[feat] retry if dns lookup fails

pkg/vpn/bonafide/bonafide.go

-// Copyright (C) 2018-2020 LEAP
+// Copyright (C) 2018-2021 LEAP
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -75,6 +75,17 @@ type geoLocation struct {
 	SortedGateways []geoGateway `json:"sortedGateways"`
 }
 
+func getAPIAddr(provider string) string {
+	switch provider {
+	case "riseup.net":
+		return "198.252.153.107"
+	case "calyx.net":
+		return "162.247.73.194"
+	default:
+		return ""
+	}
+}
+
 // New Bonafide: Initializes a Bonafide object. By default, no Credentials are passed.
 func New() *Bonafide {
 	certs := x509.NewCertPool()
@@ -179,6 +190,17 @@ func (b *Bonafide) GetPemCertificate() ([]byte, error) {
 	return ioutil.ReadAll(resp.Body)
 }
 
+func (b *Bonafide) GetPemCertificateNoDNS() ([]byte, error) {
+	req, err := http.NewRequest("POST", b.getURLNoDNS("certv3"), strings.NewReader(""))
+	resp, err := b.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	return ioutil.ReadAll(resp.Body)
+}
+
 func (b *Bonafide) getURL(object string) string {
 	switch object {
 	case "cert":
@@ -192,6 +214,23 @@ func (b *Bonafide) getURL(object string) string {
 	return ""
 }
 
+func (b *Bonafide) getURLNoDNS(object string) string {
+	p := strings.ToLower(config.Provider)
+	base := "https://" + getAPIAddr(p) + "/"
+	switch object {
+	case "cert":
+		return base + certPathv1
+	case "certv3":
+		return base + certPathv3
+	case "auth":
+		return base + authPathv3
+	case "eip":
+		return base + "3/config/eip-service.json"
+	}
+	log.Println("BUG: unknown url object")
+	return ""
+}
+
 func (b *Bonafide) maybeInitializeEIP() error {
 	if b.eip == nil {
 		err := b.fetchEipJSON()

pkg/vpn/bonafide/eip_service.go

@@ -83,6 +83,13 @@ func (b *Bonafide) fetchEipJSON() error {
 		// TODO why exactly 1 retry? Make it configurable, for tests
 		time.Sleep(retryFetchJSONSeconds * time.Second)
 		resp, err = b.client.Post(eip3API, "", nil)
+		if err != nil {
+			// TODO it might be that it's not an error, but an empty file or whatever done
+			// by DNS poisoning. Should try to parse the file.
+			uri := b.getURLNoDNS("eip")
+			log.Println("Fetching ", uri)
+			resp, err = b.client.Post(uri, "", nil)
+		}
 	}
 	defer resp.Body.Close()
 

pkg/vpn/openvpn.go

-// Copyright (C) 2018-2020 LEAP
+// Copyright (C) 2018-2021 LEAP
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -177,6 +177,7 @@ func (b *Bitmask) startOpenVPN() error {
 }
 
 func (b *Bitmask) getCert() (certPath string, err error) {
+	failed := false
 	persistentCertFile := filepath.Join(config.Path, strings.ToLower(config.Provider)+".pem")
 	if _, err := os.Stat(persistentCertFile); !os.IsNotExist(err) && isValidCert(persistentCertFile) {
 		// reuse cert. for the moment we're not writing one there, this is
@@ -191,9 +192,26 @@ func (b *Bitmask) getCert() (certPath string, err error) {
 			log.Println("Fetching certificate to", certPath)
 			cert, err := b.bonafide.GetPemCertificate()
 			if err != nil {
-				return "", err
+				log.Println(err)
+				failed = true
 			}
 			err = ioutil.WriteFile(certPath, cert, 0600)
+			if err != nil {
+				failed = true
+			}
+		}
+	}
+	if failed || !isValidCert(certPath) {
+		cert, err := b.bonafide.GetPemCertificateNoDNS()
+		if cert != nil {
+			log.Println("Successfully did certificate bypass")
+			err = nil
+		} else {
+			err = errors.New("Cannot get vpn certificate")
+		}
+		err = ioutil.WriteFile(certPath, cert, 0600)
+		if err != nil {
+			failed = true
 		}
 	}
 	return certPath, err