root/usr.sbin/ypldap/ldapclient.c
/* $OpenBSD: ldapclient.c,v 1.31 2014/11/16 23:24:44 tedu Exp $ */

/*
 * Copyright (c) 2008 Alexander Schrijver <aschrijver@openbsd.org>
 * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/tree.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <netdb.h>
#include <errno.h>
#include <err.h>
#include <event.h>
#include <fcntl.h>
#include <unistd.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "aldap.h"
#include "ypldap.h"

void    client_sig_handler(int, short, void *);
void    client_dispatch_dns(int, short, void *);
void    client_dispatch_parent(int, short, void *);
void    client_shutdown(void);
void    client_connect(int, short, void *);
void    client_configure(struct env *);
void    client_periodic_update(int, short, void *);
int     client_build_req(struct idm *, struct idm_req *, struct aldap_message *,
            int, int);
int     client_search_idm(struct env *, struct idm *, struct aldap *,
            char **, char *, int, int, enum imsg_type);
int     client_try_idm(struct env *, struct idm *);
int     client_addr_init(struct idm *);
int     client_addr_free(struct idm *);

struct aldap    *client_aldap_open(struct ypldap_addr_list *);

/*
 * dummy wrapper to provide aldap_init with its fd's.
 */
struct aldap *
client_aldap_open(struct ypldap_addr_list *addr)
{
        int                      fd = -1;
        struct ypldap_addr       *p;

        TAILQ_FOREACH(p, addr, next) {
                char                     hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
                struct sockaddr         *sa = (struct sockaddr *)&p->ss;

                if (getnameinfo(sa, sa->sa_len, hbuf, sizeof(hbuf), sbuf,
                        sizeof(sbuf), NI_NUMERICHOST | NI_NUMERICSERV))
                                errx(1, "could not get numeric hostname");

                if ((fd = socket(sa->sa_family, SOCK_STREAM, 0)) < 0)
                        return NULL;

                if (connect(fd, sa, sa->sa_len) == 0)
                        break;

                warn("connect to %s port %s (%s) failed", hbuf, sbuf, "tcp");
                close(fd);
        }

        if (fd == -1)
                return NULL;

        return aldap_init(fd);
}

int
client_addr_init(struct idm *idm)
{
        struct sockaddr_in      *sa_in;
        struct sockaddr_in6     *sa_in6;
        struct ypldap_addr         *h;

        TAILQ_FOREACH(h, &idm->idm_addr, next) {
                switch (h->ss.ss_family) {
                case AF_INET:
                        sa_in = (struct sockaddr_in *)&h->ss;
                        if (ntohs(sa_in->sin_port) == 0)
                                sa_in->sin_port = htons(LDAP_PORT);
                        idm->idm_state = STATE_DNS_DONE;
                        break;
                case AF_INET6:
                        sa_in6 = (struct sockaddr_in6 *)&h->ss;
                        if (ntohs(sa_in6->sin6_port) == 0)
                                sa_in6->sin6_port = htons(LDAP_PORT);
                        idm->idm_state = STATE_DNS_DONE;
                        break;
                default:
                        fatalx("king bula sez: wrong AF in client_addr_init");
                        /* not reached */
                }
        }

        return (0);
}

int
client_addr_free(struct idm *idm)
{
        struct ypldap_addr         *h;

        while (!TAILQ_EMPTY(&idm->idm_addr)) {
                h = TAILQ_FIRST(&idm->idm_addr);
                TAILQ_REMOVE(&idm->idm_addr, h, next);
                free(h);
        }

        return (0);
}

void
client_sig_handler(int sig, short event, void *p)
{
        switch (sig) {
        case SIGINT:
        case SIGTERM:
                client_shutdown();
                break;
        default:
                fatalx("unexpected signal");
        }
}

void
client_dispatch_dns(int fd, short events, void *p)
{
        struct imsg              imsg;
        u_int16_t                dlen;
        u_char                  *data;
        struct ypldap_addr      *h;
        int                      n, wait_cnt = 0;
        struct idm              *idm;
        int                      shut = 0;

        struct env              *env = p;
        struct imsgev           *iev = env->sc_iev_dns;
        struct imsgbuf          *ibuf = &iev->ibuf;

