78 lines
2.4 KiB
Go
78 lines
2.4 KiB
Go
package main
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import (
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"fmt"
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"log"
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"net/http"
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"os"
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"path/filepath"
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"strings"
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)
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const maxAdminRequestBody = 8 << 20
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func writeInternalError(w http.ResponseWriter, operation string, err error) {
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if err != nil {
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log.Printf("%s: %v", operation, err)
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}
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http.Error(w, "internal server error", http.StatusInternalServerError)
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}
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func writeBadGatewayError(w http.ResponseWriter, operation string, err error) {
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if err != nil {
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log.Printf("%s: %v", operation, err)
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}
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http.Error(w, "managed server request failed", http.StatusBadGateway)
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}
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// securePanelHandler applies baseline browser protections and a global request
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// body ceiling. Endpoint-specific handlers may impose a smaller limit.
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func securePanelHandler(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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w.Header().Set("X-Content-Type-Options", "nosniff")
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w.Header().Set("X-Frame-Options", "DENY")
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w.Header().Set("Referrer-Policy", "no-referrer")
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w.Header().Set("Permissions-Policy", "camera=(), microphone=(), geolocation=(), payment=()")
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w.Header().Set("Cross-Origin-Opener-Policy", "same-origin")
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w.Header().Set("Content-Security-Policy", "default-src 'self'; base-uri 'none'; frame-ancestors 'none'; object-src 'none'; form-action 'self'; img-src 'self' data:; connect-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline'")
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if strings.HasPrefix(r.URL.Path, "/api/") || r.URL.Path == "/" || r.URL.Path == "/index.html" {
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w.Header().Set("Cache-Control", "no-store")
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}
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if r.Body != nil && r.Method != http.MethodGet && r.Method != http.MethodHead {
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r.Body = http.MaxBytesReader(w, r.Body, maxAdminRequestBody)
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}
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next.ServeHTTP(w, r)
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})
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}
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// writeFileAtomic replaces a sensitive configuration file without leaving a
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// partially written file behind after a crash or interrupted request.
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func writeFileAtomic(path string, data []byte, mode os.FileMode) error {
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dir := filepath.Dir(path)
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tmp, err := os.CreateTemp(dir, ".dragoncore-*.tmp")
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if err != nil {
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return err
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}
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tmpName := tmp.Name()
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defer os.Remove(tmpName)
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if err := tmp.Chmod(mode); err != nil {
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tmp.Close()
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return err
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}
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if _, err := tmp.Write(data); err != nil {
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tmp.Close()
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return err
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}
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if err := tmp.Sync(); err != nil {
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tmp.Close()
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return err
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}
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if err := tmp.Close(); err != nil {
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return err
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}
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if err := os.Rename(tmpName, path); err != nil {
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return fmt.Errorf("replace %s: %w", path, err)
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}
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return nil
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}
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