Config.cc

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/*
 * Copyright (C) 1996-2023 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    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/basic/Config.h"
#include "auth/basic/Scheme.h"
#include "auth/basic/User.h"
#include "auth/basic/UserRequest.h"
#include "auth/CredentialsCache.h"
#include "auth/Gadgets.h"
#include "auth/State.h"
#include "auth/toUtf.h"
#include "base64.h"
#include "cache_cf.h"
#include "helper.h"
#include "HttpHeaderTools.h"
#include "HttpReply.h"
#include "mgr/Registration.h"
#include "rfc1738.h"
#include "sbuf/SBuf.h"
#include "Store.h"
#include "util.h"
#include "wordlist.h"
 
/* Basic Scheme */
static AUTHSSTATS authenticateBasicStats;
 
Helper::ClientPointer basicauthenticators;
 
static int authbasic_initialised = 0;
 
/*
 *
 * Public Functions
 *
 */
 
/* internal functions */
 
bool
Auth::Basic::Config::active() const
{
    return authbasic_initialised == 1;
}
 
bool
Auth::Basic::Config::configured() const
{
    if ((authenticateProgram != nullptr) && (authenticateChildren.n_max != 0) && !realm.isEmpty()) {
        debugs(29, 9, "returning configured");
        return true;
    }
 
    debugs(29, 9, "returning unconfigured");
    return false;
}
 
const char *
Auth::Basic::Config::type() const
{
    return Auth::Basic::Scheme::GetInstance()->type();
}
 
void
Auth::Basic::Config::fixHeader(Auth::UserRequest::Pointer, HttpReply *rep, Http::HdrType hdrType, HttpRequest *)
{
    if (authenticateProgram) {
        if (utf8) {
            debugs(29, 9, "Sending type:" << hdrType << " header: 'Basic realm=\"" << realm << "\", charset=\"UTF-8\"'");
            httpHeaderPutStrf(&rep->header, hdrType, "Basic realm=\"" SQUIDSBUFPH "\", charset=\"UTF-8\"", SQUIDSBUFPRINT(realm));
        } else {
            debugs(29, 9, "Sending type:" << hdrType << " header: 'Basic realm=\"" << realm << "\"'");
            httpHeaderPutStrf(&rep->header, hdrType, "Basic realm=\"" SQUIDSBUFPH "\"", SQUIDSBUFPRINT(realm));
        }
    }
}
 
void
Auth::Basic::Config::rotateHelpers()
{
    /* schedule closure of existing helpers */
    if (basicauthenticators) {
        helperShutdown(basicauthenticators);
    }
 
    /* NP: dynamic helper restart will ensure they start up again as needed. */
}
 
void
Auth::Basic::Config::done()
{
    Auth::SchemeConfig::done();
 
    authbasic_initialised = 0;
 
    if (basicauthenticators) {
        helperShutdown(basicauthenticators);
    }
 
    basicauthenticators = nullptr;
 
    if (authenticateProgram)
        wordlistDestroy(&authenticateProgram);
}
 
bool
Auth::Basic::Config::dump(StoreEntry * entry, const char *name, Auth::SchemeConfig * scheme) const
{
    if (!Auth::SchemeConfig::dump(entry, name, scheme))
        return false; // not configured
 
    storeAppendPrintf(entry, "%s basic credentialsttl %d seconds\n", name, (int) credentialsTTL);
    storeAppendPrintf(entry, "%s basic casesensitive %s\n", name, casesensitive ? "on" : "off");
    return true;
}
 
Auth::Basic::Config::Config() :
    credentialsTTL( 2*60*60 ),
    casesensitive(0)
{
    static const SBuf defaultRealm("Squid proxy-caching web server");
    realm = defaultRealm;
}
 
void
Auth::Basic::Config::parse(Auth::SchemeConfig * scheme, int n_configured, char *param_str)
{
    if (strcmp(param_str, "credentialsttl") == 0) {
        parse_time_t(&credentialsTTL);
    } else if (strcmp(param_str, "casesensitive") == 0) {
        parse_onoff(&casesensitive);
    } else
        Auth::SchemeConfig::parse(scheme, n_configured, param_str);
}
 
static void
authenticateBasicStats(StoreEntry * sentry)
{
    if (basicauthenticators)
        basicauthenticators->packStatsInto(sentry, "Basic Authenticator Statistics");
}
 
char *
Auth::Basic::Config::decodeCleartext(const char *httpAuthHeader, const HttpRequest *request)
{
    const char *proxy_auth = httpAuthHeader;
 
    /* trim BASIC from string */
    while (xisgraph(*proxy_auth))
        ++proxy_auth;
 
    /* Trim leading whitespace before decoding */
    while (xisspace(*proxy_auth))
        ++proxy_auth;
 
