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FAILED: patch "[PATCH] ext2: Add sanity checks for group and filesystem size" failed to apply to 4.14-stable tree

PATCH [email protected] 1 participant 1 message Oct 16, 2022

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Stable branch ext2 file system
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The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

d766f2d1e3e3 ("ext2: Add sanity checks for group and filesystem size") d9e9866803f7 ("ext2: Adjust indentation in ext2_fill_super")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d766f2d1e3e3bd44024a7f971ffcf8b8fbb7c5d2 Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Wed, 14 Sep 2022 17:24:42 +0200
Subject: [PATCH] ext2: Add sanity checks for group and filesystem size

Add sanity check that filesystem size does not exceed the underlying device size and that group size is big enough so that metadata can fit into it. This avoid trying to mount some crafted filesystems with extremely large group counts.

Reported-by [email protected]
Reported-by kernel test robot <[email protected]> # Test fixup
CC [email protected]
Signed-off-by Jan Kara <[email protected]>
fs/ext2/super.c +14 -2
index 252c742379cf..afb31af9302d 100644
@@ -1052,6 +1052,13 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 			sbi->s_blocks_per_group);
 		goto failed_mount;
 	}
+	/* At least inode table, bitmaps, and sb have to fit in one group */
+	if (sbi->s_blocks_per_group <= sbi->s_itb_per_group + 3) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #blocks per group smaller than metadata size: %lu <= %lu",
+			sbi->s_blocks_per_group, sbi->s_inodes_per_group + 3);
+		goto failed_mount;
+	}
 	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 		ext2_msg(sb, KERN_ERR,
 			"error: #fragments per group too big: %lu",

@@ -1065,9 +1072,14 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 			sbi->s_inodes_per_group);
 		goto failed_mount;
 	}
+	if (sb_bdev_nr_blocks(sb) < le32_to_cpu(es->s_blocks_count)) {
+		ext2_msg(sb, KERN_ERR,
+			 "bad geometry: block count %u exceeds size of device (%u blocks)",
+			 le32_to_cpu(es->s_blocks_count),
+			 (unsigned)sb_bdev_nr_blocks(sb));
+		goto failed_mount;
+	}
 
-	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
-		goto cantfind_ext2;
 	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 				le32_to_cpu(es->s_first_data_block) - 1)
 					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;