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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Gao Xiang <hsiangkao@redhat.com>,
        syzbot+c68f467cd7c45860e8d4@syzkaller.appspotmail.com,
        Chao Yu <yuchao0@huawei.com>, Sasha Levin <sashal@kernel.org>,
        linux-erofs@lists.ozlabs.org
Subject: [PATCH AUTOSEL 5.4 34/40] erofs: fix shift-out-of-bounds of blkszbits
Date:   Wed, 24 Feb 2021 07:53:34 -0500
Message-Id: <20210224125340.483162-34-sashal@kernel.org>
In-Reply-To: <20210224125340.483162-1-sashal@kernel.org>
References: <20210224125340.483162-1-sashal@kernel.org>
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From: Gao Xiang <hsiangkao@redhat.com>

[ Upstream commit bde545295b710bdd13a0fcd4b9fddd2383eeeb3a ]

syzbot generated a crafted bitszbits which can be shifted
out-of-bounds[1]. So directly print unsupported blkszbits
instead of blksize.

[1] https://lore.kernel.org/r/000000000000c72ddd05b9444d2f@google.com

Link: https://lore.kernel.org/r/20210120013016.14071-1-hsiangkao@aol.com
Reported-by: syzbot+c68f467cd7c45860e8d4@syzkaller.appspotmail.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/erofs/super.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 0e369494f2f2c..22e059b4f745c 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -124,8 +124,8 @@ static int erofs_read_superblock(struct super_block *sb)
 	blkszbits = dsb->blkszbits;
 	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
 	if (blkszbits != LOG_BLOCK_SIZE) {
-		erofs_err(sb, "blksize %u isn't supported on this platform",
-			  1 << blkszbits);
+		erofs_err(sb, "blkszbits %u isn't supported on this platform",
+			  blkszbits);
 		goto out;
 	}
 
-- 
2.27.0