    /* Trim trailing \n before decoding */
    // XXX: really? is the \n actually still there? does the header parse not drop it?
    char *eek = xstrdup(proxy_auth);
    strtok(eek, "\n");
 
    const size_t srcLen = strlen(eek);
    char *cleartext = static_cast<char*>(xmalloc(BASE64_DECODE_LENGTH(srcLen)+1));
 
    struct base64_decode_ctx ctx;
    base64_decode_init(&ctx);
 
    size_t dstLen = 0;
    if (base64_decode_update(&ctx, &dstLen, reinterpret_cast<uint8_t*>(cleartext), srcLen, eek) && base64_decode_final(&ctx)) {
        cleartext[dstLen] = '\0';
 
        if (utf8 && !isValidUtf8String(cleartext, cleartext + dstLen)) {
            auto str = isCP1251EncodingAllowed(request) ?
                       Cp1251ToUtf8(cleartext) : Latin1ToUtf8(cleartext);
            safe_free(cleartext);
            cleartext = xstrdup(str.c_str());
        }
 
        /*
         * Don't allow NL or CR in the credentials.
         * Oezguer Kesim <oec@codeblau.de>
         */
        debugs(29, 9, "'" << cleartext << "'");
 
        if (strcspn(cleartext, "\r\n") != strlen(cleartext)) {
            debugs(29, DBG_IMPORTANT, "WARNING: Bad characters in authorization header '" << httpAuthHeader << "'");
            safe_free(cleartext);
        }
    } else {
        debugs(29, 2, "WARNING: Invalid Base64 character in authorization header '" << httpAuthHeader << "'");
        safe_free(cleartext);
    }
 
    safe_free(eek);
    return cleartext;
}
 
Auth::UserRequest::Pointer
Auth::Basic::Config::decode(char const *proxy_auth, const HttpRequest *request, const char *aRequestRealm)
{
    Auth::UserRequest::Pointer auth_user_request = dynamic_cast<Auth::UserRequest*>(new Auth::Basic::UserRequest);
    /* decode the username */
 
    // retrieve the cleartext (in a dynamically allocated char*)
    const auto cleartext = decodeCleartext(proxy_auth, request);
 
    // empty header? no auth details produced...
    if (!cleartext)
        return auth_user_request;
 
    Auth::User::Pointer lb;
    /* permitted because local_basic is purely local function scope. */
    Auth::Basic::User *local_basic = nullptr;
 
    char *separator = strchr(cleartext, ':');
 
    lb = local_basic = new Auth::Basic::User(this, aRequestRealm);
 
    if (separator) {
        /* terminate the username */
        *separator = '\0';
        local_basic->passwd = xstrdup(separator+1);
    }
 
    if (!casesensitive)
        Tolower(cleartext);
    local_basic->username(cleartext);
 
    if (local_basic->passwd == nullptr) {
        debugs(29, 4, "no password in proxy authorization header '" << proxy_auth << "'");
        auth_user_request->setDenyMessage("no password was present in the HTTP [proxy-]authorization header. This is most likely a browser bug");
    } else {
        if (local_basic->passwd[0] == '\0') {
            debugs(29, 4, "Disallowing empty password. User is '" << local_basic->username() << "'");
            safe_free(local_basic->passwd);
            auth_user_request->setDenyMessage("Request denied because you provided an empty password. Users MUST have a password.");
        }
    }
 
    xfree(cleartext);
 
    if (!local_basic->valid()) {
        lb->auth_type = Auth::AUTH_BROKEN;
        auth_user_request->user(lb);
        return auth_user_request;
    }
 
    /* now lookup and see if we have a matching auth_user structure in memory. */
    Auth::User::Pointer auth_user;
 
    if (!(auth_user = Auth::Basic::User::Cache()->lookup(lb->userKey()))) {
        /* the user doesn't exist in the username cache yet */
        /* save the credentials */
        debugs(29, 9, "Creating new user '" << lb->username() << "'");
        /* set the auth_user type */
        lb->auth_type = Auth::AUTH_BASIC;
        /* current time for timeouts */
        lb->expiretime = current_time.tv_sec;
 
        /* this basic_user struct is the 'lucky one' to get added to the username cache */
        /* the requests after this link to the basic_user */
        /* store user in hash */
        lb->addToNameCache();
 
        auth_user = lb;
        assert(auth_user != nullptr);
    } else {
        /* replace the current cached password with the new one */
        Auth::Basic::User *basic_auth = dynamic_cast<Auth::Basic::User *>(auth_user.getRaw());
        assert(basic_auth);
        basic_auth->updateCached(local_basic);
        auth_user = basic_auth;
    }
 
    /* link the request to the in-cache user */
    auth_user_request->user(auth_user);
    return auth_user_request;
}
 
void
Auth::Basic::Config::init(Auth::SchemeConfig *)
{
    if (authenticateProgram) {
        authbasic_initialised = 1;
 
        if (basicauthenticators == nullptr)
            basicauthenticators = Helper::Client::Make("basicauthenticator");
 
        basicauthenticators->cmdline = authenticateProgram;
 
        basicauthenticators->childs.updateLimits(authenticateChildren);
 
        basicauthenticators->ipc_type = IPC_STREAM;
 
        basicauthenticators->openSessions();
    }
}
 
void
Auth::Basic::Config::registerWithCacheManager(void)
{
    Mgr::RegisterAction("basicauthenticator",
                        "Basic User Authenticator Stats",
                        authenticateBasicStats, 0, 1);
}