[PATCH 03/41] libxfs: enforce metadata inode flag

Darrick J. Wong
2024-12-06T23:40:26Z

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

Add checks for the metadata inode flag so that we don't ever leak
metadata inodes out to userspace, and we don't ever try to read a
regular inode as metadata.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/inode.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/libxfs/inode.c b/libxfs/inode.c
index 1eb0bccae48906..0598a70ff504a4 100644
--- a/libxfs/inode.c
+++ b/libxfs/inode.c
@@ -208,7 +208,8 @@ libxfs_iget(
/*
* Get a metadata inode.
*
- * The metafile type must match the file mode exactly.
+ * The metafile type must match the file mode exactly, and for files in the
+ * metadata directory tree, it must match the inode's metatype exactly.
*/
int
libxfs_trans_metafile_iget(
@@ -232,6 +233,12 @@ libxfs_trans_metafile_iget(
mode = S_IFREG;
if (inode_wrong_type(VFS_I(ip), mode))
goto bad_rele;
+ if (xfs_has_metadir(mp)) {
+ if (!xfs_is_metadir_inode(ip))
+ goto bad_rele;
+ if (metafile_type != ip->i_metatype)
+ goto bad_rele;
+ }

*ipp = ip;
return 0;