65 lines
1.3 KiB
C
65 lines
1.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_core_read.h>
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struct task_struct___bad {
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int pid;
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int fake_field;
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void *fake_field_subprog;
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} __attribute__((preserve_access_index));
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SEC("?raw_tp/sys_enter")
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int bad_relo(const void *ctx)
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{
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static struct task_struct___bad *t;
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return bpf_core_field_size(t->fake_field);
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}
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static __noinline int bad_subprog(void)
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{
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static struct task_struct___bad *t;
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/* ugliness below is a field offset relocation */
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return (void *)&t->fake_field_subprog - (void *)t;
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}
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SEC("?raw_tp/sys_enter")
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int bad_relo_subprog(const void *ctx)
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{
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static struct task_struct___bad *t;
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return bad_subprog() + bpf_core_field_size(t->pid);
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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, int);
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} existing_map SEC(".maps");
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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, int);
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} missing_map SEC(".maps");
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SEC("?raw_tp/sys_enter")
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int use_missing_map(const void *ctx)
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{
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int zero = 0, *value;
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value = bpf_map_lookup_elem(&existing_map, &zero);
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value = bpf_map_lookup_elem(&missing_map, &zero);
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return value != NULL;
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}
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char _license[] SEC("license") = "GPL";
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