mirror of
https://git.FreeBSD.org/src.git
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d6551d89a2
Reviewed by: bde
316 lines
7.9 KiB
C
316 lines
7.9 KiB
C
/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static const char copyright[] =
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"@(#) Copyright (c) 1983, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)rexecd.c 8.1 (Berkeley) 6/4/93";
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#endif
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <err.h>
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#include <errno.h>
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#include <libutil.h>
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#include <paths.h>
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#include <pwd.h>
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#include <signal.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#include <security/pam_appl.h>
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#include <security/openpam.h>
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static pam_handle_t *pamh;
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static struct pam_conv pamc = {
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openpam_nullconv,
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NULL
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};
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static int pam_flags = PAM_SILENT|PAM_DISALLOW_NULL_AUTHTOK;
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static int pam_err;
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#define pam_ok(err) ((pam_err = (err)) == PAM_SUCCESS)
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char **environ;
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char remote[MAXHOSTNAMELEN];
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struct sockaddr_storage asin;
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static void doit(struct sockaddr *);
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static void getstr(char *, int, char *);
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static void error(const char *fmt, ...);
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int no_uid_0 = 1;
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/*
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* remote execute server:
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* username\0
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* password\0
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* command\0
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* data
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*/
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/*ARGSUSED*/
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int
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main(int argc, char *argv[])
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{
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struct sockaddr_storage from;
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int fromlen;
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int ch;
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openlog("rexecd", LOG_PID, LOG_AUTH);
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while ((ch = getopt(argc, argv, "i")) != -1)
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switch (ch) {
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case 'i':
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no_uid_0 = 0;
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break;
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default:
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syslog(LOG_ERR, "usage: rexecd [-i]");
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exit(1);
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}
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argc -= optind;
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argv += optind;
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fromlen = sizeof (from);
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if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0)
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err(1, "getpeername");
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realhostname_sa(remote, sizeof(remote) - 1,
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(struct sockaddr *)&from, fromlen);
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doit((struct sockaddr *)&from);
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return(0);
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}
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static void
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doit(struct sockaddr *fromp)
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{
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char cmdbuf[NCARGS+1], *cp;
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const char *namep;
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char user[16], pass[16];
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struct passwd *pwd;
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int fd, r, sd;
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u_short port;
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int pv[2], pid, cc, nfds;
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fd_set rfds, fds;
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char buf[BUFSIZ], sig;
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int one = 1;
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char **envlist, **env;
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(void) signal(SIGINT, SIG_DFL);
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(void) signal(SIGQUIT, SIG_DFL);
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(void) signal(SIGTERM, SIG_DFL);
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dup2(STDIN_FILENO, STDOUT_FILENO);
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dup2(STDIN_FILENO, STDOUT_FILENO);
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(void) alarm(60);
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port = 0;
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for (;;) {
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char c;
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if (read(STDIN_FILENO, &c, 1) != 1)
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exit(1);
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if (c == 0)
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break;
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port = port * 10 + c - '0';
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}
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if (port != 0) {
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sd = socket(fromp->sa_family, SOCK_STREAM, 0);
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if (sd < 0)
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exit(1);
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bzero(&asin, sizeof(asin));
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asin.ss_family = fromp->sa_family;
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asin.ss_len = fromp->sa_len;
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if (bind(sd, (struct sockaddr *)&asin, asin.ss_len) < 0)
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exit(1);
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switch (fromp->sa_family) {
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case AF_INET:
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((struct sockaddr_in *)fromp)->sin_port = htons(port);
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break;
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case AF_INET6:
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((struct sockaddr_in6 *)fromp)->sin6_port = htons(port);
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break;
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default:
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exit(1);
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}
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if (connect(sd, fromp, fromp->sa_len) < 0)
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exit(1);
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}
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getstr(user, sizeof(user), "username");
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getstr(pass, sizeof(pass), "password");
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getstr(cmdbuf, sizeof(cmdbuf), "command");
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(void) alarm(0);
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if ((pwd = getpwnam(user)) == NULL || (pwd->pw_uid = 0 && no_uid_0) ||
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!pam_ok(pam_start("rexecd", user, &pamc, &pamh)) ||
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!pam_ok(pam_set_item(pamh, PAM_RHOST, remote)) ||
