From f988150eb414d0692f7cb673d89b8eab4a1bf8de Mon Sep 17 00:00:00 2001
From: JettScythe <jettscythe@hotmail.com>
Date: Wed, 22 Jul 2020 17:14:11 -0300
Subject: [PATCH] Support Cookie Authorization

---
 rpcclient/cookiefile.go     | 38 +++++++++++++++++++++++
 rpcclient/infrastructure.go | 62 +++++++++++++++++++++++++++++++++++--
 2 files changed, 98 insertions(+), 2 deletions(-)
 create mode 100644 rpcclient/cookiefile.go

diff --git a/rpcclient/cookiefile.go b/rpcclient/cookiefile.go
new file mode 100644
index 000000000..c3f7068b3
--- /dev/null
+++ b/rpcclient/cookiefile.go
@@ -0,0 +1,38 @@
+// Copyright (c) 2017 The Namecoin developers
+// Copyright (c) 2019 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package rpcclient
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func readCookieFile(path string) (username, password string, err error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	scanner.Scan()
+	err = scanner.Err()
+	if err != nil {
+		return
+	}
+	s := scanner.Text()
+
+	parts := strings.SplitN(s, ":", 2)
+	if len(parts) != 2 {
+		err = fmt.Errorf("malformed cookie file")
+		return
+	}
+
+	username, password = parts[0], parts[1]
+	return
+}
diff --git a/rpcclient/infrastructure.go b/rpcclient/infrastructure.go
index fbc8b9950..959ac50f9 100644
--- a/rpcclient/infrastructure.go
+++ b/rpcclient/infrastructure.go
@@ -19,6 +19,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -825,7 +826,12 @@ func (c *Client) sendPost(jReq *jsonRequest) {
 	httpReq.Header.Set("Content-Type", "application/json")
 
 	// Configure basic access authorization.
-	httpReq.SetBasicAuth(c.config.User, c.config.Pass)
+	user, pass, err := c.config.getAuth()
+	if err != nil {
+		jReq.responseChan <- &response{result: nil, err: err}
+		return
+	}
+	httpReq.SetBasicAuth(user, pass)
 
 	log.Tracef("Sending command [%s] with id %d", jReq.method, jReq.id)
 	c.sendPostRequest(httpReq, jReq)
@@ -1070,6 +1076,17 @@ type ConnConfig struct {
 	// Pass is the passphrase to use to authenticate to the RPC server.
 	Pass string
 
+	// CookiePath is the path to a cookie file containing the username and
+	// passphrase to use to authenticate to the RPC server.  It is used
+	// instead of User and Pass if non-empty.
+	CookiePath string
+
+	cookieLastCheckTime time.Time
+	cookieLastModTime   time.Time
+	cookieLastUser      string
+	cookieLastPass      string
+	cookieLastErr       error
+
 	// Params is the string representing the network that the server is running.
 	Params string
 
@@ -1121,6 +1138,43 @@ type ConnConfig struct {
 	EnableBCInfoHacks bool
 }
 
+// getAuth returns the username and passphrase that will actually be used for
+// this connection.  This will be the result of checking the cookie if a cookie
+// path is configured; if not, it will be the user-configured username and
+// passphrase.
+func (config *ConnConfig) getAuth() (username, passphrase string, err error) {
+	// Try username+passphrase auth first.
+	if config.Pass != "" {
+		return config.User, config.Pass, nil
+	}
+
+	// If no username or passphrase is set, try cookie auth.
+	return config.retrieveCookie()
+}
+
+// retrieveCookie returns the cookie username and passphrase.
+func (config *ConnConfig) retrieveCookie() (username, passphrase string, err error) {
+	if !config.cookieLastCheckTime.IsZero() && time.Now().Before(config.cookieLastCheckTime.Add(30*time.Second)) {
+		return config.cookieLastUser, config.cookieLastPass, config.cookieLastErr
+	}
+
+	config.cookieLastCheckTime = time.Now()
+
+	st, err := os.Stat(config.CookiePath)
+	if err != nil {
+		config.cookieLastErr = err
+		return config.cookieLastUser, config.cookieLastPass, config.cookieLastErr
+	}
+
+	modTime := st.ModTime()
+	if !modTime.Equal(config.cookieLastModTime) {
+		config.cookieLastModTime = modTime
+		config.cookieLastUser, config.cookieLastPass, config.cookieLastErr = readCookieFile(config.CookiePath)
+	}
+
+	return config.cookieLastUser, config.cookieLastPass, config.cookieLastErr
+}
+
 // newHTTPClient returns a new http client that is configured according to the
 // proxy and TLS settings in the associated connection configuration.
 func newHTTPClient(config *ConnConfig) (*http.Client, error) {
@@ -1190,7 +1244,11 @@ func dial(config *ConnConfig) (*websocket.Conn, error) {
 
 	// The RPC server requires basic authorization, so create a custom
 	// request header with the Authorization header set.
-	login := config.User + ":" + config.Pass
+	user, pass, err := config.getAuth()
+	if err != nil {
+		return nil, err
+	}
+	login := user + ":" + pass
 	auth := "Basic " + base64.StdEncoding.EncodeToString([]byte(login))
 	requestHeader := make(http.Header)
 	requestHeader.Add("Authorization", auth)