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Commit df4763be authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

ext4: validate external journal superblock checksum 



If the external journal device has metadata_csum enabled, verify
that the superblock checksum matches the block before we try to
mount.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent feb8c6d3

fs/ext4/super.c

+9 −0
Original line number Diff line number Diff line
@@ -4414,6 +4414,15 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb, 
		goto out_bdev;

	}



	if ((le32_to_cpu(es->s_feature_ro_compat) &

	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&

	    es->s_checksum != ext4_superblock_csum(sb, es)) {

		ext4_msg(sb, KERN_ERR, "external journal has "

				       "corrupt superblock");

		brelse(bh);

		goto out_bdev;

	}



	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {

		ext4_msg(sb, KERN_ERR, "journal UUID does not match");

		brelse(bh);