/* * Copyright (c) 1988, 1993, 1994 * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. */ #ifndef lint static const char copyright[] = "@(#) Copyright (c) 1988, 1993, 1994\n\ The Regents of the University of California. All rights reserved.\n"; #endif /* not lint */ #ifndef lint #if 0 static char sccsid[] = "@(#)su.c 8.3 (Berkeley) 4/2/94"; #endif static const char rcsid[] = "$Id$"; #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef LOGIN_CAP #include #ifdef LOGIN_CAP_AUTH #undef SKEY #undef KERBEROS #endif #endif #ifdef SKEY #include #endif #ifdef KERBEROS #include #include #include #define ARGSTR "-Kflm" static int kerberos(char *username, char *user, int uid, char *pword); static int koktologin(char *name, char *toname); int use_kerberos = 1; #else /* !KERBEROS */ #define ARGSTR "-flm" #endif /* KERBEROS */ char *ontty __P((void)); int chshell __P((char *)); static void usage __P((void)); int main(argc, argv) int argc; char **argv; { extern char **environ; struct passwd *pwd; #ifdef WHEELSU char *targetpass; int iswheelsu; #endif /* WHEELSU */ char *p, **g, *user, *shell=NULL, *username, **cleanenv, **nargv, **np; struct group *gr; uid_t ruid; int asme, ch, asthem, fastlogin, prio, i; enum { UNSET, YES, NO } iscsh = UNSET; #ifdef LOGIN_CAP login_cap_t *lc; int setwhat; #ifdef LOGIN_CAP_AUTH char *style, *approvep, *auth_method = NULL; #endif #endif #ifdef KERBEROS char *k; #endif char shellbuf[MAXPATHLEN]; #ifdef WHEELSU iswheelsu = #endif /* WHEELSU */ asme = asthem = fastlogin = 0; user = "root"; while(optind < argc) if((ch = getopt(argc, argv, ARGSTR)) != -1) switch((char)ch) { #ifdef KERBEROS case 'K': use_kerberos = 0; break; #endif case 'f': fastlogin = 1; break; case '-': case 'l': asme = 0; asthem = 1; break; case 'm': asme = 1; asthem = 0; break; case '?': default: usage(); } else { user = argv[optind++]; break; } if (user == NULL) usage(); if ((nargv = malloc (sizeof (char *) * (argc + 4))) == NULL) { errx(1, "malloc failure"); } nargv[argc + 3] = NULL; for (i = argc; i >= optind; i--) nargv[i + 3] = argv[i]; np = &nargv[i + 3]; argv += optind; errno = 0; prio = getpriority(PRIO_PROCESS, 0); if (errno) prio = 0; (void)setpriority(PRIO_PROCESS, 0, -2); openlog("su", LOG_CONS, 0); /* get current login name and shell */ ruid = getuid(); username = getlogin(); if (username == NULL || (pwd = getpwnam(username)) == NULL || pwd->pw_uid != ruid) pwd = getpwuid(ruid); if (pwd == NULL) errx(1, "who are you?"); username = strdup(pwd->pw_name); if (username == NULL) err(1, NULL); if (asme) { if (pwd->pw_shell != NULL && *pwd->pw_shell != '\0') { /* copy: pwd memory is recycled */ shell = strncpy(shellbuf, pwd->pw_shell, sizeof shellbuf); shellbuf[sizeof shellbuf - 1] = '\0'; } else { shell = _PATH_BSHELL; iscsh = NO; } } #ifdef LOGIN_CAP_AUTH if (auth_method = strchr(user, ':')) { *auth_method = '\0'; auth_method++; if (*auth_method == '\0') auth_method = NULL; } #endif /* !LOGIN_CAP_AUTH */ /* get target login information, default to root */ if ((pwd = getpwnam(user)) == NULL) { errx(1, "unknown login: %s", user); } #ifdef LOGIN_CAP lc = login_getpwclass(pwd); #endif #ifdef WHEELSU targetpass = strdup(pwd->pw_passwd); #endif /* WHEELSU */ if (ruid) { #ifdef KERBEROS if (use_kerberos && koktologin(username, user) && !pwd->pw_uid) { warnx("kerberos: not in %s's ACL.", user); use_kerberos = 0; } #endif { /* only allow those in group zero to su to root. */ if (pwd->pw_uid == 0 && (gr = getgrgid((gid_t)0)) && gr->gr_mem && *(gr->gr_mem)) for (g = gr->gr_mem;; ++g) { if (!*g) errx(1, "you are not in the correct group to su %s.", user); if (strcmp(username, *g) == 0) { #ifdef WHEELSU iswheelsu = 1; #endif /* WHEELSU */ break; } } } /* if target requires a password, verify it */ if (*pwd->pw_passwd) { #ifdef LOGIN_CAP_AUTH /* * This hands off authorisation to an authorisation program, * depending on the styles available for the "auth-su", * authorisation styles. */ if ((style = login_getstyle(lc, auth_method, "su")) == NULL) errx(1, "auth method available for su.