kernel: remove become_manager and minor refactors

kernel/Makefile

@@ -2,8 +2,7 @@ kernelsu-objs := ksu.o
 kernelsu-objs += allowlist.o
 kernelsu-objs += apk_sign.o
 kernelsu-objs += sucompat.o
-kernelsu-objs += uid_observer.o
-kernelsu-objs += manager.o
+kernelsu-objs += throne_tracker.o
 kernelsu-objs += core_hook.o
 kernelsu-objs += ksud.o
 kernelsu-objs += embed_ksud.o

kernel/core_hook.c

@@ -37,7 +37,8 @@
 #include "linux/vmalloc.h"
 #include "manager.h"
 #include "selinux/selinux.h"
-#include "uid_observer.h"
+#include "throne_tracker.h"
+#include "throne_tracker.h"
 #include "kernel_compat.h"
 
 static bool ksu_module_mounted = false;
@@ -199,7 +200,7 @@ int ksu_handle_rename(struct dentry *old_dentry, struct dentry *new_dentry)
 	pr_info("renameat: %s -> %s, new path: %s\n", old_dentry->d_iname,
 		new_dentry->d_iname, buf);
 
-	update_uid();
+	track_throne();
 
 	return 0;
 }

kernel/ksu.c

@@ -9,7 +9,7 @@
 #include "core_hook.h"
 #include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
-#include "uid_observer.h"
+#include "throne_tracker.h"
 
 static struct workqueue_struct *ksu_workqueue;
 
@@ -53,7 +53,7 @@ int __init kernelsu_init(void)
 
 	ksu_allowlist_init();
 
-	ksu_uid_observer_init();
+	ksu_throne_tracker_init();
 
 #ifdef CONFIG_KPROBES
 	ksu_enable_sucompat();
@@ -74,7 +74,7 @@ void kernelsu_exit(void)
 {
 	ksu_allowlist_exit();
 
-	ksu_uid_observer_exit();
+	ksu_throne_tracker_exit();
 
 	destroy_workqueue(ksu_workqueue);
 

kernel/manager.c

@@ -1,102 +0,0 @@
-#include "linux/cred.h"
-#include "linux/gfp.h"
-#include "linux/slab.h"
-#include "linux/uidgid.h"
-#include "linux/version.h"
-
-#include "linux/fdtable.h"
-#include "linux/fs.h"
-#include "linux/rcupdate.h"
-
-#include "apk_sign.h"
-#include "klog.h" // IWYU pragma: keep
-#include "ksu.h"
-#include "manager.h"
-
-uid_t ksu_manager_uid = KSU_INVALID_UID;
-
-bool become_manager(char *pkg)
-{
-	struct fdtable *files_table;
-	int i = 0;
-	struct path files_path;
-	char *cwd;
-	char *buf;
-	bool result = false;
-
-#ifdef KSU_MANAGER_PACKAGE
-	// pkg is `/<real package>`
-	if (strncmp(pkg + 1, KSU_MANAGER_PACKAGE,
-		    sizeof(KSU_MANAGER_PACKAGE)) != 0) {
-		pr_info("manager package is inconsistent with kernel build: %s\n",
-			KSU_MANAGER_PACKAGE);
-		return false;
-	}
-#endif
-	// must be zygote's direct child, otherwise any app can fork a new process and
-	// open manager's apk
-	if (task_uid(current->real_parent).val != 0) {
-		pr_info("parent is not zygote!\n");
-		return false;
-	}
-
-	buf = (char *)kmalloc(PATH_MAX, GFP_ATOMIC);
-	if (!buf) {
-		pr_err("kalloc path failed.\n");
-		return false;
-	}
-
-	files_table = files_fdtable(current->files);
-
-	int pkg_len = strlen(pkg);
-	// todo: use iterate_fd
-	for (i = 0; files_table->fd[i] != NULL; i++) {
-		files_path = files_table->fd[i]->f_path;
-		if (!d_is_reg(files_path.dentry)) {
-			continue;
-		}
-		cwd = d_path(&files_path, buf, PATH_MAX);
-		if (startswith(cwd, "/data/app/") != 0 ||
-		    endswith(cwd, "==/base.apk") != 0) {
-			// AOSP generate ramdom base64 with 16bit, without NO_PADDING, so it must have two "="
-			continue;
-		}
-		// we have found the apk!
-		pr_info("found apk: %s\n", cwd);
-		char *pkg_index = strstr(cwd, pkg);
-		if (!pkg_index) {
-			pr_info("apk path not match package name!\n");
-			continue;
-		}
-		char *next_char = pkg_index + pkg_len;
-		// because we ensure the cwd must startswith `/data/app` and endswith `base.apk`
-		// we don't need to check if the pointer is out of bounds
-		if (*next_char != '-') {
-			// from android 8.1: http://aospxref.com/android-8.1.0_r81/xref/frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java#17612
-			// to android 13: http://aospxref.com/android-13.0.0_r3/xref/frameworks/base/services/core/java/com/android/server/pm/PackageManagerServiceUtils.java#1208
-			// /data/app/~~[randomStringA]/[packageName]-[randomStringB]
-			// the previous char must be `/` and the next char must be `-`
-			// because we use strstr instead of equals, this is a strong verfication.
-			pr_info("invalid pkg: %s\n", pkg);
-			continue;
-		}
-		if (is_manager_apk(cwd)) {
-			// check passed
-			uid_t uid = current_uid().val;
-			pr_info("manager uid: %d\n", uid);
-
-			ksu_set_manager_uid(uid);
-
-			result = true;
-			goto clean;
-		} else {
-			pr_info("manager signature invalid!\n");
-		}
-
-		break;
-	}
-
-clean:
-	kfree(buf);
-	return result;
-}

