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+# 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