/*

 * Copyright (c) 2019, 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.

 */

// This library is client-side only, and only supports the default credentials.

// It speaks krb5 and SPNEGO. NTLM is excluded from SPNEGO negotiation.

//

// This library can be built directly with the following command:

//   cl -I %OPENJDK%\src\java.security.jgss\share\native\libj2gss\ sspi.cpp \

//      -link -dll -out:sspi_bridge.dll

#define UNICODE

#define _UNICODE

#include <windows.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <Strsafe.h>

#include <ntsecapi.h>

#include <new>

#define GSS_DLL_FILE

#include <gssapi.h>

#define SECURITY_WIN32

#include <sspi.h>

#pragma comment(lib, "secur32.lib")

// Otherwise an exception will be thrown

#define new new (std::nothrow)

// A debugging macro

#define PP(fmt, ...) \

        if (trace) { \

            fprintf(stderr, "[SSPI:%ld] "fmt"\n", __LINE__, ##__VA_ARGS__); \

            fflush(stderr); \

        }

#define SEC_SUCCESS(status) ((*minor_status = (status)), (status) >= SEC_E_OK)

#ifdef __cplusplus

extern "C" {

#endif /* __cplusplus */

// When SSPI_BRIDGE_TRACE is set, debug info goes to stderr. The value is ignored.

char* trace = getenv("SSPI_BRIDGE_TRACE");

void

dump(const char* title, PBYTE data, size_t len)

{

    if (trace) {

        fprintf(stderr, "==== %s ====\n", title);

        for (size_t i = 0; i < len; i++) {

            if (i != 0 && i % 16 == 0) {

                fprintf(stderr, "\n");

            }

            fprintf(stderr, "%02X ", *(data + i) & 0xff);

        }

        fprintf(stderr, "\n");

    }

}

gss_OID_desc KRB5_OID = {9, (void*)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"};

gss_OID_desc SPNEGO_OID = {6, (void*)"\x2b\x06\x01\x05\x05\x02"};

gss_OID_desc USER_NAME_OID = {10, (void*)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x01"};

gss_OID_desc KRB5_NAME_OID = {10, (void*)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x01"};

gss_OID_desc HOST_SERVICE_NAME_OID = {10, (void*)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04"};

gss_OID_desc EXPORT_NAME_OID = {6, (void*)"\x2b\x06\x01\x05\x06\x04"};

struct gss_name_struct {

    SEC_WCHAR* name;

};

struct gss_ctx_id_struct {

    CredHandle* phCred;

    CtxtHandle hCtxt;

    SecPkgContext_Sizes SecPkgContextSizes;

    SecPkgContext_NativeNames nnames;

    BOOLEAN established;

    BOOLEAN isSPNEGO;

    BOOLEAN isLocalCred;

    OM_uint32 flags;

};

struct gss_cred_id_struct {

    CredHandle* phCredK;

    CredHandle* phCredS;

    long time;

};

/* This section holds supporting functions that are not exported */

static OM_uint32

seconds_until(int inputIsUTC, TimeStamp *time)

{

    // time is local time

    LARGE_INTEGER uiLocal;

    FILETIME now;

    GetSystemTimeAsFileTime(&now);

    if (!inputIsUTC) {

        FILETIME nowLocal;

        if (FileTimeToLocalFileTime(&now, &nowLocal) == 0) {

            return -1;

        }

        now = nowLocal;

    }

    uiLocal.HighPart = now.dwHighDateTime;

    uiLocal.LowPart = now.dwLowDateTime;

    if (time->QuadPart < uiLocal.QuadPart) {

        return 0;

    }

    ULONGLONG diff = (time->QuadPart - uiLocal.QuadPart) / 10000000;

    if (diff > (ULONGLONG)~(OM_uint32)0)

        return GSS_C_INDEFINITE;

    return (OM_uint32)diff;

}

static void

show_time(char* label, TimeStamp* ts)

{

    if (trace) {

        SYSTEMTIME stLocal;

        FileTimeToSystemTime((FILETIME*)ts, &stLocal);

        // Build a string showing the date and time.

