isc/win32/fsaccess.c

	fsaccess.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2000-2002, 2004, 2007, 2013, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id: fsaccess.c,v 1.15 2007/06/19 23:47:19 tbox Exp $ */

/*
 * Note that Win32 does not have the concept of files having access
 * and ownership bits.  The FAT File system only has a readonly flag
 * for everyone and that's all. NTFS uses ACL's which is a totally
 * different concept of controlling access.
 *
 * This code needs to be revisited to set up proper access control for
 * NTFS file systems.  Nothing can be done for FAT file systems.
 */

#include <config.h>

#include <aclapi.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <io.h>
#include <errno.h>

#include <isc/file.h>
#include <isc/stat.h>

#include "errno2result.h"

/*
 * The OS-independent part of the API is in lib/isc.
 */
#include "../fsaccess.c"

/* Store the user account name locally */
static char username[255] = "\0";
static DWORD namelen = 0;

/*
 * In order to set or retrieve access information, we need to obtain
 * the File System type.  These could be UNC-type shares.
 */

BOOL
is_ntfs(const char * file) {

    char drive[255];
    char FSType[20];
    char tmpbuf[256];
    char *machinename;
    char *sharename;
    char filename[1024];

    REQUIRE(filename != NULL);

    if (isc_file_absolutepath(file, filename,
        sizeof(filename)) != ISC_R_SUCCESS) {
        return (FALSE);
    }

    /*
     * Look for c:\path\... style, c:/path/... or \\computer\shar\path...
     * the UNC style file specs
     */
    if (isalpha(filename[0]) && filename[1] == ':' &&
        (filename[2] == '\\' || filename[2] == '/')) {
        strncpy(drive, filename, 3);
        drive[3] = '\0';
    }

    else if ((filename[0] == '\\') && (filename[1] == '\\')) {
        /* Find the machine and share name and rebuild the UNC */
        strcpy(tmpbuf, filename);
        machinename = strtok(tmpbuf, "\\");
        sharename = strtok(NULL, "\\");
        strcpy(drive, "\\\\");
        strcat(drive, machinename);
        strcat(drive, "\\");
        strcat(drive, sharename);
        strcat(drive, "\\");

    }
    else /* Not determinable */
        return (FALSE);

    GetVolumeInformation(drive, NULL, 0, NULL, 0, NULL, FSType,
                 sizeof(FSType));
    if(strcmp(FSType,"NTFS") == 0)
        return (TRUE);
    else
        return (FALSE);
}

/*
 * If it's not NTFS, we assume that it is FAT and proceed
 * with almost nothing to do. Only the write flag can be set or
 * cleared.
 */
isc_result_t
FAT_fsaccess_set(const char *path, isc_fsaccess_t access) {
    int mode;
    isc_fsaccess_t bits;

    /*
     * Done with checking bad bits.  Set mode_t.
     */
    mode = 0;

#define SET_AND_CLEAR1(modebit) \
    if ((access & bits) != 0) { \
        mode |= modebit; \
        access &= ~bits; \
    }
#define SET_AND_CLEAR(user, group, other) \
    SET_AND_CLEAR1(user); \
    bits <<= STEP; \
    SET_AND_CLEAR1(group); \
    bits <<= STEP; \
    SET_AND_CLEAR1(other);

    bits = ISC_FSACCESS_READ | ISC_FSACCESS_LISTDIRECTORY;

    SET_AND_CLEAR(S_IRUSR, S_IRGRP, S_IROTH);

    bits = ISC_FSACCESS_WRITE |
           ISC_FSACCESS_CREATECHILD |
           ISC_FSACCESS_DELETECHILD;

    SET_AND_CLEAR(S_IWUSR, S_IWGRP, S_IWOTH);

