Merge pull request #1522 from subbyte/authlog

Improve RTSP server authentication handling and auditing

internal/rtsp/rtsp.go

@@ -1,6 +1,7 @@
 package rtsp
 
 import (
+	"errors"
 	"io"
 	"net"
 	"net/url"
@@ -237,7 +238,9 @@ func tcpHandler(conn *rtsp.Conn) {
 	})
 
 	if err := conn.Accept(); err != nil {
-		if err != io.EOF {
+		if errors.Is(err, rtsp.FailedAuth) {
+			log.Warn().Str("remote_addr", conn.Connection.RemoteAddr).Msg("[rtsp] failed authentication")
+		} else if err != io.EOF {
 			log.WithLevel(level).Err(err).Caller().Send()
 		}
 		if closer != nil {

pkg/rtsp/server.go

@@ -13,6 +13,8 @@ import (
 	"github.com/AlexxIT/go2rtc/pkg/tcp"
 )
 
+var FailedAuth = errors.New("failed authentication")
+
 func NewServer(conn net.Conn) *Conn {
 	return &Conn{
 		Connection: core.Connection{
@@ -45,7 +47,7 @@ func (c *Conn) Accept() error {
 
 		c.Fire(req)
 
-		if !c.auth.Validate(req) {
+		if valid, empty := c.auth.Validate(req); !valid {
 			res := &tcp.Response{
 				Status:  "401 Unauthorized",
 				Header:  map[string][]string{"Www-Authenticate": {`Basic realm="go2rtc"`}},
@@ -54,7 +56,12 @@ func (c *Conn) Accept() error {
 			if err = c.WriteResponse(res); err != nil {
 				return err
 			}
-			continue
+			if empty {
+				// eliminate false positive: ffmpeg sends first request without
+				// authorization header even if the user provides credentials
+				continue
+			}
+			return FailedAuth
 		}
 
 		// Receiver: OPTIONS > DESCRIBE > SETUP... > PLAY > TEARDOWN

pkg/tcp/auth.go

@@ -85,14 +85,14 @@ func (a *Auth) Write(req *Request) {
 	}
 }
 
-func (a *Auth) Validate(req *Request) bool {
+func (a *Auth) Validate(req *Request) (valid, empty bool) {
 	if a == nil {
-		return true
+		return true, true
 	}
 
 	header := req.Header.Get("Authorization")
 	if header == "" {
-		return false
+		return false, true
 	}
 
 	if a.Method == AuthUnknown {
@@ -100,7 +100,7 @@ func (a *Auth) Validate(req *Request) bool {
 		a.header = "Basic " + B64(a.user, a.pass)
 	}
 
-	return header == a.header
+	return header == a.header, false
 }
 
 func (a *Auth) ReadNone(res *Response) bool {