        PP("%s: %02d/%02d/%d  %02d:%02d %uld", label,

            stLocal.wMonth, stLocal.wDay, stLocal.wYear,

            stLocal.wHour, stLocal.wMinute,

            seconds_until(1, ts));

    }

}

// isSPNEGO: true, SPNEGO. false, Kerberos.

static gss_ctx_id_t

new_context(BOOLEAN isSPNEGO)

{

    gss_ctx_id_t out = new gss_ctx_id_struct;

    if (out == NULL) {

        return NULL;

    }

    out->phCred = NULL;

    out->hCtxt.dwLower = out->hCtxt.dwUpper = NULL;

    out->established = FALSE;

    out->SecPkgContextSizes.cbMaxSignature

            = out->SecPkgContextSizes.cbBlockSize

            = out->SecPkgContextSizes.cbSecurityTrailer

            = 0;

    out->nnames.sClientName = out->nnames.sServerName = NULL;

    out->isSPNEGO = isSPNEGO;

    out->isLocalCred = FALSE;

    return out;

}

static gss_cred_id_t

new_cred()

{

    gss_cred_id_t out = new gss_cred_id_struct;

    out->phCredK = out->phCredS = NULL;

    out->time = 0L;

    return out;

}

static int

flag_sspi_to_gss(int fin)

{

    int fout = 0;

    if (fin & ISC_REQ_MUTUAL_AUTH) fout |= GSS_C_MUTUAL_FLAG;

    if (fin & ISC_REQ_CONFIDENTIALITY) fout |= GSS_C_CONF_FLAG;

    if (fin & ISC_REQ_DELEGATE) fout |= GSS_C_DELEG_FLAG;

    if (fin & ISC_REQ_INTEGRITY) fout |= GSS_C_INTEG_FLAG;

    if (fin & ISC_REQ_REPLAY_DETECT) fout |= GSS_C_REPLAY_FLAG;

    if (fin & ISC_REQ_SEQUENCE_DETECT) fout |= GSS_C_SEQUENCE_FLAG;

    return fout;

}

static int

flag_gss_to_sspi(int fin)

{

    int fout = 0;

    if (fin & GSS_C_MUTUAL_FLAG) fout |= ISC_RET_MUTUAL_AUTH;

    if (fin & GSS_C_CONF_FLAG) fout |= ISC_RET_CONFIDENTIALITY;

    if (fin & GSS_C_DELEG_FLAG) fout |= ISC_RET_DELEGATE;

    if (fin & GSS_C_INTEG_FLAG) fout |= ISC_RET_INTEGRITY;

    if (fin & GSS_C_REPLAY_FLAG) fout |= ISC_RET_REPLAY_DETECT;

    if (fin & GSS_C_SEQUENCE_FLAG) fout |= ISC_RET_SEQUENCE_DETECT;

    return fout;

}

static BOOLEAN

is_same_oid(gss_const_OID o2, gss_const_OID o1)

{

    return o1 && o2 && o1->length == o2->length

            && !memcmp(o1->elements, o2->elements, o2->length);

}

static BOOLEAN

has_oid(gss_const_OID_set set, gss_const_OID oid)

{

    for (size_t i = 0; i < set->count; i++) {

        if (is_same_oid(&set->elements[i], oid)) {

            return TRUE;

        }

    }

    return FALSE;

}

static void

show_oid(gss_const_OID mech)

{

    if (trace) {

        if (is_same_oid(mech, &KRB5_OID)) {

            PP("Kerberos mech");

        } else if (is_same_oid(mech, &SPNEGO_OID)) {

            PP("SPNEGO mech");

        } else if (is_same_oid(mech, &USER_NAME_OID)) {

            PP("NT_USER_NAME name-type");

        } else if (is_same_oid(mech, &KRB5_NAME_OID)) {

            PP("KRB5_NAME name-type");

        } else if (is_same_oid(mech, &HOST_SERVICE_NAME_OID)) {

            PP("NT_HOSTBASED_SERVICE name-type");

        } else if (is_same_oid(mech, &EXPORT_NAME_OID)) {

            PP("NT_EXPORT_NAME name-type");

        } else {

            dump("UNKNOWN OID", (PBYTE)mech->elements, mech->length);

        }

    }

}

static void

show_oid_set(gss_const_OID_set mechs)

{

    if (trace) {

        if (mechs == NULL) {

            PP("OID set is NULL");

            return;

        }

        PP("gss_OID_set.count is %d", (int)mechs->count);

        for (size_t i = 0; i < mechs->count; i++) {

            show_oid(&mechs->elements[i]);

        }

    }

}

// Add realm to a name if there was none.

