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
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
/*
* The PCI Library -- Access to i386 I/O ports on Windows
*
* Copyright (c) 2004 Alexander Stock <stock.alexander@gmx.de>
* Copyright (c) 2006 Martin Mares <mj@ucw.cz>
* Copyright (c) 2021 Pali Rohár <pali@kernel.org>
*
* Can be freely distributed and used under the terms of the GNU GPL v2+
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <windows.h>
#include "win32-helpers.h"
#include "i386-io-access.h"
/*
* Define __readeflags() for MSVC and GCC compilers.
* MSVC since version 14.00 included in WDK 6001 and since version 15.00
* included in VS 2008 provides __readeflags() intrinsic for both 32 and 64-bit
* modes. WDK 6001 defines macro __BUILDMACHINE__ to value WinDDK. VS 2008 does
* not define this macro at all. MSVC throws error if name of user defined
* function conflicts with some MSVC intrinsic.
* MSVC supports inline assembly via __asm keyword in 32-bit mode only.
* GCC version 4.9.0 and higher provides __builtin_ia32_readeflags_uXX()
* builtin for XX-mode. This builtin is also available as __readeflags()
* function indirectly via <x86intrin.h> header file.
*
* CAVEAT: Semicolon in MSVC __asm block means start of the comment, and not
* end of the __asm statement, like it is for all other C statements. Also
* function which uses MSVC inline assembly cannot be inlined to another function
* (compiler reports a warning about it, not a fatal error). So we add explicit
* curly brackets for __asm blocks, remove misleading semicolons and do not
* declare functions as inline.
*/
#if defined(_MSC_VER) && (_MSC_VER >= 1500 || (_MSC_VER >= 1400 && defined(__BUILDMACHINE__)))
#pragma intrinsic(__readeflags)
#elif defined(__GNUC__) && ((__GNUC__ == 4 && __GNUC_MINOR__ >= 9) || (__GNUC__ > 4))
#include <x86intrin.h>
#elif defined(_MSC_VER) && defined(_M_IX86)
static unsigned int
__readeflags(void)
{
__asm {
pushfd
pop eax
}
}
#elif defined(__GNUC__)
static inline unsigned
#ifdef __x86_64__
long long
#endif
int
__readeflags(void)
{
unsigned
#ifdef __x86_64__
long long
#endif
int eflags;
asm volatile ("pushf\n\tpop %0\n" : "=r" (eflags));
return eflags;
}
#else
#error "Unsupported compiler"
#endif
/* Read IOPL of the current process, IOPL is stored in eflag bits [13:12]. */
#define read_iopl() ((__readeflags() >> 12) & 0x3)
/*
* Unfortunately NtSetInformationProcess() function, ProcessUserModeIOPL
* constant and all other helpers for its usage are not specified in any
* standard WinAPI header file. So define all of required constants and types.
* Function NtSetInformationProcess() is available in ntdll.dll library on all
* Windows systems but marked as it can be removed in some future version.
*/
#ifndef NTSTATUS
#define NTSTATUS LONG
#endif
#ifndef STATUS_NOT_IMPLEMENTED
#define STATUS_NOT_IMPLEMENTED (NTSTATUS)0xC0000002
#endif
#ifndef STATUS_PRIVILEGE_NOT_HELD
#define STATUS_PRIVILEGE_NOT_HELD (NTSTATUS)0xC0000061
#endif
#ifndef PROCESSINFOCLASS
#define PROCESSINFOCLASS DWORD
#endif
#ifndef ProcessUserModeIOPL
#define ProcessUserModeIOPL 16
#endif
typedef NTSTATUS (NTAPI *NtSetInformationProcessProt)(HANDLE ProcessHandle, PROCESSINFOCLASS ProcessInformationClass, PVOID ProcessInformation, ULONG ProcessInformationLength);
typedef ULONG (NTAPI *RtlNtStatusToDosErrorProt)(NTSTATUS Status);
/*
* ProcessUserModeIOPL is syscall for NT kernel to change x86 IOPL
* of the current running process to 3.
*
* Process handle argument for ProcessUserModeIOPL is ignored and
* IOPL is always changed for the current running process. So pass
* GetCurrentProcess() handle for documentation purpose. Process
* information buffer and length are unused for ProcessUserModeIOPL.
*
* ProcessUserModeIOPL may success (return value >= 0) or may fail
* because it is not implemented or because of missing privilege.
* Other errors are not defined, so handle them as unknown.
