e2fsck: check revoke block checksum during recovery

Verify the revoke block checksum when recovering the journal.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/e2fsck/recovery.c b/e2fsck/recovery.c
index a9fc3f7..8bf4401 100644 (file)
--- a/e2fsck/recovery.c
+++ b/e2fsck/recovery.c
@@ -714,6 +714,27 @@ static int do_one_pass(journal_t *journal,
        return err;
 }
 
+static int jbd2_revoke_block_csum_verify(journal_t *j,
+                                        void *buf)
+{
+       struct journal_revoke_tail *tail;
+       __u32 provided, calculated;
+
+       if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2))
+               return 1;
+
+       tail = (struct journal_revoke_tail *)(buf + j->j_blocksize -
+                       sizeof(struct journal_revoke_tail));
+       provided = tail->r_checksum;
+       tail->r_checksum = 0;
+       calculated = ext2fs_crc32c_le(~0, j->j_superblock->s_uuid,
+                                     sizeof(j->j_superblock->s_uuid));
+       calculated = ext2fs_crc32c_le(calculated, buf, j->j_blocksize);
+       tail->r_checksum = provided;
+
+       provided = ext2fs_be32_to_cpu(provided);
+       return provided == calculated;
+}
 
 /* Scan a revoke record, marking all blocks mentioned as revoked. */
 
@@ -728,6 +749,9 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
        offset = sizeof(journal_revoke_header_t);
        max = be32_to_cpu(header->r_count);
 
+       if (!jbd2_revoke_block_csum_verify(journal, header))
+               return -EINVAL;
+
        if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_64BIT))
                record_len = 8;