/*
 * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/* DEBUG: section 29    NTLM Authenticator */

/* The functions in this file handle authentication.
 * They DO NOT perform access control or auditing.
 * See acl.c for access control and client_side.c for auditing */

#include "squid.h"
#include "auth/Gadgets.h"
#include "auth/ntlm/Config.h"
#include "auth/ntlm/Scheme.h"
#include "auth/ntlm/User.h"
#include "auth/ntlm/UserRequest.h"
#include "auth/State.h"
#include "cache_cf.h"
#include "client_side.h"
#include "helper.h"
#include "http/Stream.h"
#include "HttpHeaderTools.h"
#include "HttpReply.h"
#include "HttpRequest.h"
#include "mgr/Registration.h"
#include "SquidTime.h"
#include "Store.h"
#include "wordlist.h"

/* NTLM Scheme */
static AUTHSSTATS authenticateNTLMStats;

statefulhelper *ntlmauthenticators = NULL;
static int authntlm_initialised = 0;

static hash_table *proxy_auth_cache = NULL;

void
Auth::Ntlm::Config::rotateHelpers()
{
    /* schedule closure of existing helpers */
    if (ntlmauthenticators) {
        helperStatefulShutdown(ntlmauthenticators);
    }

    /* NP: dynamic helper restart will ensure they start up again as needed. */
}

/* free any allocated configuration details */
void
Auth::Ntlm::Config::done()
{
    Auth::Config::done();

    authntlm_initialised = 0;

    if (ntlmauthenticators) {
        helperStatefulShutdown(ntlmauthenticators);
    }

    if (!shutting_down)
        return;

    delete ntlmauthenticators;
    ntlmauthenticators = NULL;

    if (authenticateProgram)
        wordlistDestroy(&authenticateProgram);

    debugs(29, DBG_IMPORTANT, "Reconfigure: NTLM authentication configuration cleared.");
}

bool
Auth::Ntlm::Config::dump(StoreEntry * entry, const char *name, Auth::Config * scheme) const
{
    if (!Auth::Config::dump(entry, name, scheme))
        return false;

    storeAppendPrintf(entry, "%s ntlm keep_alive %s\n", name, keep_alive ? "on" : "off");
    return true;
}

Auth::Ntlm::Config::Config() : keep_alive(1)
{ }

void
Auth::Ntlm::Config::parse(Auth::Config * scheme, int n_configured, char *param_str)
{
    if (strcmp(param_str, "program") == 0) {
        if (authenticateProgram)
            wordlistDestroy(&authenticateProgram);

        parse_wordlist(&authenticateProgram);

        requirePathnameExists("auth_param ntlm program", authenticateProgram->key);
    } else if (strcmp(param_str, "keep_alive") == 0) {
        parse_onoff(&keep_alive);
    } else
        Auth::Config::parse(scheme, n_configured, param_str);
}

const char *
Auth::Ntlm::Config::type() const
{
    return Auth::Ntlm::Scheme::GetInstance()->type();
}

/* Initialize helpers and the like for this auth scheme. Called AFTER parsing the
 * config file */
void
Auth::Ntlm::Config::init(Auth::Config *)
{
    if (authenticateProgram) {

        authntlm_initialised = 1;

        if (ntlmauthenticators == NULL)
            ntlmauthenticators = new statefulhelper("ntlmauthenticator");

        if (!proxy_auth_cache)
            proxy_auth_cache = hash_create((HASHCMP *) strcmp, 7921, hash_string);

        assert(proxy_auth_cache);

        ntlmauthenticators->cmdline = authenticateProgram;

        ntlmauthenticators->childs.updateLimits(authenticateChildren);

        ntlmauthenticators->ipc_type = IPC_STREAM;

        helperStatefulOpenServers(ntlmauthenticators);
    }
}

void
Auth::Ntlm::Config::registerWithCacheManager(void)
{
    Mgr::RegisterAction("ntlmauthenticator",
                        "NTLM User Authenticator Stats",
                        authenticateNTLMStats, 0, 1);
}

