From ed37ddd57099226081d2641e139eb32d0e945a5f Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Tue, 22 Nov 2022 14:19:40 -0800
Subject: [PATCH] Stricter validation

---
 native/src/zygisk/hook.cpp   | 21 +++++++++++++++++++++
 native/src/zygisk/module.hpp |  4 +---
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/native/src/zygisk/hook.cpp b/native/src/zygisk/hook.cpp
index 8bd1728f1..9dd9b7457 100644
--- a/native/src/zygisk/hook.cpp
+++ b/native/src/zygisk/hook.cpp
@@ -313,6 +313,9 @@ ZygiskModule::ZygiskModule(int id, void *handle, void *entry)
 }
 
 bool ZygiskModule::RegisterModuleImpl(ApiTable *api, long *module) {
+    if (api == nullptr || module == nullptr)
+        return false;
+
     long api_version = *module;
     // Unsupported version
     if (api_version > ZYGISK_API_VERSION)
@@ -355,6 +358,24 @@ bool ZygiskModule::RegisterModuleImpl(ApiTable *api, long *module) {
     return true;
 }
 
+bool ZygiskModule::valid() const {
+    if (mod.api_version == nullptr)
+        return false;
+    switch (*mod.api_version) {
+    case 4:
+        // fallthrough
+    case 3:
+        // fallthrough
+    case 2:
+        // fallthrough
+    case 1:
+        return mod.v1->impl && mod.v1->preAppSpecialize && mod.v1->postAppSpecialize &&
+            mod.v1->preServerSpecialize && mod.v1->postServerSpecialize;
+    default:
+        return false;
+    }
+}
+
 int ZygiskModule::connectCompanion() const {
     if (int fd = zygisk_request(ZygiskRequest::CONNECT_COMPANION); fd >= 0) {
         write_int(fd, id);
diff --git a/native/src/zygisk/module.hpp b/native/src/zygisk/module.hpp
index 9ee41a498..bab594ea0 100644
--- a/native/src/zygisk/module.hpp
+++ b/native/src/zygisk/module.hpp
@@ -180,10 +180,8 @@ struct ZygiskModule {
     void postServerSpecialize(const ServerSpecializeArgs_v1 *args) const {
         mod.v1->postServerSpecialize(mod.v1->impl, args);
     }
-    bool valid() const {
-        return entry.fn && mod.api_version;
-    }
 
+    bool valid() const;
     int connectCompanion() const;
     int getModuleDir() const;
     void setOption(zygisk::Option opt);