/* vim:set ts=4 sw=4 sts=4 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Negotiateauth
 *
 * The Initial Developer of the Original Code is Daniel Kouril.
 * Portions created by the Initial Developer are Copyright (C) 2003
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Daniel Kouril <kouril@ics.muni.cz> (original author)
 *   Wyllys Ingersoll <wyllys.ingersoll@sun.com>
 *   Christopher Nebergall <cneberg@sandia.gov>
 *   Darin Fisher <darin@meer.net>
 *   Mark Mentovai <mark@moxienet.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

//
// GSSAPI Authentication Support Module
//
// Described by IETF Internet draft: draft-brezak-kerberos-http-00.txt
// (formerly draft-brezak-spnego-http-04.txt)
//
// Also described here:
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnsecure/html/http-sso-1.asp
//
//

#include "prlink.h"
#include "nsCOMPtr.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch.h"
#include "nsIServiceManager.h"

#include "nsNegotiateAuth.h"
#include "nsNegotiateAuthGSSAPI.h"

#ifdef XP_MACOSX
#include <Kerberos/Kerberos.h>
#endif

// function pointers for gss functions
//
typedef OM_uint32 (*gss_display_status_type)(
    OM_uint32 *,
    OM_uint32,
    int,
    gss_OID,
    OM_uint32 *,
    gss_buffer_t);

typedef OM_uint32 (*gss_init_sec_context_type)(
    OM_uint32 *,
    gss_cred_id_t,
    gss_ctx_id_t *,
    gss_name_t,
    gss_OID,
    OM_uint32,
    OM_uint32,
    gss_channel_bindings_t,
    gss_buffer_t,
    gss_OID *,
    gss_buffer_t,
    OM_uint32 *,
    OM_uint32 *);
     
typedef OM_uint32 (*gss_indicate_mechs_type)(
    OM_uint32 *,
    gss_OID_set *);

typedef OM_uint32 (*gss_release_oid_set_type)(
    OM_uint32 *,
    gss_OID_set *);

typedef OM_uint32 (*gss_delete_sec_context_type)(
    OM_uint32 *,
    gss_ctx_id_t *,
    gss_buffer_t);

typedef OM_uint32 (*gss_import_name_type)(
    OM_uint32 *,
    gss_buffer_t,
    gss_OID,
    gss_name_t *);

typedef OM_uint32 (*gss_release_buffer_type)(
    OM_uint32 *,
    gss_buffer_t);

typedef OM_uint32 (*gss_release_name_type)(
    OM_uint32 *, 
    gss_name_t *);

#ifdef XP_MACOSX
typedef KLStatus (*KLCacheHasValidTickets_type)(
    KLPrincipal,
    KLKerberosVersion,
    KLBoolean *,
    KLPrincipal *,
    char **);
#endif

//-----------------------------------------------------------------------------

// We define GSS_C_NT_HOSTBASED_SERVICE explicitly since it may be referenced
// by by a different name depending on the implementation of gss but always
// has the same value

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

static const char kNegotiateAuthGssLib[] =
    "network.negotiate-auth.gsslib";
static const char kNegotiateAuthNativeImp[] = 
   "network.negotiate-auth.using-native-gsslib";

static const char *gssFuncStr[] = {
    "gss_display_status", 
    "gss_init_sec_context", 
    "gss_indicate_mechs",
    "gss_release_oid_set",
    "gss_delete_sec_context",
    "gss_import_name",
    "gss_release_buffer",
    "gss_release_name"
};

#define gssFuncItems NS_ARRAY_LENGTH(gssFuncStr)

static PRFuncPtr gssFunPtr[gssFuncItems]; 
static PRBool    gssNativeImp = PR_TRUE;
static PRBool    gssFunInit = PR_FALSE;

#define gss_display_status_ptr      ((gss_display_status_type)*gssFunPtr[0])
#define gss_init_sec_context_ptr    ((gss_init_sec_context_type)*gssFunPtr[1])
#define gss_indicate_mechs_ptr      ((gss_indicate_mechs_type)*gssFunPtr[2])
#define gss_release_oid_set_ptr     ((gss_release_oid_set_type)*gssFunPtr[3])
#define gss_delete_sec_context_ptr  ((gss_delete_sec_context_type)*gssFunPtr[4])
#define gss_import_name_ptr         ((gss_import_name_type)*gssFunPtr[5])
#define gss_release_buffer_ptr      ((gss_release_buffer_type)*gssFunPtr[6])
#define gss_release_name_ptr        ((gss_release_name_type)*gssFunPtr[7])

#ifdef XP_MACOSX
static PRFuncPtr KLCacheHasValidTicketsPtr;
#define KLCacheHasValidTickets_ptr \
        ((KLCacheHasValidTickets_type)*KLCacheHasValidTicketsPtr)
#endif

static nsresult
gssInit()
{
    nsXPIDLCString libPath;
    nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
    if (prefs) {
        prefs->GetCharPref(kNegotiateAuthGssLib, getter_Copies(libPath)); 
        prefs->GetBoolPref(kNegotiateAuthNativeImp, &gssNativeImp); 
    }

