Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
| 2 | |
| 3 | auth-kerberos.c |
| 4 | |
| 5 | Dug Song <dugsong@UMICH.EDU> |
| 6 | |
| 7 | Kerberos v4 authentication and ticket-passing routines. |
| 8 | |
Damien Miller | 68cb757 | 1999-11-08 15:49:41 +1100 | [diff] [blame] | 9 | $Id: auth-krb4.c,v 1.2 1999/11/08 04:49:41 damien Exp $ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 10 | */ |
| 11 | |
| 12 | #include "includes.h" |
| 13 | #include "packet.h" |
| 14 | #include "xmalloc.h" |
| 15 | #include "ssh.h" |
| 16 | |
| 17 | #ifdef KRB4 |
| 18 | int ssh_tf_init(uid_t uid) |
| 19 | { |
| 20 | extern char *ticket; |
| 21 | char *tkt_root = TKT_ROOT; |
| 22 | struct stat st; |
| 23 | int fd; |
| 24 | |
| 25 | /* Set unique ticket string manually since we're still root. */ |
| 26 | ticket = xmalloc(MAXPATHLEN); |
| 27 | #ifdef AFS |
| 28 | if (lstat("/ticket", &st) != -1) |
| 29 | tkt_root = "/ticket/"; |
| 30 | #endif /* AFS */ |
| 31 | snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid()); |
| 32 | (void) krb_set_tkt_string(ticket); |
| 33 | |
| 34 | /* Make sure we own this ticket file, and we created it. */ |
| 35 | if (lstat(ticket, &st) == -1 && errno == ENOENT) { |
| 36 | /* good, no ticket file exists. create it. */ |
| 37 | if ((fd = open(ticket, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1) { |
| 38 | close(fd); |
| 39 | return 1; |
| 40 | } |
| 41 | } |
| 42 | else { |
| 43 | /* file exists. make sure server_user owns it (e.g. just passed ticket), |
| 44 | and that it isn't a symlink, and that it is mode 600. */ |
| 45 | if (st.st_mode == (S_IFREG|S_IRUSR|S_IWUSR) && st.st_uid == uid) |
| 46 | return 1; |
| 47 | } |
| 48 | /* Failure. */ |
| 49 | log("WARNING: bad ticket file %s", ticket); |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | int auth_krb4(const char *server_user, KTEXT auth, char **client) |
| 54 | { |
| 55 | AUTH_DAT adat = { 0 }; |
| 56 | KTEXT_ST reply; |
| 57 | char instance[INST_SZ]; |
| 58 | int r, s; |
| 59 | u_int cksum; |
| 60 | Key_schedule schedule; |
| 61 | struct sockaddr_in local, foreign; |
| 62 | |
| 63 | s = packet_get_connection_in(); |
| 64 | |
| 65 | r = sizeof(local); |
| 66 | memset(&local, 0, sizeof(local)); |
| 67 | if (getsockname(s, (struct sockaddr *) &local, &r) < 0) |
| 68 | debug("getsockname failed: %.100s", strerror(errno)); |
| 69 | r = sizeof(foreign); |
| 70 | memset(&foreign, 0, sizeof(foreign)); |
| 71 | if (getpeername(s, (struct sockaddr *)&foreign, &r) < 0) |
| 72 | debug("getpeername failed: %.100s", strerror(errno)); |
| 73 | |
| 74 | instance[0] = '*'; instance[1] = 0; |
| 75 | |
| 76 | /* Get the encrypted request, challenge, and session key. */ |
| 77 | if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) { |
| 78 | packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]); |
| 79 | return 0; |
| 80 | } |
| 81 | des_key_sched((des_cblock *)adat.session, schedule); |
| 82 | |
| 83 | *client = xmalloc(MAX_K_NAME_SZ); |
| 84 | (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname, |
| 85 | *adat.pinst ? "." : "", adat.pinst, adat.prealm); |
| 86 | |
| 87 | /* Check ~/.klogin authorization now. */ |
| 88 | if (kuserok(&adat, (char *)server_user) != KSUCCESS) { |
| 89 | packet_send_debug("Kerberos V4 .klogin authorization failed!"); |
| 90 | log("Kerberos V4 .klogin authorization failed for %s to account %s", |
| 91 | *client, server_user); |
| 92 | return 0; |
| 93 | } |
| 94 | /* Increment the checksum, and return it encrypted with the session key. */ |
| 95 | cksum = adat.checksum + 1; |
| 96 | cksum = htonl(cksum); |
| 97 | |
| 98 | /* If we can't successfully encrypt the checksum, we send back an empty |
| 99 | message, admitting our failure. */ |
| 100 | if ((r = krb_mk_priv((u_char *)&cksum, reply.dat, sizeof(cksum)+1, |
| 101 | schedule, &adat.session, &local, &foreign)) < 0) { |
| 102 | packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]); |
| 103 | reply.dat[0] = 0; |
| 104 | reply.length = 0; |
| 105 | } |
| 106 | else |
| 107 | reply.length = r; |
| 108 | |
| 109 | /* Clear session key. */ |
| 110 | memset(&adat.session, 0, sizeof(&adat.session)); |
