tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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_filter")
23int bpf_prog1(struct pt_regs *ctx)
24{
25 int sc_nr = (int)PT_REGS_PARM1(ctx);
26
27 /* dispatch into next BPF program depending on syscall number */
28 bpf_tail_call(ctx, &progs, sc_nr);
29
30 /* fall through -> unknown syscall */
31 if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) {
32 char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n";
33 bpf_trace_printk(fmt, sizeof(fmt), sc_nr);
34 }
35 return 0;
36}
37
38/* we jump here when syscall number == __NR_write */
39PROG(__NR_write)(struct pt_regs *ctx)
40{
41 struct seccomp_data sd;
42
43 bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
44 if (sd.args[2] == 512) {
45 char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
46 bpf_trace_printk(fmt, sizeof(fmt),
47 sd.args[0], sd.args[1], sd.args[2]);
48 }
49 return 0;
50}
51
52PROG(__NR_read)(struct pt_regs *ctx)
53{
54 struct seccomp_data sd;
55
56 bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
57 if (sd.args[2] > 128 && sd.args[2] <= 1024) {
58 char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
59 bpf_trace_printk(fmt, sizeof(fmt),
60 sd.args[0], sd.args[1], sd.args[2]);
61 }
62 return 0;
63}
64
65PROG(__NR_mmap)(struct pt_regs *ctx)
66{
67 char fmt[] = "mmap\n";
68 bpf_trace_printk(fmt, sizeof(fmt));
69 return 0;
70}
71
72char _license[] SEC("license") = "GPL";
73u32 _version SEC("version") = LINUX_VERSION_CODE;