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🔒 replace insecure Math.random with crypto.getRandomValues for UUID generation #143

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Merged
MarsLuay merged 1 commit into from
Sep 8, 2026
Merged

🔒 replace insecure Math.random with crypto.getRandomValues for UUID generation #143

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24 changes: 20 additions & 4 deletions src/ShapeClipboard.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -217,14 +217,30 @@ function generateOoxmlGuid(): string {
// typeof so the headless test bundle (no DOM globals) falls back cleanly.
const cryptoApi =
(typeof activeWindow !== 'undefined' ? activeWindow.crypto : undefined)
?? (typeof window !== 'undefined' ? window.crypto : undefined);
const uuid = cryptoApi?.randomUUID?.() ?? fallbackUuid();
?? (typeof window !== 'undefined' ? window.crypto : undefined)
?? (typeof crypto !== 'undefined' ? crypto : undefined);
const uuid = cryptoApi?.randomUUID?.() ?? fallbackUuid(cryptoApi);
return `{${uuid.toUpperCase()}}`;
}

function fallbackUuid(): string {
function fallbackUuid(cryptoApi?: Crypto): string {
let bytes: Uint8Array | undefined;
let byteIndex = 0;

if (cryptoApi?.getRandomValues) {
// 30 'x' and 1 'y' character = 31 hex digits to replace
bytes = new Uint8Array(31);
// TypeScript lib typings for `Crypto.getRandomValues` can be strict about `ArrayBuffer` vs `SharedArrayBuffer` depending on the version.
cryptoApi.getRandomValues(bytes as unknown as Uint8Array & { buffer: ArrayBuffer });
}

return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (character) => {
const random = Math.floor(Math.random() * 16);
let random: number;
if (bytes) {
random = bytes[byteIndex++]! % 16;
} else {
random = Math.floor(Math.random() * 16);
}
const value = character === 'x' ? random : (random & 0x3) | 0x8;
return value.toString(16);
});
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