Annotation of src/usr.bin/ssh/auth-krb4.c, Revision 1.9
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:
1.9 ! markus 9: $Id: auth-krb4.c,v 1.8 1999/11/15 00:42:00 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: {
1.9 ! markus 23: debug("krb4_cleanup_proc called");
! 24: if (ticket) {
! 25: (void) dest_tkt();
! 26: xfree(ticket);
! 27: ticket = NULL;
! 28: }
1.6 markus 29: }
30:
1.9 ! markus 31: int
! 32: krb4_init(uid_t uid)
1.6 markus 33: {
1.9 ! markus 34: static int cleanup_registered = 0;
! 35: char *tkt_root = TKT_ROOT;
! 36: struct stat st;
! 37: int fd;
! 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
1.9 ! markus 43: if (lstat("/ticket", &st) != -1)
! 44: tkt_root = "/ticket/";
1.1 deraadt 45: #endif /* AFS */
1.9 ! 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;
! 58: }
! 59: /* Ticket file exists - make sure user owns it (just passed ticket). */
! 60: if (lstat(ticket, &st) != -1) {
! 61: if (st.st_mode == (S_IFREG | S_IRUSR | S_IWUSR) &&
! 62: st.st_uid == uid)
! 63: return 1;
! 64: }
! 65: /* Failure - cancel cleanup function, leaving bad ticket for inspection. */
! 66: log("WARNING: bad ticket file %s", ticket);
! 67: fatal_remove_cleanup(krb4_cleanup_proc, NULL);
! 68: cleanup_registered = 0;
! 69: xfree(ticket);
! 70: ticket = NULL;
! 71:
! 72: return 0;
1.1 deraadt 73: }
74:
1.9 ! markus 75: int
! 76: auth_krb4(const char *server_user, KTEXT auth, char **client)
1.1 deraadt 77: {
1.9 ! markus 78: AUTH_DAT adat = {0};
! 79: KTEXT_ST reply;
! 80: char instance[INST_SZ];
! 81: int r, s;
! 82: u_int cksum;
! 83: Key_schedule schedule;
! 84: struct sockaddr_in local, foreign;
! 85:
! 86: s = packet_get_connection_in();
! 87:
! 88: r = sizeof(local);
! 89: memset(&local, 0, sizeof(local));
! 90: if (getsockname(s, (struct sockaddr *) & local, &r) < 0)
! 91: debug("getsockname failed: %.100s", strerror(errno));
! 92: r = sizeof(foreign);
! 93: memset(&foreign, 0, sizeof(foreign));
! 94: if (getpeername(s, (struct sockaddr *) & foreign, &r) < 0) {
! 95: debug("getpeername failed: %.100s", strerror(errno));
! 96: fatal_cleanup();
! 97: }
! 98: instance[0] = '*';
! 99: instance[1] = 0;
! 100:
! 101: /* Get the encrypted request, challenge, and session key. */
! 102: if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) {
! 103: packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]);
! 104: return 0;
! 105: }
! 106: des_key_sched((des_cblock *) adat.session, schedule);
! 107:
! 108: *client = xmalloc(MAX_K_NAME_SZ);
! 109: (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname,
! 110: *adat.pinst ? "." : "", adat.pinst, adat.prealm);
! 111:
! 112: /* Check ~/.klogin authorization now. */
! 113: if (kuserok(&adat, (char *) server_user) != KSUCCESS) {
! 114: packet_send_debug("Kerberos V4 .klogin authorization failed!");
! 115: log("Kerberos V4 .klogin authorization failed for %s to account %s",
! 116: *client, server_user);
! 117: xfree(*client);
! 118: return 0;
! 119: }
! 120: /* Increment the checksum, and return it encrypted with the
! 121: session key. */
! 122: cksum = adat.checksum + 1;
! 123: cksum = htonl(cksum);
! 124:
! 125: /* If we can't successfully encrypt the checksum, we send back an
! 126: empty message, admitting our failure. */
! 127: if ((r = krb_mk_priv((u_char *) & cksum, reply.dat, sizeof(cksum) + 1,
! 128: schedule, &adat.session, &local, &foreign)) < 0) {
! 129: packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]);
! 130: reply.dat[0] = 0;
! 131: reply.length = 0;
! 132: } else
! 133: reply.length = r;
! 134:
! 135: /* Clear session key. */
! 136: memset(&adat.session, 0, sizeof(&adat.session));
! 137:
! 138: packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
