From b99acdcbfe3c8394ddd8b8d89d9bae2bbba4a459 Mon Sep 17 00:00:00 2001
From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Date: Thu, 4 Feb 2021 18:32:53 -0800
Subject: [PATCH] kasan: make addr_has_metadata() return true for valid
 addresses

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.

Link: https://lkml.kernel.org/r/20210126134409.47894-3-vincenzo.frascino@arm.com
Fixes: 2e903b91479782b7 ("kasan, arm64: implement HW_TAGS runtime")
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 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 */