        if ((events & (EV_READ | EV_WRITE)) == 0)
                fatalx("unknown event");

        if (events & EV_READ) {
                if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
                        fatal("imsg_read error");
                if (n == 0)
                        shut = 1;
        }
        if (events & EV_WRITE) {
                if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
                        fatal("msgbuf_write");
                if (n == 0)
                        shut = 1;
                goto done;
        }

        for (;;) {
                if ((n = imsg_get(ibuf, &imsg)) == -1)
                        fatal("client_dispatch_dns: imsg_get error");
                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_HOST_DNS:
                        TAILQ_FOREACH(idm, &env->sc_idms, idm_entry)
                                if (idm->idm_id == imsg.hdr.peerid)
                                        break;
                        if (idm == NULL) {
                                log_warnx("IMSG_HOST_DNS with invalid peerID");
                                break;
                        }
                        if (!TAILQ_EMPTY(&idm->idm_addr)) {
                                log_warnx("IMSG_HOST_DNS but addrs set!");
                                break;
                        }

                        dlen = imsg.hdr.len - IMSG_HEADER_SIZE;
                        if (dlen == 0) {        /* no data -> temp error */
                                idm->idm_state = STATE_DNS_TEMPFAIL;
                                break;
                        }

                        data = (u_char *)imsg.data;
                        while (dlen >= sizeof(struct sockaddr_storage)) {
                                if ((h = calloc(1, sizeof(*h))) == NULL)
                                        fatal(NULL);
                                memcpy(&h->ss, data, sizeof(h->ss));
                                TAILQ_INSERT_HEAD(&idm->idm_addr, h, next);

                                data += sizeof(h->ss);
                                dlen -= sizeof(h->ss);
                        }
                        if (dlen != 0)
                                fatalx("IMSG_HOST_DNS: dlen != 0");

                        client_addr_init(idm);

                        break;
                default:
                        break;
                }
                imsg_free(&imsg);
        }

        TAILQ_FOREACH(idm, &env->sc_idms, idm_entry) {
                if (client_try_idm(env, idm) == -1)
                        idm->idm_state = STATE_LDAP_FAIL;

                if (idm->idm_state < STATE_LDAP_DONE)
                        wait_cnt++;
        }
        if (wait_cnt == 0)
                imsg_compose_event(env->sc_iev, IMSG_END_UPDATE, 0, 0, -1,
                    NULL, 0);

done:
        if (!shut)
                imsg_event_add(iev);
        else {
                /* this pipe is dead, so remove the event handler */
                event_del(&iev->ev);
                event_loopexit(NULL);
        }
}

void
client_dispatch_parent(int fd, short events, void *p)
{
        int                      n;
        int                      shut = 0;
        struct imsg              imsg;
        struct env              *env = p;
        struct imsgev           *iev = env->sc_iev;
        struct imsgbuf          *ibuf = &iev->ibuf;

        if ((events & (EV_READ | EV_WRITE)) == 0)
                fatalx("unknown event");

        if (events & EV_READ) {
                if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
                        fatal("imsg_read error");
                if (n == 0)
                        shut = 1;
        }
        if (events & EV_WRITE) {
                if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
                        fatal("msgbuf_write");
                if (n == 0)
                        shut = 1;
                goto done;
        }

        for (;;) {
                if ((n = imsg_get(ibuf, &imsg)) == -1)
                        fatal("client_dispatch_parent: imsg_get error");
                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_CONF_START: {
                        struct env      params;

                        if (env->sc_flags & F_CONFIGURING) {
                                log_warnx("configuration already in progress");
                                break;
                        }
                        memcpy(&params, imsg.data, sizeof(params));
                        log_debug("configuration starting");
                        env->sc_flags |= F_CONFIGURING;
                        purge_config(env);
                        memcpy(&env->sc_conf_tv, &params.sc_conf_tv,
                            sizeof(env->sc_conf_tv));
                        env->sc_flags |= params.sc_flags;
                        break;
                }
                case IMSG_CONF_IDM: {
                        struct idm      *idm;

