bind/tls: allow configuring min/max TLS version, ciphers, and curves

The string here uses a character set with path.contains, which will
not work in CEL. We need to use path.matches to use regex syntax.

cmd/go-away/main.go

@@ -210,7 +210,7 @@ func main() {
 			fatal(fmt.Errorf("backend %s: failed to make reverse proxy: %w", k, err))
 		}
 
-		backend.ErrorLog = slog.NewLogLogger(slog.With("backend", k).Handler(), slog.LevelError)
+		backend.ErrorLog = slog.NewLogLogger(slog.With("backend", k).Handler(), slog.LevelDebug)
 		createdBackends[k] = backend
 	}
 
@@ -291,7 +291,7 @@ func main() {
 		fatal(fmt.Errorf("failed to create server: %w", err))
 	}
 
-	server.ErrorLog = slog.NewLogLogger(slog.With("server", "http").Handler(), slog.LevelError)
+	server.ErrorLog = slog.NewLogLogger(slog.With("server", "http").Handler(), slog.LevelDebug)
 
 	go func() {
 		handler, err := loadPolicyState()
@@ -302,6 +302,7 @@ func main() {
 		swap(handler)
 		slog.Warn(
 			"handler configuration loaded",
+			"key_fingerprint", hex.EncodeToString(handler.PrivateKeyFingerprint()),
 		)
 
 		// allow reloading from now on
@@ -336,7 +337,7 @@ func main() {
 			debugServer := http.Server{
 				Addr:     opt.BindDebug,
 				Handler:  mux,
-				ErrorLog: slog.NewLogLogger(slog.With("server", "debug").Handler(), slog.LevelError),
+				ErrorLog: slog.NewLogLogger(slog.With("server", "debug").Handler(), slog.LevelDebug),
 			}
 
 			slog.Warn(
@@ -356,7 +357,7 @@ func main() {
 			metricsServer := http.Server{
 				Addr:     opt.BindMetrics,
 				Handler:  mux,
-				ErrorLog: slog.NewLogLogger(slog.With("server", "metrics").Handler(), slog.LevelError),
+				ErrorLog: slog.NewLogLogger(slog.With("server", "metrics").Handler(), slog.LevelDebug),
 			}
 
 			slog.Warn(

examples/config.yml

@@ -24,7 +24,7 @@ bind:
 #bind-debug: ":6060"
 
 # Bind the Prometheus metrics onto /metrics path on this port
-#bind-metrics ":9090"
+#bind-metrics: ":9090"
 
 # These links will be shown on the presented challenge or error pages
 links:

examples/forgejo.yml

@@ -104,6 +104,15 @@ rules:
       - *is-bot-yandexbot
     action: pass
 
+  # Matches private networks and localhost.
+  # Uncomment this if you want to let your own tools this way
+  #  - name: allow-private-networks
+  #    conditions:
+  #      # Allows localhost and private networks CIDR
+  #      - *is-network-localhost
+  #      - *is-network-private
+  #    action: pass
+
   - name: undesired-networks
     conditions:
       - 'remoteAddress.network("huawei-cloud") || remoteAddress.network("alibaba-cloud") || remoteAddress.network("zenlayer-inc")'
@@ -287,7 +296,7 @@ rules:
         # Map OpenGraph or similar <meta> tags back to the reply, even if denied/challenged
         proxy-meta-tags: "true"
         # proxy-safe-link-tags: "true"
-        
+
       # Set additional response headers
       #response-headers:
       # X-Clacks-Overhead:

examples/generic.yml

@@ -10,7 +10,7 @@ networks:
 
 challenges:
   # Challenges will get included from snippets
-  
+
 conditions:
   # Conditions will get replaced on rules AST when found as ($condition-name)
 
@@ -27,7 +27,7 @@ conditions:
     # Old IE browsers
     - 'userAgent.matches("MSIE ([2-9]|10|11)\\.")'
     # Old Linux browsers
-    - 'userAgent.contains("Linux i[63]86") || userAgent.contains("FreeBSD i[63]86")'
+    - 'userAgent.matches("Linux i[63]86") || userAgent.matches("FreeBSD i[63]86")'
     # Old Windows browsers
     - 'userAgent.matches("Windows (3|95|98|CE)") || userAgent.matches("Windows NT [1-5]\\.")'
     # Old mobile browsers
@@ -60,6 +60,15 @@ rules:
       - *is-bot-yandexbot
     action: pass
 
