jfs: Verify inode mode when loading from disk

The inode mode loaded from corrupted disk can be invalid. Do like what
commit 0a9e740 ("isofs: Verify inode mode when loading from disk")
does.

Reported-by: syzbot <syzbot+895c23f6917da440ed0d@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=895c23f6917da440ed0d
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

Author: Tetsuo Handa

fs/jfs/inode.c

@@ -59,9 +59,15 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
 			 */
 			inode->i_link[inode->i_size] = '\0';
 		}
-	} else {
+	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+		   S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		inode->i_op = &jfs_file_inode_operations;
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+	} else {
+		printk(KERN_DEBUG "JFS: Invalid file type 0%04o for inode %lu.\n",
+		       inode->i_mode, inode->i_ino);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
 	}
 	unlock_new_inode(inode);
 	return inode;