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From: Marco Elver <elver@google.com>
To: elver@google.com, Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Jakub Jelinek <jakub@redhat.com>,
	linux-toolchains@vger.kernel.org,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-kbuild@vger.kernel.org
Subject: [PATCH -tip v4 1/3] kasan: Emit different calls for instrumentable memintrinsics
Date: Fri, 17 Feb 2023 00:45:20 +0100	[thread overview]
Message-ID: <20230216234522.3757369-1-elver@google.com> (raw)

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).

Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
v4:
* Also enable it for KASAN_SW_TAGS (__hwasan_mem*).

v3:
* No change.

v2:
* Use asan-kernel-mem-intrinsic-prefix=1, so that once GCC supports the
  param, it also works there (it needs the =1).

The Fixes tag is just there to show the dependency, and that people
shouldn't apply this patch without 69d4c0d32186.
---
 mm/kasan/kasan.h       |  4 ++++
 mm/kasan/shadow.c      | 11 +++++++++++
 scripts/Makefile.kasan |  8 ++++++++
 3 files changed, 23 insertions(+)

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 71c15438afcf..172713b87556 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -637,4 +637,8 @@ 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 */
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 98269936a5e4..f8a47cb299cb 100644
--- a/mm/kasan/shadow.c
+++ 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;
diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
index b9e94c5e7097..fa9f836f8039 100644
--- a/scripts/Makefile.kasan
+++ 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
-- 
2.39.2.637.g21b0678d19-goog


             reply	other threads:[~2023-02-16 23:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-16 23:45 Marco Elver [this message]
2023-02-16 23:45 ` [PATCH -tip v4 2/3] kasan: Treat meminstrinsic as builtins in uninstrumented files Marco Elver
2023-02-17 11:07   ` Andrey Konovalov
2023-02-17 12:55     ` Marco Elver
2023-02-16 23:45 ` [PATCH -tip v4 3/3] kasan: test: Fix test for new meminstrinsic instrumentation Marco Elver
2023-02-17  9:11   ` Alexander Potapenko
2023-02-17 11:07   ` Andrey Konovalov
2023-02-17 11:07 ` [PATCH -tip v4 1/3] kasan: Emit different calls for instrumentable memintrinsics Andrey Konovalov
2023-02-17 12:53 ` [PATCH -tip v4 4/4] kasan, x86: Don't rename memintrinsics in uninstrumented files Marco Elver
2023-02-17 13:10   ` Andrey Konovalov
2023-02-17 17:37 ` [PATCH -tip v4 1/3] kasan: Emit different calls for instrumentable memintrinsics Naresh Kamboju

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