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;

 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;