1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2022 Sony Group Corporation */
3 #include <vmlinux.h>
4 
5 #include <bpf/bpf_core_read.h>
6 #include <bpf/bpf_helpers.h>
7 #include <bpf/bpf_tracing.h>
8 #include "bpf_misc.h"
9 
10 int arg1 = 0;
11 unsigned long arg2 = 0;
12 unsigned long arg3 = 0;
13 unsigned long arg4_cx = 0;
14 unsigned long arg4 = 0;
15 unsigned long arg5 = 0;
16 
17 int arg1_core = 0;
18 unsigned long arg2_core = 0;
19 unsigned long arg3_core = 0;
20 unsigned long arg4_core_cx = 0;
21 unsigned long arg4_core = 0;
22 unsigned long arg5_core = 0;
23 
24 int option_syscall = 0;
25 unsigned long arg2_syscall = 0;
26 unsigned long arg3_syscall = 0;
27 unsigned long arg4_syscall = 0;
28 unsigned long arg5_syscall = 0;
29 
30 const volatile pid_t filter_pid = 0;
31 
32 SEC("kprobe/" SYS_PREFIX "sys_prctl")
33 int BPF_KPROBE(handle_sys_prctl)
34 {
35 	struct pt_regs *real_regs;
36 	pid_t pid = bpf_get_current_pid_tgid() >> 32;
37 	unsigned long tmp = 0;
38 
39 	if (pid != filter_pid)
40 		return 0;
41 
42 	real_regs = PT_REGS_SYSCALL_REGS(ctx);
43 
44 	/* test for PT_REGS_PARM */
45 
46 #if !defined(bpf_target_arm64) && !defined(bpf_target_s390)
47 	bpf_probe_read_kernel(&tmp, sizeof(tmp), &PT_REGS_PARM1_SYSCALL(real_regs));
48 #endif
49 	arg1 = tmp;
50 	bpf_probe_read_kernel(&arg2, sizeof(arg2), &PT_REGS_PARM2_SYSCALL(real_regs));
51 	bpf_probe_read_kernel(&arg3, sizeof(arg3), &PT_REGS_PARM3_SYSCALL(real_regs));
52 	bpf_probe_read_kernel(&arg4_cx, sizeof(arg4_cx), &PT_REGS_PARM4(real_regs));
53 	bpf_probe_read_kernel(&arg4, sizeof(arg4), &PT_REGS_PARM4_SYSCALL(real_regs));
54 	bpf_probe_read_kernel(&arg5, sizeof(arg5), &PT_REGS_PARM5_SYSCALL(real_regs));
55 
56 	/* test for the CORE variant of PT_REGS_PARM */
57 	arg1_core = PT_REGS_PARM1_CORE_SYSCALL(real_regs);
58 	arg2_core = PT_REGS_PARM2_CORE_SYSCALL(real_regs);
59 	arg3_core = PT_REGS_PARM3_CORE_SYSCALL(real_regs);
60 	arg4_core_cx = PT_REGS_PARM4_CORE(real_regs);
61 	arg4_core = PT_REGS_PARM4_CORE_SYSCALL(real_regs);
62 	arg5_core = PT_REGS_PARM5_CORE_SYSCALL(real_regs);
63 
64 	return 0;
65 }
66 
67 SEC("ksyscall/prctl")
68 int BPF_KSYSCALL(prctl_enter, int option, unsigned long arg2,
69 		 unsigned long arg3, unsigned long arg4, unsigned long arg5)
70 {
71 	pid_t pid = bpf_get_current_pid_tgid() >> 32;
72 
73 	if (pid != filter_pid)
74 		return 0;
75 
76 	option_syscall = option;
77 	arg2_syscall = arg2;
78 	arg3_syscall = arg3;
79 	arg4_syscall = arg4;
80 	arg5_syscall = arg5;
81 	return 0;
82 }
83 
84 char _license[] SEC("license") = "GPL";
85