+  # Matches private networks and localhost.
+  # Uncomment this if you want to let your own tools this way
+  #  - name: allow-private-networks
+  #    conditions:
+  #      # Allows localhost and private networks CIDR
+  #      - *is-network-localhost
+  #      - *is-network-private
+  #    action: pass
+
   - name: undesired-crawlers
     conditions:
       - '($is-headless-chromium)'

examples/snippets/networks-private.yml

@@ -0,0 +1,22 @@
+networks:
+  localhost:
+    # localhost and loopback addresses
+    - prefixes:
+      - "127.0.0.0/8"
+      - "::1/128"
+  private:
+    # Private network CIDR blocks
+    - prefixes:
+        # private networks
+        - "10.0.0.0/8"
+        - "172.16.0.0/12"
+        - "192.168.0.0/16"
+        - "fc00::/7"
+        # CGNAT
+        - "100.64.0.0/10"
+
+conditions:
+  is-network-localhost:
+    - &is-network-localhost 'remoteAddress.network("localhost")'
+  is-network-private:
+    - &is-network-private 'remoteAddress.network("private")'

lib/action/block.go

@@ -28,7 +28,9 @@ func (a Block) Handle(logger *slog.Logger, w http.ResponseWriter, r *http.Reques
 	data := challenge.RequestDataFromContext(r.Context())
 
 	w.Header().Set("Content-Type", "text/plain")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 	w.Header().Set("Connection", "close")
+
 	data.ResponseHeaders(w)
 	w.WriteHeader(a.Code)
 	_, _ = w.Write([]byte(fmt.Errorf("access blocked: blocked by administrative rule %s/%s", data.Id.String(), a.RuleHash).Error()))

lib/action/code.go

@@ -42,7 +42,11 @@ type CodeSettings struct {
 type Code int
 
 func (a Code) Handle(logger *slog.Logger, w http.ResponseWriter, r *http.Request, done func() (backend http.Handler)) (next bool, err error) {
-	challenge.RequestDataFromContext(r.Context()).ResponseHeaders(w)
+	data := challenge.RequestDataFromContext(r.Context())
+
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+
+	data.ResponseHeaders(w)
 
 	w.WriteHeader(int(a))
 	return false, nil

lib/action/drop.go

@@ -33,6 +33,8 @@ func (a Drop) Handle(logger *slog.Logger, w http.ResponseWriter, r *http.Request
 	w.Header().Set("Content-Type", "text/plain")
 	w.Header().Set("Content-Length", "0")
 	w.Header().Set("Connection", "close")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+
 	w.WriteHeader(http.StatusForbidden)
 
 	return false, nil

lib/challenge/data.go

@@ -295,8 +295,8 @@ func (d *RequestData) EvaluateChallenges(w http.ResponseWriter, r *http.Request)
 	challengeMap, err := d.verifyChallengeState()
 	if err != nil {
 		if !errors.Is(err, http.ErrNoCookie) {
-			//clear invalid cookie and continue
-			utils.ClearCookie(d.cookieName, w, r)
+			//queue resend invalid cookie and continue
+			d.challengeMapModified = true
 		}
 		challengeMap = make(TokenChallengeMap)
 	}
@@ -329,6 +329,9 @@ func (d *RequestData) ResponseHeaders(w http.ResponseWriter) {
 	//w.Header().Set("Accept-CH", "Sec-CH-UA, Sec-CH-UA-Platform")
 	//w.Header().Set("Critical-CH", "Sec-CH-UA, Sec-CH-UA-Platform")
 
+	// send Vary header to mark that response may vary based on Cookie values and other client headers
+	w.Header().Set("Vary", "Cookie, Accept, Accept-Encoding, Accept-Language, User-Agent")
+
 	if d.State.Settings().MainName != "" {
 		w.Header().Add("Via", fmt.Sprintf("%s %s@%s", d.r.Proto, d.State.Settings().MainName, d.State.Settings().MainVersion))
 	}

lib/challenge/helper.go

@@ -8,7 +8,9 @@ import (
 	"git.gammaspectra.live/git/go-away/utils"
 	"net/http"
 	"net/url"
+	"strconv"
 	"strings"
+	"time"
 )
 
