Init

2026-04-15 00:47:45 +09:00 · 2025-05-13 22:02:04 +09:00
commit 70fba2b72e
5 changed files with 623 additions and 0 deletions
--- a/webauthn_server.js
+++ b/webauthn_server.js
@@ -0,0 +1,152 @@
+// ==UserScript==
+// @name         WebAuthnOffload
+// @description  
+// @version      1.0
+// @author       @morgan9e
+// @include      *
+// @connect      127.0.0.1
+// @grant        GM_xmlhttpRequest
+// ==/UserScript==
+
+function abb64(buffer) {
+    const bytes = new Uint8Array(buffer);
+    let binary = '';
+    for (let i = 0; i < bytes.byteLength; i++) {
+        binary += String.fromCharCode(bytes[i]);
+    }
+    return btoa(binary)
+        .replace(/\+/g, '-')
+        .replace(/\//g, '_')
+        .replace(/=+$/, '');
+}
+
+function b64ab(input) {
+    const binary = atob(input.replace(/-/g, '+').replace(/_/g, '/'));
+    const bytes = new Uint8Array(binary.length);
+    for (let i = 0; i < binary.length; i++) {
+        bytes[i] = binary.charCodeAt(i);
+    }
+    return bytes.buffer;
+}
+
+function myFetch(url, options = {}) {
+  return new Promise((resolve, reject) => {
+    GM_xmlhttpRequest({
+      method: options.method || 'GET',
+      url: url,
+      headers: options.headers || {},
+      data: options.body || undefined,
+      responseType: options.responseType || 'json',
+      onload: function(response) {
+        const responseObj = {
+          ok: response.status >= 200 && response.status < 300,
+          status: response.status,
+          statusText: response.statusText,
+          headers: response.responseHeaders,
+          text: () => Promise.resolve(response.responseText),
+          json: () => Promise.resolve(JSON.parse(response.responseText)),
+          response: response
+        };
+        resolve(responseObj);
+      },
+      onerror: function(error) {
+        reject(new Error(`Request to ${url} failed`));
+      }
+    });
+  });
+}
+
+const origGet = navigator.credentials.get;
+const origCreate = navigator.credentials.create;
+
+navigator.credentials.get = async function(options) {
+    console.log("navigator.credentials.get", options)
+    try {
+        const authOptions = {publicKey: Object.assign({}, options.publicKey)};
+        console.log(authOptions);
+        authOptions.publicKey.challenge = abb64(authOptions.publicKey.challenge)
+        authOptions.publicKey.allowCredentials = authOptions.publicKey.allowCredentials.map(credential => ({
+            ...credential, id: abb64(credential.id)
+        }));
+        const response = await myFetch('http://127.0.0.1:20492', {
+            method: 'POST',
+            headers: {'Content-Type': 'application/json'},
+            body: JSON.stringify({
+                type: "get",
+                data: { ...authOptions, origin: window.origin }
+            })
+        });
+        if (!response.ok) throw new Error(`server error: ${response.status}`)
+        const resp = await response.json()
+        console.log("server response:", resp)
+        const credential = {
+            id: resp.id,
+            type: resp.type,
+            rawId: b64ab(resp.rawId),
+            response: {
+                authenticatorData: b64ab(resp.response.authenticatorData),
+                clientDataJSON: b64ab(resp.response.clientDataJSON),
+                signature: b64ab(resp.response.signature)
+            },
+            getClientExtensionResults: () => { return {} }
+        }
+        if (resp.response.userHandle) {
+            credential.response.userHandle = b64ab(resp.response.userHandle);
+        }
+        console.log(credential)
+        return credential;
+    } catch (error) {
+        console.error(`Error: ${error.message}, falling back to browser`);
+        let r = await origGet.call(navigator.credentials, options);
+        console.log(r);
+        return r;
+    }
+};
+
+navigator.credentials.create = async function(options) {
+    console.log("navigator.credentials.create", options)
+    try {
+        const authOptions = {publicKey: Object.assign({}, options.publicKey)};
+        console.log(authOptions);
+        authOptions.publicKey.challenge = abb64(authOptions.publicKey.challenge)
+        authOptions.publicKey.user.id = abb64(authOptions.publicKey.user.id)
+        const response = await myFetch('http://127.0.0.1:20492', {
+            method: 'POST',
+            headers: {'Content-Type': 'application/json'},
+            body: JSON.stringify({
+                type: "create",
+                data: { ...authOptions, origin: window.origin }
+            })
+        });
+        if (!response.ok) throw new Error(`server error: ${response.status}`)
+        const resp = await response.json()
+        console.log("server response:", resp)
+        const credential = {
+            id: resp.id,
+            type: resp.type,
+            rawId: b64ab(resp.rawId),
+            response: {
+                attestationObject: b64ab(resp.response.attestationObject),
+                clientDataJSON: b64ab(resp.response.clientDataJSON),
+                pubKeyAlgo: resp.response.pubKeyAlgo,
+                publicKey: b64ab(resp.response.publicKey),
+                transports: resp.response.transports,
+                authenticatorData: b64ab(resp.response.authenticatorData),
+                getAuthenticatorData:() => { return b64ab(resp.response.authenticatorData) },
+                getPublicKey: () => { return b64ab(resp.response.publicKey) },
+                getPublicKeyAlgorithm: () => { return resp.response.pubKeyAlgo },
+                getTransports: () => { return resp.response.transports }
+            },
+            getClientExtensionResults: () => { return {} }
+        }
+        console.log(credential)
+        return credential;
+    } catch (error) {
+        console.error(`Error: ${error.message}, falling back to browser`);
+        let r = await origCreate.call(navigator.credentials, options);
+        console.log(r);
+        return r;
+    }
+};
+
+console.log("Injected WebAuthn")