*/
static BOOL
SetProcessUserModeIOPLFunc(LPVOID Arg)
{
RtlNtStatusToDosErrorProt RtlNtStatusToDosErrorPtr = (RtlNtStatusToDosErrorProt)(((LPVOID *)Arg)[1]);
NtSetInformationProcessProt NtSetInformationProcessPtr = (NtSetInformationProcessProt)(((LPVOID *)Arg)[0]);
NTSTATUS nt_status = NtSetInformationProcessPtr(GetCurrentProcess(), ProcessUserModeIOPL, NULL, 0);
if (nt_status >= 0)
return TRUE;
/*
* If we have optional RtlNtStatusToDosError() function then use it for
* translating NT status to Win32 error. If we do not have it then translate
* two important status codes which we use later STATUS_NOT_IMPLEMENTED and
* STATUS_PRIVILEGE_NOT_HELD.
*/
if (RtlNtStatusToDosErrorPtr)
SetLastError(RtlNtStatusToDosErrorPtr(nt_status));
else if (nt_status == STATUS_NOT_IMPLEMENTED)
SetLastError(ERROR_INVALID_FUNCTION);
else if (nt_status == STATUS_PRIVILEGE_NOT_HELD)
SetLastError(ERROR_PRIVILEGE_NOT_HELD);
else
SetLastError(ERROR_GEN_FAILURE);
return FALSE;
}
/*
* Set x86 I/O Privilege Level to 3 for the whole current NT process. Do it via
* NtSetInformationProcess() call with ProcessUserModeIOPL information class,
* which is supported by 32-bit Windows NT kernel versions and requires Tcb
* privilege.
*/
static BOOL
SetProcessUserModeIOPL(VOID)
{
LPVOID Arg[2];
UINT prev_error_mode;
HMODULE ntdll;
BOOL ret;
/*
* Load ntdll.dll library with disabled critical-error-handler and
* file-not-found message box.
* It means that NT kernel does not show unwanted GUI message box to user
* when LoadLibrary() function fails.
*/
prev_error_mode = win32_change_error_mode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
ntdll = LoadLibrary(TEXT("ntdll.dll"));
win32_change_error_mode(prev_error_mode);
if (!ntdll)
{
SetLastError(ERROR_INVALID_FUNCTION);
return FALSE;
}
/* Retrieve pointer to NtSetInformationProcess() function. */
Arg[0] = (LPVOID)GetProcAddress(ntdll, "NtSetInformationProcess");
if (!Arg[0])
{
FreeLibrary(ntdll);
SetLastError(ERROR_INVALID_FUNCTION);
return FALSE;
}
/* Retrieve pointer to optional RtlNtStatusToDosError() function, it may be NULL. */
Arg[1] = (LPVOID)GetProcAddress(ntdll, "RtlNtStatusToDosError");
/* Call ProcessUserModeIOPL with Tcb privilege. */
ret = win32_call_func_with_tcb_privilege(SetProcessUserModeIOPLFunc, (LPVOID)&Arg);
FreeLibrary(ntdll);
if (!ret)
return FALSE;
/*
* Some Windows NT kernel versions (e.g. Windows 2003 x64) do not
* implement ProcessUserModeIOPL syscall at all but incorrectly
* returns success when it is called by user process. So always
* after this call verify that IOPL is set to 3.
*/
if (read_iopl() != 3)
{
SetLastError(ERROR_INVALID_FUNCTION);
return FALSE;
}
return TRUE;
}
static int
intel_setup_io(struct pci_access *a)
{
#ifndef _WIN64
/* 16/32-bit non-NT systems allow applications to access PCI I/O ports without any special setup. */
if (win32_is_non_nt_system())
{
a->debug("Detected 16/32-bit non-NT system, skipping NT setup...");
return 1;
}
#endif
/* Check if we have I/O permission */
if (read_iopl() == 3)
{
a->debug("IOPL is already set to 3, skipping NT setup...");
return 1;
}
/* On NT-based systems issue ProcessUserModeIOPL syscall which changes IOPL to 3. */
if (!SetProcessUserModeIOPL())
{
DWORD error = GetLastError();
a->debug("NT ProcessUserModeIOPL call failed: %s.", error == ERROR_INVALID_FUNCTION ? "Call is not supported" : win32_strerror(error));
return 0;
}
a->debug("NT ProcessUserModeIOPL call succeeded...");
return 1;
}
static inline void
intel_cleanup_io(struct pci_access *a UNUSED)
{
/*
* 16/32-bit non-NT systems do not use any special setup and on NT-based
* systems ProcessUserModeIOPL permanently changes IOPL to 3 for the current
* NT process, no revert for current process is possible.
*/
}
static inline void intel_io_lock(void)
{
}
static inline void intel_io_unlock(void)
{
}
|
