kernel: Resolving the issue of unavailable functionality

kernel/sucompat.c

@@ -205,8 +205,6 @@ static const char sh_path[] = SH_PATH;
 static const char su_path[] = SU_PATH;
 static const char ksud_path[] = KSUD_PATH;
 
-extern bool ksu_kernel_umount_enabled;
-
 // the call from execve_handler_pre won't provided correct value for __never_use_argument, use them after fix execve_handler_pre, keeping them for consistence for manually patched code
 int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,
                  void *__never_use_argv, void *__never_use_envp,
@@ -214,6 +212,10 @@ int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,
 {
     struct filename *filename;
 
+    if (!ksu_su_compat_enabled){
+        return 0;
+    }
+
     if (unlikely(!filename_ptr))
         return 0;
 
@@ -236,6 +238,10 @@ int ksu_handle_execveat_sucompat(int *fd, struct filename **filename_ptr,
 int ksu_handle_execveat(int *fd, struct filename **filename_ptr, void *argv,
             void *envp, int *flags)
 {
+    if (!ksu_su_compat_enabled){
+        return 0;
+    }
+
     if (ksu_handle_execveat_ksud(fd, filename_ptr, argv, envp, flags)) {
         return 0;
     }
@@ -248,6 +254,10 @@ int ksu_handle_faccessat(int *dfd, const char __user **filename_user, int *mode,
 {
     char path[sizeof(su_path) + 1] = {0};
 
+    if (!ksu_su_compat_enabled){
+        return 0;
+    }
+
     strncpy_from_user_nofault(path, *filename_user, sizeof(path));
 
     if (unlikely(!memcmp(path, su_path, sizeof(su_path)))) {
@@ -277,6 +287,10 @@ int ksu_handle_stat(int *dfd, struct filename **filename, int *flags) {
 #else
 int ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags)
 {
+    if (!ksu_su_compat_enabled){
+        return 0;
+    }
+
     if (unlikely(!filename_user)) {
         return 0;
     }
@@ -313,27 +327,31 @@ int ksu_handle_stat(int *dfd, const char __user **filename_user, int *flags)
 
 int ksu_handle_devpts(struct inode *inode)
 {
-        if (!current->mm) {
-                return 0;
-        }
-
-        uid_t uid = current_uid().val;
-        if (uid % 100000 < 10000) {
-                // not untrusted_app, ignore it
-                return 0;
-        }
-
-        if (!__ksu_is_allow_uid_for_current(uid))
-                return 0;
-
-        if (ksu_file_sid) {
-                struct inode_security_struct *sec = selinux_inode(inode);
-                if (sec) {
-                        sec->sid = ksu_file_sid;
-                }
-        }
-
+    if (!current->mm) {
         return 0;
+    }
+
+    if (!ksu_su_compat_enabled){
+        return 0;
+    }
+
+    uid_t uid = current_uid().val;
+    if (uid % 100000 < 10000) {
+        // not untrusted_app, ignore it
+        return 0;
+    }
+
+    if (!__ksu_is_allow_uid_for_current(uid))
+            return 0;
+
+    if (ksu_file_sid) {
+        struct inode_security_struct *sec = selinux_inode(inode);
+        if (sec) {
+            sec->sid = ksu_file_sid;
+        }
+    }
+
+    return 0;
 }
 #endif // #ifndef CONFIG_KSU_SUSFS