1 files changed, 54 insertions, 0 deletions
diff --git a/kernel/pid_sysctl.h b/kernel/pid_sysctl.h
new file mode 100644
index 000000000..2ee41a3a1
--- /dev/null
+++ b/kernel/pid_sysctl.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_PID_SYSCTL_H
+#define LINUX_PID_SYSCTL_H
+
+#include <linux/pid_namespace.h>
+
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
+static int pid_mfd_noexec_dointvec_minmax(struct ctl_table *table,
+	int write, void *buf, size_t *lenp, loff_t *ppos)
+{
+	struct pid_namespace *ns = task_active_pid_ns(current);
+	struct ctl_table table_copy;
+	int err, scope, parent_scope;
+
+	if (write && !ns_capable(ns->user_ns, CAP_SYS_ADMIN))
+		return -EPERM;
+
+	table_copy = *table;
+
+	/* You cannot set a lower enforcement value than your parent. */
+	parent_scope = pidns_memfd_noexec_scope(ns->parent);
+	/* Equivalent to pidns_memfd_noexec_scope(ns). */
+	scope = max(READ_ONCE(ns->memfd_noexec_scope), parent_scope);
+
+	table_copy.data = &scope;
+	table_copy.extra1 = &parent_scope;
+
+	err = proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos);
+	if (!err && write)
+		WRITE_ONCE(ns->memfd_noexec_scope, scope);
+	return err;
+}
+
+static struct ctl_table pid_ns_ctl_table_vm[] = {
+	{
+		.procname	= "memfd_noexec",
+		.data		= &init_pid_ns.memfd_noexec_scope,
+		.maxlen		= sizeof(init_pid_ns.memfd_noexec_scope),
+		.mode		= 0644,
+		.proc_handler	= pid_mfd_noexec_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_TWO,
+	},
+	{ }
+};
+static inline void register_pid_ns_sysctl_table_vm(void)
+{
+	register_sysctl("vm", pid_ns_ctl_table_vm);
+}
+#else
+static inline void register_pid_ns_sysctl_table_vm(void) {}
+#endif
+
+#endif /* LINUX_PID_SYSCTL_H */