int mm_answer_gss_accept_ctx(int sock, Buffer *m) { gss_buffer_desc in; gss_buffer_desc out = GSS_C_EMPTY_BUFFER; OM_uint32 major, minor; OM_uint32 flags = 0; /* GSI needs this */ u_int len; in.value = buffer_get_string(m, &len); in.length = len; major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); xfree(in.value); buffer_clear(m); buffer_put_int(m, major); buffer_put_string(m, out.value, out.length); buffer_put_int(m, flags); mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); gss_release_buffer(&minor, &out); if (major == GSS_S_COMPLETE) { monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); } return (0); }
int mm_answer_gss_accept_ctx(int sock, struct sshbuf *m) { gss_buffer_desc in; gss_buffer_desc out = GSS_C_EMPTY_BUFFER; OM_uint32 major, minor; OM_uint32 flags = 0; /* GSI needs this */ size_t len; u_char *p; int r; if ((r = sshbuf_get_string(m, &p, &len)) != 0) fatal("%s: buffer error: %s", __func__, ssh_err(r)); in.value = p; in.length = len; major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); free(in.value); sshbuf_reset(m); if ((r = sshbuf_put_u32(m, major)) != 0 || (r = sshbuf_put_string(m, out.value, out.length)) != 0 || (r = sshbuf_put_u32(m, flags)) != 0) fatal("%s: buffer error: %s", __func__, ssh_err(r)); mm_request_send(sock, MONITOR_ANS_GSSSTEP, m); gss_release_buffer(&minor, &out); if (major == GSS_S_COMPLETE) { monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); } return 0; }
static int input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 maj_status; u_int len; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); gssctxt = authctxt->methoddata; recv_tok.value = packet_get_string(&len); recv_tok.length = len; packet_check_eom(); /* Push the error token into GSSAPI to see what it says */ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, &send_tok, NULL)); free(recv_tok.value); /* We can't return anything to the client, even if we wanted to */ dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL); /* The client will have already moved on to the next auth */ gss_release_buffer(&maj_status, &send_tok); return 0; }
static int input_gssapi_token(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 maj_status, min_status, flags; u_int len; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); gssctxt = authctxt->methoddata; recv_tok.value = packet_get_string(&len); recv_tok.length = len; /* u_int vs. size_t */ packet_check_eom(); maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, &send_tok, &flags)); free(recv_tok.value); if (GSS_ERROR(maj_status)) { if (send_tok.length != 0) { packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); packet_put_string(send_tok.value, send_tok.length); packet_send(); } authctxt->postponed = 0; dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); userauth_finish(authctxt, 0, "gssapi-with-mic", NULL); } else { if (send_tok.length != 0) { packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); packet_put_string(send_tok.value, send_tok.length); packet_send(); } if (maj_status == GSS_S_COMPLETE) { dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); if (flags & GSS_C_INTEG_FLAG) dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, &input_gssapi_mic); else dispatch_set( SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, &input_gssapi_exchange_complete); } } #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wdeprecated-declarations" gss_release_buffer(&min_status, &send_tok); #pragma clang diagnostic pop return 0; }
static void input_gssapi_token(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 maj_status, min_status; u_int len; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); gssctxt = authctxt->methoddata; recv_tok.value = packet_get_string(&len); recv_tok.length = len; /* u_int vs. size_t */ packet_check_eom(); maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, &send_tok, NULL)); xfree(recv_tok.value); if (GSS_ERROR(maj_status)) { if (send_tok.length != 0) { packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); packet_put_string(send_tok.value, send_tok.length); packet_send(); } authctxt->postponed = 0; dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); userauth_finish(authctxt, 0, "gssapi"); } else { if (send_tok.length != 0) { packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); packet_put_string(send_tok.value, send_tok.length); packet_send(); } if (maj_status == GSS_S_COMPLETE) { dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, &input_gssapi_exchange_complete); } } gss_release_buffer(&min_status, &send_tok); }
