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