| 111 | |
| 112 | packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE); |
| 113 | packet_put_string((char *) reply.dat, reply.length); |
| 114 | packet_send(); |
| 115 | packet_write_wait(); |
| 116 | return 1; |
| 117 | } |
| 118 | #endif /* KRB4 */ |
| 119 | |
| 120 | #ifdef AFS |
| 121 | int auth_kerberos_tgt(struct passwd *pw, const char *string) |
| 122 | { |
| 123 | CREDENTIALS creds; |
| 124 | extern char *ticket; |
| 125 | int r; |
| 126 | |
| 127 | if (!radix_to_creds(string, &creds)) { |
| 128 | log("Protocol error decoding Kerberos V4 tgt"); |
| 129 | packet_send_debug("Protocol error decoding Kerberos V4 tgt"); |
| 130 | goto auth_kerberos_tgt_failure; |
| 131 | } |
| 132 | if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ |
| 133 | strlcpy(creds.service, "krbtgt", sizeof creds.service); |
| 134 | |
| 135 | if (strcmp(creds.service, "krbtgt")) { |
| 136 | log("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d", |
| 137 | creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm, |
| 138 | pw->pw_uid); |
| 139 | packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d", |
| 140 | creds.pname, creds.pinst[0] ? "." : "", creds.pinst, |
| 141 | creds.realm, pw->pw_uid); |
| 142 | goto auth_kerberos_tgt_failure; |
| 143 | } |
| 144 | if (!ssh_tf_init(pw->pw_uid) || |
| 145 | (r = in_tkt(creds.pname, creds.pinst)) || |
| 146 | (r = save_credentials(creds.service, creds.instance, creds.realm, |
| 147 | creds.session, creds.lifetime, creds.kvno, |
| 148 | &creds.ticket_st, creds.issue_date))) { |
| 149 | xfree(ticket); |
| 150 | ticket = NULL; |
| 151 | packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials"); |
| 152 | goto auth_kerberos_tgt_failure; |
| 153 | } |
| 154 | /* Successful authentication, passed all checks. */ |
| 155 | chown(ticket, pw->pw_uid, pw->pw_gid); |
| 156 | packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)", |
| 157 | creds.service, creds.instance, creds.realm, |
| 158 | creds.pname, creds.pinst[0] ? "." : "", |
| 159 | creds.pinst, creds.realm); |
| 160 | |
| 161 | packet_start(SSH_SMSG_SUCCESS); |
| 162 | packet_send(); |
| 163 | packet_write_wait(); |
| 164 | return 1; |
| 165 | |
| 166 | auth_kerberos_tgt_failure: |
| 167 | memset(&creds, 0, sizeof(creds)); |
| 168 | packet_start(SSH_SMSG_FAILURE); |
| 169 | packet_send(); |
| 170 | packet_write_wait(); |
| 171 | return 0; |
| 172 | } |
| 173 | |
Damien Miller | 68cb757 | 1999-11-08 15:49:41 +1100 | [diff] [blame] | 174 | int auth_afs_token(struct passwd *pw, const char *token_string) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 175 | { |
| 176 | CREDENTIALS creds; |
Damien Miller | 68cb757 | 1999-11-08 15:49:41 +1100 | [diff] [blame] | 177 | uid_t uid = pw->pw_uid; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 178 | |
Damien Miller | 68cb757 | 1999-11-08 15:49:41 +1100 | [diff] [blame] | 179 | if (!radix_to_creds(token_string, &creds)) { |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 180 | log("Protocol error decoding AFS token"); |
| 181 | packet_send_debug("Protocol error decoding AFS token"); |
| 182 | packet_start(SSH_SMSG_FAILURE); |
| 183 | packet_send(); |
| 184 | packet_write_wait(); |
| 185 | return 0; |
| 186 | } |
| 187 | if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ |
| 188 | strlcpy(creds.service, "afs", sizeof creds.service); |
| 189 | |
| 190 | if (strncmp(creds.pname, "AFS ID ", 7) == 0) |
| 191 | uid = atoi(creds.pname + 7); |
| 192 | |
| 193 | if (kafs_settoken(creds.realm, uid, &creds)) { |
| 194 | log("AFS token (%s@%s) rejected for uid %d", creds.pname, |
| 195 | creds.realm, uid); |
| 196 | packet_send_debug("AFS token (%s@%s) rejected for uid %d", creds.pname, |
| 197 | creds.realm, uid); |
| 198 | packet_start(SSH_SMSG_FAILURE); |
| 199 | packet_send(); |
| 200 | packet_write_wait(); |
| 201 | return 0; |
| 202 | } |
| 203 | packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service, |
| 204 | creds.realm, creds.pname, creds.realm); |
| 205 | packet_start(SSH_SMSG_SUCCESS); |
| 206 | packet_send(); |
| 207 | packet_write_wait(); |
| 208 | return 1; |
| 209 | } |
| 210 | #endif /* AFS */ |