[PATCH 6.9 277/374] kasan, fortify: properly rename memintrinsics

Greg Kroah-Hartman
2024-06-06T14:11:04Z

From: Andrey Konovalov <andreyknvl@gmail.com>

[ Upstream commit 2e577732e8d28b9183df701fb90cb7943aa4ed16 ]

After commit 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*()
functions") and the follow-up fixes, with CONFIG_FORTIFY_SOURCE enabled,
even though the compiler instruments meminstrinsics by generating calls to
__asan/__hwasan_ prefixed functions, FORTIFY_SOURCE still uses
uninstrumented memset/memmove/memcpy as the underlying functions.

As a result, KASAN cannot detect bad accesses in memset/memmove/memcpy.
This also makes KASAN tests corrupt kernel memory and cause crashes.

To fix this, use __asan_/__hwasan_memset/memmove/memcpy as the underlying
functions whenever appropriate. Do this only for the instrumented code
(as indicated by __SANITIZE_ADDRESS__).

Link: https://lkml.kernel.org/r/20240517130118.759301-1-andrey.konovalov@linux.dev
Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
Fixes: 51287dcb00cc ("kasan: emit different calls for instrumentable memintrinsics")
Fixes: 36be5cba99f6 ("kasan: treat meminstrinsic as builtins in uninstrumented files")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Reported-by: Nico Pache <npache@redhat.com>
Closes: https://lore.kernel.org/all/20240501144156.17e65021@outsider.home/
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Nico Pache <npache@redhat.com>
Acked-by: Nico Pache <npache@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/fortify-string.h | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h
index 6eaa190d0083c..9754f97e71e52 100644
--- a/include/linux/fortify-string.h
+++ b/include/linux/fortify-string.h
@@ -71,17 +71,30 @@ void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("
__ret; \
})

-#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+#if defined(__SANITIZE_ADDRESS__)
+
+#if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
+extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
+extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
+extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
+#elif defined(CONFIG_KASAN_GENERIC)
+extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(__asan_memset);
+extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(__asan_memmove);
+extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(__asan_memcpy);
+#else /* CONFIG_KASAN_SW_TAGS */
+extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(__hwasan_memset);
+extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(__hwasan_memmove);
+extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(__hwasan_memcpy);
+#endif
+
extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
-extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
-extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
-extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
+
#else

#if defined(__SANITIZE_MEMORY__)
@@ -106,6 +119,7 @@ extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size)
#define __underlying_strlen __builtin_strlen
#define __underlying_strncat __builtin_strncat
#define __underlying_strncpy __builtin_strncpy
+
#endif

/**
--
2.43.0