1 // SPDX-License-Identifier: GPL-2.0-only 1 // SPDX-License-Identifier: GPL-2.0-only
2 /* 2 /*
3 * ksyms_common.c: A split of kernel/kallsyms. 3 * ksyms_common.c: A split of kernel/kallsyms.c
4 * Contains a few generic function definations 4 * Contains a few generic function definations independent of config KALLSYMS.
5 */ 5 */
6 #include <linux/kallsyms.h> 6 #include <linux/kallsyms.h>
7 #include <linux/security.h> 7 #include <linux/security.h>
8 8
9 static inline int kallsyms_for_perf(void) 9 static inline int kallsyms_for_perf(void)
10 { 10 {
11 #ifdef CONFIG_PERF_EVENTS 11 #ifdef CONFIG_PERF_EVENTS
12 extern int sysctl_perf_event_paranoid; 12 extern int sysctl_perf_event_paranoid;
13 13
14 if (sysctl_perf_event_paranoid <= 1) 14 if (sysctl_perf_event_paranoid <= 1)
15 return 1; 15 return 1;
16 #endif 16 #endif
17 return 0; 17 return 0;
18 } 18 }
19 19
20 /* 20 /*
21 * We show kallsyms information even to normal 21 * We show kallsyms information even to normal users if we've enabled
22 * kernel profiling and are explicitly not par 22 * kernel profiling and are explicitly not paranoid (so kptr_restrict
23 * is clear, and sysctl_perf_event_paranoid is 23 * is clear, and sysctl_perf_event_paranoid isn't set).
24 * 24 *
25 * Otherwise, require CAP_SYSLOG (assuming kpt 25 * Otherwise, require CAP_SYSLOG (assuming kptr_restrict isn't set to
26 * block even that). 26 * block even that).
27 */ 27 */
28 bool kallsyms_show_value(const struct cred *cr 28 bool kallsyms_show_value(const struct cred *cred)
29 { 29 {
30 switch (kptr_restrict) { 30 switch (kptr_restrict) {
31 case 0: 31 case 0:
32 if (kallsyms_for_perf()) 32 if (kallsyms_for_perf())
33 return true; 33 return true;
34 fallthrough; 34 fallthrough;
35 case 1: 35 case 1:
36 if (security_capable(cred, &in 36 if (security_capable(cred, &init_user_ns, CAP_SYSLOG,
37 CAP_OPT_N 37 CAP_OPT_NOAUDIT) == 0)
38 return true; 38 return true;
39 fallthrough; 39 fallthrough;
40 default: 40 default:
41 return false; 41 return false;
42 } 42 }
43 } 43 }
44 44
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