Commit | Line | Data |
---|---|---|
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> | |
af392a8f | 11 | #include <uapi/linux/unistd.h> |
4b7190e8 | 12 | #include "syscall_nrs.h" |
5bacd780 AS |
13 | #include "bpf_helpers.h" |
14 | ||
15 | #define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F | |
16 | ||
17 | struct bpf_map_def SEC("maps") progs = { | |
18 | .type = BPF_MAP_TYPE_PROG_ARRAY, | |
19 | .key_size = sizeof(u32), | |
20 | .value_size = sizeof(u32), | |
4b7190e8 DD |
21 | #ifdef __mips__ |
22 | .max_entries = 6000, /* MIPS n64 syscalls start at 5000 */ | |
23 | #else | |
5bacd780 | 24 | .max_entries = 1024, |
4b7190e8 | 25 | #endif |
5bacd780 AS |
26 | }; |
27 | ||
973d94d8 | 28 | SEC("kprobe/__seccomp_filter") |
5bacd780 AS |
29 | int bpf_prog1(struct pt_regs *ctx) |
30 | { | |
973d94d8 | 31 | int sc_nr = (int)PT_REGS_PARM1(ctx); |
5bacd780 AS |
32 | |
33 | /* dispatch into next BPF program depending on syscall number */ | |
973d94d8 | 34 | bpf_tail_call(ctx, &progs, sc_nr); |
5bacd780 AS |
35 | |
36 | /* fall through -> unknown syscall */ | |
973d94d8 | 37 | if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { |
5bacd780 | 38 | char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; |
973d94d8 | 39 | bpf_trace_printk(fmt, sizeof(fmt), sc_nr); |
5bacd780 AS |
40 | } |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* we jump here when syscall number == __NR_write */ | |
4b7190e8 | 45 | PROG(SYS__NR_write)(struct pt_regs *ctx) |
5bacd780 | 46 | { |
02413cab | 47 | struct seccomp_data sd; |
5bacd780 | 48 | |
973d94d8 | 49 | bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
5bacd780 AS |
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 | ||
4b7190e8 | 58 | PROG(SYS__NR_read)(struct pt_regs *ctx) |
5bacd780 | 59 | { |
02413cab | 60 | struct seccomp_data sd; |
5bacd780 | 61 | |
973d94d8 | 62 | bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
5bacd780 AS |
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 | ||
4b7190e8 | 71 | PROG(SYS__NR_mmap)(struct pt_regs *ctx) |
5bacd780 AS |
72 | { |
73 | char fmt[] = "mmap\n"; | |
74 | bpf_trace_printk(fmt, sizeof(fmt)); | |
75 | return 0; | |
76 | } | |
77 | ||
78 | char _license[] SEC("license") = "GPL"; | |
79 | u32 _version SEC("version") = LINUX_VERSION_CODE; |