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_helpers.h"
14
15#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F
16
17struct bpf_map_def SEC("maps") progs = {
18	.type = BPF_MAP_TYPE_PROG_ARRAY,
19	.key_size = sizeof(u32),
20	.value_size = sizeof(u32),
21#ifdef __mips__
22	.max_entries = 6000, /* MIPS n64 syscalls start at 5000 */
23#else
24	.max_entries = 1024,
25#endif
26};
27
28SEC("kprobe/__seccomp_filter")
29int bpf_prog1(struct pt_regs *ctx)
30{
31	int sc_nr = (int)PT_REGS_PARM1(ctx);
 
 
32
33	/* dispatch into next BPF program depending on syscall number */
34	bpf_tail_call(ctx, &progs, sc_nr);
35
36	/* fall through -> unknown syscall */
37	if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) {
38		char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n";
39		bpf_trace_printk(fmt, sizeof(fmt), sc_nr);
40	}
41	return 0;
42}
43
44/* we jump here when syscall number == __NR_write */
45PROG(SYS__NR_write)(struct pt_regs *ctx)
46{
47	struct seccomp_data sd;
48
49	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
50	if (sd.args[2] == 512) {
51		char fmt[] = "write(fd=%d, buf=%p, size=%d)\n";
52		bpf_trace_printk(fmt, sizeof(fmt),
53				 sd.args[0], sd.args[1], sd.args[2]);
54	}
55	return 0;
56}
57
58PROG(SYS__NR_read)(struct pt_regs *ctx)
59{
60	struct seccomp_data sd;
61
62	bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx));
63	if (sd.args[2] > 128 && sd.args[2] <= 1024) {
64		char fmt[] = "read(fd=%d, buf=%p, size=%d)\n";
65		bpf_trace_printk(fmt, sizeof(fmt),
66				 sd.args[0], sd.args[1], sd.args[2]);
67	}
68	return 0;
69}
70
71PROG(SYS__NR_mmap)(struct pt_regs *ctx)
72{
73	char fmt[] = "mmap\n";
74	bpf_trace_printk(fmt, sizeof(fmt));
75	return 0;
76}
77
78char _license[] SEC("license") = "GPL";
79u32 _version SEC("version") = LINUX_VERSION_CODE;