From eda4f5b5bcf9ca36a2ba3250b366ad1fb4bab28c Mon Sep 17 00:00:00 2001
From: zhong-jiawei-1 <zhongjiawei1@huawei.com>
Date: Tue, 18 Oct 2022 17:18:47 +0800
Subject: [PATCH] runc:support namespaced kernel params can be changed in
 system container

---
 runc-1.1.3/libcontainer/rootfs_linux.go       | 26 +++++++++++++++++++
 .../libcontainer/standard_init_linux.go       |  7 +++++
 2 files changed, 33 insertions(+)

diff --git a/runc-1.1.3/libcontainer/rootfs_linux.go b/runc-1.1.3/libcontainer/rootfs_linux.go
index 3cfd2bf..4dbe9f4 100644
--- a/runc-1.1.3/libcontainer/rootfs_linux.go
+++ b/runc-1.1.3/libcontainer/rootfs_linux.go
@@ -417,6 +417,9 @@ func mountToRootfs(m *configs.Mount, c *mountConfig) error {
 		} else if fi.Mode()&os.ModeDir == 0 {
 			return fmt.Errorf("filesystem %q must be mounted on ordinary directory", m.Device)
 		}
+		if strings.HasPrefix(m.Destination, "/proc/sys/") {
+			return nil
+		}
 		if err := os.MkdirAll(dest, 0o755); err != nil {
 			return err
 		}
@@ -1009,6 +1012,29 @@ func readonlyPath(path string) error {
 	return nil
 }
 
+// remountReadWrite will bind over the top of an existing path and ensure that it is read-write.
+func remountReadWrite(path string) error {
+	for i := 0; i < 5; i++ {
+		if err := syscall.Mount("", path, "", syscall.MS_REMOUNT, ""); err != nil && !os.IsNotExist(err) {
+			switch err {
+			case syscall.EINVAL:
+				// Probably not a mountpoint, use bind-mount
+				if err := syscall.Mount(path, path, "", syscall.MS_BIND, ""); err != nil {
+					return err
+				}
+				return syscall.Mount(path, path, "", syscall.MS_BIND|syscall.MS_REMOUNT|syscall.MS_REC|defaultMountFlags, "")
+			case syscall.EBUSY:
+				time.Sleep(100 * time.Millisecond)
+				continue
+			default:
+				return err
+			}
+		}
+		return nil
+	}
+	return fmt.Errorf("unable to mount %s as readwrite max retries reached", path)
+}
+
 // remountReadonly will remount an existing mount point and ensure that it is read-only.
 func remountReadonly(m *configs.Mount) error {
 	var (
diff --git a/runc-1.1.3/libcontainer/standard_init_linux.go b/runc-1.1.3/libcontainer/standard_init_linux.go
index ab553ef..0dd51b2 100644
--- a/runc-1.1.3/libcontainer/standard_init_linux.go
+++ b/runc-1.1.3/libcontainer/standard_init_linux.go
@@ -141,6 +141,13 @@ func (l *linuxStandardInit) Init() error {
 			return fmt.Errorf("can't make %q read-only: %w", path, err)
 		}
 	}
+	for _, m := range l.config.Config.Mounts {
+		if m.Flags&syscall.MS_RDONLY == 0 && m.Device == "proc" && strings.HasPrefix(m.Destination, "/proc/sys/") {
+			if err := remountReadWrite(m.Destination); err != nil {
+				return err
+			}
+		}
+	}
 	for _, path := range l.config.Config.MaskPaths {
 		if err := maskPath(path, l.config.Config.MountLabel); err != nil {
 			return fmt.Errorf("can't mask path %s: %w", path, err)
-- 
2.30.0