    INSIST(access == 0);

    if (_chmod(path, mode) < 0)
        return (isc__errno2result(errno));

    return (ISC_R_SUCCESS);
}

isc_result_t
NTFS_Access_Control(const char *filename, const char *user, int access,
            isc_boolean_t isdir) {
    SECURITY_DESCRIPTOR sd;
    BYTE aclBuffer[1024];
    PACL pacl=(PACL)&aclBuffer;
    BYTE sidBuffer[100];
    PSID psid=(PSID) &sidBuffer;
    DWORD sidBufferSize = sizeof(sidBuffer);
    BYTE adminSidBuffer[100];
    PSID padminsid=(PSID) &adminSidBuffer;
    DWORD adminSidBufferSize = sizeof(adminSidBuffer);
    BYTE otherSidBuffer[100];
    PSID pothersid=(PSID) &otherSidBuffer;
    DWORD otherSidBufferSize = sizeof(otherSidBuffer);
    char domainBuffer[100];
    DWORD domainBufferSize = sizeof(domainBuffer);
    SID_NAME_USE snu;
    DWORD NTFSbits;
    int caccess;


    /* Initialize an ACL */
    if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION))
        return (ISC_R_NOPERM);
    if (!InitializeAcl(pacl, sizeof(aclBuffer), ACL_REVISION))
        return (ISC_R_NOPERM);
    if (!LookupAccountName(0, user, psid, &sidBufferSize, domainBuffer,
              &domainBufferSize, &snu))
        return (ISC_R_NOPERM);
    domainBufferSize = sizeof(domainBuffer);
    if (!LookupAccountName(0, "Administrators", padminsid,
        &adminSidBufferSize, domainBuffer, &domainBufferSize, &snu)) {
        (void)GetLastError();
        return (ISC_R_NOPERM);
    }
    domainBufferSize = sizeof(domainBuffer);
    if (!LookupAccountName(0, "Everyone", pothersid,
        &otherSidBufferSize, domainBuffer, &domainBufferSize, &snu)) {
        (void)GetLastError();
        return (ISC_R_NOPERM);
    }

    caccess = access;
    /* Owner check */

    NTFSbits = 0;
    if (caccess & ISC_FSACCESS_READ)
        NTFSbits |= FILE_GENERIC_READ;
    if (caccess & ISC_FSACCESS_WRITE)
        NTFSbits |= FILE_GENERIC_WRITE;
    if (caccess & ISC_FSACCESS_EXECUTE)
        NTFSbits |= FILE_GENERIC_EXECUTE;

    /* For directories check the directory-specific bits */
    if (isdir == ISC_TRUE) {
        if (caccess & ISC_FSACCESS_CREATECHILD)
            NTFSbits |= FILE_ADD_SUBDIRECTORY | FILE_ADD_FILE;
        if (caccess & ISC_FSACCESS_DELETECHILD)
            NTFSbits |= FILE_DELETE_CHILD;
        if (caccess & ISC_FSACCESS_LISTDIRECTORY)
            NTFSbits |= FILE_LIST_DIRECTORY;
        if (caccess & ISC_FSACCESS_ACCESSCHILD)
            NTFSbits |= FILE_TRAVERSE;
    }

    if (NTFSbits == (FILE_GENERIC_READ | FILE_GENERIC_WRITE
             | FILE_GENERIC_EXECUTE))
             NTFSbits |= FILE_ALL_ACCESS;
    /*
     * Owner and Administrator also get STANDARD_RIGHTS_ALL
     * to ensure that they have full control
     */

    NTFSbits |= STANDARD_RIGHTS_ALL;

    /* Add the ACE to the ACL */
    if (!AddAccessAllowedAce(pacl, ACL_REVISION, NTFSbits, psid))
        return (ISC_R_NOPERM);
    if (!AddAccessAllowedAce(pacl, ACL_REVISION, NTFSbits, padminsid))
        return (ISC_R_NOPERM);

    /*
     * Group is ignored since we can be in multiple groups or no group
     * and its meaning is not clear on Win32
     */

    caccess = caccess >> STEP;

    /*
     * Other check.  We translate this to be the same as Everyone
     */

    caccess = caccess >> STEP;

    NTFSbits = 0;
    if (caccess & ISC_FSACCESS_READ)
        NTFSbits |= FILE_GENERIC_READ;
    if (caccess & ISC_FSACCESS_WRITE)
        NTFSbits |= FILE_GENERIC_WRITE;
    if (caccess & ISC_FSACCESS_EXECUTE)
        NTFSbits |= FILE_GENERIC_EXECUTE;

