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8d58f222e8
The documentation for UBSAN_ALIGNMENT already mentions that it should
not be used on all*config builds (and for efficient-unaligned-access
architectures), so just refactor the Kconfig to correctly implement this
so randconfigs will stop creating insane images that freak out objtool
under CONFIG_UBSAN_TRAP (due to the false positives producing functions
that never return, etc).
Link: http://lkml.kernel.org/r/202005011433.C42EA3E2D@keescook
Fixes: 0887a7ebc9 ("ubsan: add trap instrumentation option")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/linux-next/202004231224.D6B3B650@keescook/
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
80 lines
2.8 KiB
Plaintext
80 lines
2.8 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_BOUNDS
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bool "Perform array index bounds checking"
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default UBSAN
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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_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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# We build with -Wno-maybe-uninitilzed, but we still want to
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# use -Wmaybe-uninitilized in allmodconfig builds.
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# So dependsy bellow used to disable this option in allmodconfig
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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 !X86 || !COMPILE_TEST
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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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