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!pam_ok(pam_set_item(pamh, PAM_AUTHTOK, pass)) ||
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!pam_ok(pam_authenticate(pamh, pam_flags)) ||
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!pam_ok(pam_acct_mgmt(pamh, pam_flags))) {
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syslog(LOG_ERR, "%s LOGIN REFUSED from %s", user, remote);
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error("Login incorrect.\n");
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exit(1);
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}
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syslog(LOG_INFO, "login from %s as %s", remote, user);
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(void) write(STDERR_FILENO, "\0", 1);
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if (port != 0) {
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(void) pipe(pv);
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pid = fork();
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if (pid == -1) {
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error("Try again.\n");
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exit(1);
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}
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if (pid) {
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/* parent */
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(void) pam_end(pamh, pam_err);
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(void) close(STDIN_FILENO);
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(void) close(STDOUT_FILENO);
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(void) close(STDERR_FILENO);
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(void) close(pv[1]);
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ioctl(pv[0], FIONBIO, (char *)&one);
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/* should set sd nbio! */
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FD_ZERO(&fds);
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FD_SET(sd, &fds);
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nfds = sd + 1;
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FD_SET(pv[0], &fds);
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if (pv[0] >= nfds)
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nfds = pv[0] + 1;
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do {
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rfds = fds;
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for (;;) {
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r = select(nfds, &rfds, NULL, NULL, NULL);
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if (r > 0)
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break;
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if (r < 0 && errno != EINTR)
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exit(0);
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}
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if (FD_ISSET(sd, &rfds)) {
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if (read(sd, &sig, 1) <= 0)
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FD_CLR(sd, &fds);
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else
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killpg(pid, sig);
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}
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if (FD_ISSET(pv[0], &fds)) {
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cc = read(pv[0], buf, sizeof (buf));
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if (cc <= 0) {
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shutdown(sd, SHUT_RDWR);
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FD_CLR(pv[0], &fds);
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} else {
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(void) write(sd, buf, cc);
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}
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}
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} while (FD_ISSET(sd, &fds) || FD_ISSET(pv[0], &fds));
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exit(0);
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}
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/* child */
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(void) close(sd);
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(void) close(pv[0]);
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dup2(pv[1], 2);
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}
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for (fd = getdtablesize(); fd > 2; fd--)
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(void) close(fd);
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if (*pwd->pw_shell == '\0')
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pwd->pw_shell = _PATH_BSHELL;
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if (setsid() == -1)
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syslog(LOG_ERR, "setsid() failed: %m");
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if (setlogin(pwd->pw_name) < 0)
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syslog(LOG_ERR, "setlogin() failed: %m");
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(void) setgid((gid_t)pwd->pw_gid);
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initgroups(pwd->pw_name, pwd->pw_gid);
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if (!pam_ok(pam_setcred(pamh, PAM_ESTABLISH_CRED)))
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syslog(LOG_ERR, "pam_setcred() failed: %s",
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pam_strerror(pamh, pam_err));
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(void) pam_setenv(pamh, "HOME", pwd->pw_dir, 1);
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(void) pam_setenv(pamh, "SHELL", pwd->pw_shell, 1);
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(void) pam_setenv(pamh, "USER", pwd->pw_name, 1);
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(void) pam_setenv(pamh, "PATH", _PATH_DEFPATH, 1);
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environ = pam_getenvlist(pamh);
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(void) pam_end(pamh, pam_err);
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(void) setuid((uid_t)pwd->pw_uid);
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cp = strrchr(pwd->pw_shell, '/');
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if (cp)
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cp++;
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else
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cp = pwd->pw_shell;
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if (chdir(pwd->pw_dir) < 0) {
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error("No remote directory.\n");
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exit(1);
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}
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execl(pwd->pw_shell, cp, "-c", cmdbuf, (char *)0);
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err(1, "%s", pwd->pw_shell);
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}
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static void
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error(const char *fmt, ...)
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{
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char buf[BUFSIZ];
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va_list ap;
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va_start(ap, fmt);
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buf[0] = 1;
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(void)vsnprintf(buf + 1, sizeof(buf) - 1, fmt, ap);
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(void)write(STDERR_FILENO, buf, strlen(buf));
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va_end(ap);
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}
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static void
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getstr(char *buf, int cnt, char *err)
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{
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char c;
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do {
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if (read(STDIN_FILENO, &c, 1) != 1)
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exit(1);
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*buf++ = c;
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if (--cnt == 0) {
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error("%s too long\n", err);
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exit(1);
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}
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} while (c != 0);
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}
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