Refine unmount

loader/src/common/daemon.cpp

@@ -58,6 +58,17 @@ namespace zygiskd {
         return socket_utils::read_string(fd);
     }
 
+    uint32_t GetProcessFlags(uid_t uid) {
+        UniqueFd fd = Connect(1);
+        if (fd == -1) {
+            PLOGE("GetProcessFlags");
+            return 0;
+        }
+        socket_utils::write_u8(fd, (uint8_t) SocketAction::GetProcessFlags);
+        socket_utils::write_u32(fd, uid);
+        return socket_utils::read_u32(fd);
+    }
+
     std::vector<Module> ReadModules() {
         std::vector<Module> modules;
         UniqueFd fd = Connect(1);

loader/src/common/socket_utils.cpp

@@ -90,6 +90,10 @@ namespace socket_utils {
         return read_exact_or<uint8_t>(fd, 0);
     }
 
+    uint32_t read_u32(int fd) {
+        return read_exact_or<uint32_t>(fd, 0);
+    }
+
     size_t read_usize(int fd) {
         return read_exact_or<size_t>(fd, 0);
     }
@@ -110,6 +114,10 @@ namespace socket_utils {
         return write_exact<uint8_t>(fd, val);
     }
 
+    bool write_u32(int fd, uint32_t val) {
+        return write_exact<uint32_t>(fd, val);
+    }
+
     bool write_string(int fd, std::string_view str) {
         return write_usize(fd, str.size()) && str.size() == xwrite(fd, str.data(), str.size());
     }

loader/src/include/daemon.h

@@ -54,6 +54,7 @@ namespace zygiskd {
         PingHeartBeat,
         RequestLogcatFd,
         ReadNativeBridge,
+        GetProcessFlags,
         ReadModules,
         RequestCompanionSocket,
         GetModuleDir,
@@ -67,6 +68,8 @@ namespace zygiskd {
 
     std::vector<Module> ReadModules();
 
+    uint32_t GetProcessFlags(uid_t uid);
+
     int ConnectCompanion(size_t index);
 
     int GetModuleDir(size_t index);

loader/src/include/socket_utils.h

@@ -13,12 +13,16 @@ namespace socket_utils {
 
     uint8_t read_u8(int fd);
 
+    uint32_t read_u32(int fd);
+
     size_t read_usize(int fd);
 
     std::string read_string(int fd);
 
     bool write_u8(int fd, uint8_t val);
 
+    bool write_u32(int fd, uint32_t val);
+
     int recv_fd(int fd);
 
     bool write_usize(int fd, size_t val);

loader/src/injector/hide.cpp

@@ -1,22 +0,0 @@
-#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);
-}
-
-void revert_unmount() {
-    parse_mnt("/proc/self/mounts", [](mntent* mentry) {
-        if (mentry->mnt_fsname == "/data/adb/ksu/modules"sv ||
-            std::string_view(mentry->mnt_opts).find("/data/adb/ksu/modules") != std::string_view::npos) {
-            lazy_unmount(mentry->mnt_fsname);
-        }
-        return true;
-    });
-}

loader/src/injector/hook.cpp

@@ -566,15 +566,13 @@ void HookContext::run_modules_post() {
 /* Zygisksu changed: Load module fds */
 void HookContext::app_specialize_pre() {
     flags[APP_SPECIALIZE] = true;
+    info_flags = zygiskd::GetProcessFlags(g_ctx->args.app->uid);
     run_modules_pre();
 }
 
 
 void HookContext::app_specialize_post() {
     run_modules_post();
-    if (info_flags & PROCESS_IS_MAGISK_APP) {
-        setenv("ZYGISK_ENABLED", "1", 1);
-    }
 
     // Cleanups
     env->ReleaseStringUTFChars(args.app->nice_name, process);

loader/src/injector/misc.cpp

@@ -35,6 +35,31 @@ void parse_mnt(const char* file, const std::function<bool(mntent*)>& fn) {
     }
 }
 
+std::list<std::string> split_str(std::string_view s, std::string_view delimiter) {
+    std::list<std::string> ret;
+    size_t pos = 0;
+    while (pos < s.size()) {
+        auto next = s.find(delimiter, pos);
+        if (next == std::string_view::npos) {
+            ret.emplace_back(s.substr(pos));
+            break;
+        }
+        ret.emplace_back(s.substr(pos, next - pos));
+        pos = next + delimiter.size();
+    }
+    return ret;
+}
+
+std::string join_str(const std::list<std::string>& list, std::string_view delimiter) {
+    std::string ret;
+    for (auto& s : list) {
+        if (!ret.empty())
+            ret += delimiter;
+        ret += s;
+    }
+    return ret;
+}
+
 sDIR make_dir(DIR *dp) {
     return sDIR(dp, [](DIR *dp){ return dp ? closedir(dp) : 1; });
 }

loader/src/injector/misc.hpp

@@ -2,10 +2,12 @@
 
 #include <dirent.h>
 #include <functional>
+#include <list>
 #include <memory>
 #include <mntent.h>
 #include <pthread.h>
 #include <stdio.h>
+#include <string>
 #include <string_view>
 
 #include "logging.h"
@@ -34,6 +36,16 @@ private:
 using thread_entry = void *(*)(void *);
 int new_daemon_thread(thread_entry entry, void *arg);
 
