fix compile on nongki branch (#602)

* fix compile

* revert some edits

kernel/kernel_compat.c

@@ -123,3 +123,27 @@ long ksu_strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
 	return ret;
 }
 #endif
+
+long ksu_copy_from_user_nofault(void *dst, const void __user *src, size_t size)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0)
+    return copy_from_user_nofault(dst, src, size);
+#else
+    // https://elixir.bootlin.com/linux/v5.8/source/mm/maccess.c#L205
+    long ret = -EFAULT;
+    mm_segment_t old_fs = get_fs();
+
+    set_fs(USER_DS);
+    // tweaked to use ksu_access_ok
+    if (ksu_access_ok(src, size)) {
+        pagefault_disable();
+        ret = __copy_from_user_inatomic(dst, src, size);
+        pagefault_enable();
+    }
+    set_fs(old_fs);
+
+    if (ret)
+        return -EFAULT;
+    return 0;
+#endif
+}

kernel/lsm_hooks.c

@@ -5,6 +5,7 @@
 #include <linux/err.h>
 
 #include "klog.h" // IWYU pragma: keep
+#include "ksud.h"
 #include "kernel_compat.h"
 #include "setuid_hook.h"
 

kernel/sucompat.c

@@ -15,6 +15,10 @@
 #include <linux/sched.h>
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0) && !KSU_OPTIONAL_SELINUX_INODE
+#include "objsec.h"
+#endif // import inode_security_struct
+
 #include "allowlist.h"
 #include "feature.h"
 #include "klog.h" // IWYU pragma: keep

kernel/supercalls.c

@@ -371,10 +371,15 @@ static int do_get_wrapper_fd(void __user *arg) {
 		goto put_orig_file;
 	}
 
+// kcompat for older kernel
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
 #define getfd_secure anon_inode_create_getfd
-#else
+#elif defined(KSU_HAS_GETFD_SECURE)
 #define getfd_secure anon_inode_getfd_secure
+#else
+// technically not a secure inode, but, this is the only way so.
+#define getfd_secure(name, ops, data, flags, __unused)						 \
+	anon_inode_getfd(name, ops, data, flags)
 #endif
 	ret = getfd_secure("[ksu_fdwrapper]", &data->ops, data, f->f_flags, NULL);
 	if (ret < 0) {
@@ -386,7 +391,11 @@ static int do_get_wrapper_fd(void __user *arg) {
 	struct inode* wrapper_inode = file_inode(pf);
 	// copy original inode mode
 	wrapper_inode->i_mode = file_inode(f)->i_mode;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0) || defined(KSU_OPTIONAL_SELINUX_INODE)
 	struct inode_security_struct *sec = selinux_inode(wrapper_inode);
+#else
+	struct inode_security_struct *sec = (struct inode_security_struct *)wrapper_inode->i_security;
+#endif
 	if (sec) {
 		sec->sid = ksu_file_sid;
 	}

kernel/supercalls.h

@@ -8,6 +8,7 @@
 #ifdef CONFIG_KPM
 #include "kpm/kpm.h"
 #endif
+#include "ksu.h"
 
 // Magic numbers for reboot hook to install fd
 #define KSU_INSTALL_MAGIC1 0xDEADBEEF