source: code/icbd.c@ 058b664

/*
 * Copyright (c) 2009 Mike Belopuhov
 * Copyright (c) 2007 Oleg Safiullin
 *
 * 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/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/tree.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sysexits.h>
#include <syslog.h>
#include <pwd.h>
#include <login_cap.h>
#include <locale.h>
#include <netdb.h>
#include <event.h>
#include <errno.h>
#include <err.h>

#include "icb.h"
#include "icbd.h"

uint64_t sessionid;
char modtab[ICB_MTABLEN][ICB_MAXNICKLEN];
int  modtabcnt;
char srvname[MAXHOSTNAMELEN];
int  creategroups;
int  foreground;
char logprefix[MAXPATHLEN/2];
int  dodns = 1;
int  dologging;
int  verbose;

void usage(void);
void getpeerinfo(struct icb_session *);
void icbd_accept(int, short, void *);
void icbd_paused(int, short, void *);
void icbd_drop(struct icb_session *, char *);
void icbd_ioerr(struct bufferevent *, short, void *);
void icbd_dispatch(struct bufferevent *, void *);
void icbd_log(struct icb_session *, int, const char *, ...);
void icbd_grplist(char *);
void icbd_modtab(char *);
void icbd_restrict(void);
void icbd_write(struct icb_session *, char *, ssize_t);

static inline int icbd_session_cmp(struct icb_session *, struct icb_session *);

RB_HEAD(icbd_sessions, icb_session) icbd_sessions;
RB_PROTOTYPE(icbd_sessions, icb_session, node, icbd_session_cmp);
RB_GENERATE(icbd_sessions, icb_session, node, icbd_session_cmp);

struct icbd_listener {
        struct event ev, pause;
};

int
main(int argc, char *argv[])
{
        struct icbd_callbacks ic = { icbd_drop, icbd_log, icbd_write };
        const char *cause = NULL;
        int ch, nsocks = 0, save_errno = 0;
        int inet4 = 0, inet6 = 0;

        RB_INIT(&icbd_sessions);

        /* init group lists before calling icb_addgroup */
        icb_init(&ic);

        while ((ch = getopt(argc, argv, "46CdG:M:nL:S:v")) != -1)
                switch (ch) {
                case '4':
                        inet4++;
                        break;
                case '6':
                        inet6++;
                        break;
                case 'C':
                        creategroups++;
                        break;
                case 'd':
                        foreground++;
                        break;
                case 'G':
                        icbd_grplist(optarg);
                        break;
                case 'L':
                        strlcpy(logprefix, optarg, sizeof logprefix);
                        dologging++;
                        break;
                case 'M':
                        icbd_modtab(optarg);
                        break;
                case 'n':
                        dodns = 0;
                        break;
                case 'S':
                        strlcpy(srvname, optarg, sizeof srvname);
                        break;
                case 'v':
                        verbose++;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        argc -= optind;
        argv += optind;

        /* add group "1" as it's a login group for most of the clients */
        if (icb_addgroup(NULL, "1", NULL) == NULL)
                err(EX_UNAVAILABLE, NULL);

        if (argc == 0)
                argc++;

        if (inet4 && inet6)
                errx(EX_USAGE, "Can't specify both -4 and -6");

        tzset();
        (void)setlocale(LC_ALL, "C");

        if (foreground)
                openlog("icbd", LOG_PID | LOG_PERROR, LOG_DAEMON);
        else
                openlog("icbd", LOG_PID | LOG_NDELAY, LOG_DAEMON);

        if (!foreground && daemon(0, 0) < 0)
                err(EX_OSERR, NULL);

