1 /*
2 * Copyright (c) 2004, 2011, 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 #include <windows.h>
27 #include <malloc.h>
28 #include <string.h>
29
30 #include "jni.h"
31 #include "jni_util.h"
32 #include "sun_management_FileSystemImpl.h"
33
34 /*
35 * Access mask to represent any file access
36 */
37 #define ANY_ACCESS (FILE_GENERIC_READ | FILE_GENERIC_WRITE | FILE_GENERIC_EXECUTE)
38
39 /*
40 * Returns JNI_TRUE if the specified file is on a file system that supports
41 * persistent ACLs (On NTFS file systems returns true, on FAT32 file systems
42 * returns false).
43 */
isSecuritySupported(JNIEnv * env,const char * path)44 static jboolean isSecuritySupported(JNIEnv* env, const char* path) {
45 char* root;
46 char* p;
47 BOOL res;
48 DWORD dwMaxComponentLength;
49 DWORD dwFlags;
50 char fsName[128];
51 DWORD fsNameLength;
52
53 /*
54 * Get root directory. Assume that files are absolute paths. For UNCs
55 * the slash after the share name is required.
56 */
57 root = strdup(path);
58 if (*root == '\\') {
59 /*
60 * \\server\share\file ==> \\server\share\
61 */
62 int slashskip = 3;
63 p = root;
64 while ((*p == '\\') && (slashskip > 0)) {
65 char* p2;
66 p++;
67 p2 = strchr(p, '\\');
68 if ((p2 == NULL) || (*p2 != '\\')) {
69 free(root);
70 JNU_ThrowIOException(env, "Malformed UNC");
71 return JNI_FALSE;
72 }
73 p = p2;
74 slashskip--;
75 }
76 if (slashskip != 0) {
77 free(root);
78 JNU_ThrowIOException(env, "Malformed UNC");
79 return JNI_FALSE;
80 }
81 p++;
82 *p = '\0';
83
84 } else {
85 p = strchr(root, '\\');
86 if (p == NULL) {
87 free(root);
88 JNU_ThrowIOException(env, "Absolute filename not specified");
89 return JNI_FALSE;
90 }
91 p++;
92 *p = '\0';
93 }
94
95
96 /*
97 * Get the volume information - this gives us the file system file and
98 * also tells us if the file system supports persistent ACLs.
99 */
100 fsNameLength = sizeof(fsName)-1;
101 res = GetVolumeInformation(root,
102 NULL, // address of name of the volume, can be NULL
103 0, // length of volume name
104 NULL, // address of volume serial number, can be NULL
105 &dwMaxComponentLength,
106 &dwFlags,
107 fsName,
108 fsNameLength);
109 if (res == 0) {
110 free(root);
111 JNU_ThrowIOExceptionWithLastError(env, "GetVolumeInformation failed");
112 return JNI_FALSE;
113 }
114
115 free(root);
116 return (dwFlags & FS_PERSISTENT_ACLS) ? JNI_TRUE : JNI_FALSE;
117 }
118
119
120 /*
121 * Returns the security descriptor for a file.
122 */
getFileSecurityDescriptor(JNIEnv * env,const char * path)123 static SECURITY_DESCRIPTOR* getFileSecurityDescriptor(JNIEnv* env, const char* path) {
124 SECURITY_DESCRIPTOR* sd;
125 DWORD len = 0;
126 SECURITY_INFORMATION info =
127 OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION;
128
129 GetFileSecurityA(path, info , 0, 0, &len);
130 if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
131 JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");
132 return NULL;
133 }
134 sd = (SECURITY_DESCRIPTOR *)malloc(len);
135 if (sd == NULL) {
136 JNU_ThrowOutOfMemoryError(env, 0);
137 } else {
138 if (!(*GetFileSecurityA)(path, info, sd, len, &len)) {
139 JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");
140 free(sd);
141 return NULL;
142 }
143 }
144 return sd;
145 }
146
147 /*
148 * Returns pointer to the SID identifying the owner of the specified
149 * file.
150 */
getFileOwner(JNIEnv * env,SECURITY_DESCRIPTOR * sd)151 static SID* getFileOwner(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {
152 SID* owner;
153 BOOL defaulted;
154
155 if (!GetSecurityDescriptorOwner(sd, &owner, &defaulted)) {
156 JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorOwner failed");
157 return NULL;
158 }
159 return owner;
160 }
161
162 /*
163 * Returns pointer discretionary access-control list (ACL) from the security
164 * descriptor of the specified file.
165 */
getFileDACL(JNIEnv * env,SECURITY_DESCRIPTOR * sd)166 static ACL* getFileDACL(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {
167 ACL *acl;
168 int defaulted, present;
169
170 if (!GetSecurityDescriptorDacl(sd, &present, &acl, &defaulted)) {
171 JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorDacl failed");
172 return NULL;
173 }
174 if (!present) {
175 JNU_ThrowInternalError(env, "Security descriptor does not contain a DACL");
176 return NULL;
177 }
178 return acl;
179 }
180
181 /*
182 * Returns JNI_TRUE if the specified owner is the only SID will access
183 * to the file.
