kasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS
This commit splits the current CONFIG_KASAN config option into two: 1. CONFIG_KASAN_GENERIC, that enables the generic KASAN mode (the one that exists now); 2. CONFIG_KASAN_SW_TAGS, that enables the software tag-based KASAN mode. The name CONFIG_KASAN_SW_TAGS is chosen as in the future we will have another hardware tag-based KASAN mode, that will rely on hardware memory tagging support in arm64. With CONFIG_KASAN_SW_TAGS enabled, compiler options are changed to instrument kernel files with -fsantize=kernel-hwaddress (except the ones for which KASAN_SANITIZE := n is set). Both CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS support both CONFIG_KASAN_INLINE and CONFIG_KASAN_OUTLINE instrumentation modes. This commit also adds empty placeholder (for now) implementation of tag-based KASAN specific hooks inserted by the compiler and adjusts common hooks implementation. While this commit adds the CONFIG_KASAN_SW_TAGS config option, this option is not selectable, as it depends on HAVE_ARCH_KASAN_SW_TAGS, which we will enable once all the infrastracture code has been added. Link: http://lkml.kernel.org/r/b2550106eb8a68b10fefbabce820910b115aa853.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov
Linus Torvalds
parent
b938fcf427
commit
2bd926b439
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@ -16,9 +16,13 @@
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/* all clang versions usable with the kernel support KASAN ABI version 5 */
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#define KASAN_ABI_VERSION 5
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#if __has_feature(address_sanitizer) || __has_feature(hwaddress_sanitizer)
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/* emulate gcc's __SANITIZE_ADDRESS__ flag */
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#if __has_feature(address_sanitizer)
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#define __SANITIZE_ADDRESS__
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#define __no_sanitize_address \
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__attribute__((no_sanitize("address", "hwaddress")))
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#else
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#define __no_sanitize_address
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#endif
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/*
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@ -143,6 +143,12 @@
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#define KASAN_ABI_VERSION 3
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#endif
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#if __has_attribute(__no_sanitize_address__)
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#define __no_sanitize_address __attribute__((no_sanitize_address))
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#else
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#define __no_sanitize_address
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#endif
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#if GCC_VERSION >= 50100
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#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
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#endif
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@ -199,19 +199,6 @@
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*/
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#define __noreturn __attribute__((__noreturn__))
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/*
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* Optional: only supported since gcc >= 4.8
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* Optional: not supported by icc
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*
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* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fsanitize_005faddress-function-attribute
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* clang: https://clang.llvm.org/docs/AttributeReference.html#no-sanitize-address-no-address-safety-analysis
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*/
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#if __has_attribute(__no_sanitize_address__)
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# define __no_sanitize_address __attribute__((__no_sanitize_address__))
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#else
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# define __no_sanitize_address
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#endif
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/*
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* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute
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* clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute
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@ -45,8 +45,6 @@ void kasan_free_pages(struct page *page, unsigned int order);
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void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
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slab_flags_t *flags);
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void kasan_cache_shrink(struct kmem_cache *cache);
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void kasan_cache_shutdown(struct kmem_cache *cache);
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void kasan_poison_slab(struct page *page);
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void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
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@ -97,8 +95,6 @@ static inline void kasan_free_pages(struct page *page, unsigned int order) {}
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static inline void kasan_cache_create(struct kmem_cache *cache,
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unsigned int *size,
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slab_flags_t *flags) {}
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static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
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static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
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static inline void kasan_poison_slab(struct page *page) {}
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static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
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@ -155,4 +151,16 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
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#endif /* CONFIG_KASAN */
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#ifdef CONFIG_KASAN_GENERIC
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void kasan_cache_shrink(struct kmem_cache *cache);
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void kasan_cache_shutdown(struct kmem_cache *cache);
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#else /* CONFIG_KASAN_GENERIC */
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static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
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static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
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#endif /* CONFIG_KASAN_GENERIC */
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#endif /* LINUX_KASAN_H */
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@ -1,36 +1,92 @@
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# This config refers to the generic KASAN mode.
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config HAVE_ARCH_KASAN
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bool
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if HAVE_ARCH_KASAN
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config HAVE_ARCH_KASAN_SW_TAGS
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bool
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config CC_HAS_KASAN_GENERIC
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def_bool $(cc-option, -fsanitize=kernel-address)
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config CC_HAS_KASAN_SW_TAGS
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def_bool $(cc-option, -fsanitize=kernel-hwaddress)
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config KASAN
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bool "KASan: runtime memory debugger"
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bool "KASAN: runtime memory debugger"
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depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
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(HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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help
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Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
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designed to find out-of-bounds accesses and use-after-free bugs.
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See Documentation/dev-tools/kasan.rst for details.
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choice
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prompt "KASAN mode"
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depends on KASAN
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default KASAN_GENERIC
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help
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KASAN has two modes: generic KASAN (similar to userspace ASan,
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x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and
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software tag-based KASAN (a version based on software memory
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tagging, arm64 only, similar to userspace HWASan, enabled with
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CONFIG_KASAN_SW_TAGS).
