ksmbd: not allow guest user on multichannel

This patch return STATUS_NOT_SUPPORTED if binding session is guest.

Cc: stable@vger.kernel.org
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-20480
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/ksmbd/smb2pdu.c

@@ -1431,7 +1431,7 @@ static int ntlm_authenticate(struct ksmbd_work *work)
 		 * Reuse session if anonymous try to connect
 		 * on reauthetication.
 		 */
-		if (ksmbd_anonymous_user(user)) {
+		if (conn->binding == false && ksmbd_anonymous_user(user)) {
 			ksmbd_free_user(user);
 			return 0;
 		}
@@ -1445,7 +1445,7 @@ static int ntlm_authenticate(struct ksmbd_work *work)
 		sess->user = user;
 	}
 
-	if (user_guest(sess->user)) {
+	if (conn->binding == false && user_guest(sess->user)) {
 		rsp->SessionFlags = SMB2_SESSION_FLAG_IS_GUEST_LE;
 	} else {
 		struct authenticate_message *authblob;
@@ -1687,6 +1687,11 @@ int smb2_sess_setup(struct ksmbd_work *work)
 			goto out_err;
 		}
 
+		if (user_guest(sess->user)) {
+			rc = -EOPNOTSUPP;
+			goto out_err;
+		}
+
 		conn->binding = true;
 	} else if ((conn->dialect < SMB30_PROT_ID ||
 		    server_conf.flags & KSMBD_GLOBAL_FLAG_SMB3_MULTICHANNEL) &&
@@ -1811,6 +1816,8 @@ int smb2_sess_setup(struct ksmbd_work *work)
 		rsp->hdr.Status = STATUS_NETWORK_SESSION_EXPIRED;
 	else if (rc == -ENOMEM)
 		rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES;
+	else if (rc == -EOPNOTSUPP)
+		rsp->hdr.Status = STATUS_NOT_SUPPORTED;
 	else if (rc)
 		rsp->hdr.Status = STATUS_LOGON_FAILURE;