| 1 | |
| 2 |
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| 3 |
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| 4 | #include <vmlinux.h>
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| 5 | #include <string.h>
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| 6 | #include <stdbool.h>
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| 7 | #include <bpf/bpf_helpers.h>
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| 8 | #include <bpf/bpf_tracing.h>
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| 9 | #include "bpf_misc.h"
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| 10 |
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| 11 | char _license[] SEC("license") = "GPL";
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| 12 |
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| 13 | const void *user_ptr = NULL;
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| 14 |
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| 15 | struct elem {
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| 16 | char data[128];
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| 17 | struct bpf_task_work tw;
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| 18 | };
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| 19 |
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| 20 | struct {
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| 21 | __uint(type, BPF_MAP_TYPE_HASH);
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| 22 | __uint(map_flags, BPF_F_NO_PREALLOC);
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| 23 | __uint(max_entries, 1);
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| 24 | __type(key, int);
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| 25 | __type(value, struct elem);
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| 26 | } hmap SEC(".maps");
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| 27 |
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| 28 | struct {
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| 29 | __uint(type, BPF_MAP_TYPE_ARRAY);
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| 30 | __uint(max_entries, 1);
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| 31 | __type(key, int);
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| 32 | __type(value, struct elem);
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| 33 | } arrmap SEC(".maps");
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| 34 |
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| 35 | static int process_work(struct bpf_map *map, void *key, void *value)
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| 36 | {
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| 37 | struct elem *work = value;
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| 38 |
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| 39 | bpf_copy_from_user_str(work->data, sizeof(work->data), (const void *)user_ptr, 0);
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| 40 | return 0;
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| 41 | }
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| 42 |
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| 43 | int key = 0;
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| 44 |
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| 45 | SEC("perf_event")
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| 46 | __failure __msg("doesn't match map pointer in R3")
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| 47 | int mismatch_map(struct pt_regs *args)
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| 48 | {
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| 49 | struct elem *work;
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| 50 | struct task_struct *task;
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| 51 |
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| 52 | task = bpf_get_current_task_btf();
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| 53 | work = bpf_map_lookup_elem(&arrmap, &key);
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| 54 | if (!work)
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| 55 | return 0;
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| 56 | bpf_task_work_schedule_resume(task, &work->tw, &hmap, process_work);
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| 57 | return 0;
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| 58 | }
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| 59 |
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| 60 | SEC("perf_event")
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| 61 | __failure __msg("R2 doesn't point to a map value")
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| 62 | int no_map_task_work(struct pt_regs *args)
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| 63 | {
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| 64 | struct task_struct *task;
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| 65 | struct bpf_task_work tw;
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| 66 |
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| 67 | task = bpf_get_current_task_btf();
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| 68 | bpf_task_work_schedule_resume(task, &tw, &hmap, process_work);
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| 69 | return 0;
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| 70 | }
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| 71 |
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| 72 | SEC("perf_event")
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| 73 | __failure __msg("Possibly NULL pointer passed to trusted R2")
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| 74 | int task_work_null(struct pt_regs *args)
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| 75 | {
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| 76 | struct task_struct *task;
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| 77 |
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| 78 | task = bpf_get_current_task_btf();
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| 79 | bpf_task_work_schedule_resume(task, NULL, &hmap, process_work);
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| 80 | return 0;
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| 81 | }
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| 82 |
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| 83 | SEC("perf_event")
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| 84 | __failure __msg("Possibly NULL pointer passed to trusted R3")
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| 85 | int map_null(struct pt_regs *args)
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| 86 | {
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| 87 | struct elem *work;
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| 88 | struct task_struct *task;
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| 89 |
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| 90 | task = bpf_get_current_task_btf();
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| 91 | work = bpf_map_lookup_elem(&arrmap, &key);
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| 92 | if (!work)
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| 93 | return 0;
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| 94 | bpf_task_work_schedule_resume(task, &work->tw, NULL, process_work);
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| 95 | return 0;
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| 96 | }
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