/* $OpenBSD: local_passwd.c,v 1.58 2019/10/24 12:56:40 anton Exp $ */ /*- * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <sys/types.h> #include <sys/stat.h> #include <sys/uio.h> #include <err.h> #include <errno.h> #include <fcntl.h> #include <paths.h> #include <pwd.h> #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <string.h> #include <unistd.h> #include <util.h> #include <login_cap.h> #include <readpassphrase.h> #define UNCHANGED_MSG "Password unchanged." static uid_t uid; extern int pwd_check(login_cap_t *, char *); extern int pwd_gettries(login_cap_t *); int local_passwd(char *, int); char *getnewpasswd(struct passwd *, login_cap_t *, int); void kbintr(int); int local_passwd(char *uname, int authenticated) { struct passwd *pw, *opw; login_cap_t *lc; sigset_t fullset; time_t period; int i, pfd, tfd = -1; int pwflags = _PASSWORD_OMITV7; if (!(pw = getpwnam_shadow(uname))) { warnx("unknown user %s.", uname); return(1); } if (unveil(_PATH_MASTERPASSWD_LOCK, "rwc") == -1) err(1, "unveil"); if (unveil(_PATH_MASTERPASSWD, "r") == -1) err(1, "unveil"); if (unveil(_PATH_LOGIN_CONF, "r") == -1) err(1, "unveil"); if (unveil(_PATH_LOGIN_CONF ".db", "r") == -1) err(1, "unveil"); if (unveil(_PATH_BSHELL, "x") == -1) err(1, "unveil"); if (unveil(_PATH_SHELLS, "r") == -1) err(1, "unveil"); if (unveil(_PATH_PWD_MKDB, "x") == -1) err(1, "unveil"); if (pledge("stdio rpath wpath cpath getpw tty id proc exec", NULL) == -1) err(1, "pledge"); if ((opw = pw_dup(pw)) == NULL) { warn(NULL); return(1); } if ((lc = login_getclass(pw->pw_class)) == NULL) { warnx("unable to get login class for user %s.", uname); free(opw); return(1); } uid = authenticated ? pw->pw_uid : getuid(); if (uid && uid != pw->pw_uid) { warnx("login/uid mismatch, username argument required."); free(opw); return(1); } /* Get the new password. */ pw->pw_passwd = getnewpasswd(pw, lc, authenticated); if (pledge("stdio rpath wpath cpath getpw id proc exec", NULL) == -1) err(1, "pledge"); /* Reset password change time based on login.conf. */ period = (time_t)login_getcaptime(lc, "passwordtime", 0, 0); if (period > 0) { pw->pw_change = time(NULL) + period; } else { /* * If the pw change time is the same we only need * to update the spwd.db file. */ if (pw->pw_change != 0) pw->pw_change = 0; else pwflags = _PASSWORD_SECUREONLY; } /* Drop user's real uid and block all signals to avoid a DoS. */ setuid(0); sigfillset(&fullset); sigdelset(&fullset, SIGINT); sigprocmask(SIG_BLOCK, &fullset, NULL); if (pledge("stdio rpath wpath cpath proc exec", NULL) == -1) err(1, "pledge"); /* Get a lock on the passwd file and open it. */ pw_init(); for (i = 1; (tfd = pw_lock(0)) == -1; i++) { if (i == 4) (void)fputs("Attempting to lock password file, " "please wait or press ^C to abort", stderr); (void)signal(SIGINT, kbintr); if (i % 16 == 0) fputc('.', stderr); usleep(250000); (void)signal(SIGINT, SIG_IGN); } if (i >= 4) fputc('\n', stderr); pfd = open(_PATH_MASTERPASSWD, O_RDONLY | O_CLOEXEC, 0); if (pfd == -1) pw_error(_PATH_MASTERPASSWD, 1, 1); /* Update master.passwd file and rebuild spwd.db. */ pw_copy(pfd, tfd, pw, opw); free(opw); if (pw_mkdb(uname, pwflags) == -1) pw_error(NULL, 0, 1); return(0); } char * getnewpasswd(struct passwd *pw, login_cap_t *lc, int authenticated) { static char hash[_PASSWORD_LEN]; char newpass[1024]; char *p, *pref; int tries, pwd_tries; sig_t saveint, savequit; saveint = signal(SIGINT, kbintr); savequit = signal(SIGQUIT, kbintr); if (!authenticated) { (void)printf("Changing password for %s.\n", pw->pw_name); if (uid != 0 && pw->pw_passwd[0] != '\0') { char oldpass[1024]; p = readpassphrase("Old password:", oldpass, sizeof(oldpass), RPP_ECHO_OFF); if (p == NULL || *p == '\0') { (void)printf("%s\n", UNCHANGED_MSG); pw_abort(); exit(p == NULL ? 1 : 0); } if (crypt_checkpass(p, pw->pw_passwd) != 0) { errno = EACCES; explicit_bzero(oldpass, sizeof(oldpass)); pw_error(NULL, 1, 1); } explicit_bzero(oldpass, sizeof(oldpass)); } } pwd_tries = pwd_gettries(lc); for (newpass[0] = '\0', tries = 0;;) { char repeat[1024]; p = readpassphrase("New password:", newpass, sizeof(newpass), RPP_ECHO_OFF); if (p == NULL || *p == '\0') { (void)printf("%s\n", UNCHANGED_MSG); pw_abort(); exit(p == NULL ? 1 : 0); } if (strcmp(p, "s/key") == 0) { printf("That password collides with a system feature. Choose another.\n"); continue; } if ((tries++ < pwd_tries || pwd_tries == 0) && pwd_check(lc, p) == 0) continue; p = readpassphrase("Retype new password:", repeat, sizeof(repeat), RPP_ECHO_OFF); if (p != NULL && strcmp(newpass, p) == 0) { explicit_bzero(repeat, sizeof(repeat)); break; } (void)printf("Mismatch; try again, EOF to quit.\n"); explicit_bzero(repeat, sizeof(repeat)); explicit_bzero(newpass, sizeof(newpass)); } (void)signal(SIGINT, saveint); (void)signal(SIGQUIT, savequit); pref = login_getcapstr(lc, "localcipher", NULL, NULL); if (crypt_newhash(newpass, pref, hash, sizeof(hash)) != 0) { (void)printf("Couldn't generate hash.\n"); explicit_bzero(newpass, sizeof(newpass)); pw_error(NULL, 0, 0); } explicit_bzero(newpass, sizeof(newpass)); free(pref); return hash; } void kbintr(int signo) { dprintf(STDOUT_FILENO, "\n%s\n", UNCHANGED_MSG); _exit(0); }