Annotation of src/usr.bin/ssh/auth-krb4.c, Revision 1.7
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:
1.7 ! markus 9: $Id: auth-krb4.c,v 1.6 1999/11/10 22:24:01 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);
1.7 ! markus 113: xfree(*client);
1.1 deraadt 114: return 0;
115: }
116: /* Increment the checksum, and return it encrypted with the session key. */
117: cksum = adat.checksum + 1;
118: cksum = htonl(cksum);
119:
120: /* If we can't successfully encrypt the checksum, we send back an empty
121: message, admitting our failure. */
122: if ((r = krb_mk_priv((u_char *)&cksum, reply.dat, sizeof(cksum)+1,
123: schedule, &adat.session, &local, &foreign)) < 0) {
1.2 dugsong 124: packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
1.1 deraadt 125: reply.dat[0] = 0;
126: reply.length = 0;
127: }
1.6 markus 128: else reply.length = r;
1.1 deraadt 129:
130: /* Clear session key. */
131: memset(&adat.session, 0, sizeof(&adat.session));
132:
133: packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
134: packet_put_string((char *) reply.dat, reply.length);
135: packet_send();
136: packet_write_wait();
137: return 1;
138: }
139: #endif /* KRB4 */
140:
141: #ifdef AFS
142: int auth_kerberos_tgt(struct passwd *pw, const char *string)
143: {
144: CREDENTIALS creds;
145:
146: if (!radix_to_creds(string, &creds)) {
147: log("Protocol error decoding Kerberos V4 tgt");
148: packet_send_debug("Protocol error decoding Kerberos V4 tgt");
149: goto auth_kerberos_tgt_failure;
150: }
151: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
1.3 deraadt 152: strlcpy(creds.service, "krbtgt", sizeof creds.service);
1.1 deraadt 153:
154: if (strcmp(creds.service, "krbtgt")) {
1.6 markus 155: log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname,
156: creds.pinst[0] ? "." : "", creds.pinst, creds.realm, pw->pw_name);
157: packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s",
1.1 deraadt 158: creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
1.6 markus 159: creds.realm, pw->pw_name);
1.1 deraadt 160: goto auth_kerberos_tgt_failure;
161: }
1.6 markus 162: if (!krb4_init(pw->pw_uid))
163: goto auth_kerberos_tgt_failure;
164:
165: if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
166: goto auth_kerberos_tgt_failure;
167:
168: if (save_credentials(creds.service, creds.instance, creds.realm,
169: creds.session, creds.lifetime, creds.kvno,
170: &creds.ticket_st, creds.issue_date) != KSUCCESS) {
1.1 deraadt 171: packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
172: goto auth_kerberos_tgt_failure;
173: }
174: /* Successful authentication, passed all checks. */
1.6 markus 175: chown(tkt_string(), pw->pw_uid, pw->pw_gid);
176:
1.2 dugsong 177: packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
1.6 markus 178: creds.service, creds.instance, creds.realm, creds.pname,
179: creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
180: memset(&creds, 0, sizeof(creds));
1.1 deraadt 181: packet_start(SSH_SMSG_SUCCESS);
182: packet_send();
183: packet_write_wait();
184: return 1;
1.6 markus 185:
186: auth_kerberos_tgt_failure:
187: krb4_cleanup_proc(NULL);
1.1 deraadt 188: memset(&creds, 0, sizeof(creds));
189: packet_start(SSH_SMSG_FAILURE);
190: packet_send();
191: packet_write_wait();
192: return 0;
193: }
194:
1.5 markus 195: int auth_afs_token(struct passwd *pw, const char *token_string)
1.1 deraadt 196: {
197: CREDENTIALS creds;
1.5 markus 198: uid_t uid = pw->pw_uid;
1.1 deraadt 199:
1.5 markus 200: if (!radix_to_creds(token_string, &creds)) {
1.1 deraadt 201: log("Protocol error decoding AFS token");
202: packet_send_debug("Protocol error decoding AFS token");
203: packet_start(SSH_SMSG_FAILURE);
204: packet_send();
205: packet_write_wait();
206: return 0;
207: }
208: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
1.3 deraadt 209: strlcpy(creds.service, "afs", sizeof creds.service);
1.1 deraadt 210:
211: if (strncmp(creds.pname, "AFS ID ", 7) == 0)
212: uid = atoi(creds.pname + 7);
213:
214: if (kafs_settoken(creds.realm, uid, &creds)) {
1.6 markus 215: log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm,
216: pw->pw_name);
217: packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname,
218: creds.realm, pw->pw_name);
219: memset(&creds, 0, sizeof(creds));
1.1 deraadt 220: packet_start(SSH_SMSG_FAILURE);
221: packet_send();
222: packet_write_wait();
223: return 0;
224: }
1.2 dugsong 225: packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
1.1 deraadt 226: creds.realm, creds.pname, creds.realm);
1.6 markus 227: memset(&creds, 0, sizeof(creds));
1.1 deraadt 228: packet_start(SSH_SMSG_SUCCESS);
229: packet_send();
230: packet_write_wait();
231: return 1;
232: }
233: #endif /* AFS */
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