bool
Auth::Ntlm::Config::active() const
{
    return authntlm_initialised == 1;
}

bool
Auth::Ntlm::Config::configured() const
{
    if ((authenticateProgram != NULL) && (authenticateChildren.n_max != 0)) {
        debugs(29, 9, HERE << "returning configured");
        return true;
    }

    debugs(29, 9, HERE << "returning unconfigured");
    return false;
}

/* NTLM Scheme */

void
Auth::Ntlm::Config::fixHeader(Auth::UserRequest::Pointer auth_user_request, HttpReply *rep, Http::HdrType hdrType, HttpRequest * request)
{
    if (!authenticateProgram)
        return;

    /* Need keep-alive */
    if (!request->flags.proxyKeepalive && request->flags.mustKeepalive)
        return;

    /* New request, no user details */
    if (auth_user_request == NULL) {
        debugs(29, 9, HERE << "Sending type:" << hdrType << " header: 'NTLM'");
        httpHeaderPutStrf(&rep->header, hdrType, "NTLM");

        if (!keep_alive) {
            /* drop the connection */
            request->flags.proxyKeepalive = false;
        }
    } else {
        Auth::Ntlm::UserRequest *ntlm_request = dynamic_cast<Auth::Ntlm::UserRequest *>(auth_user_request.getRaw());
        assert(ntlm_request != NULL);

        switch (ntlm_request->user()->credentials()) {

        case Auth::Failed:
            /* here it makes sense to drop the connection, as auth is
             * tied to it, even if MAYBE the client could handle it - Kinkie */
            request->flags.proxyKeepalive = false;
        /* fall through */

        case Auth::Ok:
        /* Special case: authentication finished OK but disallowed by ACL.
         * Need to start over to give the client another chance.
         */
        /* fall through */

        case Auth::Unchecked:
            /* semantic change: do not drop the connection.
             * 2.5 implementation used to keep it open - Kinkie */
            debugs(29, 9, HERE << "Sending type:" << hdrType << " header: 'NTLM'");
            httpHeaderPutStrf(&rep->header, hdrType, "NTLM");
            break;

        case Auth::Handshake:
            /* we're waiting for a response from the client. Pass it the blob */
            debugs(29, 9, HERE << "Sending type:" << hdrType << " header: 'NTLM " << ntlm_request->server_blob << "'");
            httpHeaderPutStrf(&rep->header, hdrType, "NTLM %s", ntlm_request->server_blob);
            safe_free(ntlm_request->server_blob);
            break;

        default:
            debugs(29, DBG_CRITICAL, "NTLM Auth fixHeader: state " << ntlm_request->user()->credentials() << ".");
            fatal("unexpected state in AuthenticateNTLMFixErrorHeader.\n");
        }
    }
}

static void
authenticateNTLMStats(StoreEntry * sentry)
{
    if (ntlmauthenticators)
        ntlmauthenticators->packStatsInto(sentry, "NTLM Authenticator Statistics");
}

/*
 * Decode a NTLM [Proxy-]Auth string, placing the results in the passed
 * Auth_user structure.
 */
Auth::UserRequest::Pointer
Auth::Ntlm::Config::decode(char const *proxy_auth, const char *aRequestRealm)
{
    Auth::Ntlm::User *newUser = new Auth::Ntlm::User(Auth::Config::Find("ntlm"), aRequestRealm);
    Auth::UserRequest::Pointer auth_user_request = new Auth::Ntlm::UserRequest();
    assert(auth_user_request->user() == NULL);

    auth_user_request->user(newUser);
    auth_user_request->user()->auth_type = Auth::AUTH_NTLM;

    auth_user_request->user()->BuildUserKey(proxy_auth, aRequestRealm);

    /* all we have to do is identify that it's NTLM - the helper does the rest */
    debugs(29, 9, HERE << "decode: NTLM authentication");
    return auth_user_request;
}