 var ErrInvalidToken = errors.New("invalid token")
@@ -47,6 +49,7 @@ const (
 	QueryArgRequestId = QueryArgPrefix + "_id"
 	QueryArgChallenge = QueryArgPrefix + "_challenge"
 	QueryArgToken     = QueryArgPrefix + "_token"
+	QueryArgBust      = QueryArgPrefix + "_bust"
 )
 
 const MakeChallengeUrlSuffix = "/make-challenge"
@@ -91,12 +94,13 @@ func VerifyUrl(r *http.Request, reg *Registration, token string) (*url.URL, erro
 	uri.Path = reg.Path + VerifyChallengeUrlSuffix
 
 	data := RequestDataFromContext(r.Context())
-	values := uri.Query()
-	values.Set(QueryArgRequestId, data.Id.String())
-	values.Set(QueryArgRedirect, redirectUrl.String())
-	values.Set(QueryArgToken, token)
-	values.Set(QueryArgChallenge, reg.Name)
-	uri.RawQuery = values.Encode()
+	values, _ := utils.ParseRawQuery(r.URL.RawQuery)
+	values.Set(QueryArgRequestId, url.QueryEscape(data.Id.String()))
+	values.Set(QueryArgRedirect, url.QueryEscape(redirectUrl.String()))
+	values.Set(QueryArgToken, url.QueryEscape(token))
+	values.Set(QueryArgChallenge, url.QueryEscape(reg.Name))
+	values.Set(QueryArgBust, url.QueryEscape(strconv.FormatInt(time.Now().UTC().UnixMilli(), 10)))
+	uri.RawQuery = utils.EncodeRawQuery(values)
 
 	return uri, nil
 }
@@ -108,13 +112,13 @@ func RedirectUrl(r *http.Request, reg *Registration) (*url.URL, error) {
 	}
 
 	data := RequestDataFromContext(r.Context())
-	values := uri.Query()
-	values.Set(QueryArgRequestId, data.Id.String())
+	values, _ := utils.ParseRawQuery(r.URL.RawQuery)
+	values.Set(QueryArgRequestId, url.QueryEscape(data.Id.String()))
 	if ref := r.Referer(); ref != "" {
-		values.Set(QueryArgReferer, r.Referer())
+		values.Set(QueryArgReferer, url.QueryEscape(r.Referer()))
 	}
-	values.Set(QueryArgChallenge, reg.Name)
-	uri.RawQuery = values.Encode()
+	values.Set(QueryArgChallenge, url.QueryEscape(reg.Name))
+	uri.RawQuery = utils.EncodeRawQuery(values)
 
 	return uri, nil
 }

lib/challenge/key.go

@@ -52,15 +52,13 @@ func GetChallengeKeyForRequest(state StateInterface, reg *Registration, until ti
 	hasher.Write([]byte{0})
 
 	// specific headers
-	for _, k := range []string{
-		"Accept-Language",
-		// General browser information
-		"User-Agent",
-		// TODO: not sent in preload
-		//"Sec-Ch-Ua",
-		//"Sec-Ch-Ua-Platform",
-	} {
-		hasher.Write([]byte(r.Header.Get(k)))
+	for _, k := range reg.KeyHeaders {
+		hasher.Write([]byte(k))
+		hasher.Write([]byte{0})
+		for _, v := range r.Header.Values(k) {
+			hasher.Write([]byte(v))
+			hasher.Write([]byte{1})
+		}
 		hasher.Write([]byte{0})
 	}
 	hasher.Write([]byte{0})

lib/challenge/preload-link/preload-link.go

@@ -44,6 +44,9 @@ func FillRegistration(state challenge.StateInterface, reg *challenge.Registratio
 
 	reg.Class = challenge.ClassTransparent
 
+	// some of regular headers are not sent in default headers
+	reg.KeyHeaders = challenge.MinimalKeyHeaders
+
 	ob := challenge.NewAwaiter[string]()
 
 	reg.Object = ob
@@ -66,9 +69,9 @@ func FillRegistration(state challenge.StateInterface, reg *challenge.Registratio
 		}
 
 		// remove redirect args
-		values := uri.Query()
+		values, _ := utils.ParseRawQuery(uri.RawQuery)
 		values.Del(challenge.QueryArgRedirect)
-		uri.RawQuery = values.Encode()
+		uri.RawQuery = utils.EncodeRawQuery(values)
 
