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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> | |
af392a8f | 11 | #include <uapi/linux/unistd.h> |
4b7190e8 | 12 | #include "syscall_nrs.h" |
5bacd780 | 13 | #include "bpf_helpers.h" |
3ac4dbe3 | 14 | #include "bpf_tracing.h" |
5bacd780 AS |
15 | |
16 | #define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F | |
17 | ||
18 | struct bpf_map_def SEC("maps") progs = { | |
19 | .type = BPF_MAP_TYPE_PROG_ARRAY, | |
20 | .key_size = sizeof(u32), | |
21 | .value_size = sizeof(u32), | |
4b7190e8 DD |
22 | #ifdef __mips__ |
23 | .max_entries = 6000, /* MIPS n64 syscalls start at 5000 */ | |
24 | #else | |
5bacd780 | 25 | .max_entries = 1024, |
4b7190e8 | 26 | #endif |
5bacd780 AS |
27 | }; |
28 | ||
973d94d8 | 29 | SEC("kprobe/__seccomp_filter") |
5bacd780 AS |
30 | int bpf_prog1(struct pt_regs *ctx) |
31 | { | |
973d94d8 | 32 | int sc_nr = (int)PT_REGS_PARM1(ctx); |
5bacd780 AS |
33 | |
34 | /* dispatch into next BPF program depending on syscall number */ | |
973d94d8 | 35 | bpf_tail_call(ctx, &progs, sc_nr); |
5bacd780 AS |
36 | |
37 | /* fall through -> unknown syscall */ | |
973d94d8 | 38 | if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { |
5bacd780 | 39 | char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; |
973d94d8 | 40 | bpf_trace_printk(fmt, sizeof(fmt), sc_nr); |
5bacd780 AS |
41 | } |
42 | return 0; | |
43 | } | |
44 | ||
45 | /* we jump here when syscall number == __NR_write */ | |
4b7190e8 | 46 | PROG(SYS__NR_write)(struct pt_regs *ctx) |
5bacd780 | 47 | { |
02413cab | 48 | struct seccomp_data sd; |
5bacd780 | 49 | |
973d94d8 | 50 | bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
5bacd780 AS |
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 | ||
4b7190e8 | 59 | PROG(SYS__NR_read)(struct pt_regs *ctx) |
5bacd780 | 60 | { |
02413cab | 61 | struct seccomp_data sd; |
5bacd780 | 62 | |
973d94d8 | 63 | bpf_probe_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); |
5bacd780 AS |
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 | ||
bb4b5c08 IK |
72 | #ifdef __NR_mmap2 |
73 | PROG(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 | |
4b7190e8 | 83 | PROG(SYS__NR_mmap)(struct pt_regs *ctx) |
5bacd780 AS |
84 | { |
85 | char fmt[] = "mmap\n"; | |
bb4b5c08 | 86 | |
5bacd780 AS |
87 | bpf_trace_printk(fmt, sizeof(fmt)); |
88 | return 0; | |
89 | } | |
bb4b5c08 | 90 | #endif |
5bacd780 AS |
91 | |
92 | char _license[] SEC("license") = "GPL"; | |
93 | u32 _version SEC("version") = LINUX_VERSION_CODE; |