Annotation of src/usr.bin/su/su.c, Revision 1.27
1.27 ! deraadt 1: /* $OpenBSD: su.c,v 1.26 1997/06/22 23:03:10 deraadt Exp $ */
1.4 deraadt 2:
1.1 deraadt 3: /*
4: * Copyright (c) 1988 The Regents of the University of California.
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by the University of
18: * California, Berkeley and its contributors.
19: * 4. Neither the name of the University nor the names of its contributors
20: * may be used to endorse or promote products derived from this software
21: * without specific prior written permission.
22: *
23: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33: * SUCH DAMAGE.
34: */
35:
36: #ifndef lint
37: char copyright[] =
38: "@(#) Copyright (c) 1988 The Regents of the University of California.\n\
39: All rights reserved.\n";
40: #endif /* not lint */
41:
42: #ifndef lint
43: /*static char sccsid[] = "from: @(#)su.c 5.26 (Berkeley) 7/6/91";*/
1.27 ! deraadt 44: static char rcsid[] = "$OpenBSD: su.c,v 1.26 1997/06/22 23:03:10 deraadt Exp $";
1.1 deraadt 45: #endif /* not lint */
46:
47: #include <sys/param.h>
48: #include <sys/time.h>
49: #include <sys/resource.h>
1.8 millert 50:
51: #include <err.h>
52: #include <errno.h>
53: #include <grp.h>
54: #include <paths.h>
55: #include <pwd.h>
1.1 deraadt 56: #include <stdio.h>
57: #include <stdlib.h>
58: #include <string.h>
1.8 millert 59: #include <syslog.h>
1.1 deraadt 60: #include <unistd.h>
1.8 millert 61:
62: #ifdef SKEY
63: #include <skey.h>
64: #endif
1.1 deraadt 65:
66: #ifdef KERBEROS
67: #include <kerberosIV/des.h>
68: #include <kerberosIV/krb.h>
69: #include <netdb.h>
70:
71: #define ARGSTR "-Kflm"
72:
73: int use_kerberos = 1;
1.25 deraadt 74: int got_ticket;
1.1 deraadt 75: #else
76: #define ARGSTR "-flm"
77: #endif
78:
1.8 millert 79: char *ontty __P((void));
80: int chshell __P((char *));
1.1 deraadt 81:
82: int
83: main(argc, argv)
84: int argc;
85: char **argv;
86: {
87: extern char **environ;
88: register struct passwd *pwd;
89: register char *p, **g;
90: struct group *gr;
1.9 millert 91: uid_t ruid;
1.1 deraadt 92: int asme, ch, asthem, fastlogin, prio;
93: enum { UNSET, YES, NO } iscsh = UNSET;
1.24 deraadt 94: char *user, *shell, *avshell, *username, **np;
1.1 deraadt 95: char shellbuf[MAXPATHLEN], avshellbuf[MAXPATHLEN];
1.24 deraadt 96: #ifdef KERBEROS
97: char *k;
98: #endif
1.1 deraadt 99:
100: asme = asthem = fastlogin = 0;
1.18 millert 101: while ((ch = getopt(argc, argv, ARGSTR)) != -1)
1.1 deraadt 102: switch((char)ch) {
103: #ifdef KERBEROS
104: case 'K':
105: use_kerberos = 0;
106: break;
107: #endif
108: case 'f':
109: fastlogin = 1;
110: break;
111: case '-':
112: case 'l':
113: asme = 0;
114: asthem = 1;
115: break;
116: case 'm':
117: asme = 1;
118: asthem = 0;
119: break;
120: case '?':
121: default:
1.7 millert 122: (void)fprintf(stderr,
123: "usage: su [%s] [login [shell arguments]]\n",
1.1 deraadt 124: ARGSTR);
125: exit(1);
126: }
127: argv += optind;
128:
129: errno = 0;
130: prio = getpriority(PRIO_PROCESS, 0);
131: if (errno)
132: prio = 0;
133: (void)setpriority(PRIO_PROCESS, 0, -2);
134: openlog("su", LOG_CONS, 0);
135:
136: /* get current login name and shell */
137: ruid = getuid();
138: username = getlogin();
139: if (username == NULL || (pwd = getpwnam(username)) == NULL ||
140: pwd->pw_uid != ruid)
141: pwd = getpwuid(ruid);
1.8 millert 142: if (pwd == NULL)
143: errx(1, "who are you?");
1.9 millert 144: if ((username = strdup(pwd->pw_name)) == NULL)