\n"); if (authenticate(user, lc ? lc->lc_class : "default", style, "su") != 0) { #ifdef WHEELSU if (!iswheelsu || authenticate(username, lc ? lc->lc_class : "default", style, "su") != 0) { #endif /* WHEELSU */ { fprintf(stderr, "Sorry\n"); syslog(LOG_AUTH|LOG_WARNING,"BAD SU %s to %s%s", username, user, ontty()); exit(1); } } /* * If authentication succeeds, run any approval * program, if applicable for this class. */ approvep = login_getcapstr(lc, "approve", NULL, NULL); if (approvep==NULL || auth_script(approvep, approvep, username, lc->lc_class, 0) == 0) { int r = auth_scan(AUTH_OKAY); /* See what the authorise program says */ if (!(r & AUTH_ROOTOKAY) && pwd->pw_uid == 0) { fprintf(stderr, "Sorry\n"); syslog(LOG_AUTH|LOG_WARNING,"UNAPPROVED ROOT SU %s%s", user, ontty()); exit(1); } } #else /* !LOGIN_CAP_AUTH */ #ifdef SKEY #ifdef WHEELSU if (iswheelsu) { pwd = getpwnam(username); } #endif /* WHEELSU */ p = skey_getpass("Password:", pwd, 1); if (!(!strcmp(pwd->pw_passwd, skey_crypt(p, pwd->pw_passwd, pwd, 1)) #ifdef WHEELSU || (iswheelsu && !strcmp(targetpass, crypt(p,targetpass))) #endif /* WHEELSU */ )) { #else p = getpass("Password:"); if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) { #endif #ifdef KERBEROS if (!use_kerberos || (use_kerberos && kerberos(username, user, pwd->pw_uid, p))) #endif { fprintf(stderr, "Sorry\n"); syslog(LOG_AUTH|LOG_WARNING, "BAD SU %s to %s%s", username, user, ontty()); exit(1); } } #ifdef WHEELSU if (iswheelsu) { pwd = getpwnam(user); } #endif /* WHEELSU */ #endif /* LOGIN_CAP_AUTH */ } if (pwd->pw_expire && time(NULL) >= pwd->pw_expire) { fprintf(stderr, "Sorry - account expired\n"); syslog(LOG_AUTH|LOG_WARNING, "BAD SU %s to %s%s", username, user, ontty()); exit(1); } } if (asme) { /* if asme and non-standard target shell, must be root */ if (!chshell(pwd->pw_shell) && ruid) errx(1, "permission denied (shell)."); } else if (pwd->pw_shell && *pwd->pw_shell) { shell = pwd->pw_shell; iscsh = UNSET; } else { shell = _PATH_BSHELL; iscsh = NO; } /* if we're forking a csh, we want to slightly muck the args */ if (iscsh == UNSET) { p = strrchr(shell, '/'); if (p) ++p; else p = shell; if ((iscsh = strcmp(p, "csh") ? NO : YES) == NO) iscsh = strcmp(p, "tcsh") ? NO : YES; } (void)setpriority(PRIO_PROCESS, 0, prio); #ifdef LOGIN_CAP /* Set everything now except the environment & umask */ setwhat = LOGIN_SETUSER|LOGIN_SETGROUP|LOGIN_SETRESOURCES|LOGIN_SETPRIORITY; /* * Don't touch resource/priority settings if -m has been * used or -l hasn't, and we're not su'ing to root. */ if ((asme || !asthem) && pwd->pw_uid) setwhat &= ~(LOGIN_SETPRIORITY|LOGIN_SETRESOURCES); if (setusercontext(lc, pwd, pwd->pw_uid, setwhat) < 0) err(1, "setusercontext"); #else /* set permissions */ if (setgid(pwd->pw_gid) < 0) err(1, "setgid"); if (initgroups(user, pwd->pw_gid)) errx(1, "initgroups failed"); if (setuid(pwd->pw_uid) < 0) err(1, "setuid"); #endif if (!asme) { if (asthem) { p = getenv("TERM"); #ifdef KERBEROS k = getenv("KRBTKFILE"); #endif if ((cleanenv = calloc(20, sizeof(char*))) == NULL) errx(1, "calloc"); cleanenv[0] = NULL; environ = cleanenv; #ifdef LOGIN_CAP /* set the su'd user's environment & umask */ setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETPATH|LOGIN_SETUMASK|LOGIN_SETENV); #else (void)setenv("PATH", _PATH_DEFPATH, 1); #endif if (p) (void)setenv("TERM", p, 1); #ifdef KERBEROS if (k) (void)setenv("KRBTKFILE", k, 1); #endif if (chdir(pwd->pw_dir) < 0) errx(1, "no directory"); } if (asthem || pwd->pw_uid) (void)setenv("USER", pwd->pw_name, 1); (void)setenv("HOME", pwd->pw_dir, 1); (void)setenv("SHELL", shell, 1); } if (iscsh == YES) { if (fastlogin) *np-- = "-f"; if (asme) *np-- = "-m"; } /* csh strips the first character... */ *np = asthem ? "-su" : iscsh == YES ? "_su" : "su"; if (ruid != 0) syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s", username, user, ontty()); login_close(lc); execv(shell, np); err(1, "%s", shell); } static void usage() { (void)fprintf(stderr, "usage: su [%s] [login [args]]\n", ARGSTR); exit(1); } int chshell(sh) char *sh; { int r = 0; char *cp; setusershell(); while (!r && (cp = getusershell()) != NULL) r = strcmp(cp, sh) == 0; endusershell(); return r; } char * ontty() { char *p; static char buf[MAXPATHLEN + 4]; buf[0] = 0; p = ttyname(STDERR_FILENO); if (p) snprintf(buf, sizeof(buf), " on %s", p); return (buf); } #ifdef KERBEROS int kerberos(username, user, uid, pword) char *username, *user; int uid; char *pword; { KTEXT_ST ticket; AUTH_DAT authdata; int kerno; u_long faddr; char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN]; char hostname[MAXHOSTNAMELEN], savehost[MAXHOSTNAMELEN]; char *krb_get_phost(); struct hostent *hp; if (krb_get_lrealm(lrealm, 1) != KSUCCESS) return (1); (void)sprintf(krbtkfile, "%s_%s_%lu", TKT_ROOT, user, (unsigned long)getuid()); (void)setenv("KRBTKFILE", krbtkfile, 1); (void)krb_set_tkt_string(krbtkfile); /* * Set real as well as effective ID to 0 for the moment, * to make the kerberos library do the right thing. */ if (setuid(0) < 0) { warn("setuid"); return (1); } /* * Little trick here -- if we are su'ing to root, * we need to get a ticket for "xxx.root", where xxx represents * the name of the person su'ing. Otherwise (non-root case), * we need to get a ticket for "yyy.", where yyy represents * the name of the person being su'd to, and the instance is null * * We should have a way to set the ticket lifetime, * with a system default for root. */ kerno = krb_get_pw_in_tkt((uid == 0 ? username : user), (uid == 0 ? "root" : ""), lrealm, "krbtgt", lrealm, DEFAULT_TKT_LIFE, pword); if (kerno != KSUCCESS) { if (kerno == KDC_PR_UNKNOWN) { warnx("kerberos: principal unknown: %s.%s@%s", (uid == 0 ? username : user), (uid == 0 ? "root" : ""), lrealm); return (1); } warnx("kerberos: unable to su: %s", krb_err_txt[kerno]); syslog(LOG_NOTICE|LOG_AUTH, "BAD Kerberos SU: %s to %s%s: %s", username, user, ontty(), krb_err_txt[kerno]); return (1); } if (chown(krbtkfile, uid, -1) < 0) { warn("chown"); (void)unlink(krbtkfile); return (1); } (void)setpriority(PRIO_PROCESS, 0, -2); if (gethostname(hostname, sizeof(hostname)) == -1) { warn("gethostname"); dest_tkt(); return (1); } (void)strncpy(savehost, krb_get_phost(hostname), sizeof(savehost)); savehost[sizeof(savehost) - 1] = '\0'; kerno = krb_mk_req(&ticket, "rcmd", savehost, lrealm, 33); if (kerno == KDC_PR_UNKNOWN) { warnx("Warning: TGT not verified."); syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s, TGT not verified (%s); %s.%s not registered?", username, user, ontty(), krb_err_txt[kerno], "rcmd", savehost); } else if (kerno != KSUCCESS) { warnx("Unable to use TGT: %s", krb_err_txt[kerno]); syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s", username, user, ontty(), krb_err_txt[kerno]); dest_tkt(); return (1); } else { if (!(hp = gethostbyname(hostname))) { warnx("can't get addr of %s", hostname); dest_tkt(); return (1); } memmove((char *)&faddr, (char *)hp->h_addr, sizeof(faddr)); if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr, &authdata, "")) != KSUCCESS) { warnx("kerberos: unable to verify rcmd ticket: %s\n", krb_err_txt[kerno]); syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s", username, user, ontty(), krb_err_txt[kerno]); dest_tkt(); return (1); } } return (0); } int koktologin(name, toname) char *name, *toname; { AUTH_DAT *kdata; AUTH_DAT kdata_st; char realm[REALM_SZ]; if (krb_get_lrealm(realm, 1) != KSUCCESS) return (1); kdata = &kdata_st; memset((char *)kdata, 0, sizeof(*kdata)); (void)strncpy(kdata->pname, name, sizeof kdata->pname - 1); (void)strncpy(kdata->pinst, ((strcmp(toname, "root") == 0) ? "root" : ""), sizeof kdata->pinst - 1); (void)strncpy(kdata->prealm, realm, sizeof kdata->prealm - 1); return (kuserok(kdata, toname)); } #endif