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Both generic and tag-based KASAN are strictly debugging features.
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config KASAN_GENERIC
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bool "Generic mode"
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depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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Enables kernel address sanitizer - runtime memory debugger,
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designed to find out-of-bounds accesses and use-after-free bugs.
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This is strictly a debugging feature and it requires a gcc version
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of 4.9.2 or later. Detection of out of bounds accesses to stack or
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global variables requires gcc 5.0 or later.
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This feature consumes about 1/8 of available memory and brings about
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~x3 performance slowdown.
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Enables generic KASAN mode.
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Supported in both GCC and Clang. With GCC it requires version 4.9.2
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or later for basic support and version 5.0 or later for detection of
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out-of-bounds accesses for stack and global variables and for inline
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instrumentation mode (CONFIG_KASAN_INLINE). With Clang it requires
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version 3.7.0 or later and it doesn't support detection of
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out-of-bounds accesses for global variables yet.
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This mode consumes about 1/8th of available memory at kernel start
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and introduces an overhead of ~x1.5 for the rest of the allocations.
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The performance slowdown is ~x3.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN doesn't work with CONFIG_DEBUG_SLAB
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Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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config KASAN_EXTRA
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bool "KAsan: extra checks"
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depends on KASAN && DEBUG_KERNEL && !COMPILE_TEST
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config KASAN_SW_TAGS
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bool "Software tag-based mode"
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depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
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depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB)
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select SLUB_DEBUG if SLUB
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select CONSTRUCTORS
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select STACKDEPOT
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help
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This enables further checks in the kernel address sanitizer, for now
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it only includes the address-use-after-scope check that can lead
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to excessive kernel stack usage, frame size warnings and longer
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compile time.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 has more
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Enables software tag-based KASAN mode.
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This mode requires Top Byte Ignore support by the CPU and therefore
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is only supported for arm64.
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This mode requires Clang version 7.0.0 or later.
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This mode consumes about 1/16th of available memory at kernel start
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and introduces an overhead of ~20% for the rest of the allocations.
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This mode may potentially introduce problems relating to pointer
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casting and comparison, as it embeds tags into the top byte of each
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pointer.
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For better error detection enable CONFIG_STACKTRACE.
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Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
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(the resulting kernel does not boot).
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endchoice
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config KASAN_EXTRA
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bool "KASAN: extra checks"
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depends on KASAN_GENERIC && DEBUG_KERNEL && !COMPILE_TEST
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help
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This enables further checks in generic KASAN, for now it only
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includes the address-use-after-scope check that can lead to
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excessive kernel stack usage, frame size warnings and longer
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compile time.
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See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715
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choice
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prompt "Instrumentation type"
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@ -53,7 +109,7 @@ config KASAN_INLINE
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memory accesses. This is faster than outline (in some workloads
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it gives about x2 boost over outline instrumentation), but
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make kernel's .text size much bigger.
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This requires a gcc version of 5.0 or later.
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For CONFIG_KASAN_GENERIC this requires GCC 5.0 or later.
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endchoice
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@ -67,11 +123,9 @@ config KASAN_S390_4_LEVEL_PAGING
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4-level paging instead.
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config TEST_KASAN
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tristate "Module for testing kasan for bug detection"
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tristate "Module for testing KASAN for bug detection"
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depends on m && KASAN
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help
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This is a test module doing various nasty things like
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out of bounds accesses, use after free. It is useful for testing
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kernel debugging features like kernel address sanitizer.
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endif
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kernel debugging features like KASAN.
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@ -2,6 +2,7 @@
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KASAN_SANITIZE := n
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UBSAN_SANITIZE_common.o := n
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UBSAN_SANITIZE_generic.o := n
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UBSAN_SANITIZE_tags.o := n
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KCOV_INSTRUMENT := n
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CFLAGS_REMOVE_generic.o = -pg
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@ -10,5 +11,8 @@ CFLAGS_REMOVE_generic.o = -pg
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CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
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CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
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CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
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obj-y := common.o generic.o report.o init.o quarantine.o
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obj-$(CONFIG_KASAN) := common.o init.o report.o
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obj-$(CONFIG_KASAN_GENERIC) += generic.o quarantine.o
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obj-$(CONFIG_KASAN_SW_TAGS) += tags.o
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@ -1,5 +1,5 @@
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/*
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* This file contains core KASAN code.
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* This file contains core generic KASAN code.
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*
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* Copyright (c) 2014 Samsung Electronics Co., Ltd.
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* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
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@ -114,7 +114,8 @@ void kasan_report(unsigned long addr, size_t size,
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bool is_write, unsigned long ip);
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void kasan_report_invalid_free(void *object, unsigned long ip);
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#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
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#if defined(CONFIG_KASAN_GENERIC) && \
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(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
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void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache);
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void quarantine_reduce(void);
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void quarantine_remove_cache(struct kmem_cache *cache);
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@ -0,0 +1,75 @@
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/*
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* This file contains core tag-based KASAN code.
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*
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* Copyright (c) 2018 Google, Inc.