145: err(1, "can't allocate memory");
1.1 deraadt 146: if (asme)
1.10 millert 147: if (pwd->pw_shell && *pwd->pw_shell) {
1.11 millert 148: shell = strncpy(shellbuf, pwd->pw_shell, sizeof(shellbuf) - 1);
1.10 millert 149: shellbuf[sizeof(shellbuf) - 1] = '\0';
150: } else {
1.1 deraadt 151: shell = _PATH_BSHELL;
152: iscsh = NO;
153: }
154:
155: /* get target login information, default to root */
156: user = *argv ? *argv : "root";
157: np = *argv ? argv : argv-1;
158:
1.8 millert 159: if ((pwd = getpwnam(user)) == NULL)
160: errx(1, "unknown login %s", user);
1.16 millert 161: if ((user = strdup(pwd->pw_name)) == NULL)
162: err(1, "can't allocate memory");
1.1 deraadt 163:
164: if (ruid) {
165: #ifdef KERBEROS
1.21 tholo 166: if (!use_kerberos || kerberos(username, user, pwd->pw_uid))
1.1 deraadt 167: #endif
168: {
169: /* only allow those in group zero to su to root. */
1.3 deraadt 170: if (pwd->pw_uid == 0 && (gr = getgrgid((gid_t)0))
171: && gr->gr_mem && *(gr->gr_mem))
1.1 deraadt 172: for (g = gr->gr_mem;; ++g) {
1.8 millert 173: if (!*g)
174: errx(1, "you are not in the correct group to su %s.", user);
175: if (strcmp(username, *g) == 0)
1.1 deraadt 176: break;
177: }
178: /* if target requires a password, verify it */
179: if (*pwd->pw_passwd) {
180: p = getpass("Password:");
181: #ifdef SKEY
182: if (strcasecmp(p, "s/key") == 0) {
1.14 millert 183: if (skey_authenticate(user))
1.8 millert 184: goto badlogin;
1.1 deraadt 185: } else
186: #endif
187: if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) {
188: badlogin:
189: fprintf(stderr, "Sorry\n");
190: syslog(LOG_AUTH|LOG_WARNING,
191: "BAD SU %s to %s%s", username,
192: user, ontty());
193: exit(1);
194: }
195: }
196: }
1.8 millert 197: if (pwd->pw_expire && time(NULL) >= pwd->pw_expire) {
198: fprintf(stderr, "Sorry - account expired\n");
199: syslog(LOG_AUTH|LOG_WARNING, "BAD SU %s to %s%s", username,
200: user, ontty());
201: exit(1);
202: }
1.1 deraadt 203: }
204:
205: if (asme) {
206: /* if asme and non-standard target shell, must be root */
1.8 millert 207: if (!chshell(pwd->pw_shell) && ruid)
208: errx(1, "permission denied (shell).");
1.1 deraadt 209: } else if (pwd->pw_shell && *pwd->pw_shell) {
210: shell = pwd->pw_shell;
211: iscsh = UNSET;
212: } else {
213: shell = _PATH_BSHELL;
214: iscsh = NO;
215: }
216:
1.8 millert 217: if (p = strrchr(shell, '/'))
1.1 deraadt 218: avshell = p+1;
219: else
220: avshell = shell;
221:
222: /* if we're forking a csh, we want to slightly muck the args */
223: if (iscsh == UNSET)
224: iscsh = strcmp(avshell, "csh") ? NO : YES;
225:
226: /* set permissions */
1.17 tholo 227: if (setegid(pwd->pw_gid) < 0)
228: err(1, "setegid");
1.8 millert 229: if (setgid(pwd->pw_gid) < 0)
230: err(1, "setgid");
231: if (initgroups(user, pwd->pw_gid))
232: err(1, "initgroups failed");
1.17 tholo 233: if (seteuid(pwd->pw_uid) < 0)
234: err(1, "seteuid");
1.8 millert 235: if (setuid(pwd->pw_uid) < 0)
236: err(1, "setuid");
1.1 deraadt 237:
238: if (!asme) {
239: if (asthem) {
240: p = getenv("TERM");
1.23 deraadt 241: #ifdef KERBEROS
242: k = getenv("KRBTKFILE");
243: #endif
244: if ((environ = calloc(1, sizeof (char *))) == NULL)
1.22 deraadt 245: errx(1, "calloc");
1.1 deraadt 246: (void)setenv("PATH", _PATH_DEFPATH, 1);
1.6 deraadt 247: if (p)
248: (void)setenv("TERM", p, 1);
1.23 deraadt 249: #ifdef KERBEROS
1.25 deraadt 250: if (k && got_ticket)
1.23 deraadt 251: (void)setenv("KRBTKFILE", k, 1);
