Share common Frida script startup logic

Author: pimterry

src/interceptors/frida/frida-android-integration.ts

@@ -16,6 +16,7 @@ import {
     FRIDA_DEFAULT_PORT,
     FRIDA_VERSION,
     FridaHost,
+    launchScript,
     testAndSelectProxyAddress
 } from './frida-integration';
 
@@ -204,34 +205,9 @@ export async function interceptAndroidFridaTarget(
             proxyPort
         );
 
-        const scriptSession = await session.createScript(interceptionScript);
-
-        let scriptLoaded = false;
-        await new Promise((resolve, reject) => {
-            session.onMessage((message) => {
-                if (message.type === 'error') {
-                    const error = new Error(message.description);
-                    error.stack = message.stack;
-
-                    if (!scriptLoaded) {
-                        reject(error);
-                    } else {
-                        console.warn('Frida Android injection error:', error);
-                    }
-                } else if (message.type === 'log') {
-                    console.log(`Frida Android [${message.level}]: ${message.payload}`);
-                } else {
-                    console.log(message);
-                }
-            });
-
-            scriptSession.loadScript()
-                .then(resolve)
-                .catch(reject);
-        });
-
-        scriptLoaded = true;
+        await launchScript(`Android (${appId})`, session, interceptionScript);
         await session.resume();
+        console.log(`Frida Android interception started: ${appId} on ${hostId} forwarding to ${proxyIp}:${proxyPort}`);
     } catch (e) {
         // If anything goes wrong, just make sure we shut down the app again
         await session.kill();

src/interceptors/frida/frida-integration.ts

@@ -91,4 +91,42 @@ export async function testAndSelectProxyAddress(
     })).catch((e) => {
         throw new FridaProxyError("No proxy IPs were reachable from the target", e);
     });
+}
+
+/**
+ * Launch a script, watching for errors during its initial exception, and logging any
+ * output or returned messages from the session to the console.
+ *
+ * Note that only one session monitor can be active at any time, so this will replace
+ * any existing session message monitoring.
+ */
+export async function launchScript(targetName: string, session: FridaJs.FridaAgentSession, script: string) {
+    const scriptSession = await session.createScript(script);
+
+    let scriptLoaded = false;
+    await new Promise((resolve, reject) => {
+        session.onMessage((message) => {
+            if (message.type === 'error') {
+                const error = new Error(message.description);
+                error.stack = message.stack;
+
+                if (!scriptLoaded) {
+                    reject(error);
+                } else {
+                    console.warn(`Frida ${targetName} injection error:`, error);
+                }
+            } else if (message.type === 'log') {
+                if (message.payload.trim() === '') return;
+                console.log(`Frida ${targetName} [${message.level}]: ${message.payload}`);
+            } else {
+                console.log(message);
+            }
+        });
+
+        scriptSession.loadScript()
+            .then(resolve)
+            .catch(reject);
+    });
+
+    scriptLoaded = true;
 }

src/interceptors/frida/frida-ios-integration.ts

@@ -6,6 +6,7 @@ import { buildIosFridaScript } from './frida-scripts';
 import {
     FRIDA_DEFAULT_PORT,
     FridaHost,
+    launchScript,
     testAndSelectProxyAddress
 } from './frida-integration';
 
@@ -121,34 +122,9 @@ export async function interceptIosFridaTarget(
             proxyPort
         );
 
-        const scriptSession = await session.createScript(interceptionScript);
-
-        let scriptLoaded = false;
-        await new Promise((resolve, reject) => {
-            session.onMessage((message) => {
-                if (message.type === 'error') {
-                    const error = new Error(message.description);
-                    error.stack = message.stack;
-
-                    if (!scriptLoaded) {
-                        reject(error);
-                    } else {
-                        console.warn('Frida iOS injection error:', error);
-                    }
-                } else if (message.type === 'log') {
-                    console.log(`Frida iOS [${message.level}]: ${message.payload}`);
-                } else {
-                    console.log(message);
-                }
-            });
-
-            scriptSession.loadScript()
-                .then(resolve)
-                .catch(reject);
-        });
-
-        scriptLoaded = true;
+        await launchScript(`iOS (${appId})`, session, interceptionScript);
         await session.resume();
+        console.log(`Frida iOS interception started: ${appId} on ${hostId} forwarding to ${proxyIp}:${proxyPort}`);
     } catch (e) {
         // If anything goes wrong, just make sure we shut down the app again
         await session.kill();