    /* For directories check the directory-specific bits */
    if (isdir == TRUE) {
        if (caccess & ISC_FSACCESS_CREATECHILD)
            NTFSbits |= FILE_ADD_SUBDIRECTORY | FILE_ADD_FILE;
        if (caccess & ISC_FSACCESS_DELETECHILD)
            NTFSbits |= FILE_DELETE_CHILD;
        if (caccess & ISC_FSACCESS_LISTDIRECTORY)
            NTFSbits |= FILE_LIST_DIRECTORY;
        if (caccess & ISC_FSACCESS_ACCESSCHILD)
            NTFSbits |= FILE_TRAVERSE;
    }
    /* Add the ACE to the ACL */
    if (!AddAccessAllowedAce(pacl, ACL_REVISION, NTFSbits,
                 pothersid))
        return (ISC_R_NOPERM);

    if (!SetSecurityDescriptorDacl(&sd, TRUE, pacl, FALSE))
        return (ISC_R_NOPERM);
    if (!SetFileSecurity(filename, DACL_SECURITY_INFORMATION, &sd)) {
        return (ISC_R_NOPERM);
    }

    return(ISC_R_SUCCESS);
}

isc_result_t
NTFS_fsaccess_set(const char *path, isc_fsaccess_t access,
          isc_boolean_t isdir){

    /*
     * For NTFS we first need to get the name of the account under
     * which BIND is running
     */
    if (namelen == 0) {
        namelen = sizeof(username);
        if (GetUserName(username, &namelen) == 0)
            return (ISC_R_FAILURE);
    }
    return (NTFS_Access_Control(path, username, access, isdir));
}

isc_result_t
isc_fsaccess_set(const char *path, isc_fsaccess_t access) {
    struct stat statb;
    isc_boolean_t is_dir = ISC_FALSE;
    isc_result_t result;

    if (stat(path, &statb) != 0)
        return (isc__errno2result(errno));

    if ((statb.st_mode & S_IFDIR) != 0)
        is_dir = ISC_TRUE;
    else if ((statb.st_mode & S_IFREG) == 0)
        return (ISC_R_INVALIDFILE);

    result = check_bad_bits(access, is_dir);
    if (result != ISC_R_SUCCESS)
        return (result);

    /*
     * Determine if this is a FAT or NTFS disk and
     * call the appropriate function to set the permissions
     */
    if (is_ntfs(path))
        return (NTFS_fsaccess_set(path, access, is_dir));
    else
        return (FAT_fsaccess_set(path, access));
}

isc_result_t
isc_fsaccess_changeowner(const char *filename, const char *user) {
    SECURITY_DESCRIPTOR psd;
    BYTE sidBuffer[500];
    BYTE groupBuffer[500];
    PSID psid=(PSID) &sidBuffer;
    DWORD sidBufferSize = sizeof(sidBuffer);
    char domainBuffer[100];
    DWORD domainBufferSize = sizeof(domainBuffer);
    SID_NAME_USE snu;
    PSID pSidGroup = (PSID) &groupBuffer;
    DWORD groupBufferSize = sizeof(groupBuffer);


    /*
     * Determine if this is a FAT or NTFS disk and
     * call the appropriate function to set the ownership
     * FAT disks do not have ownership attributes so it's
     * a noop.
     */
    if (is_ntfs(filename) == FALSE)
        return (ISC_R_SUCCESS);

    if (!InitializeSecurityDescriptor(&psd, SECURITY_DESCRIPTOR_REVISION))
        return (ISC_R_NOPERM);

    if (!LookupAccountName(0, user, psid, &sidBufferSize, domainBuffer,
        &domainBufferSize, &snu))
        return (ISC_R_NOPERM);

    /* Make sure administrators can get to it */
    domainBufferSize = sizeof(domainBuffer);
    if (!LookupAccountName(0, "Administrators", pSidGroup,
        &groupBufferSize, domainBuffer, &domainBufferSize, &snu))
        return (ISC_R_NOPERM);

    if (!SetSecurityDescriptorOwner(&psd, psid, FALSE))
        return (ISC_R_NOPERM);

    if (!SetSecurityDescriptorGroup(&psd, pSidGroup, FALSE))
        return (ISC_R_NOPERM);

    if (!SetFileSecurity(filename,
        OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION,
        &psd))
        return (ISC_R_NOPERM);

    return (ISC_R_SUCCESS);
}