1 files changed, 30 insertions, 7 deletions

diff --git a/fs/smb/server/smb_common.c b/fs/smb/server/smb_common.c
index 7de73223189a..080fbc9eb470 100644
--- a/fs/smb/server/smb_common.c
+++ b/fs/smb/server/smb_common.c
@@ -608,23 +608,46 @@ int ksmbd_smb_negotiate_common(struct ksmbd_work *work, unsigned int command)
 	struct ksmbd_conn *conn = work->conn;
 	int ret;
 
-	conn->dialect =
-		ksmbd_negotiate_smb_dialect(work->request_buf);
-	ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
-
 	if (command == SMB2_NEGOTIATE_HE) {
+		/*
+		 * An SMB2 NEGOTIATE is valid for a new connection, or after an
+		 * SMB1 multi-protocol negotiate has selected SMB2. Do not allow
+		 * a second SMB2 NEGOTIATE to replace connection-wide state
+		 * while a session setup is pending. KSMBD_SESS_NEED_RECONNECT
+		 * is a transient session state and does not restart transport
+		 * negotiation.
+		 */
+		ksmbd_conn_lock(conn);
+		if (!ksmbd_conn_new(conn) &&
+		    !ksmbd_conn_need_negotiate(conn)) {
+			work->send_no_response = 1;
+			ksmbd_conn_set_exiting(conn);
+			ksmbd_conn_unlock(conn);
+			return 0;
+		}
+
+		conn->dialect =
+			ksmbd_negotiate_smb_dialect(work->request_buf);
+		ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
 		ret = smb2_handle_negotiate(work);
+		ksmbd_conn_unlock(conn);
 		return ret;
 	}
 
 	if (command == SMB_COM_NEGOTIATE) {
+		ksmbd_conn_lock(conn);
+		conn->dialect =
+			ksmbd_negotiate_smb_dialect(work->request_buf);
+		ksmbd_debug(SMB, "conn->dialect 0x%x\n", conn->dialect);
 		if (__smb2_negotiate(conn)) {
 			init_smb3_11_server(conn);
-			init_smb2_neg_rsp(work);
+			ret = init_smb2_neg_rsp(work);
 			ksmbd_debug(SMB, "Upgrade to SMB2 negotiation\n");
-			return 0;
+		} else {
+			ret = smb_handle_negotiate(work);
 		}
-		return smb_handle_negotiate(work);
+		ksmbd_conn_unlock(conn);
+		return ret;
 	}
 
 	pr_err("Unknown SMB negotiation command: %u\n", command);