 		// Redirect URI must be absolute to work
 		uri.Scheme = utils.GetRequestScheme(r)
@@ -98,6 +101,7 @@ func FillRegistration(state challenge.StateInterface, reg *challenge.Registratio
 
 	mux.HandleFunc("GET "+reg.Path+challenge.VerifyChallengeUrlSuffix, func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/css; charset=utf-8")
+		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 		w.Header().Set("Content-Length", "0")
 
 		data := challenge.RequestDataFromContext(r.Context())

lib/challenge/register.go

@@ -35,6 +35,24 @@ var idCounter Id
 // DefaultDuration TODO: adjust
 const DefaultDuration = time.Hour * 24 * 7
 
+var DefaultKeyHeaders = []string{
+	// General browser information
+	"User-Agent",
+	// Accept headers
+	"Accept-Language",
+	"Accept-Encoding",
+
+	// NOTE: not sent in preload
+	"Sec-Ch-Ua",
+	"Sec-Ch-Ua-Platform",
+}
+
+var MinimalKeyHeaders = []string{
+	"Accept-Language",
+	// General browser information
+	"User-Agent",
+}
+
 func (r Register) Create(state StateInterface, name string, pol policy.Challenge, replacer *strings.Replacer) (*Registration, Id, error) {
 	runtime, ok := Runtimes[pol.Runtime]
 	if !ok {
@@ -42,9 +60,10 @@ func (r Register) Create(state StateInterface, name string, pol policy.Challenge
 	}
 
 	reg := &Registration{
-		Name:     name,
-		Path:     path.Join(state.UrlPath(), "challenge", name),
-		Duration: pol.Duration,
+		Name:       name,
+		Path:       path.Join(state.UrlPath(), "challenge", name),
+		Duration:   pol.Duration,
+		KeyHeaders: DefaultKeyHeaders,
 	}
 
 	if reg.Duration == 0 {
@@ -126,6 +145,9 @@ type Registration struct {
 	Verify            VerifyFunc
 	VerifyProbability float64
 
+	// KeyHeaders The client headers used in key generation, in this order
+	KeyHeaders []string
+
 	// IssueChallenge Issues a challenge to a request.
 	// If Class is ClassTransparent and VerifyResult is !VerifyResult.Ok(), continue with other challenges
 	// TODO: have this return error as well

lib/challenge/resource-load/resource-load.go

@@ -23,9 +23,13 @@ func FillRegistrationHeader(state challenge.StateInterface, reg *challenge.Regis
 			return challenge.VerifyResultFail
 		}
 
+		redirectUri, err := challenge.RedirectUrl(r, reg)
+		if err != nil {
+			return challenge.VerifyResultFail
+		}
 		// self redirect!
 		//TODO: adjust deadline
-		w.Header().Set("Refresh", "2; url="+r.URL.String())
+		w.Header().Set("Refresh", "2; url="+redirectUri.String())
 
 		state.ChallengePage(w, r, state.Settings().ChallengeResponseCode, reg, map[string]any{
 			"LinkTags": []map[string]string{
@@ -44,6 +48,7 @@ func FillRegistrationHeader(state challenge.StateInterface, reg *challenge.Regis
 	mux.HandleFunc("GET "+reg.Path+challenge.VerifyChallengeUrlSuffix, challenge.VerifyHandlerFunc(state, reg, nil, func(state challenge.StateInterface, data *challenge.RequestData, w http.ResponseWriter, r *http.Request, verifyResult challenge.VerifyResult, err error, redirect string) {
 		//TODO: add other types inside css that need to be loaded!
 		w.Header().Set("Content-Type", "text/css; charset=utf-8")
+		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 		w.Header().Set("Content-Length", "0")
 
 		data.ResponseHeaders(w)

lib/challenge/script.go

@@ -23,6 +23,7 @@ func ServeChallengeScript(w http.ResponseWriter, r *http.Request, reg *Registrat
 		//TODO: log
 		panic(err)
 	}
+
 	data.ResponseHeaders(w)
 	w.WriteHeader(http.StatusOK)
 
