filter_auth_simple.cpp

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/* This file is part of Metaproxy.
   Copyright (C) Index Data
 
Metaproxy is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
 
Metaproxy 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
for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#include "config.hpp"
 
#include <metaproxy/filter.hpp>
#include <metaproxy/package.hpp>
 
#include <boost/thread/mutex.hpp>
 
#include <metaproxy/util.hpp>
#include "filter_auth_simple.hpp"
#include <fstream>
#include <yaz/zgdu.h>
#include <yaz/diagbib1.h>
#include <yaz/tpath.h>
#include <stdio.h>
#include <errno.h>
 
namespace mp = metaproxy_1;
namespace yf = mp::filter;
 
namespace metaproxy_1 {
    namespace filter {
        class AuthSimple::Rep {
            friend class AuthSimple;
            struct PasswordAndDBs {
                std::string password;
                std::list<std::string> dbs;
                PasswordAndDBs() {};
                PasswordAndDBs(std::string pw) : password(pw) {};
                void addDB(std::string db) { dbs.push_back(db); }
            };
            boost::mutex mutex;
            bool got_userRegister, got_targetRegister;
            std::map<std::string, PasswordAndDBs> userRegister;
            std::map<std::string, std::list<std::string> > targetsByUser;
            std::map<mp::Session, std::string> userBySession;
            bool discardUnauthorisedTargets;
            Rep() { got_userRegister = false;
                    got_targetRegister = false;
                    discardUnauthorisedTargets = false; }
        };
    }
}
 
yf::AuthSimple::AuthSimple() : m_p(new Rep)
{
    // nothing to do
}
 
yf::AuthSimple::~AuthSimple()
{  // must have a destructor because of boost::scoped_ptr
}
 
 
static void die(std::string s) { throw mp::filter::FilterException(s); }
 
 
static std::string get_user(Z_InitRequest *initReq, std::string &password)
{
    Z_IdAuthentication *auth = initReq->idAuthentication;
    std::string user;
    if (auth)
    {
        const char *cp;
        switch (auth->which)
        {
        case Z_IdAuthentication_open:
            cp = strchr(auth->u.open, '/');
            if (cp)
            {
                user.assign(auth->u.open, cp - auth->u.open);
                password.assign(cp + 1);
            }
            else
                user = auth->u.open;
            break;
        case Z_IdAuthentication_idPass:
            if (auth->u.idPass->userId)
                user = auth->u.idPass->userId;
            if (auth->u.idPass->password)
                password = auth->u.idPass->password;
            break;
        }
    }
    return user;
}
 
// Read XML config.. Put config info in m_p.
void mp::filter::AuthSimple::configure(const xmlNode * ptr, bool test_only,
                                       const char *path)
{
    std::string userRegisterName;
    std::string targetRegisterName;
 
    for (ptr = ptr->children; ptr != 0; ptr = ptr->next) {
        if (ptr->type != XML_ELEMENT_NODE)
            continue;
        if (!strcmp((const char *) ptr->name, "userRegister")) {
            userRegisterName = mp::xml::get_text(ptr);
            m_p->got_userRegister = true;
        } else if (!strcmp((const char *) ptr->name, "targetRegister")) {
            targetRegisterName = mp::xml::get_text(ptr);
            m_p->got_targetRegister = true;
        } else if (!strcmp((const char *) ptr->name,
                           "discardUnauthorisedTargets")) {
            m_p->discardUnauthorisedTargets = true;
        } else {
            die("Bad element in auth_simple: <"
                + std::string((const char *) ptr->name) + ">");
        }
    }
 
    if (!m_p->got_userRegister && !m_p->got_targetRegister)
        die("auth_simple: no user-register or target-register "
            "filename specified");
 
    if (m_p->got_userRegister)
        config_userRegister(userRegisterName, path);
    if (m_p->got_targetRegister)
        config_targetRegister(targetRegisterName, path);
}
 
static void split_db(std::list<std::string> &dbs,
                     const char *databasesp)
{
    const char *cp;
    while ((cp = strchr(databasesp, ',')))
    {
        dbs.push_back(std::string(databasesp, cp - databasesp));
        databasesp = cp + 1;
    }
    dbs.push_back(std::string(databasesp));
}
 
void mp::filter::AuthSimple::config_userRegister(std::string filename,
                                                 const char *path)
{
    char fullpath[1024];
    if (!yaz_filepath_resolve(filename.c_str(), path, 0, fullpath))
        die("Could not open " + filename);
 
    std::ifstream fp(fullpath);
    if (!fp.is_open())
        die("Could not open " + filename);
 