kernel/manager.h

@@ -33,6 +33,4 @@ static inline void ksu_invalidate_manager_uid()
 	ksu_manager_uid = KSU_INVALID_UID;
 }
 
-bool become_manager(char *pkg);
-
 #endif

kernel/throne_tracker.c

@@ -11,9 +11,11 @@
 #include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
 #include "manager.h"
-#include "uid_observer.h"
+#include "throne_tracker.h"
 #include "kernel_compat.h"
 
+uid_t ksu_manager_uid = KSU_INVALID_UID;
+
 #define SYSTEM_PACKAGES_LIST_PATH "/data/system/packages.list"
 static struct work_struct ksu_update_uid_work;
 
@@ -71,6 +73,14 @@ static void crown_manager(const char *apk, struct list_head *uid_data)
 
 	pr_info("manager pkg: %s\n", pkg);
 
+#ifdef KSU_MANAGER_PACKAGE
+	// pkg is `/<real package>`
+	if (strncmp(pkg, KSU_MANAGER_PACKAGE, sizeof(KSU_MANAGER_PACKAGE))) {
+		pr_info("manager package is inconsistent with kernel build: %s\n",
+			KSU_MANAGER_PACKAGE);
+		return;
+	}
+#endif
 	struct list_head *list = (struct list_head *)uid_data;
 	struct uid_data *np;
 
@@ -292,18 +302,18 @@ out:
 	filp_close(fp, 0);
 }
 
-void update_uid()
+void track_throne()
 {
 	ksu_queue_work(&ksu_update_uid_work);
 }
 
-int ksu_uid_observer_init()
+int ksu_throne_tracker_init()
 {
 	INIT_WORK(&ksu_update_uid_work, do_update_uid);
 	return 0;
 }
 
-int ksu_uid_observer_exit()
+int ksu_throne_tracker_exit()
 {
 	return 0;
 }

kernel/throne_tracker.h

@@ -0,0 +1,10 @@
+#ifndef __KSU_H_UID_OBSERVER
+#define __KSU_H_UID_OBSERVER
+
+int ksu_throne_tracker_init();
+
+int ksu_throne_tracker_exit();
+
+void track_throne();
+
+#endif

kernel/uid_observer.h

@@ -1,10 +0,0 @@
-#ifndef __KSU_H_UID_OBSERVER
-#define __KSU_H_UID_OBSERVER
-
-int ksu_uid_observer_init();
-
-int ksu_uid_observer_exit();
-
-void update_uid();
-
-#endif