREACHABLE + bool "Perform checking for unreachable code" + # objtool already handles unreachable checking and gets angry about + # seeing UBSan instrumentation located in unreachable places. + depends on !(OBJTOOL && (STACK_VALIDATION || UNWINDER_ORC || HAVE_UACCESS_VALIDATION)) + depends on $(cc-option,-fsanitize=unreachable) + help + This option enables -fsanitize=unreachable which checks for control + flow reaching an expected-to-be-unreachable position. + +config UBSAN_BOOL + bool "Perform checking for non-boolean values used as boolean" + default UBSAN + depends on $(cc-option,-fsanitize=bool) + help + This option enables -fsanitize=bool which checks for boolean values being + loaded that are neither 0 nor 1. + +config UBSAN_ENUM + bool "Perform checking for out of bounds enum values" + default UBSAN + depends on $(cc-option,-fsanitize=enum) + help + This option enables -fsanitize=enum which checks for values being loaded + into an enum that are outside the range of given values for the given enum. + +config UBSAN_ALIGNMENT + bool "Perform checking for misaligned pointer usage" + default !HAVE_EFFICIENT_UNALIGNED_ACCESS + depends on !UBSAN_TRAP && !COMPILE_TEST + depends on $(cc-option,-fsanitize=alignment) + 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 UBSAN_SANITIZE_ALL + bool "Enable instrumentation for the entire kernel" + depends on ARCH_HAS_UBSAN_SANITIZE_ALL + 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 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 |