Other: Disable TLS pin checks on QA builds

internal/dialer/dialer_pinning_checker_default.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2022 Proton AG
+//
+// This file is part of Proton Mail Bridge.Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
+
+//go:build !build_qa
+
+package dialer
+
+import (
+	"crypto/tls"
+	"errors"
+	"net"
+)
+
+// CheckCertificate returns whether the connection presents a known TLS certificate.
+func (p *TLSPinChecker) CheckCertificate(conn net.Conn) error {
+	tlsConn, ok := conn.(*tls.Conn)
+	if !ok {
+		return errors.New("connection is not a TLS connection")
+	}
+
+	connState := tlsConn.ConnectionState()
+
+	for _, peerCert := range connState.PeerCertificates {
+		fingerprint := certFingerprint(peerCert)
+
+		for _, pin := range p.trustedPins {
+			if pin == fingerprint {
+				return nil
+			}
+		}
+	}
+
+	return ErrTLSMismatch
+}