From 0b34f9528236cc5e00ee126ab6729074927068f2 Mon Sep 17 00:00:00 2001
From: osm0sis <osm0sis@outlook.com>
Date: Mon, 22 Jan 2024 19:03:03 -0400
Subject: [PATCH] Use app data dir to detect GMS package

Prevent injecting into unrelated apps because apps can use whatever process name. This effectively restores df20bdb but with null checks added to prevent crash.

Reference: topjohnwu/Magisk@07c22cc

Co-authored-by: chiteroman <98092901+chiteroman@users.noreply.github.com>
Co-authored-by: Wang Han <416810799@qq.com>
---
 app/src/main/cpp/main.cpp | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/app/src/main/cpp/main.cpp b/app/src/main/cpp/main.cpp
index 1e317bc..b2556c8 100644
--- a/app/src/main/cpp/main.cpp
+++ b/app/src/main/cpp/main.cpp
@@ -93,21 +93,30 @@ public:
         bool isGms = false, isGmsUnstable = false;
 
         auto rawProcess = env->GetStringUTFChars(args->nice_name, nullptr);
+        auto rawDir = env->GetStringUTFChars(args->app_data_dir, nullptr);
 
-        if (rawProcess) {
-            std::string_view process(rawProcess);
-
-            isGms = process.starts_with("com.google.android.gms");
-            isGmsUnstable = process.compare("com.google.android.gms.unstable") == 0;
+        // Prevent crash on apps with no data dir
+        if (rawDir == nullptr) {
+            env->ReleaseStringUTFChars(args->nice_name, rawProcess);
+            api->setOption(zygisk::DLCLOSE_MODULE_LIBRARY);
+            return;
         }
 
+        std::string_view process(rawProcess);
+        std::string_view dir(rawDir);
+
+        isGms = dir.ends_with("/com.google.android.gms");
+        isGmsUnstable = process == "com.google.android.gms.unstable";
+
         env->ReleaseStringUTFChars(args->nice_name, rawProcess);
+        env->ReleaseStringUTFChars(args->app_data_dir, rawDir);
 
         if (!isGms) {
             api->setOption(zygisk::DLCLOSE_MODULE_LIBRARY);
             return;
         }
 
+        // We are in GMS now, force unmount
         api->setOption(zygisk::FORCE_DENYLIST_UNMOUNT);
 
         if (!isGmsUnstable) {
@@ -115,7 +124,9 @@ public:
             return;
         }
 
+        std::vector<char> jsonVector;
         long dexSize = 0, jsonSize = 0;
+
         int fd = api->connectCompanion();
 
         read(fd, &dexSize, sizeof(long));
@@ -135,22 +146,22 @@ public:
             return;
         }
 
+        LOGD("Read from file descriptor for 'dex' -> %ld bytes", dexSize);
+        LOGD("Read from file descriptor for 'json' -> %ld bytes", jsonSize);
+
         dexVector.resize(dexSize);
         read(fd, dexVector.data(), dexSize);
 
-        std::vector<char> jsonVector(jsonSize);
+        jsonVector.resize(jsonSize);
         read(fd, jsonVector.data(), jsonSize);
 
         close(fd);
 
-        LOGD("Read from file descriptor for 'dex' -> %ld bytes", dexSize);
-        LOGD("Read from file descriptor for 'json' -> %ld bytes", jsonSize);
-
-        std::string data(jsonVector.cbegin(), jsonVector.cend());
-        json = nlohmann::json::parse(data, nullptr, false, true);
+        std::string jsonString(jsonVector.cbegin(), jsonVector.cend());
+        json = nlohmann::json::parse(jsonString, nullptr, false, true);
 
         jsonVector.clear();
-        data.clear();
+        jsonString.clear();
     }
 
     void postAppSpecialize(const zygisk::AppSpecializeArgs *args) override {