252: #endif
1.5 deraadt 253:
254: seteuid(pwd->pw_uid);
255: setegid(pwd->pw_gid);
1.8 millert 256: if (chdir(pwd->pw_dir) < 0)
257: errx(1, "no directory");
1.5 deraadt 258: seteuid(0);
259: setegid(0); /* XXX use a saved gid instead? */
1.1 deraadt 260: }
1.15 millert 261: if (asthem || pwd->pw_uid) {
262: (void)setenv("LOGNAME", pwd->pw_name, 1);
1.1 deraadt 263: (void)setenv("USER", pwd->pw_name, 1);
1.15 millert 264: }
1.1 deraadt 265: (void)setenv("HOME", pwd->pw_dir, 1);
266: (void)setenv("SHELL", shell, 1);
267: }
268:
269: if (iscsh == YES) {
270: if (fastlogin)
271: *np-- = "-f";
272: if (asme)
273: *np-- = "-m";
274: }
275:
276: if (asthem) {
277: avshellbuf[0] = '-';
1.11 millert 278: strncpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 2);
1.10 millert 279: avshellbuf[sizeof(avshellbuf) - 1] = '\0';
1.1 deraadt 280: avshell = avshellbuf;
281: } else if (iscsh == YES) {
282: /* csh strips the first character... */
283: avshellbuf[0] = '_';
1.11 millert 284: strncpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 2);
1.10 millert 285: avshellbuf[sizeof(avshellbuf) - 1] = '\0';
1.1 deraadt 286: avshell = avshellbuf;
287: }
288:
289: *np = avshell;
290:
291: if (ruid != 0)
292: syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s",
293: username, user, ontty());
294:
295: (void)setpriority(PRIO_PROCESS, 0, prio);
296:
297: execv(shell, np);
1.9 millert 298: err(1, shell);
1.1 deraadt 299: }
300:
301: int
302: chshell(sh)
303: char *sh;
304: {
305: register char *cp;
306:
307: while ((cp = getusershell()) != NULL)
1.8 millert 308: if (strcmp(cp, sh) == 0)
1.1 deraadt 309: return (1);
310: return (0);
311: }
312:
313: char *
314: ontty()
315: {
316: char *p, *ttyname();
317: static char buf[MAXPATHLEN + 4];
318:
319: buf[0] = 0;
320: if (p = ttyname(STDERR_FILENO))
1.8 millert 321: snprintf(buf, sizeof(buf), " on %s", p);
1.1 deraadt 322: return (buf);
323: }
324:
325: #ifdef KERBEROS
326: kerberos(username, user, uid)
327: char *username, *user;
328: int uid;
329: {
330: KTEXT_ST ticket;
331: AUTH_DAT authdata;
332: struct hostent *hp;
333: register char *p;
334: int kerno;
1.27 ! deraadt 335: in_addr_t faddr;
1.21 tholo 336: char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN];
1.1 deraadt 337: char hostname[MAXHOSTNAMELEN], savehost[MAXHOSTNAMELEN];
338: char *ontty(), *krb_get_phost();
339:
340: if (krb_get_lrealm(lrealm, 1) != KSUCCESS)
341: return (1);
342: if (koktologin(username, lrealm, user) && !uid) {
343: (void)fprintf(stderr, "kerberos su: not in %s's ACL.\n", user);
344: return (1);
345: }
1.26 deraadt 346: (void)snprintf(krbtkfile, sizeof(krbtkfile), "%s_%s_%u", TKT_ROOT,
1.8 millert 347: user, getuid());
1.1 deraadt 348:
349: (void)setenv("KRBTKFILE", krbtkfile, 1);
350: (void)krb_set_tkt_string(krbtkfile);
351: /*
352: * Set real as well as effective ID to 0 for the moment,
353: * to make the kerberos library do the right thing.
354: */
355: if (setuid(0) < 0) {
1.8 millert 356: warn("setuid");
1.1 deraadt 357: return (1);
358: }
359:
360: /*
361: * Little trick here -- if we are su'ing to root,
362: * we need to get a ticket for "xxx.root", where xxx represents
363: * the name of the person su'ing. Otherwise (non-root case),
364: * we need to get a ticket for "yyy.", where yyy represents
365: * the name of the person being su'd to, and the instance is null
366: *
367: * We should have a way to set the ticket lifetime,
368: * with a system default for root.