+static inline bool str_contains(std::string_view s, std::string_view ss) {
+    return s.find(ss) != std::string_view::npos;
+}
+static inline bool str_starts(std::string_view s, std::string_view ss) {
+    return s.size() >= ss.size() && s.compare(0, ss.size(), ss) == 0;
+}
+static inline bool str_ends(std::string_view s, std::string_view ss) {
+    return s.size() >= ss.size() && s.compare(s.size() - ss.size(), std::string_view::npos, ss) == 0;
+}
+
 template<typename T, typename Impl>
 class stateless_allocator {
 public:
@@ -78,6 +90,25 @@ static inline sFILE xopen_file(int fd, const char *mode) {
     return make_file(fdopen(fd, mode));
 }
 
+template <typename T>
+class reversed_container {
+public:
+    reversed_container(T &base) : base(base) {}
+    decltype(std::declval<T>().rbegin()) begin() { return base.rbegin(); }
+    decltype(std::declval<T>().crbegin()) begin() const { return base.crbegin(); }
+    decltype(std::declval<T>().crbegin()) cbegin() const { return base.crbegin(); }
+    decltype(std::declval<T>().rend()) end() { return base.rend(); }
+    decltype(std::declval<T>().crend()) end() const { return base.crend(); }
+    decltype(std::declval<T>().crend()) cend() const { return base.crend(); }
+private:
+    T &base;
+};
+
+template <typename T>
+reversed_container<T> reversed(T &base) {
+    return reversed_container<T>(base);
+}
+
 template<class T>
 static inline void default_new(T *&p) { p = new T(); }
 
@@ -97,6 +128,10 @@ int parse_int(std::string_view s);
 
 void parse_mnt(const char* file, const std::function<bool(mntent*)>& fn);
 
+std::list<std::string> split_str(std::string_view s, std::string_view delimiter);
+
+std::string join_str(const std::list<std::string>& list, std::string_view delimiter);
+
 template <typename T>
 static inline T align_to(T v, int a) {
     static_assert(std::is_integral<T>::value);

loader/src/injector/module.hpp

@@ -111,12 +111,10 @@ namespace {
         PROCESS_GRANTED_ROOT = zygisk::StateFlag::PROCESS_GRANTED_ROOT,
         PROCESS_ON_DENYLIST = zygisk::StateFlag::PROCESS_ON_DENYLIST,
 
-        PROCESS_IS_SYS_UI = (1u << 29),
-        DENYLIST_ENFORCING = (1u << 30),
-        PROCESS_IS_MAGISK_APP = (1u << 31),
+        PROCESS_IS_SYS_UI = (1u << 30),
+        PROCESS_IS_KSU_APP = (1u << 31),
 
-        UNMOUNT_MASK = (PROCESS_ON_DENYLIST | DENYLIST_ENFORCING),
-        PRIVATE_MASK = (PROCESS_IS_SYS_UI | DENYLIST_ENFORCING | PROCESS_IS_MAGISK_APP)
+        PRIVATE_MASK = (PROCESS_IS_SYS_UI | PROCESS_IS_KSU_APP)
     };
 
     struct api_abi_base {

loader/src/injector/unmount.cpp

@@ -0,0 +1,73 @@
+#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);
+    } else {
+        PLOGE("Failed to unmount: %s (%s)", strerror(errno), mountpoint);
+    }
+}
+
+#define PARSE_OPT(name, flag)   \
+    if (opt == name) {          \
+        flags |= (flag);        \
+        return true;            \
+    }
+
+void revert_unmount() {
+    std::vector<std::string> targets;
+    std::list<std::pair<std::string, std::string>> backups;
+
+    targets.emplace_back("/data/adb/ksu/modules");
+    parse_mnt("/proc/self/mounts", [&](mntent* mentry) {
+        if (str_starts(mentry->mnt_fsname, "/data/adb/")) {
+            targets.emplace_back(mentry->mnt_dir);
+        }
+        if (mentry->mnt_type == "overlay"sv) {
+            if (str_contains(mentry->mnt_opts, "/data/adb/ksu/modules")) {
+                targets.emplace_back(mentry->mnt_dir);
+            } else {
+                backups.emplace_back(mentry->mnt_dir, mentry->mnt_opts);
+            }
+        }
+        return true;
+    });
+
+    for (auto& s: reversed(targets)) {
+        lazy_unmount(s.data());
+    }
+
+    parse_mnt("/proc/self/mounts", [&](mntent* mentry) {
+        if (mentry->mnt_type == "overlay"sv) {
+            for (auto it = backups.begin(); it != backups.end(); it++) {
+                backups.remove_if([&](auto& mnt) {
+                    return mnt.first == mentry->mnt_dir && mnt.second == mentry->mnt_opts;
+                });
+            }
+        }
+        return true;
+    });
+
+    for (auto& mnt: backups) {
+        auto opts = split_str(mnt.second, ",");
+        unsigned long flags = 0;
+        opts.remove_if([&](auto& opt) {
+            PARSE_OPT(MNTOPT_RO, MS_RDONLY)
+            PARSE_OPT(MNTOPT_NOSUID, MS_NOSUID)
+            PARSE_OPT("relatime", MS_RELATIME)
+            return false;
+        });
+        auto mnt_data = join_str(opts, ",");
+        if (mount("overlay", mnt.first.data(), "overlay", flags, mnt_data.data()) != -1) {
+            LOGD("Remounted (%s)", mnt.first.data());
+        } else {
+            LOGW("Failed to remount: %s (%s, %s)", strerror(errno), mnt.first.data(), mnt_data.data());
+        }
+    }
+}