    PRLibrary *lib = NULL;

    if (!libPath.IsEmpty()) {
        LOG(("Attempting to load user specified library [%s]\n", libPath.get()));
        gssNativeImp = PR_FALSE;
        lib = PR_LoadLibrary(libPath.get());
    }
    else {
        const char *const libNames[] = {
            "gss",
            "gssapi_krb5",
            "gssapi"
        };

        for (size_t i = 0; i < NS_ARRAY_LENGTH(libNames) && !lib; ++i) {
            char *libName = PR_GetLibraryName(NULL, libNames[i]);
            if (libName) {
                lib = PR_LoadLibrary(libName);
                PR_FreeLibraryName(libName);
            }
        }
    }

    if (!lib) {
        LOG(("Fail to load gssapi library\n"));
        return NS_ERROR_FAILURE;
    }

    LOG(("Attempting to load gss functions\n"));

    for (size_t i = 0; i < gssFuncItems; ++i) {
        gssFunPtr[i] = PR_FindFunctionSymbol(lib, gssFuncStr[i]);
        if (!gssFunPtr[i]) {
            LOG(("Fail to load %s function from gssapi library\n", gssFuncStr[i]));
            PR_UnloadLibrary(lib);
            return NS_ERROR_FAILURE;
        }
    }
#ifdef XP_MACOSX
    if (gssNativeImp &&
            !(KLCacheHasValidTicketsPtr =
               PR_FindFunctionSymbol(lib, "KLCacheHasValidTickets"))) {
        LOG(("Fail to load KLCacheHasValidTickets function from gssapi library\n"));
        PR_UnloadLibrary(lib);
        return NS_ERROR_FAILURE;
    }
#endif

    gssFunInit = PR_TRUE;
    return NS_OK;
}

#if defined( PR_LOGGING )

// Generate proper GSSAPI error messages from the major and
// minor status codes.
void
LogGssError(OM_uint32 maj_stat, OM_uint32 min_stat, const char *prefix)
{
    OM_uint32 new_stat;
    OM_uint32 msg_ctx = 0;
    gss_buffer_desc status1_string;
    gss_buffer_desc status2_string;
    OM_uint32 ret;
    nsCAutoString error(prefix);

    if (!gssFunInit)
        return;

    error += ": ";
    do {
        ret = gss_display_status_ptr(&new_stat,
                                     maj_stat,
                                     GSS_C_GSS_CODE,
                                     GSS_C_NULL_OID,
                                     &msg_ctx,
                                     &status1_string);
        error += (const char *) status1_string.value;
        error += '\n';
        ret = gss_display_status_ptr(&new_stat,
                                     min_stat,
                                     GSS_C_MECH_CODE,
                                     GSS_C_NULL_OID,
                                     &msg_ctx,
                                     &status2_string);
        error += (const char *) status2_string.value;
        error += '\n';
    } while (!GSS_ERROR(ret) && msg_ctx != 0);

    LOG(("%s\n", error.get()));
}

#else /* PR_LOGGING */

#define LogGssError(x,y,z)

#endif /* PR_LOGGING */

//-----------------------------------------------------------------------------

nsNegotiateAuth::nsNegotiateAuth()
    : mServiceFlags(REQ_DEFAULT)
{
    OM_uint32 minstat, majstat;
    gss_OID_set mech_set;
    gss_OID item;
    unsigned int i;
    static gss_OID_desc gss_krb5_mech_oid_desc =
        { 9, (void *) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" };
    static gss_OID_desc gss_spnego_mech_oid_desc =
        { 6, (void *) "\x2b\x06\x01\x05\x05\x02" };

    LOG(("entering nsNegotiateAuth::nsNegotiateAuth()\n"));

    if (!gssFunInit && NS_FAILED(gssInit()))
        return;

    mCtx = GSS_C_NO_CONTEXT;
    mMechOID = &gss_krb5_mech_oid_desc;

    //
    // Now, look at the list of supported mechanisms,
    // if SPNEGO is found, then use it.
    // Otherwise, set the desired mechanism to
    // GSS_C_NO_OID and let the system try to use
    // the default mechanism.
    //
    // Using Kerberos directly (instead of negotiating
    // with SPNEGO) may work in some cases depending
    // on how smart the server side is.
    //
    majstat = gss_indicate_mechs_ptr(&minstat, &mech_set);
    if (GSS_ERROR(majstat))
        return;

    for (i=0; i<mech_set->count; i++) {
        item = &mech_set->elements[i];    
        if (item->length == gss_spnego_mech_oid_desc.length &&
            !memcmp(item->elements, gss_spnego_mech_oid_desc.elements,
            item->length)) {
            // ok, we found it
            mMechOID = &gss_spnego_mech_oid_desc;
            break;
        }
    }
    gss_release_oid_set_ptr(&minstat, &mech_set);
}

void
nsNegotiateAuth::Reset()
{
    if (gssFunInit && mCtx != GSS_C_NO_CONTEXT) {
        OM_uint32 minor_status;
        gss_delete_sec_context_ptr(&minor_status, &mCtx, GSS_C_NO_BUFFER);
    }
    mCtx = GSS_C_NO_CONTEXT;
}

