Argon2: avoid loading multiple wasm modules on first initialisation (#7)

ProtonMail · Nov 21, 2023 · d1550c5 · d1550c5
1 parent a642edf
commit d1550c5
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Showing 3 changed files with 15 additions and 12 deletions.
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -66,7 +66,7 @@
     "@rollup/plugin-replace": "^2.3.2",
     "@rollup/plugin-wasm": "^6.1.2",
     "@types/chai": "^4.2.14",
-    "argon2id": "^1.0.0",
+    "argon2id": "^1.0.1",
     "benchmark": "^2.1.4",
     "bn.js": "^4.11.8",
     "chai": "^4.3.6",

diff --git a/src/type/s2k/argon2.js b/src/type/s2k/argon2.js
@@ -91,10 +91,12 @@ class Argon2S2K {
     const decodedM = 2 << (this.encodedM - 1);
 
     try {
-      if (!argon2Promise) { // first load
-        loadArgonWasmModule = loadArgonWasmModule || (await import('argon2id')).default;
-        argon2Promise = loadArgonWasmModule();
-      }
+      // on first load, the argon2 lib is imported and the WASM module is initialized.
+      // the two steps need to be atomic to avoid race conditions causing multiple wasm modules
+      // being loaded when `argon2Promise` is not initialized.
+      loadArgonWasmModule = loadArgonWasmModule || (await import('argon2id')).default;
+      argon2Promise = argon2Promise || loadArgonWasmModule();
+
       // important to keep local ref to argon2 in case the module is reloaded by another instance
       const argon2 = await argon2Promise;
 
@@ -114,6 +116,7 @@ class Argon2S2K {
       if (decodedM > ARGON2_WASM_MEMORY_THRESHOLD_RELOAD) {
         // it will be awaited if needed at the next `produceKey` invocation
         argon2Promise = loadArgonWasmModule();
+        argon2Promise.catch(() => {});
       }
       return hash;
     } catch (e) {