                        if (!(env->sc_flags & F_CONFIGURING))
                                break;
                        if ((idm = calloc(1, sizeof(*idm))) == NULL)
                                fatal(NULL);
                        memcpy(idm, imsg.data, sizeof(*idm));
                        idm->idm_env = env;
                        TAILQ_INSERT_TAIL(&env->sc_idms, idm, idm_entry);
                        break;
                }
                case IMSG_CONF_END:
                        env->sc_flags &= ~F_CONFIGURING;
                        log_debug("applying configuration");
                        client_configure(env);
                        break;
                default:
                        log_debug("client_dispatch_parent: unexpected imsg %d",
                            imsg.hdr.type);

                        break;
                }
                imsg_free(&imsg);
        }

done:
        if (!shut)
                imsg_event_add(iev);
        else {
                /* this pipe is dead, so remove the event handler */
                event_del(&iev->ev);
                event_loopexit(NULL);
        }
}

void
client_shutdown(void)
{
        log_info("ldap client exiting");
        _exit(0);
}

pid_t
ldapclient(int pipe_main2client[2])
{
        pid_t            pid;
        int              pipe_dns[2];
        struct passwd   *pw;
        struct event     ev_sigint;
        struct event     ev_sigterm;
        struct env       env;

        switch (pid = fork()) {
        case -1:
                fatal("cannot fork");
                break;
        case 0:
                break;
        default:
                return (pid);
        }

        memset(&env, 0, sizeof(env));
        TAILQ_INIT(&env.sc_idms);

        if ((pw = getpwnam(YPLDAP_USER)) == NULL)
                fatal("getpwnam");

        if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe_dns) == -1)
                fatal("socketpair");
        ypldap_dns(pipe_dns, pw);
        close(pipe_dns[1]);

#ifndef DEBUG
        if (chroot(pw->pw_dir) == -1)
                fatal("chroot");
        if (chdir("/") == -1)
                fatal("chdir");
#else
#warning disabling chrooting in DEBUG mode
#endif
        setproctitle("ldap client");
        ypldap_process = PROC_CLIENT;

#ifndef DEBUG
        if (setgroups(0, NULL) ||
            setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
            setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
                fatal("cannot drop privileges");
#else
#warning disabling privilege revocation in DEBUG mode
#endif

        event_init();
        signal(SIGPIPE, SIG_IGN);
        signal_set(&ev_sigint, SIGINT, client_sig_handler, NULL);
        signal_set(&ev_sigterm, SIGTERM, client_sig_handler, NULL);
        signal_add(&ev_sigint, NULL);
        signal_add(&ev_sigterm, NULL);

        close(pipe_main2client[0]);
        if ((env.sc_iev = calloc(1, sizeof(*env.sc_iev))) == NULL)
                fatal(NULL);
        if ((env.sc_iev_dns = calloc(1, sizeof(*env.sc_iev_dns))) == NULL)
                fatal(NULL);

        env.sc_iev->events = EV_READ;
        env.sc_iev->data = &env;
        imsg_init(&env.sc_iev->ibuf, pipe_main2client[1]);
        env.sc_iev->handler = client_dispatch_parent;
        event_set(&env.sc_iev->ev, env.sc_iev->ibuf.fd, env.sc_iev->events,
            env.sc_iev->handler, &env);
        event_add(&env.sc_iev->ev, NULL);

        env.sc_iev_dns->events = EV_READ;
        env.sc_iev_dns->data = &env;
        imsg_init(&env.sc_iev_dns->ibuf, pipe_dns[0]);
        env.sc_iev_dns->handler = client_dispatch_dns;
        event_set(&env.sc_iev_dns->ev, env.sc_iev_dns->ibuf.fd,
            env.sc_iev_dns->events, env.sc_iev_dns->handler, &env);
        event_add(&env.sc_iev_dns->ev, NULL);

        event_dispatch();
        client_shutdown();

        return (0);

}

int
client_build_req(struct idm *idm, struct idm_req *ir, struct aldap_message *m,
    int min_attr, int max_attr)
{
        char    **ldap_attrs;
        int      i, k;

        memset(ir, 0, sizeof(*ir));
        for (i = min_attr; i < max_attr; i++) {
                if (idm->idm_flags & F_FIXED_ATTR(i)) {
                        if (strlcat(ir->ir_line, idm->idm_attrs[i],
                            sizeof(ir->ir_line)) >= sizeof(ir->ir_line))
                                /*
                                 * entry yields a line > 1024, trash it.
                                 */
                                return (-1);

