server: Parse IPs properly for getRemoteAddr (#3790)

This supports IPv6 addresses which have multiple colons like [::1]:57579

Author: j0sh

server/mediaserver.go

@@ -13,6 +13,7 @@ import (
 	"io/ioutil"
 	"math/big"
 	"mime/multipart"
+	"net"
 	"net/http"
 	"net/textproto"
 	"net/url"
@@ -1660,7 +1661,16 @@ func getRemoteAddr(r *http.Request) string {
 	if proxiedAddr := r.Header.Get("X-Forwarded-For"); proxiedAddr != "" {
 		addr = strings.Split(proxiedAddr, ",")[0]
 	}
-	return strings.Split(addr, ":")[0]
+
+	// addr is typically in the format "ip:port"
+	// Need to extract just the IP. Handle IPv6 too.
+	host, _, err := net.SplitHostPort(strings.TrimSpace(addr))
+	if err != nil {
+		// probably not a real IP
+		return addr
+	}
+
+	return host
 }
 
 func mediaCompatible(a, b ffmpeg.MediaFormatInfo) bool {

server/mediaserver_test.go

@@ -1577,3 +1577,49 @@ func mustParseUrl(t *testing.T, str string) *url.URL {
 	}
 	return url
 }
+
+func TestGetRemoteAddr(t *testing.T) {
+	type tc struct {
+		name       string
+		remoteAddr string // r.RemoteAddr
+		xff        string // "" = header not present
+		want       string
+	}
+
+	cases := []tc{
+		// --- No X-Forwarded-For (uses RemoteAddr) ---
+		{"remote IPv4 with port", "203.0.113.9:54321", "", "203.0.113.9"},
+		{"remote hostname with port", "example.com:80", "", "example.com"},
+		{"remote bracketed IPv6 with port", "[2001:db8::1]:443", "", "2001:db8::1"},
+		{"remote IPv6 with zone", "[fe80::1%lo0]:1234", "", "fe80::1%lo0"},
+		{"remote IPv4 no port (SplitHostPort error)", "192.0.2.10", "", "192.0.2.10"},
+		{"remote bare IPv6 no port (SplitHostPort error)", "2001:db8::2", "", "2001:db8::2"},
+		{"remote empty string", "", "", ""},
+		{"remote malformed string", "1.2.3.4, nonsense", "", "1.2.3.4, nonsense"},
+
+		// --- X-Forwarded-For present (takes first comma-delimited token) ---
+		{"xff single IPv4 no port", "203.0.113.9:54321", "198.51.100.7", "198.51.100.7"},
+		{"xff single IPv4 with port", "203.0.113.9:54321", "198.51.100.7:8080", "198.51.100.7"},
+		{"xff single hostname with port", "203.0.113.9:54321", "edge.example.net:8443", "edge.example.net"},
+		{"xff single bracketed IPv6 with port", "203.0.113.9:54321", "[2001:db8::7]:9443", "2001:db8::7"},
+		{"xff IPv4-mapped IPv6 with port", "203.0.113.9:54321", "[::ffff:192.0.2.128]:12345", "::ffff:192.0.2.128"},
+		{"xff multiple entries with port", "203.0.113.9:54321", "198.51.100.7:8080, 10.0.0.1:80", "198.51.100.7"},
+		{"xff multiple entries no port", "203.0.113.9:54321", "198.51.100.7, 10.0.0.1", "198.51.100.7"},
+		{"xff first entry empty", "203.0.113.9:54321", ", 198.51.100.7", ""},
+		{"xff first entry has spaces", "203.0.113.9:54321", " \t\r198.51.100.7:8080 ", "198.51.100.7"},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			r := &http.Request{
+				RemoteAddr: tt.remoteAddr,
+				Header:     make(http.Header),
+			}
+			if tt.xff != "" {
+				r.Header.Set("X-Forwarded-For", tt.xff)
+			}
+			got := getRemoteAddr(r)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}