scsi: pvscsi: check command descriptor ring buffer size (CVE-2016-4952)
[qemu.git] / qga / vss-win32.c
1 /*
2 * QEMU Guest Agent VSS utility functions
3 *
4 * Copyright Hitachi Data Systems Corp. 2013
5 *
6 * Authors:
7 * Tomoki Sekiyama <tomoki.sekiyama@hds.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 */
12
13 #include "qemu/osdep.h"
14 #include <windows.h>
15 #include "qga/guest-agent-core.h"
16 #include "qga/vss-win32.h"
17 #include "qga/vss-win32/requester.h"
18
19 #define QGA_VSS_DLL "qga-vss.dll"
20
21 static HMODULE provider_lib;
22
23 /* Call a function in qga-vss.dll with the specified name */
24 static HRESULT call_vss_provider_func(const char *func_name)
25 {
26 FARPROC WINAPI func;
27
28 g_assert(provider_lib);
29
30 func = GetProcAddress(provider_lib, func_name);
31 if (!func) {
32 char *msg;
33 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
34 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(),
35 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
36 (char *)&msg, 0, NULL);
37 fprintf(stderr, "failed to load %s from %s: %s",
38 func_name, QGA_VSS_DLL, msg);
39 LocalFree(msg);
40 return E_FAIL;
41 }
42
43 return func();
44 }
45
46 /* Check whether this OS version supports VSS providers */
47 static bool vss_check_os_version(void)
48 {
49 OSVERSIONINFO OSver;
50
51 OSver.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
52 GetVersionEx(&OSver);
53 if ((OSver.dwMajorVersion == 5 && OSver.dwMinorVersion >= 2) ||
54 OSver.dwMajorVersion > 5) {
55 BOOL wow64 = false;
56 #ifndef _WIN64
57 /* Provider doesn't work under WOW64 (32bit agent on 64bit OS) */
58 if (!IsWow64Process(GetCurrentProcess(), &wow64)) {
59 fprintf(stderr, "failed to IsWow64Process (Error: %lx\n)\n",
60 GetLastError());
61 return false;
62 }
63 if (wow64) {
64 fprintf(stderr, "Warning: Running under WOW64\n");
65 }
66 #endif
67 return !wow64;
68 }
69 return false;
70 }
71
72 /* Load qga-vss.dll */
73 bool vss_init(bool init_requester)
74 {
75 if (!vss_check_os_version()) {
76 /* Do nothing if OS doesn't support providers. */
77 fprintf(stderr, "VSS provider is not supported in this OS version: "
78 "fsfreeze is disabled.\n");
79 return false;
80 }
81
82 provider_lib = LoadLibraryA(QGA_VSS_DLL);
83 if (!provider_lib) {
84 char *msg;
85 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
86 FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(),
87 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
88 (char *)&msg, 0, NULL);
89 fprintf(stderr, "failed to load %s: %sfsfreeze is disabled\n",
90 QGA_VSS_DLL, msg);
91 LocalFree(msg);
92 return false;
93 }
94
95 if (init_requester) {
96 HRESULT hr = call_vss_provider_func("requester_init");
97 if (FAILED(hr)) {
98 fprintf(stderr, "fsfreeze is disabled.\n");
99 vss_deinit(false);
100 return false;
101 }
102 }
103
104 return true;
105 }
106
107 /* Unload qga-provider.dll */
108 void vss_deinit(bool deinit_requester)
109 {
110 if (deinit_requester) {
111 call_vss_provider_func("requester_deinit");
112 }
113 FreeLibrary(provider_lib);
114 provider_lib = NULL;
115 }
116
117 bool vss_initialized(void)
118 {
119 return !!provider_lib;
120 }
121
122 int ga_install_vss_provider(void)
123 {
124 HRESULT hr;
125
126 if (!vss_init(false)) {
127 fprintf(stderr, "Installation of VSS provider is skipped. "
128 "fsfreeze will be disabled.\n");
129 return 0;
130 }
131 hr = call_vss_provider_func("COMRegister");
132 vss_deinit(false);
133
134 return SUCCEEDED(hr) ? 0 : EXIT_FAILURE;
135 }
136
137 void ga_uninstall_vss_provider(void)
138 {
139 if (!vss_init(false)) {
140 fprintf(stderr, "Removal of VSS provider is skipped.\n");
141 return;
142 }
143 call_vss_provider_func("COMUnregister");
144 vss_deinit(false);
145 }
146
147 /* Call VSS requester and freeze/thaw filesystems and applications */
148 void qga_vss_fsfreeze(int *nr_volume, Error **errp, bool freeze)
149 {
150 const char *func_name = freeze ? "requester_freeze" : "requester_thaw";
151 QGAVSSRequesterFunc func;
152 ErrorSet errset = {
153 .error_setg_win32_wrapper = error_setg_win32_internal,
154 .errp = errp,
155 };
156
157 g_assert(errp); /* requester.cpp requires it */
158 func = (QGAVSSRequesterFunc)GetProcAddress(provider_lib, func_name);
159 if (!func) {
160 error_setg_win32(errp, GetLastError(), "failed to load %s from %s",
161 func_name, QGA_VSS_DLL);
162 return;
163 }
164
165 func(nr_volume, &errset);
166 }