kernel/pid_sysctl.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef LINUX_PID_SYSCTL_H
   3 #define LINUX_PID_SYSCTL_H
   4
   5 #include <linux/pid_namespace.h>
   6
   7 #if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
   8 static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns)
   9 {
  10         ns->memfd_noexec_scope =
  11                 task_active_pid_ns(current)->memfd_noexec_scope;
  12 }
  13
  14 static int pid_mfd_noexec_dointvec_minmax(struct ctl_table *table,
  15         int write, void *buf, size_t *lenp, loff_t *ppos)
  16 {
  17         struct pid_namespace *ns = task_active_pid_ns(current);
  18         struct ctl_table table_copy;
  19
  20         if (write && !ns_capable(ns->user_ns, CAP_SYS_ADMIN))
  21                 return -EPERM;
  22
  23         table_copy = *table;
  24         if (ns != &init_pid_ns)
  25                 table_copy.data = &ns->memfd_noexec_scope;
  26
  27         /*
  28          * set minimum to current value, the effect is only bigger
  29          * value is accepted.
  30          */
  31         if (*(int *)table_copy.data > *(int *)table_copy.extra1)
  32                 table_copy.extra1 = table_copy.data;
  33
  34         return proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos);
  35 }
  36
  37 static struct ctl_table pid_ns_ctl_table_vm[] = {
  38         {
  39                 .procname       = "memfd_noexec",
  40                 .data           = &init_pid_ns.memfd_noexec_scope,
  41                 .maxlen         = sizeof(init_pid_ns.memfd_noexec_scope),
  42                 .mode           = 0644,
  43                 .proc_handler   = pid_mfd_noexec_dointvec_minmax,
  44                 .extra1         = SYSCTL_ZERO,
  45                 .extra2         = SYSCTL_TWO,
  46         },
  47         { }
  48 };
  49 static inline void register_pid_ns_sysctl_table_vm(void)
  50 {
  51         register_sysctl("vm", pid_ns_ctl_table_vm);
  52 }
  53 #else
  54 static inline void initialize_memfd_noexec_scope(struct pid_namespace *ns) {}
  55 static inline void register_pid_ns_sysctl_table_vm(void) {}
  56 #endif
  57
  58 #endif /* LINUX_PID_SYSCTL_H */