switch random_get to use crypto.getRandomValues

bjorn3 · May 1, 2024 · 6729ef8 · 6729ef8
1 parent 74f6ce5
commit 6729ef8
Showing 1 changed file with 11 additions and 3 deletions.
diff --git a/src/wasi.ts b/src/wasi.ts
@@ -825,9 +825,17 @@ export default class WASI {
       },
       sched_yield() {},
       random_get(buf: number, buf_len: number) {
-        const buffer8 = new Uint8Array(self.inst.exports.memory.buffer);
-        for (let i = 0; i < buf_len; i++) {
-          buffer8[buf + i] = (Math.random() * 256) | 0;
+        const buffer8 = new Uint8Array(
+          self.inst.exports.memory.buffer,
+        ).subarray(buf, buf + buf_len);
+
+        let i = 0;
+        for (; i < buf_len; ) {
+          const next_i = i + 65_536;
+          globalThis.crypto.getRandomValues(
+            buffer8.subarray(i, next_i > buf_len ? buf_len : next_i),
+          );
+          i = next_i;
         }
       },
       // eslint-disable-next-line @typescript-eslint/no-unused-vars