        (void)event_init();

        for (ch = 0; ch < argc; ch++) {
                struct addrinfo hints, *res, *res0;
                struct icbd_listener *l;
                char *addr, *port;
                int error, s, on = 1;

                addr = port = NULL;
                if (argv[ch] != NULL) {
                        if (argv[ch][0] != ':')
                                addr = argv[ch];
                        if ((port = strrchr(argv[ch], ':')) != NULL)
                                *port++ = '\0';
                }

                bzero(&hints, sizeof hints);
                if (inet4 || inet6)
                        hints.ai_family = inet4 ? PF_INET : PF_INET6;
                else
                        hints.ai_family = PF_UNSPEC;
                hints.ai_socktype = SOCK_STREAM;
                hints.ai_flags = AI_PASSIVE;
                if ((error = getaddrinfo(addr, port ? port : "icb", &hints,
                    &res0)) != 0) {
                        syslog(LOG_ERR, "%s", gai_strerror(error));
                        return (EX_UNAVAILABLE);
                }

                for (res = res0; res != NULL; res = res->ai_next) {
                        if ((s = socket(res->ai_family, res->ai_socktype,
                            res->ai_protocol)) < 0) {
                                cause = "socket";
                                save_errno = errno;
                                continue;
                        }

                        if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on,
                            sizeof on) < 0) {
                                cause = "SO_REUSEADDR";
                                save_errno = errno;
                                (void)close(s);
                                continue;
                        }

                        if (bind(s, res->ai_addr, res->ai_addrlen) < 0) {
                                cause = "bind";
                                save_errno = errno;
                                (void)close(s);
                                continue;
                        }

                        (void)listen(s, TCP_BACKLOG);

                        if ((l = calloc(1, sizeof *l)) == NULL)
                                err(EX_UNAVAILABLE, NULL);
                        event_set(&l->ev, s, EV_READ | EV_PERSIST, icbd_accept, l);
                        if (event_add(&l->ev, NULL) < 0) {
                                syslog(LOG_ERR, "event_add: %m");
                                return (EX_UNAVAILABLE);
                        }
                        evtimer_set(&l->pause, icbd_paused, l);

                        nsocks++;
                }

                freeaddrinfo(res0);
        }

        if (nsocks == 0) {
                errno = save_errno;
                syslog(LOG_ERR, "%s: %m", cause);
                return (EX_UNAVAILABLE);
        }

        /* start the logger service */
        logger_init();

        /* start a dns resolver thread */
        dns_init();

        if (!foreground)
                icbd_restrict();

        (void)signal(SIGPIPE, SIG_IGN);

        (void)event_dispatch();

        syslog(LOG_ERR, "event_dispatch: %m");

        return (EX_UNAVAILABLE);
}

static inline int
icbd_session_cmp(struct icb_session *a, struct icb_session *b)
{
        if (a->id > b->id)
                return (1);
        if (a->id < b->id)
                return (-1);
        return (0);
}

inline struct icb_session *
icbd_session_lookup(uint64_t sid)
{
        struct icb_session key;

        key.id = sid;
        return (RB_FIND(icbd_sessions, &icbd_sessions, &key));
}

void
icbd_accept(int fd, short event __attribute__((__unused__)),
    void *arg)
{
        struct icbd_listener *l = arg;
        struct sockaddr_storage ss;
        struct timeval p = { 1, 0 };
        struct icb_session *is;
        socklen_t ss_len = sizeof ss;
        int s, on = 1, tos = IPTOS_LOWDELAY;

        ss.ss_len = ss_len;
        s = accept(fd, (struct sockaddr *)&ss, &ss_len);
        if (s == -1) {
                switch (errno) {
                case EINTR:
                case EWOULDBLOCK:
                case ECONNABORTED:
                        return;
                case EMFILE:
                case ENFILE:
                        event_del(&l->ev);
                        evtimer_add(&l->pause, &p);
                        return;
                default:
                        syslog(LOG_ERR, "accept: %m");
                        return;
                }
        }

        if (ss.ss_family == AF_INET)
                if (setsockopt(s, IPPROTO_IP, IP_TOS, &tos, sizeof tos) < 0)
                        syslog(LOG_WARNING, "IP_TOS: %m");
        if (setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof on) < 0)
                syslog(LOG_WARNING, "SO_KEEPALIVE: %m");
        if ((is = calloc(1, sizeof *is)) == NULL) {
                syslog(LOG_ERR, "calloc: %m");
                (void)close(s);
                return;
        }
        if ((is->bev = bufferevent_new(s, icbd_dispatch, NULL, icbd_ioerr,
            is)) == NULL) {
                syslog(LOG_ERR, "bufferevent_new: %m");
                (void)close(s);
                free(is);
                return;
        }
        if (bufferevent_enable(is->bev, EV_READ)) {
                syslog(LOG_ERR, "bufferevent_enable: %m");
                (void)close(s);
                bufferevent_free(is->bev);
                free(is);
                return;
        }

        is->id = sessionid++;
        RB_INSERT(icbd_sessions, &icbd_sessions, is);

