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