[PATCH] xfs: check hash ordering in xfs_da3_node_verify

[Yuto Ohnuki <ytohnuki@amazon.com>]

The DA node verifier checks header fields such as level and count, but
it does not verify that the btree hash values are in non-decreasing
order.

DA node blocks are traversed by searching the btree array for the first
hash value that exceeds the lookup hash, which requires the hash values
to be ordered correctly.

Add a hash order check to xfs_da3_node_verify, similar to the existing
validation in xfs_dir3_leaf_check_int, so that misordered node
blocks are detected as metadata corruption.

Signed-off-by: Yuto Ohnuki <ytohnuki@amazon.com>
---
 fs/xfs/libxfs/xfs_da_btree.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index ad801b7bd2dd..ef49df22899e 100644
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -225,6 +225,7 @@ xfs_da3_node_verify(
 	struct xfs_da_intnode	*hdr = bp->b_addr;
 	struct xfs_da3_icnode_hdr ichdr;
 	xfs_failaddr_t		fa;
+	int			i;
 
 	xfs_da3_node_hdr_from_disk(mp, &ichdr, hdr);
 
@@ -247,7 +248,12 @@ xfs_da3_node_verify(
 	    ichdr.count > mp->m_attr_geo->node_ents)
 		return __this_address;
 
-	/* XXX: hash order check? */
+	/* Check hash value order. */
+	for (i = 0; i + 1 < ichdr.count; i++) {
+		if (be32_to_cpu(ichdr.btree[i].hashval) >
+				be32_to_cpu(ichdr.btree[i + 1].hashval))
+			return __this_address;
+	}
 
 	return NULL;
 }
-- 
2.50.1




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