[PATCH 5.12 030/384] erofs: add unsupported inode i_format check

[Greg Kroah-Hartman]

From: Gao Xiang <hsiangkao@xxxxxxxxxx>

commit 24a806d849c0b0c1d0cd6a6b93ba4ae4c0ec9f08 upstream.

If any unknown i_format fields are set (may be of some new incompat
inode features), mark such inode as unsupported.

Just in case of any new incompat i_format fields added in the future.

Link: https://lore.kernel.org/r/20210329003614.6583-1-hsiangkao@xxxxxxx
Fixes: 431339ba9042 ("staging: erofs: add inode operations")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.19+
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/erofs/erofs_fs.h |    3 +++
 fs/erofs/inode.c    |    7 +++++++
 2 files changed, 10 insertions(+)

--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -75,6 +75,9 @@ static inline bool erofs_inode_is_data_c
 #define EROFS_I_VERSION_BIT             0
 #define EROFS_I_DATALAYOUT_BIT          1
 
+#define EROFS_I_ALL	\
+	((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 1)
+
 /* 32-byte reduced form of an ondisk inode */
 struct erofs_inode_compact {
 	__le16 i_format;	/* inode format hints */
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -44,6 +44,13 @@ static struct page *erofs_read_inode(str
 	dic = page_address(page) + *ofs;
 	ifmt = le16_to_cpu(dic->i_format);
 
+	if (ifmt & ~EROFS_I_ALL) {
+		erofs_err(inode->i_sb, "unsupported i_format %u of nid %llu",
+			  ifmt, vi->nid);
+		err = -EOPNOTSUPP;
+		goto err_out;
+	}
+
 	vi->datalayout = erofs_inode_datalayout(ifmt);
 	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
 		erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",