[PATCH] ext4: validate external journal superblock checksum
From: Darrick J. Wong <hidden>
Date: 2014-09-08 19:43:43
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
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: Darrick J. Wong <redacted> --- fs/ext4/super.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7045f1d..222ed5d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c@@ -4372,6 +4372,15 @@ 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);