@@ -30,7 +31,7 @@ func ServeChallengeScript(w http.ResponseWriter, r *http.Request, reg *Registrat
 		"Id":              data.Id.String(),
 		"Path":            reg.Path,
 		"Parameters":      paramData,
-		"Random":          utils.CacheBust(),
+		"Random":          utils.StaticCacheBust(),
 		"Challenge":       reg.Name,
 		"ChallengeScript": script,
 		"Strings":         data.State.Strings(),

lib/challenge/wasm/registration.go

@@ -97,7 +97,7 @@ func FillJavaScriptRegistration(state challenge.StateInterface, reg *challenge.R
 	reg.IssueChallenge = func(w http.ResponseWriter, r *http.Request, key challenge.Key, expiry time.Time) challenge.VerifyResult {
 		state.ChallengePage(w, r, state.Settings().ChallengeResponseCode, reg, map[string]any{
 			"EndTags": []template.HTML{
-				template.HTML(fmt.Sprintf("<script async type=\"module\" src=\"%s?cacheBust=%s\"></script>", reg.Path+"/script.mjs", utils.CacheBust())),
+				template.HTML(fmt.Sprintf("<script async type=\"module\" src=\"%s?cacheBust=%s\"></script>", reg.Path+"/script.mjs", utils.StaticCacheBust())),
 			},
 		})
 		return challenge.VerifyResultNone
@@ -164,6 +164,9 @@ func FillJavaScriptRegistration(state challenge.StateInterface, reg *challenge.R
 				w.Header()[k] = v
 			}
 			w.Header().Set("Content-Length", fmt.Sprintf("%d", len(out.Data)))
+			w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+
+			data.ResponseHeaders(w)
 			w.WriteHeader(out.Code)
 			_, _ = w.Write(out.Data)
 			return nil

lib/http.go

@@ -246,19 +246,20 @@ func (state *State) handleRequest(w http.ResponseWriter, r *http.Request) {
 		if fromChallenge {
 			r.Header.Del("Referer")
 		}
-		q := r.URL.Query()
 
+		q := r.URL.Query()
 		if ref := q.Get(challenge.QueryArgReferer); ref != "" {
 			r.Header.Set("Referer", ref)
 		}
 
+		rawQ, _ := utils.ParseRawQuery(r.URL.RawQuery)
 		// delete query parameters that were set by go-away
-		for k := range q {
+		for k := range rawQ {
 			if strings.HasPrefix(k, challenge.QueryArgPrefix) {
-				q.Del(k)
+				rawQ.Del(k)
 			}
 		}
-		r.URL.RawQuery = q.Encode()
+		r.URL.RawQuery = utils.EncodeRawQuery(rawQ)
 
 		data.ExtraHeaders.Set("X-Away-Rule", ruleName)
 		data.ExtraHeaders.Set("X-Away-Action", string(ruleAction))

lib/settings/bind.go

@@ -13,10 +13,18 @@ import (
 	"net/http"
 	"os"
 	"strconv"
+	"strings"
 	"sync/atomic"
 	"time"
 )
 
+type TLSEntry struct {
+	// Certificate Path to the certificate file
+	Certificate string `yaml:"certificate"`
+	// Key Path to the corresponding key file
+	Key string `yaml:"key"`
+}
+
 type Bind struct {
 	Address    string `yaml:"address"`
 	Network    string `yaml:"network"`
@@ -28,11 +36,35 @@ type Bind struct {
 	// TLSAcmeAutoCert URL to ACME directory, or letsencrypt
 	TLSAcmeAutoCert string `yaml:"tls-acme-autocert"`
 
-	// TLSCertificate Alternate to TLSAcmeAutoCert
+	// TLSEntries Alternate to TLSAcmeAutoCert. Allows multiple entries with matching.
+	// Entries on this list can be live-reloaded if application implements SIGHUP handling
+	TLSEntries []TLSEntry `yaml:"tls-entries"`
+
+	// TLSCertificate Alternate to TLSAcmeAutoCert. Preferred over TLSEntries if specified.
 	TLSCertificate string `yaml:"tls-certificate"`
-	// TLSPrivateKey Alternate to TLSAcmeAutoCert
+	// TLSPrivateKey Alternate to TLSAcmeAutoCert. Preferred over TLSEntries if specified.
 	TLSPrivateKey string `yaml:"tls-key"`
 
