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: 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: 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 */ |
55 | |