| 1 | // SPDX-License-Identifier: GPL-2.0-only |
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| 2 | /* |
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| 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 | /* |
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| 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, ns: &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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| 44 | |
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