From d4167581357fcc65076a32b4872e9ab7495daff4 Mon Sep 17 00:00:00 2001
From: Nullptr <noreply@nullptr.icu>
Date: Thu, 2 Feb 2023 20:51:36 +0800
Subject: [PATCH] Add basic hide

---
 loader/src/injector/deny.hpp   | 52 ----------------------------------
 loader/src/injector/hide.cpp   | 23 +++++++++++++++
 loader/src/injector/hook.cpp   |  2 +-
 loader/src/injector/misc.cpp   | 12 ++++++++
 loader/src/injector/misc.hpp   | 14 +++++----
 loader/src/injector/zygisk.hpp |  2 ++
 6 files changed, 47 insertions(+), 58 deletions(-)
 delete mode 100644 loader/src/injector/deny.hpp
 create mode 100644 loader/src/injector/hide.cpp

diff --git a/loader/src/injector/deny.hpp b/loader/src/injector/deny.hpp
deleted file mode 100644
index 656b1dc..0000000
--- a/loader/src/injector/deny.hpp
+++ /dev/null
@@ -1,52 +0,0 @@
-#pragma once
-
-#include <pthread.h>
-#include <string_view>
-#include <functional>
-#include <map>
-#include <atomic>
-
-#include <daemon.hpp>
-
-#define ISOLATED_MAGIC "isolated"
-
-namespace DenyRequest {
-enum : int {
-    ENFORCE,
-    DISABLE,
-    ADD,
-    REMOVE,
-    LIST,
-    STATUS,
-
-    END
-};
-}
-
-namespace DenyResponse {
-enum : int {
-    OK,
-    ENFORCED,
-    NOT_ENFORCED,
-    ITEM_EXIST,
-    ITEM_NOT_EXIST,
-    INVALID_PKG,
-    NO_NS,
-    ERROR,
-
-    END
-};
-}
-
-// CLI entries
-int enable_deny();
-int disable_deny();
-int add_list(int client);
-int rm_list(int client);
-void ls_list(int client);
-
-// Utility functions
-bool is_deny_target(int uid, std::string_view process);
-void revert_unmount();
-
-extern std::atomic<bool> denylist_enforced;
diff --git a/loader/src/injector/hide.cpp b/loader/src/injector/hide.cpp
new file mode 100644
index 0000000..a3ac031
--- /dev/null
+++ b/loader/src/injector/hide.cpp
@@ -0,0 +1,23 @@
+#include <sys/mount.h>
+
+#include "logging.h"
+#include "misc.hpp"
+#include "zygisk.hpp"
+
+using namespace std::string_view_literals;
+
+static void lazy_unmount(const char* mountpoint) {
+    if (umount2(mountpoint, MNT_DETACH) != -1)
+        LOGD("Unmounted (%s)", mountpoint);
+}
+
+#define OVERLAY_MNT(dir) (mentry->mnt_type == "overlay"sv && std::string_view(mentry->mnt_dir).starts_with("/" #dir))
+
+void revert_unmount() {
+    parse_mnt("/proc/self/mounts", [](mntent* mentry) {
+        if (OVERLAY_MNT("system") || OVERLAY_MNT("vendor") || OVERLAY_MNT("product") || OVERLAY_MNT("system_ext")) {
+            lazy_unmount(mentry->mnt_fsname);
+        }
+        return true;
+    });
+}
diff --git a/loader/src/injector/hook.cpp b/loader/src/injector/hook.cpp
index 8dcebc6..7024036 100644
--- a/loader/src/injector/hook.cpp
+++ b/loader/src/injector/hook.cpp
@@ -193,7 +193,7 @@ DCL_HOOK_FUNC(int, unshare, int flags) {
         // Simply avoid doing any unmounts for SysUI to avoid potential issues.
         (g_ctx->info_flags & PROCESS_IS_SYS_UI) == 0) {
         if (g_ctx->flags[DO_REVERT_UNMOUNT]) {
-            // FIXME: revert_unmount();
+            revert_unmount();
         }
 
         /* Zygisksu changed: No umount app_process */
diff --git a/loader/src/injector/misc.cpp b/loader/src/injector/misc.cpp
index 959c733..d7b5131 100644
--- a/loader/src/injector/misc.cpp
+++ b/loader/src/injector/misc.cpp
@@ -23,6 +23,18 @@ int parse_int(std::string_view s) {
     return val;
 }
 
+void parse_mnt(const char* file, const std::function<bool(mntent*)>& fn) {
+    auto fp = sFILE(setmntent(file, "re"), endmntent);
+    if (fp) {
+        mntent mentry{};
+        char buf[PATH_MAX];
+        while (getmntent_r(fp.get(), &mentry, buf, sizeof(buf))) {
+            if (!fn(&mentry))
+                break;
+        }
+    }
+}
+
 sDIR make_dir(DIR *dp) {
     return sDIR(dp, [](DIR *dp){ return dp ? closedir(dp) : 1; });
 }
diff --git a/loader/src/injector/misc.hpp b/loader/src/injector/misc.hpp
index 6f45852..6d09dce 100644
--- a/loader/src/injector/misc.hpp
+++ b/loader/src/injector/misc.hpp
@@ -1,12 +1,14 @@
 #pragma once
 
-#include <pthread.h>
-#include "logging.h"
 #include <dirent.h>
-#include <stdio.h>
-
-#include <string_view>
+#include <functional>
 #include <memory>
+#include <mntent.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <string_view>
+
+#include "logging.h"
 
 #define DISALLOW_COPY_AND_MOVE(clazz) \
 clazz(const clazz &) = delete; \
@@ -93,6 +95,8 @@ struct StringCmp {
  */
 int parse_int(std::string_view s);
 
+void parse_mnt(const char* file, const std::function<bool(mntent*)>& fn);
+
 template <typename T>
 static inline T align_to(T v, int a) {
     static_assert(std::is_integral<T>::value);
diff --git a/loader/src/injector/zygisk.hpp b/loader/src/injector/zygisk.hpp
index de3673c..addfdea 100644
--- a/loader/src/injector/zygisk.hpp
+++ b/loader/src/injector/zygisk.hpp
@@ -7,3 +7,5 @@
 extern void *self_handle;
 
 void hook_functions();
+
+void revert_unmount();