// Returns a newly allocated name.

static WCHAR*

get_full_name(WCHAR* input)

{

    // input has realm, no need to add one

    for (int i = 0;; i++) {

        if (!input[i]) { // the end

            break;

        }

        if (input[i] == L'\\') { // escaped

            i++;

            continue;

        }

        if (input[i] == L'@') {

            return _wcsdup(input);

        }

    }

    // Always use the default domain

    WCHAR* realm = _wgetenv(L"USERDNSDOMAIN");

    if (realm == NULL) {

        realm = L"";

    }

    size_t oldlen = wcslen(input);

    size_t newlen = oldlen + 1 + wcslen(realm) + 1;

    WCHAR* fullname = new WCHAR[newlen];

    if (!fullname) {

        return NULL;

    }

    wcscpy_s(fullname, newlen, input);

    wcscat_s(fullname, newlen, L"@");

    wcscat_s(fullname, newlen, realm);

    PP("get_full_name returns %ls", fullname);

    return fullname;

}

/* End support section */

/* This section holds GSS-API exported functions */

#define CHECK_OUTPUT(x)  if (!x) return GSS_S_CALL_INACCESSIBLE_WRITE;

#define CHECK_BUFFER(b)  if (!b || !b->value) return GSS_S_CALL_INACCESSIBLE_READ;

#define CHECK_OID(o)     if (!o || !o->elements) return GSS_S_CALL_INACCESSIBLE_READ;

#define CHECK_NAME(n)    if (!n || !(n->name)) return GSS_S_BAD_NAME;

#define CHECK_CONTEXT(c) if (!c) return GSS_S_NO_CONTEXT;

#define CHECK_CRED(c)    if (!c || (!(cred_handle->phCredK) && !(cred_handle->phCredS))) \

                                return GSS_S_NO_CRED;

__declspec(dllexport) OM_uint32

gss_release_name(OM_uint32 *minor_status,

                 gss_name_t *name)

{

    PP(">>>> Calling gss_release_name %p...", *name);

    if (name != NULL && *name != GSS_C_NO_NAME) {

        if ((*name)->name != NULL) {

            delete[] (*name)->name;

        }

        delete *name;

        *name = GSS_C_NO_NAME;

    }

    return GSS_S_COMPLETE;

}

__declspec(dllexport) OM_uint32

gss_import_name(OM_uint32 *minor_status,

                gss_const_buffer_t input_name_buffer,

                gss_const_OID input_name_type,

                gss_name_t *output_name)

{

    PP(">>>> Calling gss_import_name...");

    CHECK_BUFFER(input_name_buffer)

    CHECK_OUTPUT(output_name)

    int len = (int)input_name_buffer->length;

    LPSTR input = (LPSTR)input_name_buffer->value;

    if (input_name_type != NULL

            && is_same_oid(input_name_type, &EXPORT_NAME_OID)) {

        if (len < 4 || input[0] != 4 || input[1] != 1 || input[2] != 0) {

            return GSS_S_FAILURE;

        }

        int mechLen = (int)input[3]; /* including 06 len */

        len -= mechLen + 8; /* 4 header bytes, and an int32 length after OID */

        if (len <= 0) {

            return GSS_S_FAILURE;

        }

        // Reject if mech is not krb5

        if (mechLen - 2!= KRB5_OID.length ||

                memcmp(input + 6, KRB5_OID.elements, mechLen - 2)) {

            return GSS_S_FAILURE;;

        }

        input = input + mechLen + 8;

    }

    SEC_WCHAR* value = new SEC_WCHAR[len + 1];

    if (value == NULL) {

        goto err;

    }

    len = MultiByteToWideChar(CP_UTF8, 0, input, len, value, len+1);

    if (len == 0) {

        goto err;

    }

    value[len] = 0;

    PP("import_name from %ls", value);

    if (len > 33 && !wcscmp(value+len-33, L"@WELLKNOWN:ORG.H5L.REFERALS-REALM")) {

        // Remove the wellknown referrals realms

        value[len-33] = 0;

        len -= 33;

