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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+9991561e714f597095da@syzkaller.appspotmail.com,
        Jan Kara <jack@suse.cz>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 116/139] udf: Limit sparing table size
Date:   Tue, 27 Oct 2020 14:50:10 +0100
Message-Id: <20201027134907.647267552@linuxfoundation.org>
In-Reply-To: <20201027134902.130312227@linuxfoundation.org>
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From: Jan Kara <jack@suse.cz>

[ Upstream commit 44ac6b829c4e173fdf6df18e6dd86aecf9a3dc99 ]

Although UDF standard allows it, we don't support sparing table larger
than a single block. Check it during mount so that we don't try to
access memory beyond end of buffer.

Reported-by: syzbot+9991561e714f597095da@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/udf/super.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 4abdba453885e..c8c037e8e57b5 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1391,6 +1391,12 @@ static int udf_load_sparable_map(struct super_block *sb,
 			(int)spm->numSparingTables);
 		return -EIO;
 	}
+	if (le32_to_cpu(spm->sizeSparingTable) > sb->s_blocksize) {
+		udf_err(sb, "error loading logical volume descriptor: "
+			"Too big sparing table size (%u)\n",
+			le32_to_cpu(spm->sizeSparingTable));
+		return -EIO;
+	}
 
 	for (i = 0; i < spm->numSparingTables; i++) {
 		loc = le32_to_cpu(spm->locSparingTable[i]);
-- 
2.25.1