1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * sysctl.c: General linux system control interface
4 */
5
6 #include <linux/sysctl.h>
7 #include <linux/printk.h>
8 #include <linux/capability.h>
9 #include <linux/ratelimit.h>
10 #include "internal.h"
11
12 static const int ten_thousand = 10000;
13
14 static int proc_dointvec_minmax_sysadmin(const struct ctl_table *table, int write,
15 void *buffer, size_t *lenp, loff_t *ppos)
16 {
17 if (write && !capable(CAP_SYS_ADMIN))
18 return -EPERM;
19
20 return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
21 }
22
23 static struct ctl_table printk_sysctls[] = {
24 {
25 .procname = "printk",
26 .data = &console_loglevel,
27 .maxlen = 4*sizeof(int),
28 .mode = 0644,
29 .proc_handler = proc_dointvec,
30 },
31 {
32 .procname = "printk_ratelimit",
33 .data = &printk_ratelimit_state.interval,
34 .maxlen = sizeof(int),
35 .mode = 0644,
36 .proc_handler = proc_dointvec_jiffies,
37 },
38 {
39 .procname = "printk_ratelimit_burst",
40 .data = &printk_ratelimit_state.burst,
41 .maxlen = sizeof(int),
42 .mode = 0644,
43 .proc_handler = proc_dointvec,
44 },
45 {
46 .procname = "printk_delay",
47 .data = &printk_delay_msec,
48 .maxlen = sizeof(int),
49 .mode = 0644,
50 .proc_handler = proc_dointvec_minmax,
51 .extra1 = SYSCTL_ZERO,
52 .extra2 = (void *)&ten_thousand,
53 },
54 {
55 .procname = "printk_devkmsg",
56 .data = devkmsg_log_str,
57 .maxlen = DEVKMSG_STR_MAX_SIZE,
58 .mode = 0644,
59 .proc_handler = devkmsg_sysctl_set_loglvl,
60 },
61 {
62 .procname = "dmesg_restrict",
63 .data = &dmesg_restrict,
64 .maxlen = sizeof(int),
65 .mode = 0644,
66 .proc_handler = proc_dointvec_minmax_sysadmin,
67 .extra1 = SYSCTL_ZERO,
68 .extra2 = SYSCTL_ONE,
69 },
70 {
71 .procname = "kptr_restrict",
72 .data = &kptr_restrict,
73 .maxlen = sizeof(int),
74 .mode = 0644,
75 .proc_handler = proc_dointvec_minmax_sysadmin,
76 .extra1 = SYSCTL_ZERO,
77 .extra2 = SYSCTL_TWO,
78 },
79 };
80
81 void __init printk_sysctl_init(void)
82 {
83 register_sysctl_init("kernel", printk_sysctls);
84 }
85
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