kernel: Apply the susfs patch

Co-authored-by: simonpunk <simonpunk2016@gmail.com>
Co-authored-by: ShirkNeko <109797057+ShirkNeko@users.noreply.github.com>

kernel/selinux/selinux.c

@@ -166,3 +166,96 @@ u32 ksu_get_ksu_file_sid()
     }
     return ksu_file_sid;
 }
+
+#ifdef CONFIG_KSU_SUSFS
+#define KERNEL_INIT_DOMAIN "u:r:init:s0"
+#define KERNEL_ZYGOTE_DOMAIN "u:r:zygote:s0"
+#define KERNEL_KERNEL_DOMAIN "u:r:kernel:s0"
+#ifndef KERNEL_SU_DOMAIN
+#define KERNEL_SU_DOMAIN "u:r:su:s0"
+#endif // #ifndef KERNEL_SU_DOMAIN
+u32 susfs_ksu_sid = 0;
+u32 susfs_init_sid = 0;
+u32 susfs_zygote_sid = 0;
+u32 susfs_kernel_sid = 0;
+
+static inline void susfs_set_sid(const char *secctx_name, u32 *out_sid)
+{
+    int err;
+    
+    if (!secctx_name || !out_sid) {
+        pr_err("secctx_name || out_sid is NULL\n");
+        return;
+    }
+
+    err = security_secctx_to_secid(secctx_name, strlen(secctx_name),
+                       out_sid);
+    if (err) {
+        pr_err("failed setting sid for '%s', err: %d\n", secctx_name, err);
+        return;
+    }
+    pr_info("sid '%u' is set for secctx_name '%s'\n", *out_sid, secctx_name);
+}
+
+bool susfs_is_sid_equal(void *sec, u32 sid2) {
+    struct task_security_struct *tsec = (struct task_security_struct *)sec;
+    if (!tsec) {
+        return false;
+    }
+    return tsec->sid == sid2;
+}
+
+u32 susfs_get_sid_from_name(const char *secctx_name)
+{
+    u32 out_sid = 0;
+    int err;
+    
+    if (!secctx_name) {
+        pr_err("secctx_name is NULL\n");
+        return 0;
+    }
+    err = security_secctx_to_secid(secctx_name, strlen(secctx_name),
+                       &out_sid);
+    if (err) {
+        pr_err("failed getting sid from secctx_name: %s, err: %d\n", secctx_name, err);
+        return 0;
+    }
+    return out_sid;
+}
+
+u32 susfs_get_current_sid(void) {
+    return current_sid();
+}
+
+void susfs_set_zygote_sid(void)
+{
+    susfs_set_sid(KERNEL_ZYGOTE_DOMAIN, &susfs_zygote_sid);
+}
+
+bool susfs_is_current_zygote_domain(void) {
+    return unlikely(current_sid() == susfs_zygote_sid);
+}
+
+void susfs_set_ksu_sid(void)
+{
+    susfs_set_sid(KERNEL_SU_DOMAIN, &susfs_ksu_sid);
+}
+
+bool susfs_is_current_ksu_domain(void) {
+    return unlikely(current_sid() == susfs_ksu_sid);
+}
+
+void susfs_set_init_sid(void)
+{
+    susfs_set_sid(KERNEL_INIT_DOMAIN, &susfs_init_sid);
+}
+
+bool susfs_is_current_init_domain(void) {
+    return unlikely(current_sid() == susfs_init_sid);
+}
+
+void susfs_set_kernel_sid(void)
+{
+    susfs_set_sid(KERNEL_KERNEL_DOMAIN, &susfs_kernel_sid);
+}
+#endif