From 09f7c338da7818fd33af401d855b895550e7c170 Mon Sep 17 00:00:00 2001
From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Date: Tue, 28 Sep 2021 19:19:17 +0300
Subject: [Backport 09f7c338da78] src: Reject mount if boot's cluster size
 < media sector size

If we continue to work in this case, then we can corrupt fs.
Fixes: 82cae269cfa9 ("src: Add initialization of super block").

Reviewed-by: Kari Argillander <kari.argillander@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
---
 src/super.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/super.c b/src/super.c
index 800897777eb03855f702e8acf15b39d02c1c2fbf..e9b6a37345769700f682809832d84d8dfc7b9414 100644
--- a/src/super.c
+++ b/src/super.c
@@ -763,9 +763,20 @@ 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;
 
-	if (sbi->cluster_size < sbi->sector_size)
+	/* Compare boot's cluster and sector. */
+	if (sbi->cluster_size < boot_sector_size)
 		goto out;
 
+	/* Compare boot's cluster and media sector. */
+	if (sbi->cluster_size < sector_size) {
+		/* No way to use ntfs_get_block in this case. */
+		ntfs_err(
+			sb,
+			"Failed to mount 'cause NTFS's cluster size (%u) is less than media sector size (%u)",
+			sbi->cluster_size, sector_size);
+		goto out;
+	}
+
 	sbi->cluster_mask = sbi->cluster_size - 1;
 	sbi->cluster_mask_inv = ~(u64)sbi->cluster_mask;
 	sbi->record_size = record_size = boot->record_size < 0
-- 
2.31.1