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5bacd780 AS |
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 | ||
15 | struct 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 | ||
22 | SEC("kprobe/seccomp_phase1") | |
23 | int bpf_prog1(struct pt_regs *ctx) | |
24 | { | |
25 | struct seccomp_data sd = {}; | |
26 | ||
27 | bpf_probe_read(&sd, sizeof(sd), (void *)ctx->di); | |
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 */ | |
41 | PROG(__NR_write)(struct pt_regs *ctx) | |
42 | { | |
43 | struct seccomp_data sd = {}; | |
44 | ||
45 | bpf_probe_read(&sd, sizeof(sd), (void *)ctx->di); | |
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 | ||
54 | PROG(__NR_read)(struct pt_regs *ctx) | |
55 | { | |
56 | struct seccomp_data sd = {}; | |
57 | ||
58 | bpf_probe_read(&sd, sizeof(sd), (void *)ctx->di); | |
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 | ||
67 | PROG(__NR_mmap)(struct pt_regs *ctx) | |
68 | { | |
69 | char fmt[] = "mmap\n"; | |
70 | bpf_trace_printk(fmt, sizeof(fmt)); | |
71 | return 0; | |
72 | } | |
73 | ||
74 | char _license[] SEC("license") = "GPL"; | |
75 | u32 _version SEC("version") = LINUX_VERSION_CODE; |