From 7e1e590523aa892fc225e740cdcba8ec4213f960 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?YC=E9=85=B1luyancib?= <luyancib@qq.com>
Date: Thu, 27 Feb 2025 18:50:34 +0800
Subject: [PATCH] Kernel:Add auto backport into the kernel source

Copy from KSUN

Co-Authored-By: Rifat Azad <33044977+rifsxd@users.noreply.github.com>
---
 kernel/Makefile | 55 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/kernel/Makefile b/kernel/Makefile
index 378f60e156af..72dd0333f92c 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -14,6 +14,61 @@ kernelsu-objs += selinux/rules.o
 ccflags-y += -I$(srctree)/security/selinux -I$(srctree)/security/selinux/include
 ccflags-y += -I$(objtree)/security/selinux -include $(srctree)/include/uapi/asm-generic/errno.h
 
+# Determine the appropriate atomic function and apply patch accordingly
+ifeq ($(shell grep -q "atomic_inc_not_zero" $(srctree)/kernel/cred.c; echo $$?),0)
+ATOMIC_INC_FUNC = atomic_inc_not_zero
+else ifeq ($(shell grep -q "atomic_long_inc_not_zero" $(srctree)/kernel/cred.c; echo $$?),0)
+ATOMIC_INC_FUNC = atomic_long_inc_not_zero
+else
+$(info --  Neither atomic_inc_not_zero nor atomic_long_inc_not_zero found in kernel/cred.c)
+endif
+
+# Inform which function is being patched
+$(info --  Using $(ATOMIC_INC_FUNC) in get_cred_rcu patch.)
+
+ifneq ($(shell grep -Eq "^static int can_umount" $(srctree)/fs/namespace.c; echo $$?),0)
+$(info -- Adding function 'static int can_umount(const struct path *path, int flags);' to $(srctree)/fs/namespace.c)
+CAN_UMOUNT = static int can_umount(const struct path *path, int flags)\n\
+{\n\t\
+        struct mount *mnt = real_mount(path->mnt);\n\t\
+        if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW))\n\t\t\
+                return -EINVAL;\n\t\
+        if (!may_mount())\n\t\t\
+                return -EPERM;\n\t\
+        if (path->dentry != path->mnt->mnt_root)\n\t\t\
+                return -EINVAL;\n\t\
+        if (!check_mnt(mnt))\n\t\t\
+                return -EINVAL;\n\t\
+        if (mnt->mnt.mnt_flags & MNT_LOCKED)\n\t\t\
+                return -EINVAL;\n\t\
+        if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))\n\t\t\
+                return -EPERM;\n\t\
+        return 0;\n\
+}\n
+$(shell sed -i '/^static bool is_mnt_ns_file/i $(CAN_UMOUNT)' $(srctree)/fs/namespace.c;)
+endif
+
+ifneq ($(shell grep -Eq "^int path_umount" $(srctree)/fs/namespace.c; echo $$?),0)
+$(info --  Adding function 'int path_umount(struct path *path, int flags);' to $(srctree)/fs/namespace.c)
+PATH_UMOUNT = int path_umount(struct path *path, int flags)\n\
+{\n\t\
+        struct mount *mnt = real_mount(path->mnt);\n\t\
+        int ret;\n\t\
+        ret = can_umount(path, flags);\n\t\
+        if (!ret)\n\t\t\
+                ret = do_umount(mnt, flags);\n\t\
+        dput(path->dentry);\n\t\
+        mntput_no_expire(mnt);\n\t\
+        return ret;\n\
+}\n
+$(shell sed -i '/^static bool is_mnt_ns_file/i $(PATH_UMOUNT)' $(srctree)/fs/namespace.c;)
+endif
+
+ifneq ($(shell grep -Eq "^int path_umount" $(srctree)/fs/internal.h; echo $$?),0)
+$(shell sed -i '/^extern void __init mnt_init/a int path_umount(struct path *path, int flags);' $(srctree)/fs/internal.h;)
+$(info --  Adding 'int path_umount(struct path *path, int flags);' to $(srctree)/fs/internal.h)
+endif
+
 # Do checks before compile
 ifneq ($(shell grep -q "int path_umount" $(srctree)/fs/namespace.c; echo $$?),0)
 $(error -- Backporting path_umount is mandatory !! Read: https://kernelsu.org/guide/how-to-integrate-for-non-gki.html#how-to-backport-path-umount)