45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
|
package secure
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
"crypto/rand"
|
||
|
|
"encoding/base64"
|
||
|
|
"io"
|
||
|
|
"net/http"
|
||
|
|
)
|
||
|
|
|
||
|
|
type key int
|
||
|
|
|
||
|
|
const cspNonceKey key = iota
|
||
|
|
|
||
|
|
// CSPNonce returns the nonce value associated with the present request. If no nonce has been generated it returns an empty string.
|
||
|
|
func CSPNonce(c context.Context) string {
|
||
|
|
if val, ok := c.Value(cspNonceKey).(string); ok {
|
||
|
|
return val
|
||
|
|
}
|
||
|
|
|
||
|
|
return ""
|
||
|
|
}
|
||
|
|
|
||
|
|
// WithCSPNonce returns a context derived from ctx containing the given nonce as a value.
|
||
|
|
//
|
||
|
|
// This is intended for testing or more advanced use-cases;
|
||
|
|
// For ordinary HTTP handlers, clients can rely on this package's middleware to populate the CSP nonce in the context.
|
||
|
|
func WithCSPNonce(ctx context.Context, nonce string) context.Context {
|
||
|
|
return context.WithValue(ctx, cspNonceKey, nonce)
|
||
|
|
}
|
||
|
|
|
||
|
|
func withCSPNonce(r *http.Request, nonce string) *http.Request {
|
||
|
|
return r.WithContext(WithCSPNonce(r.Context(), nonce))
|
||
|
|
}
|
||
|
|
|
||
|
|
func cspRandNonce() string {
|
||
|
|
var buf [cspNonceSize]byte
|
||
|
|
_, err := io.ReadFull(rand.Reader, buf[:])
|
||
|
|
if err != nil {
|
||
|
|
panic("CSP Nonce rand.Reader failed" + err.Error())
|
||
|
|
}
|
||
|
|
|
||
|
|
return base64.RawStdEncoding.EncodeToString(buf[:])
|
||
|
|
}
|