Annotation of src/usr.bin/ssh/auth-krb4.c, Revision 1.6
1.1 deraadt 1: /*
2:
3: auth-kerberos.c
4:
1.2 dugsong 5: Dug Song <dugsong@UMICH.EDU>
1.1 deraadt 6:
1.2 dugsong 7: Kerberos v4 authentication and ticket-passing routines.
1.1 deraadt 8:
1.6 ! markus 9: $Id: auth-krb4.c,v 1.5 1999/11/02 19:10:14 markus Exp $
1.1 deraadt 10: */
11:
12: #include "includes.h"
13: #include "packet.h"
14: #include "xmalloc.h"
15: #include "ssh.h"
16:
17: #ifdef KRB4
1.6 ! markus 18: char *ticket = NULL;
! 19:
! 20: void
! 21: krb4_cleanup_proc(void *ignore)
1.1 deraadt 22: {
1.6 ! markus 23: debug("krb4_cleanup_proc called");
! 24:
! 25: if (ticket) {
! 26: (void) dest_tkt();
! 27: xfree(ticket);
! 28: ticket = NULL;
! 29: }
! 30: }
! 31:
! 32: int krb4_init(uid_t uid)
! 33: {
! 34: static int cleanup_registered = 0;
1.1 deraadt 35: char *tkt_root = TKT_ROOT;
36: struct stat st;
37: int fd;
1.6 ! markus 38:
! 39: if (!ticket) {
! 40: /* Set unique ticket string manually since we're still root. */
! 41: ticket = xmalloc(MAXPATHLEN);
1.1 deraadt 42: #ifdef AFS
1.6 ! markus 43: if (lstat("/ticket", &st) != -1)
! 44: tkt_root = "/ticket/";
1.1 deraadt 45: #endif /* AFS */
1.6 ! markus 46: snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid());
! 47: (void) krb_set_tkt_string(ticket);
! 48: }
! 49: /* Register ticket cleanup in case of fatal error. */
! 50: if (!cleanup_registered) {
! 51: fatal_add_cleanup(krb4_cleanup_proc, NULL);
! 52: cleanup_registered = 1;
! 53: }
! 54: /* Try to create our ticket file. */
! 55: if ((fd = mkstemp(ticket)) != -1) {
! 56: close(fd);
! 57: return 1;
1.1 deraadt 58: }
1.6 ! markus 59: /* Ticket file exists - make sure user owns it (just passed ticket). */
! 60: if (lstat(ticket, &st) != -1) {
1.1 deraadt 61: if (st.st_mode == (S_IFREG|S_IRUSR|S_IWUSR) && st.st_uid == uid)
62: return 1;
63: }
1.6 ! markus 64: /* Failure - cancel cleanup function, leaving bad ticket for inspection. */
1.2 dugsong 65: log("WARNING: bad ticket file %s", ticket);
1.6 ! markus 66: fatal_remove_cleanup(krb4_cleanup_proc, NULL);
! 67: cleanup_registered = 0;
! 68: xfree(ticket);
! 69: ticket = NULL;
! 70:
1.1 deraadt 71: return 0;
72: }
73:
74: int auth_krb4(const char *server_user, KTEXT auth, char **client)
75: {
76: AUTH_DAT adat = { 0 };
77: KTEXT_ST reply;
78: char instance[INST_SZ];
79: int r, s;
1.4 deraadt 80: u_int cksum;
1.1 deraadt 81: Key_schedule schedule;
82: struct sockaddr_in local, foreign;
83:
84: s = packet_get_connection_in();
85:
86: r = sizeof(local);
87: memset(&local, 0, sizeof(local));
88: if (getsockname(s, (struct sockaddr *) &local, &r) < 0)
89: debug("getsockname failed: %.100s", strerror(errno));
90: r = sizeof(foreign);
91: memset(&foreign, 0, sizeof(foreign));
92: if (getpeername(s, (struct sockaddr *)&foreign, &r) < 0)
93: debug("getpeername failed: %.100s", strerror(errno));
94:
95: instance[0] = '*'; instance[1] = 0;
96:
97: /* Get the encrypted request, challenge, and session key. */
1.2 dugsong 98: if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) {
1.1 deraadt 99: packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]);
100: return 0;
101: }
102: des_key_sched((des_cblock *)adat.session, schedule);
103:
104: *client = xmalloc(MAX_K_NAME_SZ);
1.2 dugsong 105: (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
106: *adat.pinst ? "." : "", adat.pinst, adat.prealm);
1.1 deraadt 107:
108: /* Check ~/.klogin authorization now. */
109: if (kuserok(&adat, (char *)server_user) != KSUCCESS) {
110: packet_send_debug("Kerberos V4 .klogin authorization failed!");
1.2 dugsong 111: log("Kerberos V4 .klogin authorization failed for %s to account %s",
1.1 deraadt 112: *client, server_user);
113: return 0;
114: }
115: /* Increment the checksum, and return it encrypted with the session key. */
116: cksum = adat.checksum + 1;
117: cksum = htonl(cksum);
118:
119: /* If we can't successfully encrypt the checksum, we send back an empty
120: message, admitting our failure. */
121: if ((r = krb_mk_priv((u_char *)&cksum, reply.dat, sizeof(cksum)+1,
122: schedule, &adat.session, &local, &foreign)) < 0) {
