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Diffstat (limited to 'lib/Kconfig.ubsan')
| -rw-r--r-- | lib/Kconfig.ubsan | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan new file mode 100644 index 0000000000..59e21bfec1 --- /dev/null +++ b/lib/Kconfig.ubsan @@ -0,0 +1,163 @@ +# 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 "Abort on Sanitizer warnings (smaller kernel but less verbose)" + depends on !COMPILE_TEST + 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. + + Also note that selecting Y will cause your kernel to Oops + with an "illegal instruction" error with no further details + when a UBSAN violation occurs. (Except on arm64, which will + report which Sanitizer failed.) This may make it hard to + determine whether an Oops was caused by UBSAN or to figure + out the details of a UBSAN violation. It makes the kernel log + output less useful for bug reports. + +config CC_HAS_UBSAN_BOUNDS_STRICT + def_bool $(cc-option,-fsanitize=bounds-strict) + help + The -fsanitize=bounds-strict option is only available on GCC, + but uses the more strict handling of arrays that includes knowledge + of flexible arrays, which is comparable to Clang's regular + -fsanitize=bounds. + +config CC_HAS_UBSAN_ARRAY_BOUNDS + def_bool $(cc-option,-fsanitize=array-bounds) + help + Under Clang, the -fsanitize=bounds option is actually composed + of two more specific options, -fsanitize=array-bounds and + -fsanitize=local-bounds. However, -fsanitize=local-bounds can + only be used when trap mode is enabled. (See also the help for + CONFIG_LOCAL_BOUNDS.) Explicitly check for -fsanitize=array-bounds + so that we can build up the options needed for UBSAN_BOUNDS + with or without UBSAN_TRAP. + +config UBSAN_BOUNDS + bool "Perform array index bounds checking" + default UBSAN + depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS_STRICT + 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_BOUNDS_STRICT + def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_BOUNDS_STRICT + help + GCC's bounds sanitizer. This option is used to select the + correct options in Makefile.ubsan. + +config UBSAN_ARRAY_BOUNDS + def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_ARRAY_BOUNDS + help + Clang's array bounds sanitizer. This option is used to select + the correct options in Makefile.ubsan. + +config UBSAN_LOCAL_BOUNDS + def_bool UBSAN_ARRAY_BOUNDS && UBSAN_TRAP + help + This option enables Clang's -fsanitize=local-bounds which traps + when an access 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. Since this option is + trap-only, it depends on CONFIG_UBSAN_TRAP. + +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 |