184 */
isAccessUserOnly(JNIEnv * env,SID * owner,ACL * acl)185 static jboolean isAccessUserOnly(JNIEnv* env, SID* owner, ACL* acl) {
186 ACL_SIZE_INFORMATION acl_size_info;
187 DWORD i;
188
189 /*
190 * If there's no DACL then there's no access to the file
191 */
192 if (acl == NULL) {
193 return JNI_TRUE;
194 }
195
196 /*
197 * Get the ACE count
198 */
199 if (!GetAclInformation(acl, (void *) &acl_size_info, sizeof(acl_size_info),
200 AclSizeInformation)) {
201 JNU_ThrowIOExceptionWithLastError(env, "GetAclInformation failed");
202 return JNI_FALSE;
203 }
204
205 /*
206 * Iterate over the ACEs. For each "allow" type check that the SID
207 * matches the owner, and check that the access is read only.
208 */
209 for (i = 0; i < acl_size_info.AceCount; i++) {
210 void* ace;
211 ACCESS_ALLOWED_ACE *access;
212 SID* sid;
213
214 if (!GetAce(acl, i, &ace)) {
215 JNU_ThrowIOExceptionWithLastError(env, "GetAce failed");
216 return -1;
217 }
218 if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceType != ACCESS_ALLOWED_ACE_TYPE) {
219 continue;
220 }
221 access = (ACCESS_ALLOWED_ACE *)ace;
222 sid = (SID *) &access->SidStart;
223 if (!EqualSid(owner, sid)) {
224 /*
225 * If the ACE allows any access then the file is not secure.
226 */
227 if (access->Mask & ANY_ACCESS) {
228 return JNI_FALSE;
229 }
230 }
231 }
232 return JNI_TRUE;
233 }
234
235
236 /*
237 * Class: sun_management_FileSystemImpl
238 * Method: init0
239 * Signature: ()V
240 */
Java_sun_management_FileSystemImpl_init0(JNIEnv * env,jclass ignored)241 JNIEXPORT void JNICALL Java_sun_management_FileSystemImpl_init0
242 (JNIEnv *env, jclass ignored)
243 {
244 /* nothing to do */
245 }
246
247 /*
248 * Class: sun_management_FileSystemImpl
249 * Method: isSecuritySupported0
250 * Signature: (Ljava/lang/String;)Z
251 */
Java_sun_management_FileSystemImpl_isSecuritySupported0(JNIEnv * env,jclass ignored,jstring str)252 JNIEXPORT jboolean JNICALL Java_sun_management_FileSystemImpl_isSecuritySupported0
253 (JNIEnv *env, jclass ignored, jstring str)
254 {
255 jboolean res;
256 jboolean isCopy;
257 const char* path;
258
259 path = JNU_GetStringPlatformChars(env, str, &isCopy);
260 if (path != NULL) {
261 res = isSecuritySupported(env, path);
262 if (isCopy) {
263 JNU_ReleaseStringPlatformChars(env, str, path);
264 }
265 return res;
266 } else {
267 /* exception thrown - doesn't matter what we return */
268 return JNI_TRUE;
269 }
270 }
271
272
273 /*
274 * Class: sun_management_FileSystemImpl
275 * Method: isAccessUserOnly0
276 * Signature: (Ljava/lang/String;)Z
277 */
Java_sun_management_FileSystemImpl_isAccessUserOnly0(JNIEnv * env,jclass ignored,jstring str)278 JNIEXPORT jboolean JNICALL Java_sun_management_FileSystemImpl_isAccessUserOnly0
279 (JNIEnv *env, jclass ignored, jstring str)
280 {
281 jboolean res = JNI_FALSE;
282 jboolean isCopy;
283 const char* path;
284
285 path = JNU_GetStringPlatformChars(env, str, &isCopy);
286 if (path != NULL) {
287 /*
288 * From the security descriptor get the file owner and
289 * DACL. Then check if anybody but the owner has access
290 * to the file.
291 */
292 SECURITY_DESCRIPTOR* sd = getFileSecurityDescriptor(env, path);
293 if (sd != NULL) {
294 SID *owner = getFileOwner(env, sd);
295 if (owner != NULL) {
296 ACL* acl = getFileDACL(env, sd);
297 if (acl != NULL) {
298 res = isAccessUserOnly(env, owner, acl);
299 } else {
300 /*
301 * If acl is NULL it means that an exception was thrown
302 * or there is "all acess" to the file.
303 */
304 res = JNI_FALSE;
305 }
306 }
307 free(sd);
308 }
309 if (isCopy) {
310 JNU_ReleaseStringPlatformChars(env, str, path);
311 }
312 }
313 return res;
314 }
315