                        if (i == ATTR_UID) {
                                ir->ir_key.ik_uid = strtonum(
                                    idm->idm_attrs[i], 0,
                                    UID_MAX, NULL);
                        } else if (i == ATTR_GR_GID) {
                                ir->ir_key.ik_gid = strtonum(
                                    idm->idm_attrs[i], 0,
                                    GID_MAX, NULL);
                        }
                } else if (idm->idm_list & F_LIST(i)) {
                        aldap_match_attr(m, idm->idm_attrs[i], &ldap_attrs);
                        for (k = 0; k >= 0 && ldap_attrs && ldap_attrs[k] != NULL; k++) {
                                /* XXX: Fail when attributes have illegal characters e.g. ',' */
                                if (strlcat(ir->ir_line, ldap_attrs[k],
                                    sizeof(ir->ir_line)) >= sizeof(ir->ir_line))
                                        continue;
                                if (ldap_attrs[k+1] != NULL)
                                        if (strlcat(ir->ir_line, ",",
                                                    sizeof(ir->ir_line))
                                            >= sizeof(ir->ir_line)) {
                                                aldap_free_attr(ldap_attrs);
                                                return (-1);
                                        }
                        }
                        aldap_free_attr(ldap_attrs);
                } else {
                        if (aldap_match_attr(m, idm->idm_attrs[i], &ldap_attrs) == -1)
                                return (-1);
                        if (strlcat(ir->ir_line, ldap_attrs[0],
                            sizeof(ir->ir_line)) >= sizeof(ir->ir_line)) {
                                aldap_free_attr(ldap_attrs);
                                return (-1);
                        }
                        if (i == ATTR_UID) {
                                ir->ir_key.ik_uid = strtonum(
                                    ldap_attrs[0], 0, UID_MAX, NULL);
                        } else if (i == ATTR_GR_GID) {
                                ir->ir_key.ik_uid = strtonum(
                                    ldap_attrs[0], 0, GID_MAX, NULL);
                        }
                        aldap_free_attr(ldap_attrs);
                }

                if (i + 1 != max_attr)
                        if (strlcat(ir->ir_line, ":",
                            sizeof(ir->ir_line)) >= sizeof(ir->ir_line))
                                return (-1);
        }

        return (0);
}

int
client_search_idm(struct env *env, struct idm *idm, struct aldap *al,
    char **attrs, char *filter, int min_attr, int max_attr,
    enum imsg_type type)
{
        struct idm_req           ir;
        struct aldap_message    *m;
        struct aldap_page_control *pg = NULL;
        const char              *errstr;
        char                    *dn;

        dn = idm->idm_basedn;
        if (type == IMSG_GRP_ENTRY && idm->idm_groupdn[0] != '\0')
                dn = idm->idm_groupdn;

        do {
                if (aldap_search(al, dn, LDAP_SCOPE_SUBTREE,
                    filter, attrs, 0, 0, 0, pg) == -1) {
                        aldap_get_errno(al, &errstr);
                        log_debug("%s", errstr);
                        return (-1);
                }

                if (pg != NULL) {
                        aldap_freepage(pg);
                        pg = NULL;
                }

                while ((m = aldap_parse(al)) != NULL) {
                        if (al->msgid != m->msgid) {
                                goto fail;
                        }
                        
                        if (m->message_type == LDAP_RES_SEARCH_RESULT) {
                                if (m->page != NULL && m->page->cookie_len != 0)
                                        pg = m->page;
                                else
                                        pg = NULL;

                                aldap_freemsg(m);
                                break;
                        }

                        if (m->message_type != LDAP_RES_SEARCH_ENTRY) {
                                goto fail;
                        }

                        if (client_build_req(idm, &ir, m, min_attr, max_attr) == 0)
                                imsg_compose_event(env->sc_iev, type, 0, 0, -1,
                                    &ir, sizeof(ir));