! 139: packet_put_string((char *) reply.dat, reply.length);
! 140: packet_send();
! 141: packet_write_wait();
! 142: return 1;
1.1 deraadt 143: }
144: #endif /* KRB4 */
145:
146: #ifdef AFS
1.9 ! markus 147: int
! 148: auth_kerberos_tgt(struct passwd *pw, const char *string)
1.1 deraadt 149: {
1.9 ! markus 150: CREDENTIALS creds;
! 151:
! 152: if (!radix_to_creds(string, &creds)) {
! 153: log("Protocol error decoding Kerberos V4 tgt");
! 154: packet_send_debug("Protocol error decoding Kerberos V4 tgt");
! 155: goto auth_kerberos_tgt_failure;
! 156: }
! 157: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
! 158: strlcpy(creds.service, "krbtgt", sizeof creds.service);
! 159:
! 160: if (strcmp(creds.service, "krbtgt")) {
! 161: log("Kerberos V4 tgt (%s%s%s@%s) rejected for %s", creds.pname,
! 162: creds.pinst[0] ? "." : "", creds.pinst, creds.realm, pw->pw_name);
! 163: packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for %s",
! 164: creds.pname, creds.pinst[0] ? "." : "", creds.pinst,
! 165: creds.realm, pw->pw_name);
! 166: goto auth_kerberos_tgt_failure;
! 167: }
! 168: if (!krb4_init(pw->pw_uid))
! 169: goto auth_kerberos_tgt_failure;
! 170:
! 171: if (in_tkt(creds.pname, creds.pinst) != KSUCCESS)
! 172: goto auth_kerberos_tgt_failure;
! 173:
! 174: if (save_credentials(creds.service, creds.instance, creds.realm,
! 175: creds.session, creds.lifetime, creds.kvno,
! 176: &creds.ticket_st, creds.issue_date) != KSUCCESS) {
! 177: packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials");
! 178: goto auth_kerberos_tgt_failure;
! 179: }
! 180: /* Successful authentication, passed all checks. */
! 181: chown(tkt_string(), pw->pw_uid, pw->pw_gid);
! 182:
! 183: packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)",
! 184: creds.service, creds.instance, creds.realm, creds.pname,
! 185: creds.pinst[0] ? "." : "", creds.pinst, creds.realm);
! 186: memset(&creds, 0, sizeof(creds));
! 187: packet_start(SSH_SMSG_SUCCESS);
! 188: packet_send();
! 189: packet_write_wait();
! 190: return 1;
! 191:
! 192: auth_kerberos_tgt_failure:
! 193: krb4_cleanup_proc(NULL);
! 194: memset(&creds, 0, sizeof(creds));
! 195: packet_start(SSH_SMSG_FAILURE);
! 196: packet_send();
! 197: packet_write_wait();
! 198: return 0;
1.1 deraadt 199: }
200:
1.9 ! markus 201: int
! 202: auth_afs_token(struct passwd *pw, const char *token_string)
1.1 deraadt 203: {
1.9 ! markus 204: CREDENTIALS creds;
! 205: uid_t uid = pw->pw_uid;
1.1 deraadt 206:
1.9 ! markus 207: if (!radix_to_creds(token_string, &creds)) {
! 208: log("Protocol error decoding AFS token");
! 209: packet_send_debug("Protocol error decoding AFS token");
! 210: packet_start(SSH_SMSG_FAILURE);
! 211: packet_send();
! 212: packet_write_wait();
! 213: return 0;
! 214: }
! 215: if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */
! 216: strlcpy(creds.service, "afs", sizeof creds.service);
! 217:
! 218: if (strncmp(creds.pname, "AFS ID ", 7) == 0)
! 219: uid = atoi(creds.pname + 7);
! 220:
! 221: if (kafs_settoken(creds.realm, uid, &creds)) {
! 222: log("AFS token (%s@%s) rejected for %s", creds.pname, creds.realm,
! 223: pw->pw_name);
! 224: packet_send_debug("AFS token (%s@%s) rejected for %s", creds.pname,
! 225: creds.realm, pw->pw_name);
! 226: memset(&creds, 0, sizeof(creds));
! 227: packet_start(SSH_SMSG_FAILURE);
! 228: packet_send();
! 229: packet_write_wait();
! 230: return 0;
! 231: }
! 232: packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service,
! 233: creds.realm, creds.pname, creds.realm);
! 234: memset(&creds, 0, sizeof(creds));
! 235: packet_start(SSH_SMSG_SUCCESS);
! 236: packet_send();
! 237: packet_write_wait();
! 238: return 1;
1.1 deraadt 239: }
240: #endif /* AFS */
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