1.2 dugsong 123: packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
1.1 deraadt 124: reply.dat[0] = 0;
125: reply.length = 0;
126: }
1.6 ! markus 127: else reply.length = r;
1.1 deraadt 128:
129: /* Clear session key. */
130: memset(&adat.session, 0, sizeof(&adat.session));
131:
132: packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
133: packet_put_string((char *) reply.dat, reply.length);
134: packet_send();
135: packet_write_wait();
136: return 1;
137: }
138: #endif /* KRB4 */
139:
140: #ifdef AFS
141: int auth_kerberos_tgt(struct passwd *pw, const char *string)
142: {
143: CREDENTIALS creds;
144:
145: if (!radix_to_creds(string, &creds)) {
146: log("Protocol error decoding Kerberos V4 tgt");
147: packet_send_debug("Protocol error decoding Kerberos V4 tgt");
148: goto auth_kerberos_tgt_failure;
149: }
150: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
1.3 deraadt 151: strlcpy(creds.service, "krbtgt", sizeof creds.service);
1.1 deraadt 152:
153: if (strcmp(creds.service, "krbtgt")) {
1.6 ! markus 154: log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname,
! 155: creds.pinst[0] ? "." : "", creds.pinst, creds.realm, pw->pw_name);
! 156: packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s",
1.1 deraadt 157: creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
1.6 ! markus 158: creds.realm, pw->pw_name);
1.1 deraadt 159: goto auth_kerberos_tgt_failure;
160: }
1.6 ! markus 161: if (!krb4_init(pw->pw_uid))
! 162: goto auth_kerberos_tgt_failure;
! 163:
! 164: if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
! 165: goto auth_kerberos_tgt_failure;
! 166:
! 167: if (save_credentials(creds.service, creds.instance, creds.realm,
! 168: creds.session, creds.lifetime, creds.kvno,
! 169: &creds.ticket_st, creds.issue_date) != KSUCCESS) {
1.1 deraadt 170: packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
171: goto auth_kerberos_tgt_failure;
172: }
173: /* Successful authentication, passed all checks. */
1.6 ! markus 174: chown(tkt_string(), pw->pw_uid, pw->pw_gid);
! 175:
1.2 dugsong 176: packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
1.6 ! markus 177: creds.service, creds.instance, creds.realm, creds.pname,
! 178: creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
! 179: memset(&creds, 0, sizeof(creds));
1.1 deraadt 180: packet_start(SSH_SMSG_SUCCESS);
181: packet_send();
182: packet_write_wait();
183: return 1;
1.6 ! markus 184:
! 185: auth_kerberos_tgt_failure:
! 186: krb4_cleanup_proc(NULL);
1.1 deraadt 187: memset(&creds, 0, sizeof(creds));
188: packet_start(SSH_SMSG_FAILURE);
189: packet_send();
190: packet_write_wait();
191: return 0;
192: }
193:
1.5 markus 194: int auth_afs_token(struct passwd *pw, const char *token_string)
1.1 deraadt 195: {
196: CREDENTIALS creds;
1.5 markus 197: uid_t uid = pw->pw_uid;
1.1 deraadt 198:
1.5 markus 199: if (!radix_to_creds(token_string, &creds)) {
1.1 deraadt 200: log("Protocol error decoding AFS token");
201: packet_send_debug("Protocol error decoding AFS token");
202: packet_start(SSH_SMSG_FAILURE);
203: packet_send();
204: packet_write_wait();
205: return 0;
206: }
207: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
1.3 deraadt 208: strlcpy(creds.service, "afs", sizeof creds.service);
1.1 deraadt 209:
210: if (strncmp(creds.pname, "AFS ID ", 7) == 0)
211: uid = atoi(creds.pname + 7);
212:
213: if (kafs_settoken(creds.realm, uid, &creds)) {
1.6 ! markus 214: log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm,
! 215: pw->pw_name);
! 216: packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname,
! 217: creds.realm, pw->pw_name);
! 218: memset(&creds, 0, sizeof(creds));
1.1 deraadt 219: packet_start(SSH_SMSG_FAILURE);
220: packet_send();
221: packet_write_wait();
222: return 0;
223: }
1.2 dugsong 224: packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
1.1 deraadt 225: creds.realm, creds.pname, creds.realm);
1.6 ! markus 226: memset(&creds, 0, sizeof(creds));
1.1 deraadt 227: packet_start(SSH_SMSG_SUCCESS);
228: packet_send();
229: packet_write_wait();
230: return 1;
231: }
232: #endif /* AFS */
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