Added content security policy structure

- Added content security policy header generators structure (current not in used)

src/mod/dynamicproxy/permissionpolicy/contentsecuritypolicy.go

@@ -0,0 +1,123 @@
+package permissionpolicy
+
+import (
+	"net/http"
+	"strings"
+)
+
+/*
+	Content Security Policy
+
+	This is a content security policy header modifier that changes
+	the request content security policy fields
+
+	author: tobychui
+
+	//TODO: intergrate this with the dynamic proxy module
+*/
+
+type ContentSecurityPolicy struct {
+	DefaultSrc              []string `json:"default_src"`
+	ScriptSrc               []string `json:"script_src"`
+	StyleSrc                []string `json:"style_src"`
+	ImgSrc                  []string `json:"img_src"`
+	ConnectSrc              []string `json:"connect_src"`
+	FontSrc                 []string `json:"font_src"`
+	ObjectSrc               []string `json:"object_src"`
+	MediaSrc                []string `json:"media_src"`
+	FrameSrc                []string `json:"frame_src"`
+	WorkerSrc               []string `json:"worker_src"`
+	ChildSrc                []string `json:"child_src"`
+	ManifestSrc             []string `json:"manifest_src"`
+	PrefetchSrc             []string `json:"prefetch_src"`
+	FormAction              []string `json:"form_action"`
+	FrameAncestors          []string `json:"frame_ancestors"`
+	BaseURI                 []string `json:"base_uri"`
+	Sandbox                 []string `json:"sandbox"`
+	ReportURI               []string `json:"report_uri"`
+	ReportTo                []string `json:"report_to"`
+	UpgradeInsecureRequests bool     `json:"upgrade_insecure_requests"`
+	BlockAllMixedContent    bool     `json:"block_all_mixed_content"`
+}
+
+// GetDefaultContentSecurityPolicy returns a ContentSecurityPolicy struct with default permissive settings
+func GetDefaultContentSecurityPolicy() *ContentSecurityPolicy {
+	return &ContentSecurityPolicy{
+		DefaultSrc:              []string{"*"},
+		ScriptSrc:               []string{"*"},
+		StyleSrc:                []string{"*"},
+		ImgSrc:                  []string{"*"},
+		ConnectSrc:              []string{"*"},
+		FontSrc:                 []string{"*"},
+		ObjectSrc:               []string{"*"},
+		MediaSrc:                []string{"*"},
+		FrameSrc:                []string{"*"},
+		WorkerSrc:               []string{"*"},
+		ChildSrc:                []string{"*"},
+		ManifestSrc:             []string{"*"},
+		PrefetchSrc:             []string{"*"},
+		FormAction:              []string{"*"},
+		FrameAncestors:          []string{"*"},
+		BaseURI:                 []string{"*"},
+		Sandbox:                 []string{},
+		ReportURI:               []string{},
+		ReportTo:                []string{},
+		UpgradeInsecureRequests: false,
+		BlockAllMixedContent:    false,
+	}
+}
+
+// ToHeader converts a ContentSecurityPolicy struct into a CSP header key-value pair
+func (csp *ContentSecurityPolicy) ToHeader() []string {
+	directives := []string{}
+
+	addDirective := func(name string, sources []string) {
+		if len(sources) > 0 {
+			directives = append(directives, name+" "+strings.Join(sources, " "))
+		}
+	}
+
+	addDirective("default-src", csp.DefaultSrc)
+	addDirective("script-src", csp.ScriptSrc)
+	addDirective("style-src", csp.StyleSrc)
+	addDirective("img-src", csp.ImgSrc)
+	addDirective("connect-src", csp.ConnectSrc)
+	addDirective("font-src", csp.FontSrc)
+	addDirective("object-src", csp.ObjectSrc)
+	addDirective("media-src", csp.MediaSrc)
+	addDirective("frame-src", csp.FrameSrc)
+	addDirective("worker-src", csp.WorkerSrc)
+	addDirective("child-src", csp.ChildSrc)
+	addDirective("manifest-src", csp.ManifestSrc)
+	addDirective("prefetch-src", csp.PrefetchSrc)
+	addDirective("form-action", csp.FormAction)
+	addDirective("frame-ancestors", csp.FrameAncestors)
+	addDirective("base-uri", csp.BaseURI)
+	if len(csp.Sandbox) > 0 {
+		directives = append(directives, "sandbox "+strings.Join(csp.Sandbox, " "))
+	}
+	if len(csp.ReportURI) > 0 {
+		addDirective("report-uri", csp.ReportURI)
+	}
+	if len(csp.ReportTo) > 0 {
+		addDirective("report-to", csp.ReportTo)
+	}
+	if csp.UpgradeInsecureRequests {
+		directives = append(directives, "upgrade-insecure-requests")
+	}
+	if csp.BlockAllMixedContent {
+		directives = append(directives, "block-all-mixed-content")
+	}
+
+	headerValue := strings.Join(directives, "; ")
+	return []string{"Content-Security-Policy", headerValue}
+}
+
+// InjectContentSecurityPolicyHeader injects the CSP header into the response
+func InjectContentSecurityPolicyHeader(w http.ResponseWriter, csp *ContentSecurityPolicy) {
+	if csp == nil || w.Header().Get("Content-Security-Policy") != "" {
+		return
+	}
+	headerKV := csp.ToHeader()
+	w.Header().Set(headerKV[0], headerKV[1])
+}