                        aldap_freemsg(m);       
                }
        } while (pg != NULL);

        return (0);

fail:
        aldap_freemsg(m);       
        if (pg != NULL) {
                aldap_freepage(pg);
        }

        return (-1);
}

int
client_try_idm(struct env *env, struct idm *idm)
{
        const char              *where;
        char                    *attrs[ATTR_MAX+1];
        int                      i, j;
        struct aldap_message    *m;
        struct aldap            *al;

        where = "connect";
        if ((al = client_aldap_open(&idm->idm_addr)) == NULL)
                return (-1);

        if (idm->idm_flags & F_NEEDAUTH) {
                where = "binding";
                if (aldap_bind(al, idm->idm_binddn, idm->idm_bindcred) == -1)
                        goto bad;

                where = "parsing";
                if ((m = aldap_parse(al)) == NULL)
                        goto bad;
                where = "verifying msgid";
                if (al->msgid != m->msgid) {
                        aldap_freemsg(m);
                        goto bad;
                }
                aldap_freemsg(m);
        }

        memset(attrs, 0, sizeof(attrs));
        for (i = 0, j = 0; i < ATTR_MAX; i++) {
                if (idm->idm_flags & F_FIXED_ATTR(i))
                        continue;
                attrs[j++] = idm->idm_attrs[i];
        }
        attrs[j] = NULL;

        /*
         * build password line.
         */
        where = "search";
        log_debug("searching password entries");
        if (client_search_idm(env, idm, al, attrs,
            idm->idm_filters[FILTER_USER], 0, ATTR_MAX, IMSG_PW_ENTRY) == -1)
                goto bad;

        memset(attrs, 0, sizeof(attrs));
        for (i = ATTR_GR_MIN, j = 0; i < ATTR_GR_MAX; i++) {
                if (idm->idm_flags & F_FIXED_ATTR(i))
                        continue;
                attrs[j++] = idm->idm_attrs[i];
        }
        attrs[j] = NULL;

        /*
         * build group line.
         */
        where = "search";
        log_debug("searching group entries");
        if (client_search_idm(env, idm, al, attrs,
            idm->idm_filters[FILTER_GROUP], ATTR_GR_MIN, ATTR_GR_MAX,
            IMSG_GRP_ENTRY) == -1)
                goto bad;

        aldap_close(al);

        idm->idm_state = STATE_LDAP_DONE;

        return (0);
bad:
        aldap_close(al);
        log_debug("directory %s errored out in %s", idm->idm_name, where);
        return (-1);
}

void
client_periodic_update(int fd, short event, void *p)
{
        struct env      *env = p;

        struct idm      *idm;
        int              fail_cnt = 0;

        /* If LDAP isn't finished, notify the master process to trash the
         * update. */
        TAILQ_FOREACH(idm, &env->sc_idms, idm_entry) {
                if (idm->idm_state < STATE_LDAP_DONE)
                        fail_cnt++;

                idm->idm_state = STATE_NONE;

                client_addr_free(idm);
        }
        if (fail_cnt > 0) {
                log_debug("trash the update");
                imsg_compose_event(env->sc_iev, IMSG_TRASH_UPDATE, 0, 0, -1,
                    NULL, 0);
        }

        client_configure(env);
}

void
client_configure(struct env *env)
{
        struct timeval   tv;
        struct idm      *idm;
        u_int16_t        dlen;

        log_debug("connecting to directories");

        imsg_compose_event(env->sc_iev, IMSG_START_UPDATE, 0, 0, -1, NULL, 0);

        /* Start the DNS lookups */
        TAILQ_FOREACH(idm, &env->sc_idms, idm_entry) {
                dlen = strlen(idm->idm_name) + 1;
                imsg_compose_event(env->sc_iev_dns, IMSG_HOST_DNS, idm->idm_id,
                    0, -1, idm->idm_name, dlen);
        }

        tv.tv_sec = env->sc_conf_tv.tv_sec;
        tv.tv_usec = env->sc_conf_tv.tv_usec;
        evtimer_set(&env->sc_conf_ev, client_periodic_update, env);
        evtimer_add(&env->sc_conf_ev, &tv);
}