fix: PSK extension w/o session cache crashing (#177)

Fixes a bug causing client to crash (SIGSEGV) WHEN PSK extension is set with empty session cache AND server sends HelloRetryRequest.
refraction-networking · Mar 30, 2023 · 7aa684a · 7aa684a
1 parent 3721531
commit 7aa684a
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/u_tls_extensions.go b/u_tls_extensions.go
@@ -1859,6 +1859,9 @@ type FakePreSharedKeyExtension struct {
 }
 
 func (e *FakePreSharedKeyExtension) writeToUConn(uc *UConn) error {
+	if session, ok := uc.config.ClientSessionCache.Get(clientSessionCacheKey(uc.conn.RemoteAddr(), uc.config)); !ok || session == nil {
+		return nil // don't write the extension if there is no session
+	}
 	uc.HandshakeState.Hello.PskIdentities = e.PskIdentities
 	uc.HandshakeState.Hello.PskBinders = e.PskBinders
 	return nil