NS_IMPL_ISUPPORTS1(nsNegotiateAuth, nsIAuthModule)

NS_IMETHODIMP
nsNegotiateAuth::Init(const char *serviceName,
                      PRUint32    serviceFlags,
                      const PRUnichar *domain,
                      const PRUnichar *username,
                      const PRUnichar *password)
{
    // we don't expect to be passed any user credentials
    NS_ASSERTION(!domain && !username && !password, "unexpected credentials");

    // it's critial that the caller supply a service name to be used
    NS_ENSURE_TRUE(serviceName && *serviceName, NS_ERROR_INVALID_ARG);

    LOG(("entering nsNegotiateAuth::Init()\n"));

    if (!gssFunInit)
       return NS_ERROR_NOT_INITIALIZED;

    mServiceName = serviceName;
    mServiceFlags = serviceFlags;
    return NS_OK;
}

NS_IMETHODIMP
nsNegotiateAuth::GetNextToken(const void *inToken,
                              PRUint32    inTokenLen,
                              void      **outToken,
                              PRUint32   *outTokenLen)
{
    OM_uint32 major_status, minor_status;
    OM_uint32 req_flags = 0;
    gss_buffer_desc input_token = GSS_C_EMPTY_BUFFER;
    gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER;
    gss_buffer_t  in_token_ptr = GSS_C_NO_BUFFER;
    gss_name_t server;

    LOG(("entering nsNegotiateAuth::GetNextToken()\n"));

    if (!gssFunInit)
       return NS_ERROR_NOT_INITIALIZED;

    if (mServiceFlags & REQ_DELEGATE)
        req_flags |= GSS_C_DELEG_FLAG;

    input_token.value = (void *)mServiceName.get();
    input_token.length = mServiceName.Length() + 1;

    major_status = gss_import_name_ptr(&minor_status,
                                   &input_token,
                                   &gss_c_nt_hostbased_service,
                                   &server);
    input_token.value = NULL;
    input_token.length = 0;
    if (GSS_ERROR(major_status)) {
        LogGssError(major_status, minor_status, "gss_import_name() failed");
        return NS_ERROR_FAILURE;
    }

    if (inToken) {
        input_token.length = inTokenLen;
        input_token.value = (void *) inToken;
        in_token_ptr = &input_token;
    }
    else if (mCtx != GSS_C_NO_CONTEXT) {
        // If there is no input token, then we are starting a new
        // authentication sequence.  If we have already initialized our
        // security context, then we're in trouble because it means that the
        // first sequence failed.  We need to bail or else we might end up in
        // an infinite loop.
        LOG(("Cannot restart authentication sequence!"));
        return NS_ERROR_UNEXPECTED; 
    }

#if defined(XP_MACOSX)
    // Suppress Kerberos prompts to get credentials.  See bug 240643.
    // We can only use Mac OS X specific kerb functions if we are using 
    // the native lib

    KLBoolean found;
    if (gssNativeImp &&
        (KLCacheHasValidTickets_ptr(NULL, kerberosVersion_V5, &found, NULL,
                                    NULL)
         != klNoErr || !found))
    {
        major_status = GSS_S_FAILURE;
        minor_status = 0;
    }
    else
#endif /* XP_MACOSX */
    major_status = gss_init_sec_context_ptr(&minor_status,
                                            GSS_C_NO_CREDENTIAL,
                                            &mCtx,
                                            server,
                                            mMechOID,
                                            req_flags,
                                            GSS_C_INDEFINITE,
                                            GSS_C_NO_CHANNEL_BINDINGS,
                                            in_token_ptr,
                                            nsnull,
                                            &output_token,
                                            nsnull,
                                            nsnull);

    nsresult rv;
    if (GSS_ERROR(major_status)) {
        LogGssError(major_status, minor_status, "gss_init_sec_context() failed");
        Reset();
        rv = NS_ERROR_FAILURE;
        goto end;
    }
    if (major_status == GSS_S_COMPLETE) {
        //
        // We are done with this authentication, reset the context. 
        //
        Reset();
    }
    else if (major_status == GSS_S_CONTINUE_NEEDED) {
        //
        // The important thing is that we do NOT reset the
        // context here because it will be needed on the
        // next call.
        //
    } 

    if (output_token.length == 0) {
        LOG(("  No GSS output token to send, exiting"));
        rv = NS_ERROR_FAILURE;
        goto end;
    }

    *outTokenLen = output_token.length;
    *outToken = nsMemory::Clone(output_token.value, output_token.length);

    gss_release_buffer_ptr(&minor_status, &output_token);
    rv = NS_OK;

end:
    gss_release_name_ptr(&minor_status, &server);

    LOG(("  leaving nsNegotiateAuth::GetNextToken [rv=%x]", rv));
    return rv;
}