kernel: precise trigger timing of post-fs-data (#118)

* kernel: add report_event cmd

* ksud: report event

* kernel: trigger on_post_fs_data

* ksud: comment unused code

* [skip ci] run clang-format

Signed-off-by: Ylarod <me@ylarod.cn>

* ci: use custom key to sign official bootimgs

* format ksud

* reject non root

* remove

Signed-off-by: Ylarod <me@ylarod.cn>

kernel/allowlist.c

@@ -5,8 +5,9 @@
 #include "linux/printk.h"
 #include "linux/slab.h"
 
-#include "selinux/selinux.h"
 #include "klog.h" // IWYU pragma: keep
+#include "selinux/selinux.h"
+
 #define FILE_MAGIC 0x7f4b5355 // ' KSU', u32
 #define FILE_FORMAT_VERSION 1 // u32
 
@@ -27,7 +28,8 @@ static struct work_struct ksu_load_work;
 
 bool persistent_allow_list(void);
 
-void ksu_show_allow_list(void){
+void ksu_show_allow_list(void)
+{
 	struct perm_data *p = NULL;
 	struct list_head *pos = NULL;
 	pr_info("ksu_show_allow_list");
@@ -179,7 +181,8 @@ void do_load_allow_list(struct work_struct *work)
 #ifdef CONFIG_KSU_DEBUG
 		int errno = PTR_ERR(fp);
 		if (errno == -ENOENT) {
-			ksu_allow_uid(2000, true, true); // allow adb shell by default
+			ksu_allow_uid(2000, true,
+				      true); // allow adb shell by default
 		} else {
 			pr_err("load_allow_list open file failed: %d\n",
 			       PTR_ERR(fp));

kernel/core_hook.c

@@ -4,6 +4,7 @@
 #include "linux/kernel.h"
 #include "linux/kprobes.h"
 #include "linux/lsm_hooks.h"
+#include "linux/printk.h"
 #include "linux/uaccess.h"
 #include "linux/uidgid.h"
 #include "linux/version.h"
@@ -15,11 +16,12 @@
 #include "allowlist.h"
 #include "arch.h"
 #include "core_hook.h"
+#include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
+#include "ksud.h"
 #include "manager.h"
 #include "selinux/selinux.h"
 #include "uid_observer.h"
-#include "klog.h" // IWYU pragma: keep
 
 static inline bool is_allow_su()
 {
@@ -200,6 +202,34 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 		}
 	}
 
+	if (arg2 == CMD_REPORT_EVENT) {
+		if (0 != current_uid().val) {
+			return 0;
+		}
+		switch (arg3) {
+		case EVENT_POST_FS_DATA: {
+			static bool post_fs_data_lock = false;
+			if (!post_fs_data_lock) {
+				post_fs_data_lock = true;
+				pr_info("post-fs-data triggered");
+				on_post_fs_data();
+			}
+			break;
+		}
+		case EVENT_BOOT_COMPLETED: {
+			static bool boot_complete_lock = false;
+			if (!boot_complete_lock) {
+				boot_complete_lock = true;
+				pr_info("boot_complete triggered");
+			}
+			break;
+		}
+		default:
+			break;
+		}
+		return 0;
+	}
+
 	// all other cmds are for 'root manager'
 	if (!is_manager()) {
 		pr_info("Only manager can do cmd: %d\n", arg2);

kernel/ksu.c

@@ -1,13 +1,13 @@
+#include "linux/fs.h"
 #include "linux/module.h"
 #include "linux/workqueue.h"
-#include "linux/fs.h"
 
 #include "allowlist.h"
 #include "arch.h"
 #include "core_hook.h"
+#include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
 #include "uid_observer.h"
-#include "klog.h" // IWYU pragma: keep
 
 static struct workqueue_struct *ksu_workqueue;
 

kernel/ksu.h

@@ -8,13 +8,16 @@
 #define KERNEL_SU_OPTION 0xDEADBEEF
 
 #define CMD_GRANT_ROOT 0
-
 #define CMD_BECOME_MANAGER 1
 #define CMD_GET_VERSION 2
 #define CMD_ALLOW_SU 3
 #define CMD_DENY_SU 4
 #define CMD_GET_ALLOW_LIST 5
 #define CMD_GET_DENY_LIST 6
+#define CMD_REPORT_EVENT 7
+
+#define EVENT_POST_FS_DATA 1
+#define EVENT_BOOT_COMPLETED 2
 
 bool ksu_queue_work(struct work_struct *work);
 

kernel/ksud.c

@@ -4,6 +4,7 @@
 #include "linux/err.h"
 #include "linux/fs.h"
 #include "linux/kprobes.h"
+#include "linux/printk.h"
 #include "linux/types.h"
 #include "linux/uaccess.h"
 #include "linux/version.h"
@@ -11,8 +12,8 @@
 
 #include "allowlist.h"
 #include "arch.h"
-#include "selinux/selinux.h"
 #include "klog.h" // IWYU pragma: keep
+#include "selinux/selinux.h"
 
 static const char KERNEL_SU_RC[] =
 	"\n"
@@ -47,6 +48,18 @@ static bool vfs_read_hook = true;
 static bool execveat_hook = true;
 #endif
 
+void on_post_fs_data(void)
+{
+	static bool done = false;
+	if (done) {
+		pr_info("on_post_fs_data already done");
+		return;
+	}
+	done = true;
+	pr_info("ksu_load_allow_list");
+	ksu_load_allow_list();
+}
+
 int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
 			     void *argv, void *envp, int *flags)
 {
@@ -85,7 +98,7 @@ int ksu_handle_execveat_ksud(int *fd, struct filename **filename_ptr,
 	    !memcmp(filename->name, app_process, sizeof(app_process) - 1)) {
 		first_app_process = false;
 		pr_info("exec app_process, /data prepared!\n");
-		ksu_load_allow_list();
+		on_post_fs_data(); // we keep this for old ksud
 		stop_execve_hook();
 	}
 

kernel/ksud.h

@@ -0,0 +1,6 @@
+#ifndef __KSU_H_KSUD
+#define __KSU_H_KSUD
+
+void on_post_fs_data(void);
+
+#endif

kernel/manager.c

@@ -9,9 +9,9 @@
 #include "linux/rcupdate.h"
 
 #include "apk_sign.h"
+#include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
 #include "manager.h"
-#include "klog.h" // IWYU pragma: keep
 
 uid_t ksu_manager_uid = INVALID_UID;
 

kernel/selinux/rules.c

@@ -1,9 +1,9 @@
 #include "linux/version.h"
 
+#include "../klog.h" // IWYU pragma: keep
 #include "selinux.h"
 #include "sepolicy.h"
 #include "ss/services.h"
-#include "../klog.h" // IWYU pragma: keep
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 10, 0)
 #define SELINUX_POLICY_INSTEAD_SELINUX_SS

kernel/selinux/selinux.c

@@ -1,5 +1,5 @@
-#include "objsec.h"
 #include "selinux.h"
+#include "objsec.h"
 
 #include "../klog.h" // IWYU pragma: keep
 

kernel/uid_observer.c

@@ -8,10 +8,10 @@
 #include "linux/workqueue.h"
 
 #include "allowlist.h"
+#include "klog.h" // IWYU pragma: keep
 #include "ksu.h"
 #include "manager.h"
 #include "uid_observer.h"
-#include "klog.h" // IWYU pragma: keep
 
 #define SYSTEM_PACKAGES_LIST_PATH "/data/system/packages.list"
 static struct work_struct ksu_update_uid_work;