diff options
Diffstat (limited to 'auth-krb4.c')
| -rw-r--r-- | auth-krb4.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/auth-krb4.c b/auth-krb4.c new file mode 100644 index 00000000..720f3a4c --- /dev/null +++ b/auth-krb4.c @@ -0,0 +1,209 @@ +/* + + auth-kerberos.c + + Dug Song <dugsong@UMICH.EDU> + + Kerberos v4 authentication and ticket-passing routines. + + $Id: auth-krb4.c,v 1.1 1999/10/27 03:42:43 damien Exp $ +*/ + +#include "includes.h" +#include "packet.h" +#include "xmalloc.h" +#include "ssh.h" + +#ifdef KRB4 +int ssh_tf_init(uid_t uid) +{ + extern char *ticket; + char *tkt_root = TKT_ROOT; + struct stat st; + int fd; + + /* Set unique ticket string manually since we're still root. */ + ticket = xmalloc(MAXPATHLEN); +#ifdef AFS + if (lstat("/ticket", &st) != -1) + tkt_root = "/ticket/"; +#endif /* AFS */ + snprintf(ticket, MAXPATHLEN, "%s%d_%d", tkt_root, uid, getpid()); + (void) krb_set_tkt_string(ticket); + + /* Make sure we own this ticket file, and we created it. */ + if (lstat(ticket, &st) == -1 && errno == ENOENT) { + /* good, no ticket file exists. create it. */ + if ((fd = open(ticket, O_RDWR|O_CREAT|O_EXCL, 0600)) != -1) { + close(fd); + return 1; + } + } + else { + /* file exists. make sure server_user owns it (e.g. just passed ticket), + and that it isn't a symlink, and that it is mode 600. */ + if (st.st_mode == (S_IFREG|S_IRUSR|S_IWUSR) && st.st_uid == uid) + return 1; + } + /* Failure. */ + log("WARNING: bad ticket file %s", ticket); + return 0; +} + +int auth_krb4(const char *server_user, KTEXT auth, char **client) +{ + AUTH_DAT adat = { 0 }; + KTEXT_ST reply; + char instance[INST_SZ]; + int r, s; + u_int cksum; + Key_schedule schedule; + struct sockaddr_in local, foreign; + + s = packet_get_connection_in(); + + r = sizeof(local); + memset(&local, 0, sizeof(local)); + if (getsockname(s, (struct sockaddr *) &local, &r) < 0) + debug("getsockname failed: %.100s", strerror(errno)); + r = sizeof(foreign); + memset(&foreign, 0, sizeof(foreign)); + if (getpeername(s, (struct sockaddr *)&foreign, &r) < 0) + debug("getpeername failed: %.100s", strerror(errno)); + + instance[0] = '*'; instance[1] = 0; + + /* Get the encrypted request, challenge, and session key. */ + if ((r = krb_rd_req(auth, KRB4_SERVICE_NAME, instance, 0, &adat, ""))) { + packet_send_debug("Kerberos V4 krb_rd_req: %.100s", krb_err_txt[r]); + return 0; + } + des_key_sched((des_cblock *)adat.session, schedule); + + *client = xmalloc(MAX_K_NAME_SZ); + (void) snprintf(*client, MAX_K_NAME_SZ, "%s%s%s@%s", adat.pname, + *adat.pinst ? "." : "", adat.pinst, adat.prealm); + + /* Check ~/.klogin authorization now. */ + if (kuserok(&adat, (char *)server_user) != KSUCCESS) { + packet_send_debug("Kerberos V4 .klogin authorization failed!"); + log("Kerberos V4 .klogin authorization failed for %s to account %s", + *client, server_user); + return 0; + } + /* Increment the checksum, and return it encrypted with the session key. */ + cksum = adat.checksum + 1; + cksum = htonl(cksum); + + /* If we can't successfully encrypt the checksum, we send back an empty + message, admitting our failure. */ + if ((r = krb_mk_priv((u_char *)&cksum, reply.dat, sizeof(cksum)+1, + schedule, &adat.session, &local, &foreign)) < 0) { + packet_send_debug("Kerberos V4 mk_priv: (%d) %s", r, krb_err_txt[r]); + reply.dat[0] = 0; + reply.length = 0; + } + else + reply.length = r; + + /* Clear session key. */ + memset(&adat.session, 0, sizeof(&adat.session)); + + packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE); + packet_put_string((char *) reply.dat, reply.length); + packet_send(); + packet_write_wait(); + return 1; +} +#endif /* KRB4 */ + +#ifdef AFS +int auth_kerberos_tgt(struct passwd *pw, const char *string) +{ + CREDENTIALS creds; + extern char *ticket; + int r; + + if (!radix_to_creds(string, &creds)) { + log("Protocol error decoding Kerberos V4 tgt"); + packet_send_debug("Protocol error decoding Kerberos V4 tgt"); + goto auth_kerberos_tgt_failure; + } + if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ + strlcpy(creds.service, "krbtgt", sizeof creds.service); + + if (strcmp(creds.service, "krbtgt")) { + log("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d", + creds.pname, creds.pinst[0] ? "." : "", creds.pinst, creds.realm, + pw->pw_uid); + packet_send_debug("Kerberos V4 tgt (%s%s%s@%s) rejected for uid %d", + creds.pname, creds.pinst[0] ? "." : "", creds.pinst, + creds.realm, pw->pw_uid); + goto auth_kerberos_tgt_failure; + } + if (!ssh_tf_init(pw->pw_uid) || + (r = in_tkt(creds.pname, creds.pinst)) || + (r = save_credentials(creds.service, creds.instance, creds.realm, + creds.session, creds.lifetime, creds.kvno, + &creds.ticket_st, creds.issue_date))) { + xfree(ticket); + ticket = NULL; + packet_send_debug("Kerberos V4 tgt refused: couldn't save credentials"); + goto auth_kerberos_tgt_failure; + } + /* Successful authentication, passed all checks. */ + chown(ticket, pw->pw_uid, pw->pw_gid); + packet_send_debug("Kerberos V4 tgt accepted (%s.%s@%s, %s%s%s@%s)", + creds.service, creds.instance, creds.realm, + creds.pname, creds.pinst[0] ? "." : "", + creds.pinst, creds.realm); + + packet_start(SSH_SMSG_SUCCESS); + packet_send(); + packet_write_wait(); + return 1; + +auth_kerberos_tgt_failure: + memset(&creds, 0, sizeof(creds)); + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + return 0; +} + +int auth_afs_token(char *server_user, uid_t uid, const char *string) +{ + CREDENTIALS creds; + + if (!radix_to_creds(string, &creds)) { + log("Protocol error decoding AFS token"); + packet_send_debug("Protocol error decoding AFS token"); + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + return 0; + } + if (strncmp(creds.service, "", 1) == 0) /* backward compatibility */ + strlcpy(creds.service, "afs", sizeof creds.service); + + if (strncmp(creds.pname, "AFS ID ", 7) == 0) + uid = atoi(creds.pname + 7); + + if (kafs_settoken(creds.realm, uid, &creds)) { + log("AFS token (%s@%s) rejected for uid %d", creds.pname, + creds.realm, uid); + packet_send_debug("AFS token (%s@%s) rejected for uid %d", creds.pname, + creds.realm, uid); + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + return 0; + } + packet_send_debug("AFS token accepted (%s@%s, %s@%s)", creds.service, + creds.realm, creds.pname, creds.realm); + packet_start(SSH_SMSG_SUCCESS); + packet_send(); + packet_write_wait(); + return 1; +} +#endif /* AFS */ |