[PATCH 31/48] xfs: validate attr done items during recovery

[Dave Chinner <dgc@kernel.org>]

An attr done item is a single fixed size region, but recovery only checked its
length in the commit handler and never checked its padding.

Validate the region length and require the padding to be zero as the item is
decoded. The commit handler can then trust the item, so the length check is
removed from it.

Assisted-by: LLM
Signed-off-by: Dave Chinner <dgc@kernel.org>
---
 fs/xfs/xfs_attr_item.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
index a53ee2b0c54a..a6e36b2aa7b3 100644
--- a/fs/xfs/xfs_attr_item.c
+++ b/fs/xfs/xfs_attr_item.c
@@ -1167,14 +1167,35 @@ xlog_recover_attrd_commit_pass2(
 	struct xfs_attrd_log_format	*attrd_formatp;
 
 	attrd_formatp = item->ri_buf[0].iov_base;
-	if (item->ri_buf[0].iov_len != sizeof(struct xfs_attrd_log_format)) {
-		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, log->l_mp,
-				item->ri_buf[0].iov_base, item->ri_buf[0].iov_len);
+	xlog_recover_release_intent(log, XFS_LI_ATTRI,
+				    attrd_formatp->alfd_alf_id);
+	return 0;
+}
+
+/* The attrd is a single fixed size region. */
+static int
+xlog_recover_attrd_validate_region(
+	struct xlog			*log,
+	struct xlog_recover_item	*item,
+	int				region_index)
+{
+	struct xfs_attrd_log_format	*attrd_formatp =
+		item->ri_buf[region_index].iov_base;
+
+	if (item->ri_buf[region_index].iov_len !=
+			sizeof(struct xfs_attrd_log_format)) {
+		xfs_warn(log->l_mp, "ATTRD: bad item region length %zu recovered.",
+				item->ri_buf[region_index].iov_len);
+		return -EFSCORRUPTED;
+	}
+
+	/* The padding is always written as zero. */
+	if (attrd_formatp->__pad != 0) {
+		xfs_warn(log->l_mp, "ATTRD: bad padding 0x%x recovered.",
+				attrd_formatp->__pad);
 		return -EFSCORRUPTED;
 	}
 
-	xlog_recover_release_intent(log, XFS_LI_ATTRI,
-				    attrd_formatp->alfd_alf_id);
 	return 0;
 }
 
@@ -1203,5 +1224,8 @@ static const struct xfs_item_ops xfs_attrd_item_ops = {
 
 const struct xlog_recover_item_ops xlog_attrd_item_ops = {
 	.item_type	= XFS_LI_ATTRD,
+	.min_hdr_len	= sizeof(struct xfs_attrd_log_format),
+	.validate_nregions = xlog_recover_single_region,
+	.validate_region = xlog_recover_attrd_validate_region,
 	.commit_pass2	= xlog_recover_attrd_commit_pass2,
 };
-- 
2.55.0