/*

 * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <windows.h>

#include <malloc.h>

#include <string.h>

#include "jni.h"

#include "jni_util.h"

#include "jdk_internal_agent_FileSystemImpl.h"

JNIEXPORT jint JNICALL DEF_JNI_OnLoad(JavaVM *vm, void *reserved)

{

    JNIEnv* env;

    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_2) != JNI_OK) {

        return JNI_EVERSION; /* JNI version not supported */

    }

    return JNI_VERSION_10;

}

/*

 * Access mask to represent any file access

 */

#define ANY_ACCESS (FILE_GENERIC_READ | FILE_GENERIC_WRITE | FILE_GENERIC_EXECUTE)

/*

 * Returns JNI_TRUE if the specified file is on a file system that supports

 * persistent ACLs (On NTFS file systems returns true, on FAT32 file systems

 * returns false).

 */

static jboolean isSecuritySupported(JNIEnv* env, const char* path) {

    char* root;

    char* p;

    BOOL res;

    DWORD dwMaxComponentLength;

    DWORD dwFlags;

    char fsName[128];

    DWORD fsNameLength;

    /*

     * Get root directory. Assume that files are absolute paths. For UNCs

     * the slash after the share name is required.

     */

    root = strdup(path);

    if (*root == '\\') {

        /*

         * \\server\share\file ==> \\server\share\

         */

        int slashskip = 3;

        p = root;

        while ((*p == '\\') && (slashskip > 0)) {

            char* p2;

            p++;

            p2 = strchr(p, '\\');

            if ((p2 == NULL) || (*p2 != '\\')) {

                free(root);

                JNU_ThrowIOException(env, "Malformed UNC");

                return JNI_FALSE;

            }

            p = p2;

            slashskip--;

        }

        if (slashskip != 0) {

            free(root);

            JNU_ThrowIOException(env, "Malformed UNC");

            return JNI_FALSE;

        }

        p++;

        *p = '\0';

    } else {

        p = strchr(root, '\\');

        if (p == NULL) {

            free(root);

            JNU_ThrowIOException(env, "Absolute filename not specified");

            return JNI_FALSE;

        }

        p++;

        *p = '\0';

    }

    /*

     * Get the volume information - this gives us the file system file and

     * also tells us if the file system supports persistent ACLs.

     */

    fsNameLength = sizeof(fsName)-1;

    res = GetVolumeInformation(root,

                               NULL,        // address of name of the volume, can be NULL

                               0,           // length of volume name

                               NULL,        // address of volume serial number, can be NULL

                               &dwMaxComponentLength,

                               &dwFlags,

                               fsName,

                               fsNameLength);

    if (res == 0) {

        free(root);

        JNU_ThrowIOExceptionWithLastError(env, "GetVolumeInformation failed");

        return JNI_FALSE;

    }

    free(root);

    return (dwFlags & FS_PERSISTENT_ACLS) ? JNI_TRUE : JNI_FALSE;

}

/*

 * Returns the security descriptor for a file.

 */

static SECURITY_DESCRIPTOR* getFileSecurityDescriptor(JNIEnv* env, const char* path) {

    SECURITY_DESCRIPTOR* sd;

    DWORD len = 0;

    SECURITY_INFORMATION info =

        OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION;

    GetFileSecurityA(path, info , 0, 0, &len);

    if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {

        JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");

        return NULL;

    }

    sd = (SECURITY_DESCRIPTOR *)malloc(len);

    if (sd == NULL) {

        JNU_ThrowOutOfMemoryError(env, 0);

    } else {

        if (!(*GetFileSecurityA)(path, info, sd, len, &len)) {

            JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");

            free(sd);

            return NULL;

        }

    }

    return sd;

}

/*

 * Returns pointer to the SID identifying the owner of the specified

 * file.

 */

static SID* getFileOwner(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {

    SID* owner;

    BOOL defaulted;

    if (!GetSecurityDescriptorOwner(sd, &owner, &defaulted)) {

        JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorOwner failed");

        return NULL;

    }

    return owner;

}

/*

 * Returns pointer discretionary access-control list (ACL) from the security

 * descriptor of the specified file.

