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Message-ID: <6036b141-56e2-0d08-b9ff-641c3451f45a@paragon-software.com>
Date:   Mon, 27 Sep 2021 18:48:00 +0300
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Subject: [PATCH 2/3] fs/ntfs3: Reject mount if boot's cluster size < media
 sector size
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From:   Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
To:     <ntfs3@lists.linux.dev>
CC:     <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>
References: <16cbff75-f705-37cb-ad3f-43d433352f6b@paragon-software.com>
In-Reply-To: <16cbff75-f705-37cb-ad3f-43d433352f6b@paragon-software.com>
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If we continue to work in this case, then we can corrupt fs.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
---
 fs/ntfs3/super.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index 7099d9b1f3aa..193f9a98f6ab 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -763,9 +763,14 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 	sbi->mft.lbo = mlcn << sbi->cluster_bits;
 	sbi->mft.lbo2 = mlcn2 << sbi->cluster_bits;
 
+	/* Compare boot's cluster and sector. */
 	if (sbi->cluster_size < sbi->sector_size)
 		goto out;
 
+	/* Compare boot's cluster and media sector. */
+	if (sbi->cluster_size < sector_size)
+		goto out; /* No way to use ntfs_get_block in this case. */
+
 	sbi->cluster_mask = sbi->cluster_size - 1;
 	sbi->cluster_mask_inv = ~(u64)sbi->cluster_mask;
 	sbi->record_size = record_size = boot->record_size < 0
-- 
2.33.0