        /* save host information */
        getpeerinfo(is);

        /* start icb conversation */
        icb_start(is);
}

void
icbd_paused(int fd __attribute__((__unused__)),
        short events __attribute__((__unused__)), void *arg)
{
        struct icbd_listener *l = arg;
        event_add(&l->ev, NULL);
}

__dead void
usage(void)
{
        extern char *__progname;

        (void)fprintf(stderr, "usage: %s [-46Cdv] [-G group1[,group2,...]] "
           "[-L prefix] [-M modtab]\n\t[-S name] [[addr][:port] ...]\n",
            __progname);
        exit(EX_USAGE);
}

/*
 *  bufferevent functions
 */
void
icbd_ioerr(struct bufferevent *bev __attribute__((__unused__)), short what,
    void *arg)
{
        struct icb_session *is = (struct icb_session *)arg;

        if (what & EVBUFFER_TIMEOUT)
                icbd_drop(is, "timeout");
        else if (what & EVBUFFER_EOF)
                icbd_drop(is, NULL);
        else if (what & EVBUFFER_ERROR)
                icbd_drop(is, (what & EVBUFFER_READ) ? "read error" :
                    "write error");
}

void
icbd_dispatch(struct bufferevent *bev, void *arg)
{
        struct icb_session *is = (struct icb_session *)arg;

        while (EVBUFFER_LENGTH(EVBUFFER_INPUT(bev)) > 0) {
                if (is->length == 0) {
                        /* read length */
                        is->rlen = bufferevent_read(bev, is->buffer, 1);
                        is->length = (size_t)(unsigned char)is->buffer[0];
                        if (is->length == 0) {
                                icbd_drop(is, "invalid packet");
                                return;
                        }
                }
                /* read as much as we can */
                is->rlen += bufferevent_read(bev, &is->buffer[is->rlen],
                    is->length);
#ifdef DEBUG
                {
                        int i;

                        printf("-> read %lu out of %lu from %s:%d:\n",
                            is->rlen, is->length, is->host, is->port);
                        for (i = 0; i < (int)is->rlen; i++)
                                printf(" %02x", (unsigned char)is->buffer[i]);
                        printf("\n");
                }
#endif
                /* see you next time around */
                if (is->rlen < is->length)
                        return;
                /* process the message in full */
                icb_input(is);
                is->rlen = is->length = 0;
        }
}

void
icbd_write(struct icb_session *is, char *buf, ssize_t size)
{
        if (bufferevent_write(is->bev, buf, size) == -1)
                syslog(LOG_ERR, "bufferevent_write: %m");
#ifdef DEBUG
        {
                int i;

                printf("-> wrote %lu to %s:%d:\n", size, is->host, is->port);
                for (i = 0; i < size; i++)
                        printf(" %02x", (unsigned char)buf[i]);
                printf("\n");
        }
#endif
}

void
icbd_drop(struct icb_session *is, char *reason)
{
        if (reason) {
                icb_remove(is, reason);
                icbd_log(is, LOG_DEBUG, reason);
        } else
                icb_remove(is, NULL);
        (void)evbuffer_write(EVBUFFER_OUTPUT(is->bev), EVBUFFER_FD(is->bev));
        (void)close(EVBUFFER_FD(is->bev));
        bufferevent_free(is->bev);
        RB_REMOVE(icbd_sessions, &icbd_sessions, is);
        free(is);
}

void
icbd_log(struct icb_session *is, int level, const char *fmt, ...)
{
        char buf[512];
        va_list ap;

        if (!verbose && level == LOG_DEBUG)
                return;

        va_start(ap, fmt);
        (void)vsnprintf(buf, sizeof buf, fmt, ap);
        va_end(ap);
        if (is)
                syslog(level, "%s:%u: %s", is->host, is->port, buf);
        else
                syslog(level, "%s", buf);
}

void
icbd_restrict(void)
{
        struct stat     sb;
        struct passwd   *pw;