+	// General TLS config
+	// TLSMinVersion TLS Minimum supported version.
+	// Default is Golang's default, at writing time it's TLS 1.2. Lowest supported is TLS 1.0
+	TLSMinVersion string `yaml:"tls-min-version"`
+
+	// TLSMaxVersion TLS Maximum supported version.
+	// Default is Golang's default, at writing time it's TLS 1.3, and is automatically increased.
+	// Lowest supported is TLS 1.2
+	TLSMaxVersion string `yaml:"tls-max-version"`
+
+	// TLSCurves List of supported TLS curve ids from Golang internals
+	// See this list https://github.com/golang/go/blob/go1.24.0/src/crypto/tls/common.go#L138-L153 for supported values
+	// Default values are chosen by Golang. It's recommended to leave the default
+	TLSCurves []tls.CurveID `yaml:"tls-curves"`
+
+	// TLSCiphers List of supported TLS ciphers from Golang internals, case sensitive. TLS 1.3 suites are not configurable.
+	// See this list https://github.com/golang/go/blob/go1.24.0/src/crypto/tls/cipher_suites.go#L56-L73 for supported values
+	// Default values are chosen by Golang. It's recommended to leave the default
+	TLSCiphers []string `yaml:"tls-ciphers"`
+
 	// ReadTimeout is the maximum duration for reading the entire
 	// request, including the body. A zero or negative value means
 	// there will be no timeout.
@@ -104,6 +136,105 @@ func (b *Bind) Server(backends map[string]http.Handler, acmeCachePath string) (*
 			"TLS enabled",
 			"certificate", b.TLSCertificate,
 		)
+	} else if len(b.TLSEntries) > 0 {
+		tlsConfig = &tls.Config{}
+		var err error
+
+		var certificatesPtr atomic.Pointer[[]tls.Certificate]
+
+		swapTls := func() error {
+			certs := make([]tls.Certificate, 0, len(b.TLSEntries))
+			for _, entry := range b.TLSEntries {
+				cert, err := tls.LoadX509KeyPair(entry.Certificate, entry.Key)
+				if err != nil {
+					return fmt.Errorf("failed to load TLS certificate %s: %w", entry.Certificate, err)
+				}
+				certs = append(certs, cert)
+			}
+			certificatesPtr.Swap(&certs)
+			return nil
+		}
+
+		tlsConfig.GetCertificate = func(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
+			certs := certificatesPtr.Load()
+
+			if certs == nil || len(*certs) == 0 {
+				panic("no certificates found")
+			}
+
+			for _, cert := range *certs {
+				if err := clientHello.SupportsCertificate(&cert); err == nil {
+					return &cert, nil
+				}
+			}
+
+			// if none match, return first
+			return &(*certs)[0], nil
+		}
+
+		err = swapTls()
+		if err != nil {
+			return nil, nil, err
+		}
+
+		slog.Warn(
+			"TLS enabled with multiple certificates",
+			"certificates", len(b.TLSEntries),
+		)
+	}
+
+	if tlsConfig != nil {
+		if b.TLSMinVersion != "" {
+			switch strings.NewReplacer("-", "", "_", "", " ", "", ".", "").Replace(strings.ToLower(b.TLSMinVersion)) {
+			case "13", "tls13":
+				tlsConfig.MinVersion = tls.VersionTLS13
+			case "12", "tls12":
+				tlsConfig.MinVersion = tls.VersionTLS12
+			case "11", "tls11":
+				tlsConfig.MinVersion = tls.VersionTLS11
+			case "10", "tls10":
+				tlsConfig.MinVersion = tls.VersionTLS10
+			default:
+				return nil, nil, fmt.Errorf("unsupported minimum TLS version: %s", b.TLSMinVersion)
+			}
+		}
+
+		if b.TLSMaxVersion != "" {
+			switch strings.NewReplacer("-", "", "_", "", " ", "", ".", "").Replace(strings.ToLower(b.TLSMaxVersion)) {
+			case "13", "tls13":
+				tlsConfig.MaxVersion = tls.VersionTLS13
+			case "12", "tls12":
+				tlsConfig.MaxVersion = tls.VersionTLS12
+			default:
+				return nil, nil, fmt.Errorf("unsupported maximum TLS version: %s", b.TLSMinVersion)
+			}
+		}
+
+		if len(b.TLSCiphers) > 0 {
+			for _, cipher := range b.TLSCiphers {
+				if c := func() *tls.CipherSuite {
+					for _, c := range tls.CipherSuites() {
+						if c.Name == cipher {
+							return c
+						}
+					}
+					for _, c := range tls.InsecureCipherSuites() {
+						if c.Name == cipher {
+							return c
+						}
+					}
+					return nil
+				}(); c != nil {
+					tlsConfig.CipherSuites = append(tlsConfig.CipherSuites, c.ID)
+				} else {
+					return nil, nil, fmt.Errorf("unsupported TLS cipher suite: %s", cipher)
+				}
+			}
+		}
+
+		if len(b.TLSCurves) > 0 {
+			tlsConfig.CurvePreferences = append(tlsConfig.CurvePreferences, b.TLSCurves...)
+		}
 	}
 