369: */
370: kerno = krb_get_pw_in_tkt((uid == 0 ? username : user),
371: (uid == 0 ? "root" : ""), lrealm,
372: "krbtgt", lrealm, DEFAULT_TKT_LIFE, 0);
373:
374: if (kerno != KSUCCESS) {
375: if (kerno == KDC_PR_UNKNOWN) {
1.8 millert 376: warnx("kerberos principal unknown: %s.%s@%s",
1.1 deraadt 377: (uid == 0 ? username : user),
378: (uid == 0 ? "root" : ""), lrealm);
379: return (1);
380: }
1.8 millert 381: warnx("unable to su: %s", krb_err_txt[kerno]);
1.1 deraadt 382: syslog(LOG_NOTICE|LOG_AUTH,
383: "BAD Kerberos SU: %s to %s%s: %s",
384: username, user, ontty(), krb_err_txt[kerno]);
385: return (1);
386: }
387:
388: if (chown(krbtkfile, uid, -1) < 0) {
1.8 millert 389: warn("chown");
1.1 deraadt 390: (void)unlink(krbtkfile);
391: return (1);
392: }
393:
394: (void)setpriority(PRIO_PROCESS, 0, -2);
395:
396: if (gethostname(hostname, sizeof(hostname)) == -1) {
1.8 millert 397: warn("gethostname");
1.1 deraadt 398: dest_tkt();
399: return (1);
400: }
401:
1.11 millert 402: (void)strncpy(savehost, krb_get_phost(hostname), sizeof(savehost) - 1);
1.1 deraadt 403: savehost[sizeof(savehost) - 1] = '\0';
404:
405: kerno = krb_mk_req(&ticket, "rcmd", savehost, lrealm, 33);
406:
407: if (kerno == KDC_PR_UNKNOWN) {
1.8 millert 408: warnx("Warning: TGT not verified.");
1.1 deraadt 409: syslog(LOG_NOTICE|LOG_AUTH,
410: "%s to %s%s, TGT not verified (%s); %s.%s not registered?",
411: username, user, ontty(), krb_err_txt[kerno],
412: "rcmd", savehost);
413: } else if (kerno != KSUCCESS) {
1.8 millert 414: warnx("Unable to use TGT: %s", krb_err_txt[kerno]);
1.1 deraadt 415: syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s",
416: username, user, ontty(), krb_err_txt[kerno]);
417: dest_tkt();
418: return (1);
419: } else {
420: if (!(hp = gethostbyname(hostname))) {
1.8 millert 421: warnx("can't get addr of %s", hostname);
1.1 deraadt 422: dest_tkt();
423: return (1);
424: }
1.10 millert 425: (void)memcpy((void *)&faddr, (void *)hp->h_addr, sizeof(faddr));
1.1 deraadt 426:
427: if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr,
428: &authdata, "")) != KSUCCESS) {
1.8 millert 429: warnx("unable to verify rcmd ticket: %s",
430: krb_err_txt[kerno]);
1.1 deraadt 431: syslog(LOG_NOTICE|LOG_AUTH,
432: "failed su: %s to %s%s: %s", username,
433: user, ontty(), krb_err_txt[kerno]);
434: dest_tkt();
435: return (1);
436: }
437: }
1.25 deraadt 438: got_ticket = 1;
1.1 deraadt 439: return (0);
440: }
441:
442: koktologin(name, realm, toname)
443: char *name, *realm, *toname;
444: {
445: register AUTH_DAT *kdata;
446: AUTH_DAT kdata_st;
447:
1.13 deraadt 448: memset((void *)&kdata_st, 0, sizeof(kdata_st));
1.1 deraadt 449: kdata = &kdata_st;
1.10 millert 450:
1.11 millert 451: (void)strncpy(kdata->pname, name, sizeof(kdata->pname) - 1);
1.10 millert 452: kdata->pname[sizeof(kdata->pname) - 1] = '\0';
453:
454: (void)strncpy(kdata->pinst,
1.11 millert 455: ((strcmp(toname, "root") == 0) ? "root" : ""), sizeof(kdata->pinst) - 1);
1.13 deraadt 456: kdata->pinst[sizeof(kdata->pinst) -1] = '\0';
1.10 millert 457:
1.11 millert 458: (void)strncpy(kdata->prealm, realm, sizeof(kdata->prealm) - 1);
1.10 millert 459: kdata->prealm[sizeof(kdata->prealm) -1] = '\0';
460:
1.1 deraadt 461: return (kuserok(kdata, toname));
462: }
463: #endif
![[BACK]](/icons/back.gif){kind=icon}
Return to su.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / su