isofs: Verify inode mode when loading from disk

Verify that the inode mode is sane when loading it from the disk to
avoid complaints from VFS about setting up invalid inodes.

Reported-by: syzbot+895c23f6917da440ed0d@syzkaller.appspotmail.com
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/20250709095545.31062-2-jack@suse.cz
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: jankara

fs/isofs/inode.c

@@ -1440,9 +1440,16 @@ static int isofs_read_inode(struct inode *inode, int relocated)
 		inode->i_op = &page_symlink_inode_operations;
 		inode_nohighmem(inode);
 		inode->i_data.a_ops = &isofs_symlink_aops;
-	} else
+	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+		   S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		/* XXX - parse_rock_ridge_inode() had already set i_rdev. */
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+	} else {
+		printk(KERN_DEBUG "ISOFS: Invalid file type 0%04o for inode %lu.\n",
+			inode->i_mode, inode->i_ino);
+		ret = -EIO;
+		goto fail;
+	}
 
 	ret = 0;
 out: