Add iOS BoringSSL script for full TLS override

ios/ios-tls-override.js

@@ -0,0 +1,48 @@
+// Since iOS 11 (2017) Apple has used BoringSSL internally to handle all TLS. This code
+// hooks low-level BoringSSL calls, to override all custom certificate validation options complete.
+// This is a good intro: https://nabla-c0d3.github.io/blog/2019/05/18/ssl-kill-switch-for-ios12/
+
+try {
+    Module.ensureInitialized("libboringssl.dylib");
+} catch (e) {
+    try {
+	    Module.load("libboringssl.dylib");
+    } catch (e) {
+        console.log('Could not load BoringSSL to hook TLS');
+        if (DEBUG_MODE) console.log(e);
+    }
+}
+
+const SSL_VERIFY_NONE = 0x0;
+
+const VerificationCallback = new NativeCallback(function (ssl, out_alert){
+	return SSL_VERIFY_NONE;
+},'int',['pointer','pointer']);
+
+[
+    Module.findExportByName("libboringssl.dylib", "SSL_set_custom_verify"),
+    Module.findExportByName("libboringssl.dylib", "SSL_CTX_set_custom_verify")
+
+].filter(Boolean).forEach((set_custom_verify_addr) => {
+    const set_custom_verify_fn = new NativeFunction(
+        set_custom_verify_addr,
+        'void', ['pointer', 'int', 'pointer']
+    );
+
+    // When this function is called, ignore the provided callback, and
+    // configure our callback instead:
+    Interceptor.replace(set_custom_verify_fn, new NativeCallback(function(ssl, mode, _ignoredProvidedCallback) {
+        set_custom_verify_fn(ssl, mode, VerificationCallback);
+    }, 'void', ['pointer', 'int', 'pointer']));
+});
+
+// Hooking this is apparently required for some verification paths which check the
+// result is not 0x0. Any return value should work fine though.
+const ssl_get_psk_identity = new NativeFunction(
+	Module.findExportByName("libboringssl.dylib", "SSL_get_psk_identity"),
+	'pointer', ['pointer']
+);
+
+Interceptor.replace(ssl_get_psk_identity, new NativeCallback(function(ssl) {
+	return "PSK_IDENTITY_PLACEHOLDER";
+}, 'pointer', ['pointer']));