ksmbd: no response from compound read

ksmbd doesn't support compound read. If client send read-read in
compound to ksmbd, there can be memory leak from read buffer.
Windows and linux clients doesn't send it to server yet. For now,
No response from compound read. compound read will be supported soon.

Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-21587, ZDI-CAN-21588
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/smb2pdu.c

@@ -6214,6 +6214,11 @@ int smb2_read(struct ksmbd_work *work)
 	unsigned int max_read_size = conn->vals->max_read_size;
 
 	WORK_BUFFERS(work, req, rsp);
+	if (work->next_smb2_rcv_hdr_off) {
+		work->send_no_response = 1;
+		err = -EOPNOTSUPP;
+		goto out;
+	}
 
 	if (test_share_config_flag(work->tcon->share_conf,
 				   KSMBD_SHARE_FLAG_PIPE)) {