1 /*
2 * Copyright (c) 2008, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.nio.fs;
27
28 import jdk.internal.vm.Continuation;
29 import jdk.internal.vm.ContinuationSupport;
30
31 import static sun.nio.fs.WindowsNativeDispatcher.*;
32 import static sun.nio.fs.WindowsConstants.*;
33
34 /**
35 * Security related utility methods.
36 */
37
38 class WindowsSecurity {
39 private WindowsSecurity() { }
40
41 // opens process token for given access
42 private static long openProcessToken(int access) {
43 try {
44 return OpenProcessToken(GetCurrentProcess(), access);
45 } catch (WindowsException x) {
46 return 0L;
47 }
48 }
49
50 /**
51 * Returns the access token for this process with TOKEN_DUPLICATE access
52 */
53 static final long processTokenWithDuplicateAccess =
54 openProcessToken(TOKEN_DUPLICATE);
55
56 /**
57 * Returns the access token for this process with TOKEN_QUERY access
58 */
59 static final long processTokenWithQueryAccess =
60 openProcessToken(TOKEN_QUERY);
61
62 /**
63 * Returned by enablePrivilege when code may require a given privilege.
64 * The drop method should be invoked after the operation completes so as
65 * to revert the privilege.
66 */
67 static interface Privilege {
68 void drop();
69 }
70
71 /**
72 * Attempts to enable the given privilege for this method.
73 */
74 static Privilege enablePrivilege(String priv) {
75 final long pLuid;
76 try {
77 pLuid = LookupPrivilegeValue(priv);
78 } catch (WindowsException x) {
79 // indicates bug in caller
80 throw new AssertionError(x);
81 }
82
83 long hToken = 0L;
84 boolean impersontating = false;
85 boolean elevated = false;
86 try {
87 hToken = OpenThreadToken(GetCurrentThread(),
88 TOKEN_ADJUST_PRIVILEGES, false);
89 if (hToken == 0L && processTokenWithDuplicateAccess != 0L) {
90 hToken = DuplicateTokenEx(processTokenWithDuplicateAccess,
91 (TOKEN_ADJUST_PRIVILEGES|TOKEN_IMPERSONATE));
92 SetThreadToken(0L, hToken);
93 impersontating = true;
94 }
95
96 if (hToken != 0L) {
97 AdjustTokenPrivileges(hToken, pLuid, SE_PRIVILEGE_ENABLED);
98 elevated = true;
99 }
100 } catch (WindowsException x) {
101 // nothing to do, privilege not enabled
102 }
103
104 final long token = hToken;
105 final boolean stopImpersontating = impersontating;
106 final boolean needToRevert = elevated;
107
108 // prevent yielding with privileges
109 boolean pinned = ContinuationSupport.pinIfSupported();
110 return () -> {
111 try {
112 if (token != 0L) {
113 try {
114 if (stopImpersontating)
115 SetThreadToken(0L, 0L);
116 else if (needToRevert)
117 AdjustTokenPrivileges(token, pLuid, 0);
118 } catch (WindowsException x) {
119 // should not happen
120 throw new AssertionError(x);
121 } finally {
122 CloseHandle(token);
123 }
124 }
125 } finally {
126 LocalFree(pLuid);
127 if (pinned) Continuation.unpin();
128 }
129 };
130 }
131
132 /**
133 * Check the access right against the securityInfo in the current thread.
134 */
135 static boolean checkAccessMask(long securityInfo, int accessMask,
136 int genericRead, int genericWrite, int genericExecute, int genericAll)
137 throws WindowsException
138 {
139 int privileges = TOKEN_QUERY;
140 long hToken = OpenThreadToken(GetCurrentThread(), privileges, false);
141 if (hToken == 0L && processTokenWithDuplicateAccess != 0L)
142 hToken = DuplicateTokenEx(processTokenWithDuplicateAccess,
143 privileges);
144
145 boolean hasRight = false;
146 if (hToken != 0L) {
147 try {
148 hasRight = AccessCheck(hToken, securityInfo, accessMask,
149 genericRead, genericWrite, genericExecute, genericAll);
150 } finally {
151 CloseHandle(hToken);
152 }
153 }
154 return hasRight;
155 }
156
157 }