    while (!fp.eof())
    {
        char buf[1000];
        fp.getline(buf, sizeof buf);
        if (*buf == '\0' || *buf == '#')
            continue;
        char *passwdp = strchr(buf, ':');
        if (passwdp == 0)
            die("auth_simple user-register '" + filename + "': " +
                "no password on line: '" + buf + "'");
        *passwdp++ = 0;
        char *databasesp = strchr(passwdp, ':');
        if (databasesp == 0)
            die("auth_simple user-register '" + filename + "': " +
                "no databases on line: '" + buf + ":" + passwdp + "'");
        *databasesp++ = 0;
        yf::AuthSimple::Rep::PasswordAndDBs tmp(passwdp);
        split_db(tmp.dbs, databasesp);
        m_p->userRegister[buf] = tmp;
 
        if (0)
        {                // debugging
            printf("Added user '%s' -> password '%s'\n", buf, passwdp);
            std::list<std::string>::const_iterator i;
            for (i = tmp.dbs.begin(); i != tmp.dbs.end(); i++)
                printf("db '%s'\n", (*i).c_str());
        }
    }
}
 
 
// I feel a little bad about the duplication of code between this and
// config_userRegister().  But not bad enough to refactor.
//
void mp::filter::AuthSimple::config_targetRegister(std::string filename,
                                                   const char *path)
{
    char fullpath[1024];
    if (!yaz_filepath_resolve(filename.c_str(), path, 0, fullpath))
        die("Could not open " + filename);
    std::ifstream fp(fullpath);
    if (!fp.is_open())
        die("Could not open " + filename);
 
    while (!fp.eof()) {
        char buf[1000];
        fp.getline(buf, sizeof buf);
        if (*buf == '\0' || *buf == '#')
            continue;
        char *targetsp = strchr(buf, ':');
        if (targetsp == 0)
            die("auth_simple target-register '" + filename + "': " +
                "no targets on line: '" + buf + "'");
        *targetsp++ = 0;
        std::list<std::string> tmp;
        split_db(tmp, targetsp);
        m_p->targetsByUser[buf] = tmp;
 
        if (0) {                // debugging
            printf("Added user '%s' with targets:\n", buf);
            std::list<std::string>::const_iterator i;
            for (i = tmp.begin(); i != tmp.end(); i++) {
                printf("\t%s\n", (*i).c_str());
            }
        }
    }
}
 
 
void yf::AuthSimple::process(mp::Package &package) const
{
    Z_GDU *gdu = package.request().get();
 
    if (!gdu || gdu->which != Z_GDU_Z3950) {
        // Pass on the package -- This means that authentication is
        // waived, which may not be the correct thing for non-Z APDUs
        // as it means that SRW sessions don't demand authentication
        return package.move();
    }
 
    if (m_p->got_userRegister) {
        switch (gdu->u.z3950->which) {
        case Z_APDU_initRequest: return process_init(package);
        case Z_APDU_searchRequest: return process_search(package);
        case Z_APDU_scanRequest: return process_scan(package);
            // In theory, we should check database authorisation for
            // extended services, too (A) the proxy currently does not
            // implement XS and turns off its negotiation bit; (B) it
            // would be insanely complex to do as the top-level XS request
            // structure does not carry a database name, but it is buried
            // down in some of the possible EXTERNALs used as
            // taskSpecificParameters; and (C) since many extended
            // services modify the database, we'd need to more exotic
            // authorisation database than we want to support.
        default: break;
        }
    }
 
    if (m_p->got_targetRegister && gdu->u.z3950->which == Z_APDU_initRequest)
        return check_targets(package);
 
    // Operations other than those listed above do not require authorisation
    return package.move();
}
 
 
static void reject_init(mp::Package &package, int err, const char *addinfo);
 
 
void yf::AuthSimple::process_init(mp::Package &package) const
{
    Z_InitRequest *initReq = package.request().get()->u.z3950->u.initRequest;
 
    std::string password;
    std::string user = get_user(initReq, password);
 
    if (user.length() == 0)
        return reject_init(package, 0, "no credentials supplied");
 
    if (m_p->userRegister.count(user)) {
        // groupId is ignored, in accordance with ancient tradition.
        yf::AuthSimple::Rep::PasswordAndDBs pdbs =
            m_p->userRegister[user];
        if (pdbs.password == password) {
            // Success!  Remember who the user is for future reference
            {
                boost::mutex::scoped_lock lock(m_p->mutex);
                m_p->userBySession[package.session()] = user;
            }
            return package.move();
        }
    }
 
