55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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struct map_elem {
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struct bpf_timer timer;
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struct bpf_spin_lock lock;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct map_elem);
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} amap SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct map_elem);
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} hmap SEC(".maps");
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int pid = 0;
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int crash_map = 0; /* 0 for amap, 1 for hmap */
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SEC("fentry/do_nanosleep")
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int sys_enter(void *ctx)
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{
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struct map_elem *e, value = {};
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void *map = crash_map ? (void *)&hmap : (void *)&amap;
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if (bpf_get_current_task_btf()->tgid != pid)
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return 0;
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*(void **)&value = (void *)0xdeadcaf3;
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bpf_map_update_elem(map, &(int){0}, &value, 0);
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/* For array map, doing bpf_map_update_elem will do a
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* check_and_free_timer_in_array, which will trigger the crash if timer
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* pointer was overwritten, for hmap we need to use bpf_timer_cancel.
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*/
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if (crash_map == 1) {
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e = bpf_map_lookup_elem(map, &(int){0});
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if (!e)
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return 0;
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bpf_timer_cancel(&e->timer);
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}
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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