153 lines
3.5 KiB
C
153 lines
3.5 KiB
C
/*
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* Copyright (c) 2009 Michael Shalayeff
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* All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN
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* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <sysexits.h>
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#include <login_cap.h>
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#include <event.h>
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#include <pwd.h>
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#include <netdb.h>
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#include "icb.h"
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#include "icbd.h"
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void dns_dispatch(int, short, void *);
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int dns_pipe;
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int
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icbd_dns_init(void)
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{
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struct event ev;
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int pipe[2];
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struct passwd *pw;
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if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pipe) == -1) {
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syslog(LOG_ERR, "socketpair: %m");
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exit(EX_OSERR);
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}
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switch (fork()) {
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case -1:
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syslog(LOG_ERR, "fork: %m");
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exit(EX_OSERR);
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case 0:
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break;
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default:
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close(pipe[1]);
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dns_pipe = pipe[0];
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return (0);
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}
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setproctitle("dns resolver");
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close(pipe[0]);
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if ((pw = getpwnam(ICBD_USER)) == NULL) {
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syslog(LOG_ERR, "No passwd entry for %s", ICBD_USER);
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exit(EX_NOUSER);
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}
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if (setusercontext(NULL, pw, pw->pw_uid,
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LOGIN_SETALL & ~LOGIN_SETUSER) < 0)
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exit(EX_NOPERM);
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if (setuid(pw->pw_uid) < 0) {
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syslog(LOG_ERR, "%d: %m", pw->pw_uid);
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exit(EX_NOPERM);
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}
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if (chdir("/") < 0) {
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syslog(LOG_ERR, "chdir: %m");
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exit(EX_UNAVAILABLE);
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}
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event_init();
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event_set(&ev, pipe[1], EV_READ | EV_PERSIST, dns_dispatch, NULL);
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if (event_add(&ev, NULL) < 0) {
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syslog(LOG_ERR, "event_add: %m");
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exit (EX_UNAVAILABLE);
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}
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return event_dispatch();
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}
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void
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dns_dispatch(int fd, short event, void *arg)
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{
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char host[NI_MAXHOST];
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struct sockaddr_storage ss;
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struct sockaddr *sa = (struct sockaddr *)&ss;
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int gerr, ss_len = sizeof ss;
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arg = NULL;
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if (event != EV_READ)
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return;
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if (read(fd, &ss, ss_len) != ss_len) {
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syslog(LOG_ERR, "dns read: %m");
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exit(1);
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}
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if ((gerr = getnameinfo(sa, sa->sa_len,
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host, sizeof host, NULL, 0, NI_NOFQDN))) {
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syslog(LOG_ERR, "getnameinfo: %s", gai_strerror(gerr));
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write(fd, host, sizeof host);
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return;
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}
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if (verbose)
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syslog(LOG_DEBUG, "dns_dispatch: resolved %s", host);
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if (write(fd, host, sizeof host) != sizeof host)
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syslog(LOG_ERR, "dns write: %m");
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}
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int
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dns_rresolv(struct icb_session *is, struct sockaddr_storage *ss)
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{
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/* one-shot event for the reply */
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event_set(&is->ev, dns_pipe, EV_READ, icbd_dns, is);
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if (event_add(&is->ev, NULL) < 0) {
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syslog(LOG_ERR, "event_add: %m");
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exit (EX_UNAVAILABLE);
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}
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inet_ntop(ss->ss_family, ss->ss_family == AF_INET ?
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(void *)&((struct sockaddr_in *)ss)->sin_addr :
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(void *)&((struct sockaddr_in6 *)ss)->sin6_addr,
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is->host, sizeof is->host);
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if (verbose)
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syslog(LOG_DEBUG, "resolving: %s", is->host);
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if (write(dns_pipe, ss, sizeof *ss) != sizeof *ss) {
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syslog(LOG_ERR, "write: %m");
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exit (EX_OSERR);
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}
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return 0;
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}
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