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e3117404b4
Rust supports KASAN via LLVM, but prior to this patch, the flags aren't set properly. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Matthew Maurer <mmaurer@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Link: https://lore.kernel.org/r/20240820194910.187826-4-mmaurer@google.com [ Applied "SW_TAGS KASAN" nit. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
105 lines
3.7 KiB
Makefile
105 lines
3.7 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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ifdef CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX
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# Safe for compiler to generate meminstrinsic calls in uninstrumented files.
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CFLAGS_KASAN_NOSANITIZE :=
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else
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# Don't let compiler generate memintrinsic calls in uninstrumented files
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# because they are instrumented.
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CFLAGS_KASAN_NOSANITIZE := -fno-builtin
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endif
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KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
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cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
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rustc-param = $(call rustc-option, -Cllvm-args=-$(1),)
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check-args = $(foreach arg,$(2),$(call $(1),$(arg)))
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kasan_params :=
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ifdef CONFIG_KASAN_STACK
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stack_enable := 1
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else
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stack_enable := 0
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endif
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ifdef CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_INLINE
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# When the number of memory accesses in a function is less than this
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# call threshold number, the compiler will use inline instrumentation.
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# 10000 is chosen offhand as a sufficiently large number to make all
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# kernel functions to be instrumented inline.
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call_threshold := 10000
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else
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call_threshold := 0
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endif
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# First, enable -fsanitize=kernel-address together with providing the shadow
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# mapping offset, as for GCC, -fasan-shadow-offset fails without -fsanitize
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# (GCC accepts the shadow mapping offset via -fasan-shadow-offset instead of
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# a --param like the other KASAN parameters).
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# Instead of ifdef-checking the compiler, rely on cc-option.
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CFLAGS_KASAN := $(call cc-option, -fsanitize=kernel-address \
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-fasan-shadow-offset=$(KASAN_SHADOW_OFFSET), \
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$(call cc-option, -fsanitize=kernel-address \
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-mllvm -asan-mapping-offset=$(KASAN_SHADOW_OFFSET)))
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# The minimum supported `rustc` version has a minimum supported LLVM
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# version late enough that we can assume support for -asan-mapping-offset.
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RUSTFLAGS_KASAN := -Zsanitizer=kernel-address \
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-Zsanitizer-recover=kernel-address \
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-Cllvm-args=-asan-mapping-offset=$(KASAN_SHADOW_OFFSET)
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# Now, add other parameters enabled similarly in GCC, Clang, and rustc.
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# As some of them are not supported by older compilers, these will be filtered
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# through `cc-param` or `rust-param` as applicable.
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kasan_params += asan-instrumentation-with-call-threshold=$(call_threshold) \
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asan-stack=$(stack_enable) \
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asan-instrument-allocas=1 \
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asan-globals=1
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# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
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# instead. With compilers that don't support this option, compiler-inserted
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# memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
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kasan_params += asan-kernel-mem-intrinsic-prefix=1
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endif # CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_SW_TAGS
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CFLAGS_KASAN := -fsanitize=kernel-hwaddress
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# This sets flags that will enable SW_TAGS KASAN once enabled in Rust. These
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# will not work today, and is guarded against in dependencies for CONFIG_RUST.
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RUSTFLAGS_KASAN := -Zsanitizer=kernel-hwaddress \
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-Zsanitizer-recover=kernel-hwaddress
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ifdef CONFIG_KASAN_INLINE
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kasan_params += hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
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else
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kasan_params += hwasan-instrument-with-calls=1
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endif
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kasan_params += hwasan-instrument-stack=$(stack_enable) \
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hwasan-use-short-granules=0 \
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hwasan-inline-all-checks=0
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# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
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ifeq ($(call clang-min-version, 150000)$(call gcc-min-version, 130000),y)
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kasan_params += hwasan-kernel-mem-intrinsic-prefix=1
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endif
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endif # CONFIG_KASAN_SW_TAGS
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# Add all as-supported KASAN LLVM parameters requested by the configuration.
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CFLAGS_KASAN += $(call check-args, cc-param, $(kasan_params))
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ifdef CONFIG_RUST
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# Avoid calling `rustc-param` unless Rust is enabled.
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RUSTFLAGS_KASAN += $(call check-args, rustc-param, $(kasan_params))
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endif # CONFIG_RUST
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export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE RUSTFLAGS_KASAN
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