linux-kernel - [PATCH] fix comparison of unsigned expression

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20231128075532.110251-1-haibo.li@mediatek.com>
Date:   Tue, 28 Nov 2023 15:55:32 +0800
From:   Haibo Li <haibo.li@...iatek.com>
To:     <linux-kernel@...r.kernel.org>
CC:     Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        "Andrew Morton" <akpm@...ux-foundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        <kasan-dev@...glegroups.com>, <linux-mm@...ck.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <xiaoming.yu@...iatek.com>,
        Haibo Li <haibo.li@...iatek.com>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH] fix comparison of unsigned expression < 0

Kernel test robot reported:

'''
mm/kasan/report.c:637 kasan_non_canonical_hook() warn:
unsigned 'addr' is never less than zero.
'''
The KASAN_SHADOW_OFFSET is 0 on loongarch64.

To fix it,check the KASAN_SHADOW_OFFSET before do comparison.

Signed-off-by: Haibo Li <haibo.li@...iatek.com>
Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/
  202311270743.3oTCwYPd-lkp@...el.com/
---
 mm/kasan/report.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index e77facb62900..dafec2df0268 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -634,10 +634,10 @@ void kasan_non_canonical_hook(unsigned long addr)
 {
 	unsigned long orig_addr;
 	const char *bug_type;
-
+#if KASAN_SHADOW_OFFSET > 0
 	if (addr < KASAN_SHADOW_OFFSET)
 		return;
-
+#endif
 	orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT;
 	/*
 	 * For faults near the shadow address for NULL, we can be fairly certain
-- 
2.18.0