kernel: added new prctl CMD_GET_MANAGER_UID to get the uid of the crowned manager

manager: show crowned manager uid in infocard when developer options is enabled

kernel/core_hook.c

@@ -328,6 +328,17 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 		return 0;
 	}
 
+	if (arg2 == CMD_GET_MANAGER_UID) {
+        uid_t manager_uid = ksu_get_manager_uid();
+        if (copy_to_user((void __user *)arg3, &manager_uid, sizeof(manager_uid))) {
+            pr_err("prctl reply error, cmd: %lu\n", arg2);
+        }
+        if (copy_to_user(result, &reply_ok, sizeof(reply_ok))) {
+            pr_err("prctl reply error, cmd: %lu\n", arg2);
+        }
+        return 0;
+    }
+
 	if (arg2 == CMD_HOOK_MODE) {
 #ifdef CONFIG_KSU_KPROBES_HOOK
 		const char *mode = "Kprobes";

kernel/ksu.h

@@ -24,6 +24,7 @@
 #define CMD_IS_SU_ENABLED 14
 #define CMD_ENABLE_SU 15
 #define CMD_HOOK_MODE 16
+#define CMD_GET_MANAGER_UID 17
 
 #define EVENT_POST_FS_DATA 1
 #define EVENT_BOOT_COMPLETED 2

manager/app/src/main/cpp/jni.cc

@@ -25,6 +25,13 @@ Java_com_rifsxd_ksunext_Natives_getVersion(JNIEnv *env, jobject) {
     return get_version();
 }
 
+extern "C"
+JNIEXPORT jint JNICALL
+Java_com_rifsxd_ksunext_Natives_getManagerUid(JNIEnv *env, jobject) {
+    uid_t manager_uid = get_manager_uid();
+    return (jint)manager_uid;
+}
+
 extern "C"
 JNIEXPORT jstring JNICALL
 Java_com_rifsxd_ksunext_Natives_getHookMode(JNIEnv *env, jobject) {

manager/app/src/main/cpp/ksu.cc

@@ -30,6 +30,7 @@
 #define CMD_IS_SU_ENABLED 14
 #define CMD_ENABLE_SU 15
 #define CMD_HOOK_MODE 16
+#define CMD_GET_MANAGER_UID 17
 
 static bool ksuctl(int cmd, void* arg1, void* arg2) {
     int32_t result = 0;
@@ -63,12 +64,19 @@ int get_version(void) {
     return version;
 }
 
+uid_t get_manager_uid() {
+    uid_t manager_uid = (uid_t)-1;
+    ksuctl(CMD_GET_MANAGER_UID, &manager_uid, nullptr);
+    return manager_uid;
+}
+
 const char* get_hook_mode() {
     static char mode[16];
     ksuctl(CMD_HOOK_MODE, mode, nullptr);
     return mode;
 }
 
+
 bool get_allow_list(int *uids, int *size) {
     return ksuctl(CMD_GET_SU_LIST, uids, size);
 }

manager/app/src/main/cpp/ksu.h

@@ -11,6 +11,8 @@ bool become_manager(const char *);
 
 int get_version();
 
+uid_t get_manager_uid();
+
 const char* get_hook_mode();
 
 bool get_allow_list(int *uids, int *size);

manager/app/src/main/java/com/rifsxd/ksunext/Natives.kt

@@ -28,6 +28,9 @@ object Natives {
     // 12569: support get hook mode
     const val MINIMAL_SUPPORTED_HOOK_MODE = 12569
 
+    // 12750: support get manager UID
+    const val MINIMAL_SUPPORTED_MANAGER_UID = 12751
+
     const val KERNEL_SU_DOMAIN = "u:r:su:s0"
 
     const val ROOT_UID = 0
@@ -54,6 +57,12 @@ object Natives {
 
     external fun uidShouldUmount(uid: Int): Boolean
 
+    /**
+     * Get the UID of the current root manager.
+     * @return manager UID, or -1 if unavailable.
+     */
+    external fun getManagerUid(): Int
+
     /**
      * Get a string indicating the SU hook mode enabled in kernel.
      * The return values are:

manager/app/src/main/java/com/rifsxd/ksunext/ui/screen/Home.kt

@@ -550,6 +550,8 @@ private fun InfoCard(autoExpand: Boolean = false) {
 
     var expanded by rememberSaveable { mutableStateOf(false) }
 
+    val developerOptionsEnabled = prefs.getBoolean("enable_developer_options", false)
+
     LaunchedEffect(autoExpand) {
         if (autoExpand) {
             expanded = true
@@ -598,7 +600,14 @@ private fun InfoCard(autoExpand: Boolean = false) {
                 val managerVersion = getManagerVersion(context)
                 InfoCardItem(
                     label = stringResource(R.string.home_manager_version),
-                    content = "${managerVersion.first} (${managerVersion.second})",
+                    content = if (
+                        developerOptionsEnabled &&
+                        Natives.version >= Natives.MINIMAL_SUPPORTED_MANAGER_UID
+                    ) {
+                        "${managerVersion.first} (${managerVersion.second}) | UID: ${Natives.getManagerUid()}"
+                    } else {
+                        "${managerVersion.first} (${managerVersion.second})"
+                    },
                     icon = painterResource(R.drawable.ic_ksu_next),
                 )