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1/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7#include <linux/ptrace.h>
8#include <linux/version.h>
9#include <uapi/linux/bpf.h>
10#include <uapi/linux/seccomp.h>
11#include "bpf_helpers.h"
12
13#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F
14
15struct bpf_map_def SEC("maps") progs = {
16 .type = BPF_MAP_TYPE_PROG_ARRAY,
17 .key_size = sizeof(u32),
18 .value_size = sizeof(u32),
19 .max_entries = 1024,
20};
21
22SEC("kprobe/seccomp_phase1")
23int bpf_prog1(struct pt_regs *ctx)
24{
25 struct seccomp_data sd = {};
26
27 bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM1(ctx));
28
29 /* dispatch into next BPF program depending on syscall number */
30 bpf_tail_call(ctx, &progs, sd.nr);
31
32 /* fall through -> unknown syscall */
33 if (sd.nr >= __NR_getuid && sd.nr <= __NR_getsid) {
34 char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n";
35 bpf_trace_printk(fmt, sizeof(fmt), sd.nr);
36 }
37 return 0;
38}
39
40/* we jump here when syscall number == __NR_write */
41PROG(__NR_write)(struct pt_regs *ctx)
42{
43 struct seccomp_data sd = {};
44
45 bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM1(ctx));
46 if (sd.args[2] == 512) {
47 char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
48 bpf_trace_printk(fmt, sizeof(fmt),
49 sd.args[0], sd.args[1], sd.args[2]);
50 }
51 return 0;
52}
53
54PROG(__NR_read)(struct pt_regs *ctx)
55{
56 struct seccomp_data sd = {};
57
58 bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM1(ctx));
59 if (sd.args[2] > 128 && sd.args[2] <= 1024) {
60 char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
61 bpf_trace_printk(fmt, sizeof(fmt),
62 sd.args[0], sd.args[1], sd.args[2]);
63 }
64 return 0;
65}
66
67PROG(__NR_mmap)(struct pt_regs *ctx)
68{
69 char fmt[] = "mmap\n";
70 bpf_trace_printk(fmt, sizeof(fmt));
71 return 0;
72}
73
74char _license[] SEC("license") = "GPL";
75u32 _version SEC("version") = LINUX_VERSION_CODE;
1/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7#include <linux/ptrace.h>
8#include <linux/version.h>
9#include <uapi/linux/bpf.h>
10#include <uapi/linux/seccomp.h>
11#include <uapi/linux/unistd.h>
12#include "syscall_nrs.h"
13#include <bpf/bpf_helpers.h>
14#include <bpf/bpf_tracing.h>
15
16#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F
17
18struct {
19 __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
20 __uint(key_size, sizeof(u32));
21 __uint(value_size, sizeof(u32));
22#ifdef __mips__
23 __uint(max_entries, 6000); /* MIPS n64 syscalls start at 5000 */
24#else
25 __uint(max_entries, 1024);
26#endif
27} progs SEC(".maps");
28
29SEC("kprobe/__seccomp_filter")
30int bpf_prog1(struct pt_regs *ctx)
31{
32 int sc_nr = (int)PT_REGS_PARM1(ctx);
33
34 /* dispatch into next BPF program depending on syscall number */
35 bpf_tail_call(ctx, &progs, sc_nr);
36
37 /* fall through -> unknown syscall */
38 if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) {
39 char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n";
40 bpf_trace_printk(fmt, sizeof(fmt), sc_nr);
41 }
42 return 0;
43}
44
45/* we jump here when syscall number == __NR_write */
46PROG(SYS__NR_write)(struct pt_regs *ctx)
47{
48 struct seccomp_data sd;
49
50 bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
51 if (sd.args[2] == 512) {
52 char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
53 bpf_trace_printk(fmt, sizeof(fmt),
54 sd.args[0], sd.args[1], sd.args[2]);
55 }
56 return 0;
57}
58
59PROG(SYS__NR_read)(struct pt_regs *ctx)
60{
61 struct seccomp_data sd;
62
63 bpf_probe_read_kernel(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
64 if (sd.args[2] > 128 && sd.args[2] <= 1024) {
65 char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
66 bpf_trace_printk(fmt, sizeof(fmt),
67 sd.args[0], sd.args[1], sd.args[2]);
68 }
69 return 0;
70}
71
72#ifdef __NR_mmap2
73PROG(SYS__NR_mmap2)(struct pt_regs *ctx)
74{
75 char fmt[] = "mmap2\n";
76
77 bpf_trace_printk(fmt, sizeof(fmt));
78 return 0;
79}
80#endif
81
82#ifdef __NR_mmap
83PROG(SYS__NR_mmap)(struct pt_regs *ctx)
84{
85 char fmt[] = "mmap\n";
86
87 bpf_trace_printk(fmt, sizeof(fmt));
88 return 0;
89}
90#endif
91
92char _license[] SEC("license") = "GPL";
93u32 _version SEC("version") = LINUX_VERSION_CODE;