samsa/internal/middleware/security.go
Franz Kafka a9ae69cad5
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fix(security): allow HTMX CDN and inline scripts in CSP
script-src now permits 'unsafe-inline' and https://unpkg.com so the
autocomplete script and HTMX library load correctly.
2026-03-22 17:22:31 +00:00

92 lines
2.6 KiB
Go

// kafka — a privacy-respecting metasearch engine
// Copyright (C) 2026-present metamorphosis-dev
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
package middleware
import (
"net/http"
"strconv"
"strings"
)
// SecurityHeadersConfig controls which security headers are set.
type SecurityHeadersConfig struct {
// FrameOptions controls X-Frame-Options. Default: "DENY".
FrameOptions string
// HSTSMaxAge controls the max-age for Strict-Transport-Security.
// Set to 0 to disable HSTS (useful for local dev). Default: 31536000 (1 year).
HSTSMaxAge int
// HSTSPreloadDomains adds "includeSubDomains; preload" to HSTS.
HSTSPreloadDomains bool
// ReferrerPolicy controls the Referrer-Policy header. Default: "no-referrer".
ReferrerPolicy string
// CSP controls Content-Security-Policy. Default: a restrictive policy.
// Set to "" to disable CSP entirely.
CSP string
}
// SecurityHeaders returns middleware that sets standard HTTP security headers
// on every response.
func SecurityHeaders(cfg SecurityHeadersConfig) func(http.Handler) http.Handler {
frameOpts := cfg.FrameOptions
if frameOpts == "" {
frameOpts = "DENY"
}
hstsAge := cfg.HSTSMaxAge
if hstsAge == 0 {
hstsAge = 31536000 // 1 year
}
refPol := cfg.ReferrerPolicy
if refPol == "" {
refPol = "no-referrer"
}
csp := cfg.CSP
if csp == "" {
csp = defaultCSP()
}
hstsValue := "max-age=" + strconv.Itoa(hstsAge)
if cfg.HSTSPreloadDomains {
hstsValue += "; includeSubDomains; preload"
}
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("X-Content-Type-Options", "nosniff")
w.Header().Set("X-Frame-Options", frameOpts)
w.Header().Set("Referrer-Policy", refPol)
w.Header().Set("Permissions-Policy", "camera=(), microphone=(), geolocation=()")
w.Header().Set("Content-Security-Policy", csp)
if hstsAge > 0 {
w.Header().Set("Strict-Transport-Security", hstsValue)
}
next.ServeHTTP(w, r)
})
}
}
// defaultCSP returns a restrictive Content-Security-Policy for the
// metasearch engine.
func defaultCSP() string {
return strings.Join([]string{
"default-src 'self'",
"script-src 'self' 'unsafe-inline' https://unpkg.com",
"style-src 'self' 'unsafe-inline'",
"img-src 'self' https: data:",
"connect-src 'self'",
"font-src 'self'",
"frame-ancestors 'none'",
"base-uri 'self'",
"form-action 'self'",
}, "; ")
}