From b42db0860e13067fcc7cbfba3966c9e652668bbc Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@sandeen.net>
Date: Mon, 16 Apr 2018 23:06:53 -0700
Subject: [PATCH] xfs: enhance dinode verifier

Add several more validations to xfs_dinode_verify:

- For LOCAL data fork formats, di_nextents must be 0.
- For LOCAL attr fork formats, di_anextents must be 0.
- For inodes with no attr fork offset,
  - format must be XFS_DINODE_FMT_EXTENTS if set at all
  - di_anextents must be 0.

Thanks to dchinner for pointing out a couple related checks I had
forgotten to add.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199377
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_inode_buf.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index ef68b1de006a..1201107eabc6 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -466,6 +466,8 @@ xfs_dinode_verify(
 				return __this_address;
 			if (di_size > XFS_DFORK_DSIZE(dip, mp))
 				return __this_address;
+			if (dip->di_nextents)
+				return __this_address;
 			/* fall through */
 		case XFS_DINODE_FMT_EXTENTS:
 		case XFS_DINODE_FMT_BTREE:
@@ -484,12 +486,31 @@ xfs_dinode_verify(
 	if (XFS_DFORK_Q(dip)) {
 		switch (dip->di_aformat) {
 		case XFS_DINODE_FMT_LOCAL:
+			if (dip->di_anextents)
+				return __this_address;
+		/* fall through */
 		case XFS_DINODE_FMT_EXTENTS:
 		case XFS_DINODE_FMT_BTREE:
 			break;
 		default:
 			return __this_address;
 		}
+	} else {
+		/*
+		 * If there is no fork offset, this may be a freshly-made inode
+		 * in a new disk cluster, in which case di_aformat is zeroed.
+		 * Otherwise, such an inode must be in EXTENTS format; this goes
+		 * for freed inodes as well.
+		 */
+		switch (dip->di_aformat) {
+		case 0:
+		case XFS_DINODE_FMT_EXTENTS:
+			break;
+		default:
+			return __this_address;
+		}
+		if (dip->di_anextents)
+			return __this_address;
 	}

 	/* only version 3 or greater inodes are extensively verified here */
-- 
2.17.0

