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  */

    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  */

   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  */

   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  */

   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  */

   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  */

   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  */

   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  */

   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 }