[PATCH 7.3.y 1/2] xfs: break out xattr entry checks into separate functions

[Sasha Levin <sashal@kernel.org>]

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

[ Upstream commit 9eb04a6d41c7e474d4665118895c3c2d8e5a2741 ]

We're going to add more xattr entry checking code in xchk_xattr_entry so
break these out into separate functions so that we don't go crazy
indenting.  There's a slight behavior change here where we skip updating
the usedmap if we've decided the xattr structure is corrupt.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Stable-dep-of: 91c41f952490 ("xfs: check for buffer overruns when examining local/remote xattr entries")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/xfs/scrub/attr.c | 90 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 68 insertions(+), 22 deletions(-)

diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index 842d65834afbc..f7c00ea1af5d3 100644
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -293,6 +293,66 @@ xchk_xattr_set_map(
 	return ret;
 }
 
+static unsigned int
+xchk_xattr_local_entry(
+	struct xchk_da_btree		*ds,
+	int				level,
+	char				*buf_end,
+	struct xfs_attr_leafblock	*leaf,
+	int				idx)
+{
+	struct xfs_attr_leaf_name_local	*lentry =
+			xfs_attr3_leaf_name_local(leaf, idx);
+	char				*name_end;
+	unsigned int			namesize;
+
+	namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
+			be16_to_cpu(lentry->valuelen));
+	name_end = (char *)lentry + namesize;
+	if (lentry->namelen == 0) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+	if (name_end > buf_end) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+
+	return namesize;
+}
+
+static unsigned int
+xchk_xattr_remote_entry(
+	struct xchk_da_btree		*ds,
+	int				level,
+	char				*buf_end,
+	struct xfs_attr_leafblock	*leaf,
+	int				idx,
+	struct xfs_attr_leaf_entry	*ent)
+{
+	struct xfs_attr_leaf_name_remote *rentry =
+			xfs_attr3_leaf_name_remote(leaf, idx);
+	char				*name_end;
+	unsigned int			namesize;
+
+	namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
+	name_end = (char *)rentry + namesize;
+	if (rentry->namelen == 0) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+	if (rentry->valueblk == 0 && !(ent->flags & XFS_ATTR_INCOMPLETE)) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+	if (name_end > buf_end) {
+		xchk_da_set_corrupt(ds, level);
+		return 0;
+	}
+
+	return namesize;
+}
+
 /*
  * Check this leaf entry's relations to everything else.
  * Returns the number of bytes used for the name/value data.
@@ -311,9 +371,6 @@ xchk_xattr_entry(
 {
 	struct xfs_mount		*mp = ds->state->mp;
 	struct xchk_xattr_buf		*ab = ds->sc->buf;
-	char				*name_end;
-	struct xfs_attr_leaf_name_local	*lentry;
-	struct xfs_attr_leaf_name_remote *rentry;
 	unsigned int			nameidx;
 	unsigned int			namesize;
 
@@ -333,25 +390,14 @@ xchk_xattr_entry(
 	}
 
 	/* Check the name information. */
-	if (ent->flags & XFS_ATTR_LOCAL) {
-		lentry = xfs_attr3_leaf_name_local(leaf, idx);
-		namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
-				be16_to_cpu(lentry->valuelen));
-		name_end = (char *)lentry + namesize;
-		if (lentry->namelen == 0)
-			xchk_da_set_corrupt(ds, level);
-	} else {
-		rentry = xfs_attr3_leaf_name_remote(leaf, idx);
-		namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
-		name_end = (char *)rentry + namesize;
-		if (rentry->namelen == 0)
-			xchk_da_set_corrupt(ds, level);
-		if (rentry->valueblk == 0 &&
-		    !(ent->flags & XFS_ATTR_INCOMPLETE))
-			xchk_da_set_corrupt(ds, level);
-	}
-	if (name_end > buf_end)
-		xchk_da_set_corrupt(ds, level);
+	if (ent->flags & XFS_ATTR_LOCAL)
+		namesize = xchk_xattr_local_entry(ds, level, buf_end, leaf,
+				idx);
+	else
+		namesize = xchk_xattr_remote_entry(ds, level, buf_end, leaf,
+				idx, ent);
+	if (!namesize)
+		return;
 
 	if (!xchk_xattr_set_map(ds->sc, ab->usedmap, nameidx, namesize))
 		xchk_da_set_corrupt(ds, level);
-- 
2.53.0