From c3ee82ce47af63eca2075d8af956d468f508942e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 18 May 2019 18:11:13 +0200 Subject: [PATCH] x86/boot: Provide KASAN compatible aliases for string routines The KASAN subsystem wraps calls to memcpy(), memset() and memmove() to sanitize the arguments before invoking the actual routines, which have been renamed to __memcpy(), __memset() and __memmove(), respectively. When CONFIG_KASAN is enabled for the kernel build but KASAN code generation is disabled for the compilation unit (which is needed for things like the EFI stub or the decompressor), the string routines are just #define'd to their __ prefixed names so that they are simply invoked directly. This does however rely on those __ prefixed names to exist in the symbol namespace, which is not currently the case for the x86 decompressor, which may lead to errors like drivers/firmware/efi/libstub/tpm.o: In function `efi_retrieve_tpm2_eventlog': tpm.c:(.text+0x2a8): undefined reference to `__memcpy' So let's expose the __ prefixed symbols in the decompressor when KASAN is enabled. Signed-off-by: Ard Biesheuvel Acked-by: Jarkko Sakkinen Cc: Andrey Konovalov Cc: Borislav Petkov Cc: Linus Torvalds Cc: Matthew Garrett Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/string.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c index 19dbbcdd1a53d..81fc1eaa32299 100644 --- a/arch/x86/boot/compressed/string.c +++ b/arch/x86/boot/compressed/string.c @@ -11,7 +11,7 @@ #include "../string.c" #ifdef CONFIG_X86_32 -static void *__memcpy(void *dest, const void *src, size_t n) +static void *____memcpy(void *dest, const void *src, size_t n) { int d0, d1, d2; asm volatile( @@ -25,7 +25,7 @@ static void *__memcpy(void *dest, const void *src, size_t n) return dest; } #else -static void *__memcpy(void *dest, const void *src, size_t n) +static void *____memcpy(void *dest, const void *src, size_t n) { long d0, d1, d2; asm volatile( @@ -56,7 +56,7 @@ void *memmove(void *dest, const void *src, size_t n) const unsigned char *s = src; if (d <= s || d - s >= n) - return __memcpy(dest, src, n); + return ____memcpy(dest, src, n); while (n-- > 0) d[n] = s[n]; @@ -71,5 +71,11 @@ void *memcpy(void *dest, const void *src, size_t n) warn("Avoiding potentially unsafe overlapping memcpy()!"); return memmove(dest, src, n); } - return __memcpy(dest, src, n); + return ____memcpy(dest, src, n); } + +#ifdef CONFIG_KASAN +extern void *__memset(void *s, int c, size_t n) __alias(memset); +extern void *__memmove(void *dest, const void *src, size_t n) __alias(memmove); +extern void *__memcpy(void *dest, const void *src, size_t n) __alias(memcpy); +#endif -- 2.30.2