commit 42a7106de636ebf9c0b93d25b4230e14f5f2682e
author Darrick J. Wong <djwong@us.ibm.com> Sun May 27 08:08:24 2012 -0400
committer Theodore Ts'o <tytso@mit.edu> Sun May 27 08:08:24 2012 -0400
tree 321f2e97768bc12962babb018004f8f6b1f7e57f
parent 4fd5ea43bc11602bfabe2c8f5378586d34bd2b0a

jbd2: checksum revocation blocks

Compute and verify revoke blocks inside the journal.

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

fs/jbd2/recovery.c

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 980f3d6..728ecd0 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -706,6 +706,25 @@
 	return err;
 }
 
+static int jbd2_revoke_block_csum_verify(journal_t *j,
+					 void *buf)
+{
+	struct jbd2_journal_revoke_tail *tail;
+	__u32 provided, calculated;
+
+	if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+		return 1;
+
+	tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
+			sizeof(struct jbd2_journal_revoke_tail));
+	provided = tail->r_checksum;
+	tail->r_checksum = 0;
+	calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+	tail->r_checksum = provided;
+
+	provided = be32_to_cpu(provided);
+	return provided == calculated;
+}
 
 /* Scan a revoke record, marking all blocks mentioned as revoked. */
 
@@ -720,6 +739,9 @@
 	offset = sizeof(jbd2_journal_revoke_header_t);
 	max = be32_to_cpu(header->r_count);
 
+	if (!jbd2_revoke_block_csum_verify(journal, header))
+		return -EINVAL;
+
 	if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
 		record_len = 8;