    } else if (value[len-1] == L'@') {

        // Remove the empty realm. It might come from an NT_EXPORT_NAME.

        value[len-1] = 0;

        len--;

    }

    if (len == 0) {

        goto err;

    }

    if (input_name_type != NULL

            && is_same_oid(input_name_type, &HOST_SERVICE_NAME_OID)) {

        // HOST_SERVICE_NAME_OID takes the form of service@host.

        for (int i = 0; i < len; i++) {

            if (value[i] == L'\\') {

                i++;

                continue;

            }

            if (value[i] == L'@') {

                value[i] = L'/';

                break;

            }

        }

        PP("Host-based service now %ls", value);

    }

    PP("import_name to %ls", value);

    gss_name_struct* name = new gss_name_struct;

    if (name == NULL) {

        goto err;

    }

    name->name = value;

    *output_name = (gss_name_t) name;

    return GSS_S_COMPLETE;

err:

    if (value != NULL) {

        delete[] value;

    }

    return GSS_S_FAILURE;

}

__declspec(dllexport) OM_uint32

gss_compare_name(OM_uint32 *minor_status,

                 gss_const_name_t name1,

                 gss_const_name_t name2,

                 int *name_equal)

{

    PP(">>>> Calling gss_compare_name...");

    CHECK_NAME(name1)

    CHECK_NAME(name2)

    CHECK_OUTPUT(name_equal)

    *name_equal = 0;

    SEC_WCHAR* n1 = name1->name;

    SEC_WCHAR* n2 = name2->name;

    PP("Comparing %ls and %ls", n1, n2);

    int l1 = lstrlen(n1);

    int l2 = lstrlen(n2);

    int r1 = l1; // position of @ or the end if none

    int r2 = l2;

    int i;

    for (i = 0; i < l1; i++) {

        if (n1[i] == L'\\') {

            i++;

            continue;

        }

        if (n1[i] == L'@') {

            r1 = i;

            break;

        }

    }

    for (i = 0; i < l2; i++) {

        if (n2[i] == L'\\') {

            i++;

            continue;

        }

        if (n2[i] == L'@') {

            r2 = i;

            break;

        }

    }

    if (l1 < l2 && l1 != r2

            || l2 < l1 && l2 != l1) {

        return GSS_S_COMPLETE; // different

    }

    if (l1 > l2) {

        l1 = l2; // choose the smaller one. longer=smaller @ ...

    }

    // Two names are equal if they are the same or one has no realm and

    // one has realm but they have the same name. If both have realm but

    // different, they are treated different even if the names are the same.

    // Note: the default name concept is not used here.

    // Principal names on Windows are case-insensitive, both user name

    // and service principal name.

    if (CompareStringEx(LOCALE_NAME_SYSTEM_DEFAULT, NORM_IGNORECASE,

            n1, l1, n2, l1, NULL, NULL, 0) == CSTR_EQUAL) {

        *name_equal = 1;

    }

    return GSS_S_COMPLETE;

}

__declspec(dllexport) OM_uint32

gss_canonicalize_name(OM_uint32 *minor_status,

                      gss_const_name_t input_name,

                      gss_const_OID mech_type,

                      gss_name_t *output_name)

{

    PP(">>>> Calling gss_canonicalize_name...");

    CHECK_NAME(input_name)

    CHECK_OID(mech_type)

    CHECK_OUTPUT(output_name)

    if (!is_same_oid(mech_type, &KRB5_OID)) {

        PP("Cannot canonicalize to non-krb5 OID");

        return GSS_S_BAD_MECH;

    }

    gss_name_t names2 = new gss_name_struct;

    if (names2 == NULL) {

        return GSS_S_FAILURE;

    }

    names2->name = get_full_name(input_name->name);

    if (names2->name == NULL) {

        delete names2;

        return GSS_S_FAILURE;

    }

    *output_name = names2;

    return GSS_S_COMPLETE;

}

__declspec(dllexport) OM_uint32

gss_export_name(OM_uint32 *minor_status,

                gss_const_name_t input_name,

                gss_buffer_t exported_name)

{

    PP(">>>> Calling gss_export_name...");

    CHECK_NAME(input_name)

    CHECK_OUTPUT(exported_name)

    OM_uint32 result = GSS_S_FAILURE;