 */

static ACL* getFileDACL(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {

    ACL *acl;

    int defaulted, present;

    if (!GetSecurityDescriptorDacl(sd, &present, &acl, &defaulted)) {

        JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorDacl failed");

        return NULL;

    }

    if (!present) {

        JNU_ThrowInternalError(env, "Security descriptor does not contain a DACL");

        return NULL;

    }

    return acl;

}

/*

 * Returns JNI_TRUE if the specified owner is the only SID will access

 * to the file.

 */

static jboolean isAccessUserOnly(JNIEnv* env, SID* owner, ACL* acl) {

    ACL_SIZE_INFORMATION acl_size_info;

    DWORD i;

    /*

     * If there's no DACL then there's no access to the file

     */

    if (acl == NULL) {

        return JNI_TRUE;

    }

    /*

     * Get the ACE count

     */

    if (!GetAclInformation(acl, (void *) &acl_size_info, sizeof(acl_size_info),

                           AclSizeInformation)) {

        JNU_ThrowIOExceptionWithLastError(env, "GetAclInformation failed");

        return JNI_FALSE;

    }

    /*

     * Iterate over the ACEs. For each "allow" type check that the SID

     * matches the owner, and check that the access is read only.

     */

    for (i = 0; i < acl_size_info.AceCount; i++) {

        void* ace;

        ACCESS_ALLOWED_ACE *access;

        SID* sid;

        if (!GetAce(acl, i, &ace)) {

            JNU_ThrowIOExceptionWithLastError(env, "GetAce failed");

            return -1;

        }

        if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceType != ACCESS_ALLOWED_ACE_TYPE) {

            continue;

        }

        access = (ACCESS_ALLOWED_ACE *)ace;

        sid = (SID *) &access->SidStart;

        if (!EqualSid(owner, sid)) {

            /*

             * If the ACE allows any access then the file is not secure.

             */

            if (access->Mask & ANY_ACCESS) {

                return JNI_FALSE;

            }

        }

    }

    return JNI_TRUE;

}

/*

 * Class:     jdk_internal_agent_FileSystemImpl

 * Method:    init0

 * Signature: ()V

 */

JNIEXPORT void JNICALL Java_jdk_internal_agent_FileSystemImpl_init0

  (JNIEnv *env, jclass ignored)

{

        /* nothing to do */

}

/*

 * Class:     jdk_internal_agent_FileSystemImpl

 * Method:    isSecuritySupported0

 * Signature: (Ljava/lang/String;)Z

 */

JNIEXPORT jboolean JNICALL Java_jdk_internal_agent_FileSystemImpl_isSecuritySupported0

  (JNIEnv *env, jclass ignored, jstring str)

{

    jboolean res;

    jboolean isCopy;

    const char* path;

    path = JNU_GetStringPlatformChars(env, str, &isCopy);

    if (path != NULL) {

        res = isSecuritySupported(env, path);

        if (isCopy) {

            JNU_ReleaseStringPlatformChars(env, str, path);

        }

        return res;

    } else {

        /* exception thrown - doesn't matter what we return */

        return JNI_TRUE;

    }

}

/*

 * Class:     jdk_internal_agent_FileSystemImpl

 * Method:    isAccessUserOnly0

 * Signature: (Ljava/lang/String;)Z

 */

JNIEXPORT jboolean JNICALL Java_jdk_internal_agent_FileSystemImpl_isAccessUserOnly0

  (JNIEnv *env, jclass ignored, jstring str)

{

    jboolean res = JNI_FALSE;

    jboolean isCopy;

    const char* path;

    path = JNU_GetStringPlatformChars(env, str, &isCopy);

    if (path != NULL) {

        /*

         * From the security descriptor get the file owner and

         * DACL. Then check if anybody but the owner has access

         * to the file.

         */

        SECURITY_DESCRIPTOR* sd = getFileSecurityDescriptor(env, path);

        if (sd != NULL) {

            SID *owner = getFileOwner(env, sd);

            if (owner != NULL) {

                ACL* acl = getFileDACL(env, sd);

                if (acl != NULL) {

                    res = isAccessUserOnly(env, owner, acl);

                } else {

                    /*

                     * If acl is NULL it means that an exception was thrown

                     * or there is "all acess" to the file.

                     */

                    res = JNI_FALSE;

                }

            }

            free(sd);

        }

        if (isCopy) {

            JNU_ReleaseStringPlatformChars(env, str, path);

        }

    }

    return res;

}