Annotation of src/usr.bin/ssh/auth-krb4.c, Revision 1.10
1.1 deraadt 1: /*
1.10 ! deraadt 2: * Dug Song <dugsong@UMICH.EDU>
! 3: * Kerberos v4 authentication and ticket-passing routines.
! 4: */
1.1 deraadt 5:
6: #include "includes.h"
7: #include "packet.h"
8: #include "xmalloc.h"
9: #include "ssh.h"
10:
11: #ifdef KRB4
1.6 markus 12: char *ticket = NULL;
13:
14: void
15: krb4_cleanup_proc(void *ignore)
1.1 deraadt 16: {
1.9 markus 17: debug("krb4_cleanup_proc called");
18: if (ticket) {
19: (void) dest_tkt();
20: xfree(ticket);
21: ticket = NULL;
22: }
1.6 markus 23: }
24:
1.9 markus 25: int
26: krb4_init(uid_t uid)
1.6 markus 27: {
1.9 markus 28: static int cleanup_registered = 0;
29: char *tkt_root = TKT_ROOT;
30: struct stat st;
31: int fd;
32:
33: if (!ticket) {
34: /* Set unique ticket string manually since we're still root. */
35: ticket = xmalloc(MAXPATHLEN);
1.1 deraadt 36: #ifdef AFS
1.9 markus 37: if (lstat("/ticket", &st) != -1)
38: tkt_root = "/ticket/";
1.1 deraadt 39: #endif /* AFS */
1.9 markus 40: snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid());
41: (void) krb_set_tkt_string(ticket);
42: }
43: /* Register ticket cleanup in case of fatal error. */
44: if (!cleanup_registered) {
45: fatal_add_cleanup(krb4_cleanup_proc, NULL);
46: cleanup_registered = 1;
47: }
48: /* Try to create our ticket file. */
49: if ((fd = mkstemp(ticket)) != -1) {
50: close(fd);
51: return 1;
52: }
53: /* Ticket file exists - make sure user owns it (just passed ticket). */
54: if (lstat(ticket, &st) != -1) {
55: if (st.st_mode == (S_IFREG | S_IRUSR | S_IWUSR) &&
56: st.st_uid == uid)
57: return 1;
58: }
59: /* Failure - cancel cleanup function, leaving bad ticket for inspection. */
60: log("WARNING: bad ticket file %s", ticket);
61: fatal_remove_cleanup(krb4_cleanup_proc, NULL);
62: cleanup_registered = 0;
63: xfree(ticket);
64: ticket = NULL;
65:
66: return 0;
1.1 deraadt 67: }
68:
1.9 markus 69: int
70: auth_krb4(const char *server_user, KTEXT auth, char **client)
1.1 deraadt 71: {
1.9 markus 72: AUTH_DAT adat = {0};
73: KTEXT_ST reply;
74: char instance[INST_SZ];
75: int r, s;
76: u_int cksum;
77: Key_schedule schedule;
78: struct sockaddr_in local, foreign;
79:
80: s = packet_get_connection_in();
81:
82: r = sizeof(local);
83: memset(&local, 0, sizeof(local));
84: if (getsockname(s, (struct sockaddr *) & local, &r) < 0)
85: debug("getsockname failed: %.100s", strerror(errno));
86: r = sizeof(foreign);
87: memset(&foreign, 0, sizeof(foreign));
88: if (getpeername(s, (struct sockaddr *) & foreign, &r) < 0) {
89: debug("getpeername failed: %.100s", strerror(errno));
90: fatal_cleanup();
91: }
92: instance[0] = '*';
93: instance[1] = 0;
94:
95: /* Get the encrypted request, challenge, and session key. */
96: if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) {
97: packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]);
98: return 0;
99: }
100: des_key_sched((des_cblock *) adat.session, schedule);
101:
102: *client = xmalloc(MAX_K_NAME_SZ);
103: (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
1.10 ! deraadt 104: *adat.pinst ? "." : "", adat.pinst, adat.prealm);
1.9 markus 105:
106: /* Check ~/.klogin authorization now. */
107: if (kuserok(&adat, (char *) server_user) != KSUCCESS) {
108: packet_send_debug("Kerberos V4 .klogin authorization failed!");
109: log("Kerberos V4 .klogin authorization failed for %s to account %s",
110: *client, server_user);
111: xfree(*client);
112: return 0;
113: }
114: /* Increment the checksum, and return it encrypted with the
115: 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
120: empty message, admitting our failure. */
121: if ((r = krb_mk_priv((u_char *) & cksum, reply.dat, sizeof(cksum) + 1,