        if ((pw = getpwnam(ICBD_USER)) == NULL) {
                syslog(LOG_ERR, "No passwd entry for %s", ICBD_USER);
                exit(EX_NOUSER);
        }

        if (setusercontext(NULL, pw, pw->pw_uid,
            LOGIN_SETALL & ~LOGIN_SETUSER) < 0)
                exit(EX_NOPERM);

        if (stat(pw->pw_dir, &sb) == -1) {
                syslog(LOG_ERR, "%s: %m", pw->pw_name);
                exit(EX_NOPERM);
        }

        if (sb.st_uid != 0 || (sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
                syslog(LOG_ERR, "bad directory permissions");
                exit(EX_NOPERM);
        }

        if (chroot(pw->pw_dir) < 0) {
                syslog(LOG_ERR, "%s: %m", pw->pw_dir);
                exit(EX_UNAVAILABLE);
        }

        if (chdir("/") < 0) {
                syslog(LOG_ERR, "/: %m");
                exit(EX_UNAVAILABLE);
        }

        if (setuid(pw->pw_uid) < 0) {
                syslog(LOG_ERR, "%d: %m", pw->pw_uid);
                exit(EX_NOPERM);
        }

        (void)setproctitle("icbd");
}

void
icbd_grplist(char *list)
{
        char *s, *s1, *s2;
        int last = 0;

        if (!list || strlen(list) == 0)
                return;

        /* "group1[:pass1][,group2[:pass2],...]" */
        s = list;
        s1 = s2 = NULL;
        while (!last && s) {
                if ((s1 = strchr(s, ',')) != NULL)
                        *s1 = '\0';
                else {
                        last = 1;
                        s1 = s;
                }
                if ((s2 = strchr(s, ':')) != NULL)
                        *s2 = '\0';
                if (icb_addgroup(NULL, s, s2 ? ++s2 : NULL) == NULL)
                        err(EX_UNAVAILABLE, NULL);
                s = ++s1;
                s1 = s2 = NULL;
        }
}

void
icbd_modtab(char *mtab)
{
        FILE *fp;
        char *buf, *lbuf;
        size_t len;

        if ((fp = fopen(mtab, "r")) == NULL)
                err(EX_NOINPUT, "%s", mtab);

        bzero(modtab, ICB_MTABLEN * ICB_MAXNICKLEN);
        lbuf = NULL;
        while ((buf = fgetln(fp, &len)) && modtabcnt < ICB_MTABLEN) {
                if (buf[len - 1] == '\n')
                        buf[len - 1] = '\0';
                else {
                        /* EOF without EOL, copy and add the NUL */
                        if ((lbuf = malloc(len + 1)) == NULL)
                                err(1, NULL);
                        memcpy(lbuf, buf, len);
                        lbuf[len] = '\0';
                        buf = lbuf;
                }
                while (buf[0] == ' ' || buf[0] == '\t')
                        buf++;
                if (buf[0] == '#' || buf[0] == '\0')
                        continue;
                strlcpy(modtab[modtabcnt++], buf, ICB_MAXNICKLEN);
        }
        free(lbuf);

        qsort(modtab, modtabcnt, ICB_MAXNICKLEN,
            (int (*)(const void *, const void *))strcmp);

        fclose(fp);
}

time_t
getmonotime(void)
{
        struct timespec ts;

        if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
                syslog(LOG_ERR, "%m");
                exit(EX_OSERR);
        }
        return (ts.tv_sec);
}

void
getpeerinfo(struct icb_session *is)
{
        struct sockaddr_storage ss;
        struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
        socklen_t ss_len = sizeof ss;

        bzero(&ss, sizeof ss);
        if (getpeername(EVBUFFER_FD(is->bev), (struct sockaddr *)&ss,
            &ss_len) != 0)
                return;

        is->port = 0;
        switch (ss.ss_family) {
        case AF_INET:
                is->port = ntohs(sin->sin_port);
                break;

        case AF_INET6:
                is->port = ntohs(sin6->sin6_port);
                break;
        }

        inet_ntop(ss.ss_family, ss.ss_family == AF_INET ?
            (void *)&sin->sin_addr : (void *)&sin6->sin6_addr,
            is->host, sizeof is->host);

        dns_rresolv(is, &ss);
}