You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
73 lines
1.9 KiB
73 lines
1.9 KiB
/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com |
|
* |
|
* This program is free software; you can redistribute it and/or |
|
* modify it under the terms of version 2 of the GNU General Public |
|
* License as published by the Free Software Foundation. |
|
*/ |
|
#include <linux/ptrace.h> |
|
#include <linux/version.h> |
|
#include <uapi/linux/bpf.h> |
|
#include <uapi/linux/seccomp.h> |
|
#include "bpf_helpers.h" |
|
|
|
#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F |
|
|
|
struct bpf_map_def SEC("maps") progs = { |
|
.type = BPF_MAP_TYPE_PROG_ARRAY, |
|
.key_size = sizeof(u32), |
|
.value_size = sizeof(u32), |
|
.max_entries = 1024, |
|
}; |
|
|
|
SEC("kprobe/__seccomp_filter") |
|
int bpf_prog1(struct pt_regs *ctx) |
|
{ |
|
int sc_nr = (int)PT_REGS_PARM1(ctx); |
|
|
|
/* dispatch into next BPF program depending on syscall number */ |
|
bpf_tail_call(ctx, &progs, sc_nr); |
|
|
|
/* fall through -> unknown syscall */ |
|
if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { |
|
char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; |
|
bpf_trace_printk(fmt, sizeof(fmt), sc_nr); |
|
} |
|
return 0; |
|
} |
|
|
|
/* we jump here when syscall number == __NR_write */ |
|
PROG(__NR_write)(struct pt_regs *ctx) |
|
{ |
|
struct seccomp_data sd; |
|
|
|
bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
|
if (sd.args[2] == 512) { |
|
char fmt[] = "write(fd=%d, buf=%p, size=%d)\n"; |
|
bpf_trace_printk(fmt, sizeof(fmt), |
|
sd.args[0], sd.args[1], sd.args[2]); |
|
} |
|
return 0; |
|
} |
|
|
|
PROG(__NR_read)(struct pt_regs *ctx) |
|
{ |
|
struct seccomp_data sd; |
|
|
|
bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
|
if (sd.args[2] > 128 && sd.args[2] <= 1024) { |
|
char fmt[] = "read(fd=%d, buf=%p, size=%d)\n"; |
|
bpf_trace_printk(fmt, sizeof(fmt), |
|
sd.args[0], sd.args[1], sd.args[2]); |
|
} |
|
return 0; |
|
} |
|
|
|
PROG(__NR_mmap)(struct pt_regs *ctx) |
|
{ |
|
char fmt[] = "mmap\n"; |
|
bpf_trace_printk(fmt, sizeof(fmt)); |
|
return 0; |
|
} |
|
|
|
char _license[] SEC("license") = "GPL"; |
|
u32 _version SEC("version") = LINUX_VERSION_CODE;
|
|
|