DenyList unmount without magiskd

native/jni/zygisk/deny/deny.hpp

@@ -20,9 +20,7 @@ void ls_list(int client);
 // Utility functions
 bool is_deny_target(int uid, std::string_view process);
 
-// Revert
-void revert_daemon(int pid, int client);
-void revert_unmount(int pid = -1);
+void revert_unmount();
 
 extern std::atomic<bool> denylist_enabled;
 extern int cached_manager_app_id;

native/jni/zygisk/deny/revert.cpp

@@ -2,8 +2,6 @@
 
 #include <magisk.hpp>
 #include <utils.hpp>
-#include <selinux.hpp>
-#include <resetprop.hpp>
 
 #include "deny.hpp"
 
@@ -14,23 +12,9 @@ static void lazy_unmount(const char* mountpoint) {
         LOGD("denylist: Unmounted (%s)\n", mountpoint);
 }
 
-void revert_daemon(int pid, int client) {
-    if (fork_dont_care() == 0) {
-        revert_unmount(pid);
-        write_int(client, 0);
-        _exit(0);
-    }
-}
-
 #define TMPFS_MNT(dir) (mentry->mnt_type == "tmpfs"sv && str_starts(mentry->mnt_dir, "/" #dir))
 
-void revert_unmount(int pid) {
-    if (pid > 0) {
-        if (switch_mnt_ns(pid))
-            return;
-        LOGD("denylist: handling PID=[%d]\n", pid);
-    }
-
+void revert_unmount() {
     vector<string> targets;
 
     // Unmount dummy skeletons and MAGISKTMP

native/jni/zygisk/entry.cpp

@@ -202,17 +202,6 @@ std::vector<int> remote_get_info(int uid, const char *process, AppInfo *info) {
     return fds;
 }
 
-int remote_request_unmount() {
-    if (int fd = connect_daemon(); fd >= 0) {
-        write_int(fd, ZYGISK_REQUEST);
-        write_int(fd, ZYGISK_UNMOUNT);
-        int ret = read_int(fd);
-        close(fd);
-        return ret;
-    }
-    return DAEMON_ERROR;
-}
-
 // The following code runs in magiskd
 
 static bool get_exe(int pid, char *buf, size_t sz) {
@@ -373,15 +362,6 @@ static void get_process_info(int client, const sock_cred *cred) {
     }
 }
 
-static void do_unmount(int client, const sock_cred *cred) {
-    if (denylist_enabled) {
-        LOGD("zygisk: cleanup mount namespace for pid=[%d]\n", cred->pid);
-        revert_daemon(cred->pid, client);
-    } else {
-        write_int(client, DENY_NOT_ENFORCED);
-    }
-}
-
 static void send_log_pipe(int fd) {
     // There is race condition here, but we can't really do much about it...
     if (logd_fd >= 0) {
@@ -405,9 +385,6 @@ void zygisk_handler(int client, const sock_cred *cred) {
     case ZYGISK_GET_INFO:
         get_process_info(client, cred);
         break;
-    case ZYGISK_UNMOUNT:
-        do_unmount(client, cred);
-        break;
     case ZYGISK_GET_LOG_PIPE:
         send_log_pipe(client);
         break;

native/jni/zygisk/hook.cpp

@@ -10,6 +10,7 @@
 #include "zygisk.hpp"
 #include "memory.hpp"
 #include "module.hpp"
+#include "deny/deny.hpp"
 
 using namespace std;
 using jni_hook::hash_map;
@@ -50,7 +51,6 @@ struct HookContext {
     HookContext() : pid(-1), info{} {}
 
     static void close_fds();
-    void toggle_unmount();
 
     DCL_PRE_POST(fork)
     void run_modules_pre(const vector<int> &fds);
@@ -144,25 +144,18 @@ DCL_HOOK_FUNC(int, fork) {
     return (g_ctx && g_ctx->pid >= 0) ? g_ctx->pid : old_fork();
 }
 
-// Unmount app_process overlays in the process's private mount namespace
+// Unmount stuffs in the process's private mount namespace
 DCL_HOOK_FUNC(int, unshare, int flags) {
     int res = old_unshare(flags);
     if (g_ctx && res == 0) {
-        umount2("/system/bin/app_process64", MNT_DETACH);
-        umount2("/system/bin/app_process32", MNT_DETACH);
-    }
-    return res;
-}
-
-// This is the latest point where we can still connect to the magiskd main socket
-DCL_HOOK_FUNC(int, selinux_android_setcontext,
-        uid_t uid, int isSystemServer, const char *seinfo, const char *pkgname) {
-    if (g_ctx && g_ctx->flags[UNMOUNT_FLAG]) {
-        if (remote_request_unmount() == 0) {
-            ZLOGD("mount namespace cleaned up\n");
+        if (g_ctx->flags[UNMOUNT_FLAG]) {
+            revert_unmount();
+        } else {
+            umount2("/system/bin/app_process64", MNT_DETACH);
+            umount2("/system/bin/app_process32", MNT_DETACH);
         }
     }
-    return old_selinux_android_setcontext(uid, isSystemServer, seinfo, pkgname);
+    return res;
 }
 
 // A place to clean things up before calling into zygote::ForkCommon/SpecializeCommon
@@ -313,7 +306,7 @@ void ZygiskModule::setOption(zygisk::Option opt) {
         return;
     switch (opt) {
     case zygisk::FORCE_DENYLIST_UNMOUNT:
-        g_ctx->toggle_unmount();
+        g_ctx->flags[UNMOUNT_FLAG] = true;
         break;
     case zygisk::DLCLOSE_MODULE_LIBRARY:
         unload = true;
@@ -362,13 +355,6 @@ void HookContext::close_fds() {
     close(logd_fd.exchange(-1));
 }
 
-void HookContext::toggle_unmount() {
-    if (flags[APP_SPECIALIZE]) {
-        // TODO: Handle MOUNT_EXTERNAL_NONE
-        flags[UNMOUNT_FLAG] = args->mount_external != 0;
-    }
-}
-
 // -----------------------------------------------------------------
 
 void HookContext::nativeSpecializeAppProcess_pre() {
@@ -383,8 +369,9 @@ void HookContext::nativeSpecializeAppProcess_pre() {
 
     auto module_fds = remote_get_info(args->uid, process, &info);
     if (info.on_denylist) {
+        // TODO: Handle MOUNT_EXTERNAL_NONE on older platforms
         ZLOGI("[%s] is on the denylist\n", process);
-        toggle_unmount();
+        flags[UNMOUNT_FLAG] = true;
     } else {
         run_modules_pre(module_fds);
     }
@@ -513,7 +500,6 @@ void hook_functions() {
 
     XHOOK_REGISTER(ANDROID_RUNTIME, fork);
     XHOOK_REGISTER(ANDROID_RUNTIME, unshare);
-    XHOOK_REGISTER(ANDROID_RUNTIME, selinux_android_setcontext);
     XHOOK_REGISTER(ANDROID_RUNTIME, jniRegisterNativeMethods);
     XHOOK_REGISTER_SYM(ANDROID_RUNTIME, "__android_log_close", android_log_close);
     hook_refresh();

native/jni/zygisk/zygisk.hpp

@@ -10,7 +10,6 @@
 enum : int {
     ZYGISK_SETUP,
     ZYGISK_GET_INFO,
-    ZYGISK_UNMOUNT,
     ZYGISK_GET_LOG_PIPE,
     ZYGISK_CONNECT_COMPANION,
 };