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* Author: Andrey Konovalov <andreyknvl@google.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#define DISABLE_BRANCH_PROFILING
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#include <linux/export.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <linux/kasan.h>
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#include <linux/kernel.h>
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#include <linux/kmemleak.h>
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#include <linux/linkage.h>
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#include <linux/memblock.h>
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#include <linux/memory.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/printk.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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#include <linux/slab.h>
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#include <linux/stacktrace.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/vmalloc.h>
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#include <linux/bug.h>
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#include "kasan.h"
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#include "../slab.h"
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void check_memory_region(unsigned long addr, size_t size, bool write,
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unsigned long ret_ip)
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{
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}
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#define DEFINE_HWASAN_LOAD_STORE(size) \
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void __hwasan_load##size##_noabort(unsigned long addr) \
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{ \
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} \
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EXPORT_SYMBOL(__hwasan_load##size##_noabort); \
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void __hwasan_store##size##_noabort(unsigned long addr) \
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{ \
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} \
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EXPORT_SYMBOL(__hwasan_store##size##_noabort)
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DEFINE_HWASAN_LOAD_STORE(1);
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DEFINE_HWASAN_LOAD_STORE(2);
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DEFINE_HWASAN_LOAD_STORE(4);
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DEFINE_HWASAN_LOAD_STORE(8);
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DEFINE_HWASAN_LOAD_STORE(16);
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void __hwasan_loadN_noabort(unsigned long addr, unsigned long size)
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{
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}
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EXPORT_SYMBOL(__hwasan_loadN_noabort);
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void __hwasan_storeN_noabort(unsigned long addr, unsigned long size)
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{
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}
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EXPORT_SYMBOL(__hwasan_storeN_noabort);
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void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size)
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{
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}
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EXPORT_SYMBOL(__hwasan_tag_memory);
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@ -2992,7 +2992,7 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
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do_slab_free(s, page, head, tail, cnt, addr);
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}
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#ifdef CONFIG_KASAN
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#ifdef CONFIG_KASAN_GENERIC
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void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
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{
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do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
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@ -1,5 +1,6 @@
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# SPDX-License-Identifier: GPL-2.0
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ifdef CONFIG_KASAN
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ifdef CONFIG_KASAN_GENERIC
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ifdef CONFIG_KASAN_INLINE
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call_threshold := 10000
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else
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@ -12,36 +13,44 @@ CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
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cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
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ifeq ($(call cc-option, $(CFLAGS_KASAN_MINIMAL) -Werror),)
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ifneq ($(CONFIG_COMPILE_TEST),y)
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$(warning Cannot use CONFIG_KASAN: \
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-fsanitize=kernel-address is not supported by compiler)
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endif
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else
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# -fasan-shadow-offset fails without -fsanitize
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CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
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# -fasan-shadow-offset fails without -fsanitize
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CFLAGS_KASAN_SHADOW := $(call cc-option, -fsanitize=kernel-address \
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-fasan-shadow-offset=$(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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ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
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CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
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else
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# Now add all the compiler specific options that are valid standalone
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CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
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$(call cc-param,asan-globals=1) \
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$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
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$(call cc-param,asan-stack=1) \
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$(call cc-param,asan-use-after-scope=1) \
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$(call cc-param,asan-instrument-allocas=1)
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endif
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ifeq ($(strip $(CFLAGS_KASAN_SHADOW)),)
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CFLAGS_KASAN := $(CFLAGS_KASAN_MINIMAL)
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else
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# Now add all the compiler specific options that are valid standalone
|
||||
CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
|
||||
$(call cc-param,asan-globals=1) \
|
||||
$(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
|
||||
$(call cc-param,asan-stack=1) \
|
||||
$(call cc-param,asan-use-after-scope=1) \
|
||||
$(call cc-param,asan-instrument-allocas=1)
|
||||
endif
|
||||
|
||||
ifdef CONFIG_KASAN_EXTRA
|
||||
CFLAGS_KASAN += $(call cc-option, -fsanitize-address-use-after-scope)
|
||||
endif
|
||||
|
||||
CFLAGS_KASAN_NOSANITIZE := -fno-builtin
|
||||
endif # CONFIG_KASAN_GENERIC
|
||||
|
||||
ifdef CONFIG_KASAN_SW_TAGS
|
||||
|
||||
ifdef CONFIG_KASAN_INLINE
|
||||
instrumentation_flags := -mllvm -hwasan-mapping-offset=$(KASAN_SHADOW_OFFSET)
|
||||
else
|
||||
instrumentation_flags := -mllvm -hwasan-instrument-with-calls=1
|
||||
endif
|
||||
|
||||
CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
|
||||
-mllvm -hwasan-instrument-stack=0 \
|
||||
$(instrumentation_flags)
|
||||
|
||||
endif # CONFIG_KASAN_SW_TAGS
|
||||
|
||||
ifdef CONFIG_KASAN
|
||||
CFLAGS_KASAN_NOSANITIZE := -fno-builtin
|
||||
endif
|
||||
|
|
|
|||
Loading…
Reference in New Issue