 	var serverHandler atomic.Pointer[http.Handler]

lib/state.go

@@ -114,9 +114,9 @@ func NewState(p policy.Policy, opt settings.Settings, settings policy.StateSetti
 				return nil, fmt.Errorf("error loading template %s: %w", state.opt.ChallengeTemplate, err)
 			}
 			state.opt.ChallengeTemplate = name
+		} else {
+			return nil, fmt.Errorf("no template defined for %s", state.opt.ChallengeTemplate)
 		}
-
-		return nil, fmt.Errorf("no template defined for %s", state.opt.ChallengeTemplate)
 	}
 
 	state.networks = make(map[string]func() cidranger.Ranger)

lib/template.go

@@ -78,7 +78,7 @@ func (state *State) ChallengePage(w http.ResponseWriter, r *http.Request, status
 	data := challenge.RequestDataFromContext(r.Context())
 	input := make(map[string]any)
 	input["Id"] = data.Id.String()
-	input["Random"] = utils.CacheBust()
+	input["Random"] = utils.StaticCacheBust()
 
 	input["Path"] = state.UrlPath()
 	input["Links"] = state.opt.Links
@@ -100,6 +100,7 @@ func (state *State) ChallengePage(w http.ResponseWriter, r *http.Request, status
 	state.addCachedTags(data, r, input)
 
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 
 	buf := bytes.NewBuffer(make([]byte, 0, 8192))
 
@@ -116,12 +117,13 @@ func (state *State) ChallengePage(w http.ResponseWriter, r *http.Request, status
 func (state *State) ErrorPage(w http.ResponseWriter, r *http.Request, status int, err error, redirect string) {
 	data := challenge.RequestDataFromContext(r.Context())
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 
 	buf := bytes.NewBuffer(make([]byte, 0, 8192))
 
 	input := map[string]any{
 		"Id":        data.Id.String(),
-		"Random":    utils.CacheBust(),
+		"Random":    utils.StaticCacheBust(),
 		"Error":     err.Error(),
 		"Path":      state.UrlPath(),
 		"Theme":     "",

utils/http.go

@@ -7,11 +7,13 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
+	"maps"
 	"net"
 	"net/http"
 	"net/http/httputil"
 	"net/netip"
 	"net/url"
+	"slices"
 	"strings"
 	"time"
 )
@@ -167,15 +169,51 @@ func GetRemoteAddress(ctx context.Context) *netip.AddrPort {
 	return &ip
 }
 
-func CacheBust() string {
-	return cacheBust
-}
-
-var cacheBust string
-
-func init() {
-
-	buf := make([]byte, 16)
+func RandomCacheBust(n int) string {
+	buf := make([]byte, n)
 	_, _ = rand.Read(buf)
-	cacheBust = base64.RawURLEncoding.EncodeToString(buf)
+	return base64.RawURLEncoding.EncodeToString(buf)
+}
+
+var staticCacheBust = RandomCacheBust(16)
+
+func StaticCacheBust() string {
+	return staticCacheBust
+}
+
+func ParseRawQuery(rawQuery string) (m url.Values, err error) {
+	m = make(url.Values)
+	for rawQuery != "" {
+		var key string
+		key, rawQuery, _ = strings.Cut(rawQuery, "&")
+		if strings.Contains(key, ";") {
+			err = fmt.Errorf("invalid semicolon separator in query")
+			continue
+		}
+		if key == "" {
+			continue
+		}
+		key, value, _ := strings.Cut(key, "=")
+		m[key] = append(m[key], value)
+	}
+	return m, err
+}
+
+func EncodeRawQuery(v url.Values) string {
+	if len(v) == 0 {
+		return ""
+	}
+	var buf strings.Builder
+	for _, k := range slices.Sorted(maps.Keys(v)) {
+		vs := v[k]
+		for _, v := range vs {
+			if buf.Len() > 0 {
+				buf.WriteByte('&')
+			}
+			buf.WriteString(k)
+			buf.WriteByte('=')
+			buf.WriteString(v)
+		}
+	}
+	return buf.String()
 }