[PATCH v4 3/3] kasan: Make addr_has_metadata() return true for valid addresses

[Vincenzo Frascino]

Currently, addr_has_metadata() returns true for every address.
An invalid address (e.g. NULL) passed to the function when,
KASAN_HW_TAGS is enabled, leads to a kernel panic.

Make addr_has_metadata() return true for valid addresses only.

Note: KASAN_HW_TAGS support for vmalloc will be added with a future
patch.

Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
---
 mm/kasan/kasan.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index cc4d9e1d49b1..8c706e7652f2 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -209,7 +209,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write,
 
 static inline bool addr_has_metadata(const void *addr)
 {
-	return true;
+	return (is_vmalloc_addr(addr) || virt_addr_valid(addr));
 }
 
 #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
-- 
2.30.0