1.10 ! deraadt 122: schedule, &adat.session, &local, &foreign)) < 0) {
1.9 markus 123: packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
124: reply.dat[0] = 0;
125: reply.length = 0;
126: } else
127: reply.length = r;
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;
1.1 deraadt 137: }
138: #endif /* KRB4 */
139:
140: #ifdef AFS
1.9 markus 141: int
142: auth_kerberos_tgt(struct passwd *pw, const char *string)
1.1 deraadt 143: {
1.9 markus 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 */
152: strlcpy(creds.service, "krbtgt", sizeof creds.service);
153:
154: if (strcmp(creds.service, "krbtgt")) {
155: log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname,
1.10 ! deraadt 156: creds.pinst[0] ? "." : "", creds.pinst, creds.realm,
! 157: pw->pw_name);
1.9 markus 158: packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s",
1.10 ! deraadt 159: creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
! 160: creds.realm, pw->pw_name);
1.9 markus 161: goto auth_kerberos_tgt_failure;
162: }
163: if (!krb4_init(pw->pw_uid))
164: goto auth_kerberos_tgt_failure;
165:
166: if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
167: goto auth_kerberos_tgt_failure;
168:
169: if (save_credentials(creds.service, creds.instance, creds.realm,
1.10 ! deraadt 170: creds.session, creds.lifetime, creds.kvno,
! 171: &creds.ticket_st, creds.issue_date) != KSUCCESS) {
1.9 markus 172: packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
173: goto auth_kerberos_tgt_failure;
174: }
175: /* Successful authentication, passed all checks. */
176: chown(tkt_string(), pw->pw_uid, pw->pw_gid);
177:
178: packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
1.10 ! deraadt 179: creds.service, creds.instance, creds.realm, creds.pname,
! 180: creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
1.9 markus 181: memset(&creds, 0, sizeof(creds));
182: packet_start(SSH_SMSG_SUCCESS);
183: packet_send();
184: packet_write_wait();
185: return 1;
186:
187: auth_kerberos_tgt_failure:
188: krb4_cleanup_proc(NULL);
189: memset(&creds, 0, sizeof(creds));
190: packet_start(SSH_SMSG_FAILURE);
191: packet_send();
192: packet_write_wait();
193: return 0;
1.1 deraadt 194: }
195:
1.9 markus 196: int
197: auth_afs_token(struct passwd *pw, const char *token_string)
1.1 deraadt 198: {
1.9 markus 199: CREDENTIALS creds;
200: uid_t uid = pw->pw_uid;
1.1 deraadt 201:
1.9 markus 202: if (!radix_to_creds(token_string, &creds)) {
203: log("Protocol error decoding AFS token");
204: packet_send_debug("Protocol error decoding AFS token");
205: packet_start(SSH_SMSG_FAILURE);
206: packet_send();
207: packet_write_wait();
208: return 0;
209: }
210: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
211: strlcpy(creds.service, "afs", sizeof creds.service);
212:
213: if (strncmp(creds.pname, "AFS ID ", 7) == 0)
214: uid = atoi(creds.pname + 7);
215:
216: if (kafs_settoken(creds.realm, uid, &creds)) {
217: log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm,
218: pw->pw_name);
219: packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname,
1.10 ! deraadt 220: creds.realm, pw->pw_name);
1.9 markus 221: memset(&creds, 0, sizeof(creds));
222: packet_start(SSH_SMSG_FAILURE);
223: packet_send();
224: packet_write_wait();
225: return 0;
226: }
227: packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
1.10 ! deraadt 228: creds.realm, creds.pname, creds.realm);
1.9 markus 229: memset(&creds, 0, sizeof(creds));
230: packet_start(SSH_SMSG_SUCCESS);
231: packet_send();
232: packet_write_wait();
233: return 1;
1.1 deraadt 234: }
235: #endif /* AFS */
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