| 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 int pid_mfd_noexec_dointvec_minmax(struct ctl_table *table, |
| 9 | int write, void *buf, size_t *lenp, loff_t *ppos) |
| 10 | { |
| 11 | struct pid_namespace *ns = task_active_pid_ns(current); |
| 12 | struct ctl_table table_copy; |
| 13 | int err, scope, parent_scope; |
| 14 | |
| 15 | if (write && !ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
| 16 | return -EPERM; |
| 17 | |
| 18 | table_copy = *table; |
| 19 | |
| 20 | /* You cannot set a lower enforcement value than your parent. */ |
| 21 | parent_scope = pidns_memfd_noexec_scope(ns->parent); |
| 22 | /* Equivalent to pidns_memfd_noexec_scope(ns). */ |
| 23 | scope = max(READ_ONCE(ns->memfd_noexec_scope), parent_scope); |
| 24 | |
| 25 | table_copy.data = &scope; |
| 26 | table_copy.extra1 = &parent_scope; |
| 27 | |
| 28 | err = proc_dointvec_minmax(&table_copy, write, buf, lenp, ppos); |
| 29 | if (!err && write) |
| 30 | WRITE_ONCE(ns->memfd_noexec_scope, scope); |
| 31 | return err; |
| 32 | } |
| 33 | |
| 34 | static struct ctl_table pid_ns_ctl_table_vm[] = { |
| 35 | { |
| 36 | .procname = "memfd_noexec", |
| 37 | .data = &init_pid_ns.memfd_noexec_scope, |
| 38 | .maxlen = sizeof(init_pid_ns.memfd_noexec_scope), |
| 39 | .mode = 0644, |
| 40 | .proc_handler = pid_mfd_noexec_dointvec_minmax, |
| 41 | .extra1 = SYSCTL_ZERO, |
| 42 | .extra2 = SYSCTL_TWO, |
| 43 | }, |
| 44 | { } |
| 45 | }; |
| 46 | static inline void register_pid_ns_sysctl_table_vm(void) |
| 47 | { |
| 48 | register_sysctl("vm", pid_ns_ctl_table_vm); |
| 49 | } |
| 50 | #else |
| 51 | static inline void register_pid_ns_sysctl_table_vm(void) {} |
| 52 | #endif |
| 53 | |
| 54 | #endif /* LINUX_PID_SYSCTL_H */ |