The patch titled
Subject: kasan: emit different calls for instrumentable memintrinsics
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
kasan-emit-different-calls-for-instrumentable-memintrinsics.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kasan-emit-different-calls-for-instrumentable-memintrinsics.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Marco Elver <elver@xxxxxxxxxx>
Subject: kasan: emit different calls for instrumentable memintrinsics
Date: Fri, 24 Feb 2023 09:59:39 +0100
Clang 15 provides an option to prefix memcpy/memset/memmove calls with
__asan_/__hwasan_ in instrumented functions:
https://reviews.llvm.org/D122724
GCC will add support in future:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108777
Use it to regain KASAN instrumentation of memcpy/memset/memmove on
architectures that require noinstr to be really free from instrumented
mem*() functions (all GENERIC_ENTRY architectures).
Link: https://lkml.kernel.org/r/20230224085942.1791837-1-elver@xxxxxxxxxx
Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Tested-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jakub Jelinek <jakub@xxxxxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx> # build only
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Nicolas Schier <nicolas@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/kasan/kasan.h~kasan-emit-different-calls-for-instrumentable-memintrinsics
+++ b/mm/kasan/kasan.h
@@ -666,4 +666,8 @@ void __hwasan_storeN_noabort(unsigned long addr, size_t size);
void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
+void *__hwasan_memset(void *addr, int c, size_t len);
+void *__hwasan_memmove(void *dest, const void *src, size_t len);
+void *__hwasan_memcpy(void *dest, const void *src, size_t len);
+
#endif /* __MM_KASAN_KASAN_H */
--- a/mm/kasan/shadow.c~kasan-emit-different-calls-for-instrumentable-memintrinsics
+++ b/mm/kasan/shadow.c
@@ -107,6 +107,17 @@ void *__asan_memcpy(void *dest, const void *src, size_t len)
}
EXPORT_SYMBOL(__asan_memcpy);
+#ifdef CONFIG_KASAN_SW_TAGS
+void *__hwasan_memset(void *addr, int c, size_t len) __alias(__asan_memset);
+EXPORT_SYMBOL(__hwasan_memset);
+#ifdef __HAVE_ARCH_MEMMOVE
+void *__hwasan_memmove(void *dest, const void *src, size_t len) __alias(__asan_memmove);
+EXPORT_SYMBOL(__hwasan_memmove);
+#endif
+void *__hwasan_memcpy(void *dest, const void *src, size_t len) __alias(__asan_memcpy);
+EXPORT_SYMBOL(__hwasan_memcpy);
+#endif
+
void kasan_poison(const void *addr, size_t size, u8 value, bool init)
{
void *shadow_start, *shadow_end;
--- a/scripts/Makefile.kasan~kasan-emit-different-calls-for-instrumentable-memintrinsics
+++ b/scripts/Makefile.kasan
@@ -38,6 +38,11 @@ endif
CFLAGS_KASAN += $(call cc-param,asan-stack=$(stack_enable))
+# Instrument memcpy/memset/memmove calls by using instrumented __asan_mem*()
+# instead. With compilers that don't support this option, compiler-inserted
+# memintrinsics won't be checked by KASAN on GENERIC_ENTRY architectures.
+CFLAGS_KASAN += $(call cc-param,asan-kernel-mem-intrinsic-prefix=1)
+
endif # CONFIG_KASAN_GENERIC
ifdef CONFIG_KASAN_SW_TAGS
@@ -54,6 +59,9 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
$(call cc-param,hwasan-inline-all-checks=0) \
$(instrumentation_flags)
+# Instrument memcpy/memset/memmove calls by using instrumented __hwasan_mem*().
+CFLAGS_KASAN += $(call cc-param,hwasan-kernel-mem-intrinsic-prefix=1)
+
endif # CONFIG_KASAN_SW_TAGS
export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE
_
Patches currently in -mm which might be from elver@xxxxxxxxxx are
kasan-emit-different-calls-for-instrumentable-memintrinsics.patch
kasan-treat-meminstrinsic-as-builtins-in-uninstrumented-files.patch
kasan-test-fix-test-for-new-meminstrinsic-instrumentation.patch
kasan-x86-dont-rename-memintrinsics-in-uninstrumented-files.patch
