-
Notifications
You must be signed in to change notification settings - Fork 41
/
main.go
122 lines (103 loc) · 2.43 KB
/
main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
package main
import (
_ "embed"
"fmt"
"github.com/cilium/ebpf"
"github.com/cilium/ebpf/asm"
"github.com/sirupsen/logrus"
"log"
"time"
manager "github.com/gojue/ebpfmanager"
)
var Probe []byte
const eBPFFuncName = "kprobe__security_socket_create"
const eBPFAsmValue = 255
var m1 = &manager.Manager{
Probes: []*manager.Probe{
{
UID: "MyFirstHook",
Section: "kprobe/vfs_mkdir",
AttachToFuncName: "vfs_mkdir",
EbpfFuncName: eBPFFuncName,
},
},
InstructionPatchers: []manager.InstructionPatcherFunc{patchBPFTelemetry},
}
const BPFTelemetryPatchCall = -1
func getAllProgramSpecs(m *manager.Manager) ([]*ebpf.ProgramSpec, error) {
var specs []*ebpf.ProgramSpec
for _, p := range m.Probes {
oldID := manager.ProbeIdentificationPair{p.UID, p.EbpfFuncName}
s, present, err := m.GetProgramSpec(oldID)
if err != nil {
return nil, err
}
if !present {
return nil, fmt.Errorf("could not find ProgramSpec for probe %v", oldID)
}
specs = append(specs, s...)
}
return specs, nil
}
func patchBPFTelemetry(m *manager.Manager) error {
specs, err := getAllProgramSpecs(m)
if err != nil {
return err
}
for _, spec := range specs {
if spec == nil {
continue
}
iter := spec.Instructions.Iterate()
for iter.Next() {
ins := iter.Ins
if !ins.IsBuiltinCall() {
continue
}
if ins.Constant != BPFTelemetryPatchCall {
continue
}
*ins = asm.Mov.Imm(asm.R1, int32(eBPFAsmValue)).WithMetadata(ins.Metadata)
}
}
return nil
}
func main() {
if err := run(); err != nil {
log.Fatal(err)
}
}
func run() error {
if err := m1.Init(recoverAssets()); err != nil {
return err
}
defer func() {
if err := m1.Stop(manager.CleanAll); err != nil {
log.Print(err)
}
}()
if err := m1.Start(); err != nil {
return err
}
log.Println("=> Use 'bpftool prog dump xlated id <prog-id>' to verify that the instruction has been patched")
log.Println("=> Enter to exit")
// check output with `bpftool prog dump xlated id <prog-id>`
/*
root@vm-ubuntu-arm64:/home/cfc4n# bpftool prog dump xlated id 664
0: (b7) r1 = 0
1: (b7) r1 = 255
2: (b7) r0 = 1
3: (95) exit
*/
// wait for eBPF program to be loaded
time.Sleep(time.Second * 3)
err := check(eBPFFuncName)
if err != nil {
logrus.Errorf("failed to check eBPF program: %v", err)
}
if err = m1.Stop(manager.CleanAll); err != nil {
logrus.Fatal(err)
}
log.Println("=> Stopped the manager")
return nil
}