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/* 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(const 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 */
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