    return reject_init(package, 0, "username/password combination rejected");
}
 
 
// I find it unutterable disappointing that I have to provide this
static bool contains(std::list<std::string> list, std::string thing) {
    std::list<std::string>::const_iterator i;
    for (i = list.begin(); i != list.end(); i++)
        if (mp::util::database_name_normalize(*i) ==
            mp::util::database_name_normalize(thing))
            return true;
 
    return false;
}
 
 
void yf::AuthSimple::process_search(mp::Package &package) const
{
    Z_SearchRequest *req =
        package.request().get()->u.z3950->u.searchRequest;
 
    if (m_p->userBySession.count(package.session()) == 0) {
        // It's a non-authenticated session, so just accept the operation
        return package.move();
    }
 
    std::string user = m_p->userBySession[package.session()];
    yf::AuthSimple::Rep::PasswordAndDBs pdb = m_p->userRegister[user];
    for (int i = 0; i < req->num_databaseNames; i++) {
        if (!contains(pdb.dbs, req->databaseNames[i]) &&
            !contains(pdb.dbs, "*")) {
            // Make an Search rejection APDU
            mp::odr odr;
            Z_APDU *apdu = odr.create_searchResponse(
                package.request().get()->u.z3950,
                YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED,
                req->databaseNames[i]);
            package.response() = apdu;
            package.session().close();
            return;
        }
    }
 
    // All the requested databases are acceptable
    return package.move();
}
 
 
void yf::AuthSimple::process_scan(mp::Package &package) const
{
    Z_ScanRequest *req =
        package.request().get()->u.z3950->u.scanRequest;
 
    if (m_p->userBySession.count(package.session()) == 0) {
        // It's a non-authenticated session, so just accept the operation
        return package.move();
    }
 
    std::string user = m_p->userBySession[package.session()];
    yf::AuthSimple::Rep::PasswordAndDBs pdb = m_p->userRegister[user];
    for (int i = 0; i < req->num_databaseNames; i++) {
        if (!contains(pdb.dbs, req->databaseNames[i]) &&
            !contains(pdb.dbs, "*")) {
            // Make an Scan rejection APDU
            mp::odr odr;
            Z_APDU *apdu = odr.create_scanResponse(
                package.request().get()->u.z3950,
                YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED,
                req->databaseNames[i]);
            package.response() = apdu;
            package.session().close();
            return;
        }
    }
 
    // All the requested databases are acceptable
    return package.move();
}
 
 
static void reject_init(mp::Package &package, int err, const char *addinfo) {
    if (err == 0)
        err = YAZ_BIB1_INIT_AC_AUTHENTICATION_SYSTEM_ERROR;
    // Make an Init rejection APDU
    Z_GDU *gdu = package.request().get();
    mp::odr odr;
    Z_APDU *apdu = odr.create_initResponse(gdu->u.z3950, err, addinfo);
    *apdu->u.initResponse->result = 0; // reject
    package.response() = apdu;
    package.session().close();
}
 
void yf::AuthSimple::check_targets(mp::Package & package) const
{
    Z_InitRequest *initReq = package.request().get()->u.z3950->u.initRequest;
 
    std::string password;
    std::string user = get_user(initReq, password);
    std::list<std::string> authorisedTargets = m_p->targetsByUser[user];
 
    std::list<std::string> targets;
    Z_OtherInformation **otherInfo = &initReq->otherInfo;
    mp::util::remove_vhost_otherinfo(otherInfo, targets);
 
    // Check each of the targets specified in the otherInfo package
    std::list<std::string>::iterator i;
 
    i = targets.begin();
    while (i != targets.end()) {
        if (contains(authorisedTargets, *i) ||
            contains(authorisedTargets, "*")) {
            i++;
        } else {
            if (!m_p->discardUnauthorisedTargets)
                return reject_init(package,
                    YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED, i->c_str());
            i = targets.erase(i);
        }
    }
 
    if (targets.size() == 0)
        return reject_init(package,
                           YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED,
                           // ### It would be better to use the Z-db name
                           "all databases");
    mp::odr odr;
    mp::util::set_vhost_otherinfo(otherInfo, odr, targets);
    package.move();
}
 
 
static mp::filter::Base* filter_creator()
{
    return new mp::filter::AuthSimple;
}
 
extern "C" {
    struct metaproxy_1_filter_struct metaproxy_1_filter_auth_simple = {
        0,
        "auth_simple",
        filter_creator
    };
}
 
 
/*
 * Local variables:
 * c-basic-offset: 4
 * c-file-style: "Stroustrup"
 * indent-tabs-mode: nil
 * End:
 * vim: shiftwidth=4 tabstop=8 expandtab
 */