1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
|
/*
* Copyright (c) 2015 Egor Tensin <Egor.Tensin@gmail.com>
* This file is part of the "Windows 7 drivers" project.
* For details, see https://github.com/egor-tensin/windows7-drivers.
* Distributed under the MIT License.
*/
#include <ntddk.h>
static __int64 old_msr_value = 0;
static void *old_ki_fast_call_entry = NULL;
static void __stdcall log_system_call()
{
static LONG count = 0;
static const LONG throttle = 10000;
LONG n = InterlockedIncrement(&count);
if (n % throttle == 0)
DbgPrint("Another %ld of `sysenter`s (eax=)!\n", throttle);
}
static void __declspec(naked) new_ki_fast_call_entry()
{
__asm
{
pushad
pushfd
mov ecx, 0x23
push 0x30
pop fs
mov ds, cx
mov es, cx
call log_system_call
popfd
popad
jmp [old_ki_fast_call_entry]
}
}
#define IA32_SYSENTER_EIP 0x176
static void hook_sysenter()
{
/*
__asm
{
mov ecx, IA32_SYSENTER_EIP
rdmsr
mov old_ki_fast_call_entry, eax
mov eax, new_ki_fast_call_entry
xor edx, edx
wrmsr
}
*/
old_msr_value = __readmsr(IA32_SYSENTER_EIP);
#pragma warning(push)
#pragma warning(disable: 4305)
old_ki_fast_call_entry = (void *) old_msr_value;
#pragma warning(pop)
__writemsr(IA32_SYSENTER_EIP, new_ki_fast_call_entry);
}
static void unhook_sysenter()
{
/*
__asm
{
mov ecx, IA32_SYSENTER_EIP
mov eax, old_ki_fast_call_entry
xor edx, edx
wrmsr
}
*/
__writemsr(IA32_SYSENTER_EIP, old_msr_value);
}
static void on_driver_unload(DRIVER_OBJECT *driver_object)
{
KTIMER timer;
LARGE_INTEGER time_out;
UNREFERENCED_PARAMETER(driver_object);
unhook_sysenter();
KeInitializeTimer(&timer);
time_out.QuadPart = -30000000;
KeSetTimer(&timer, time_out, NULL);
KeWaitForSingleObject(&timer, Executive, KernelMode, FALSE, NULL);
}
NTSTATUS DriverEntry(
DRIVER_OBJECT *driver_object,
UNICODE_STRING *registry_path)
{
UNREFERENCED_PARAMETER(registry_path);
driver_object->DriverUnload = on_driver_unload;
hook_sysenter();
return STATUS_SUCCESS;
}
|
