Revert "feat: header based acls (#337)" (#340)

This reverts commit f0d2da281a.

internal/utils/label_utils.go

@@ -0,0 +1,48 @@
+package utils
+
+import (
+	"net/http"
+	"strings"
+	"tinyauth/internal/config"
+
+	"github.com/traefik/paerser/parser"
+)
+
+func GetLabels(labels map[string]string) (config.Labels, error) {
+	var labelsParsed config.Labels
+
+	err := parser.Decode(labels, &labelsParsed, "tinyauth", "tinyauth.apps")
+	if err != nil {
+		return config.Labels{}, err
+	}
+
+	return labelsParsed, nil
+}
+
+func ParseHeaders(headers []string) map[string]string {
+	headerMap := make(map[string]string)
+	for _, header := range headers {
+		split := strings.SplitN(header, "=", 2)
+		if len(split) != 2 || strings.TrimSpace(split[0]) == "" || strings.TrimSpace(split[1]) == "" {
+			continue
+		}
+		key := SanitizeHeader(strings.TrimSpace(split[0]))
+		if strings.ContainsAny(key, " \t") {
+			continue
+		}
+		key = http.CanonicalHeaderKey(key)
+		value := SanitizeHeader(strings.TrimSpace(split[1]))
+		headerMap[key] = value
+	}
+	return headerMap
+}
+
+func SanitizeHeader(header string) string {
+	return strings.Map(func(r rune) rune {
+		// Allow only printable ASCII characters (32-126) and safe whitespace (space, tab)
+		if r == ' ' || r == '\t' || (r >= 32 && r <= 126) {
+			return r
+		}
+		return -1
+	}, header)
+}