linux-kernel - [PATCH v2 1/2] arm64: Fix kernel address detection of __is_lm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210121131956.23246-2-vincenzo.frascino@arm.com>
Date:   Thu, 21 Jan 2021 13:19:55 +0000
From:   Vincenzo Frascino <vincenzo.frascino@....com>
To:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com
Cc:     Vincenzo Frascino <vincenzo.frascino@....com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Leon Romanovsky <leonro@...lanox.com>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>
Subject: [PATCH v2 1/2] arm64: Fix kernel address detection of __is_lm_address()

Currently, the __is_lm_address() check just masks out the top 12 bits
of the address, but if they are 0, it still yields a true result.
This has as a side effect that virt_addr_valid() returns true even for
invalid virtual addresses (e.g. 0x0).

Fix the detection checking that it's actually a kernel address starting
at PAGE_OFFSET.

Fixes: f4693c2716b35 ("arm64: mm: extend linear region for 52-bit VA configurations")
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Suggested-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@....com>
---
 arch/arm64/include/asm/memory.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 18fce223b67b..e04ac898ffe4 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -249,7 +249,7 @@ static inline const void *__tag_set(const void *addr, u8 tag)
 /*
  * The linear kernel range starts at the bottom of the virtual address space.
  */
-#define __is_lm_address(addr)	(((u64)(addr) & ~PAGE_OFFSET) < (PAGE_END - PAGE_OFFSET))
+#define __is_lm_address(addr)	(((u64)(addr) ^ PAGE_OFFSET) < (PAGE_END - PAGE_OFFSET))
 
 #define __lm_to_phys(addr)	(((addr) & ~PAGE_OFFSET) + PHYS_OFFSET)
 #define __kimg_to_phys(addr)	((addr) - kimage_voffset)
-- 
2.30.0