Merge pull request lib#1035 from bjornouderoelink/fix-concurrent-map-writes

Fix lib#1031: concurrent map writes

Author: maddyblue

conn.go

@@ -298,7 +298,13 @@ func (c *Connector) open(ctx context.Context) (cn *conn, err error) {
 	// the user.
 	defer errRecoverNoErrBadConn(&err)
 
-	o := c.opts
+	// Create a new values map (copy). This makes it so maps in different
+	// connections do not reference the same underlying data structure, so it
+	// is safe for multiple connections to concurrently write to their opts.
+	o := make(values)
+	for k, v := range c.opts {
+		o[k] = v
+	}
 
 	bad := &atomic.Value{}
 	bad.Store(false)
@@ -1100,7 +1106,7 @@ func isDriverSetting(key string) bool {
 		return true
 	case "password":
 		return true
-	case "sslmode", "sslcert", "sslkey", "sslrootcert":
+	case "sslmode", "sslcert", "sslkey", "sslrootcert", "sslinline":
 		return true
 	case "fallback_application_name":
 		return true

conn_go18.go

@@ -129,7 +129,16 @@ func (cn *conn) watchCancel(ctx context.Context) func() {
 }
 
 func (cn *conn) cancel(ctx context.Context) error {
-	c, err := dial(ctx, cn.dialer, cn.opts)
+	// Create a new values map (copy). This makes sure the connection created
+	// in this method cannot write to the same underlying data, which could
+	// cause a concurrent map write panic. This is necessary because cancel
+	// is called from a goroutine in watchCancel.
+	o := make(values)
+	for k, v := range cn.opts {
+		o[k] = v
+	}
+
+	c, err := dial(ctx, cn.dialer, o)
 	if err != nil {
 		return err
 	}
@@ -142,7 +151,7 @@ func (cn *conn) cancel(ctx context.Context) error {
 			c:   c,
 			bad: bad,
 		}
-		err = can.ssl(cn.opts)
+		err = can.ssl(o)
 		if err != nil {
 			return err
 		}

ssl.go

@@ -59,9 +59,6 @@ func ssl(o values) (func(net.Conn) (net.Conn, error), error) {
 		return nil, err
 	}
 
-	// This pseudo-parameter is not recognized by the PostgreSQL server, so let's delete it after use.
-	delete(o, "sslinline")
-
 	// Accept renegotiation requests initiated by the backend.
 	//
 	// Renegotiation was deprecated then removed from PostgreSQL 9.5, but
@@ -89,9 +86,6 @@ func sslClientCertificates(tlsConf *tls.Config, o values) error {
 	sslinline := o["sslinline"]
 	if sslinline == "true" {
 		cert, err := tls.X509KeyPair([]byte(o["sslcert"]), []byte(o["sslkey"]))
-		// Clear out these params, in case they were to be sent to the PostgreSQL server by mistake
-		o["sslcert"] = ""
-		o["sslkey"] = ""
 		if err != nil {
 			return err
 		}
@@ -157,8 +151,6 @@ func sslCertificateAuthority(tlsConf *tls.Config, o values) error {
 
 		var cert []byte
 		if sslinline == "true" {
-			// // Clear out this param, in case it were to be sent to the PostgreSQL server by mistake
-			o["sslrootcert"] = ""
 			cert = []byte(sslrootcert)
 		} else {
 			var err error