[PATCH 3/6] xfs: fix memcpy fortify errors in CUI log format copying

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Starting in 6.1, CONFIG_FORTIFY_SOURCE checks the length parameter of
memcpy.  Since we're already fixing problems with BUI item copying, we
should fix it everything else.

Refactor the xfs_cui_copy_format function to handle the copying of the
head and the flex array members separately.  While we're at it, fix a
minor validation deficiency in the recovery function.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_ondisk.h        |    4 ++++
 fs/xfs/xfs_refcount_item.c |   45 +++++++++++++++++++++-----------------------
 2 files changed, 25 insertions(+), 24 deletions(-)


diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 56917e236370..e20d2844b0c5 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -136,9 +136,13 @@ xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(struct xfs_attrd_log_format,	16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bui_log_format,	16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_bud_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_cui_log_format,	16);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_cud_log_format,	16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_map_extent,		32);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_phys_extent,		16);
 
 	XFS_CHECK_OFFSET(struct xfs_bui_log_format, bui_extents,	16);
+	XFS_CHECK_OFFSET(struct xfs_cui_log_format, cui_extents,	16);
 
 	/*
 	 * The v5 superblock format extended several v4 header structures with
diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
index 7e97bf19793d..24cf4c64ebaa 100644
--- a/fs/xfs/xfs_refcount_item.c
+++ b/fs/xfs/xfs_refcount_item.c
@@ -622,28 +622,18 @@ static const struct xfs_item_ops xfs_cui_item_ops = {
 	.iop_relog	= xfs_cui_item_relog,
 };
 
-/*
- * Copy an CUI format buffer from the given buf, and into the destination
- * CUI format structure.  The CUI/CUD items were designed not to need any
- * special alignment handling.
- */
-static int
+static inline void
 xfs_cui_copy_format(
-	struct xfs_log_iovec		*buf,
-	struct xfs_cui_log_format	*dst_cui_fmt)
+	struct xfs_cui_log_format	*dst,
+	const struct xfs_cui_log_format	*src)
 {
-	struct xfs_cui_log_format	*src_cui_fmt;
-	uint				len;
+	unsigned int			i;
 
-	src_cui_fmt = buf->i_addr;
-	len = xfs_cui_log_format_sizeof(src_cui_fmt->cui_nextents);
+	memcpy(dst, src, offsetof(struct xfs_cui_log_format, cui_extents));
 
-	if (buf->i_len == len) {
-		memcpy(dst_cui_fmt, src_cui_fmt, len);
-		return 0;
-	}
-	XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
-	return -EFSCORRUPTED;
+	for (i = 0; i < src->cui_nextents; i++)
+		memcpy(&dst->cui_extents[i], &src->cui_extents[i],
+				sizeof(struct xfs_phys_extent));
 }
 
 /*
@@ -660,19 +650,26 @@ xlog_recover_cui_commit_pass2(
 	struct xlog_recover_item	*item,
 	xfs_lsn_t			lsn)
 {
-	int				error;
 	struct xfs_mount		*mp = log->l_mp;
 	struct xfs_cui_log_item		*cuip;
 	struct xfs_cui_log_format	*cui_formatp;
+	size_t				len;
 
 	cui_formatp = item->ri_buf[0].i_addr;
 
+	if (item->ri_buf[0].i_len < xfs_cui_log_format_sizeof(0)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
+		return -EFSCORRUPTED;
+	}
+
+	len = xfs_cui_log_format_sizeof(cui_formatp->cui_nextents);
+	if (item->ri_buf[0].i_len != len) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
+		return -EFSCORRUPTED;
+	}
+
 	cuip = xfs_cui_init(mp, cui_formatp->cui_nextents);
-	error = xfs_cui_copy_format(&item->ri_buf[0], &cuip->cui_format);
-	if (error) {
-		xfs_cui_item_free(cuip);
-		return error;
-	}
+	xfs_cui_copy_format(&cuip->cui_format, cui_formatp);
 	atomic_set(&cuip->cui_next_extent, cui_formatp->cui_nextents);
 	/*
 	 * Insert the intent into the AIL directly and drop one reference so