static int input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) { Authctxt *authctxt = ssh->authctxt; Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 maj_status; int r; u_char *p; size_t len; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); gssctxt = authctxt->methoddata; if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || (r = sshpkt_get_end(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); recv_tok.value = p; recv_tok.length = len; /* Push the error token into GSSAPI to see what it says */ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, &send_tok, NULL)); free(recv_tok.value); /* We can't return anything to the client, even if we wanted to */ ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL); /* The client will have already moved on to the next auth */ gss_release_buffer(&maj_status, &send_tok); return 0; }
void kexgss_server(Kex *kex) { OM_uint32 maj_status, min_status; /* * Some GSSAPI implementations use the input value of ret_flags (an * output variable) as a means of triggering mechanism specific * features. Initializing it to zero avoids inadvertently * activating this non-standard behaviour. */ OM_uint32 ret_flags = 0; gss_buffer_desc gssbuf, recv_tok, msg_tok; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; Gssctxt *ctxt = NULL; u_int slen, klen, kout, hashlen; u_char *kbuf, *hash; DH *dh; int min = -1, max = -1, nbits = -1; BIGNUM *shared_secret = NULL; BIGNUM *dh_client_pub = NULL; int type = 0; gss_OID oid; char *mechs; /* Initialise GSSAPI */ /* If we're rekeying, privsep means that some of the private structures * in the GSSAPI code are no longer available. This kludges them back * into life */ if (!ssh_gssapi_oid_table_ok()) if ((mechs = ssh_gssapi_server_mechanisms())) xfree(mechs); debug2("%s: Identifying %s", __func__, kex->name); oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type); if (oid == GSS_C_NO_OID) fatal("Unknown gssapi mechanism"); debug2("%s: Acquiring credentials", __func__); if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid)))) fatal("Unable to acquire credentials for the server"); switch (kex->kex_type) { case KEX_GSS_GRP1_SHA1: dh = dh_new_group1(); break; case KEX_GSS_GRP14_SHA1: dh = dh_new_group14(); break; case KEX_GSS_GEX_SHA1: debug("Doing group exchange"); packet_read_expect(SSH2_MSG_KEXGSS_GROUPREQ); min = packet_get_int(); nbits = packet_get_int(); max = packet_get_int(); min = MAX(DH_GRP_MIN, min); max = MIN(DH_GRP_MAX, max); packet_check_eom(); if (max < min || nbits < min || max < nbits) fatal("GSS_GEX, bad parameters: %d !< %d !< %d", min, nbits, max); dh = PRIVSEP(choose_dh(min, nbits, max)); if (dh == NULL) packet_disconnect("Protocol error: no matching group found"); packet_start(SSH2_MSG_KEXGSS_GROUP); packet_put_bignum2(dh->p); packet_put_bignum2(dh->g); packet_send(); packet_write_wait(); break; default: fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type); } dh_gen_key(dh, kex->we_need * 8); do { debug("Wait SSH2_MSG_GSSAPI_INIT"); type = packet_read(); switch(type) { case SSH2_MSG_KEXGSS_INIT: if (dh_client_pub != NULL) fatal("Received KEXGSS_INIT after initialising"); recv_tok.value = packet_get_string(&slen); recv_tok.length = slen; if ((dh_client_pub = BN_new()) == NULL) fatal("dh_client_pub == NULL"); packet_get_bignum2(dh_client_pub); /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */ break; case SSH2_MSG_KEXGSS_CONTINUE: recv_tok.value = packet_get_string(&slen); recv_tok.length = slen; break; default: packet_disconnect( "Protocol error: didn't expect packet type %d", type); } maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok, &send_tok, &ret_flags)); xfree(recv_tok.value); if (maj_status != GSS_S_COMPLETE && send_tok.length == 0) fatal("Zero length token output when incomplete"); if (dh_client_pub == NULL) fatal("No client public key"); if (maj_status & GSS_S_CONTINUE_NEEDED) { debug("Sending GSSAPI_CONTINUE"); packet_start(SSH2_MSG_KEXGSS_CONTINUE); packet_put_string(send_tok.value, send_tok.length); packet_send(); gss_release_buffer(&min_status, &send_tok); } } while (maj_status & GSS_S_CONTINUE_NEEDED); if (GSS_ERROR(maj_status)) { if (send_tok.length > 0) { packet_start(SSH2_MSG_KEXGSS_CONTINUE); packet_put_string(send_tok.value, send_tok.length); packet_send(); } fatal("accept_ctx died"); } if (!(ret_flags & GSS_C_MUTUAL_FLAG)) fatal("Mutual Authentication flag wasn't set"); if (!(ret_flags & GSS_C_INTEG_FLAG)) fatal("Integrity flag wasn't set"); if (!dh_pub_is_valid(dh, dh_client_pub)) packet_disconnect("bad client public DH value"); klen = DH_size(dh); kbuf = xmalloc(klen); kout = DH_compute_key(kbuf, dh_client_pub, dh); if (kout < 0) fatal("DH_compute_key: failed"); shared_secret = BN_new(); if (shared_secret == NULL) fatal("kexgss_server: BN_new failed"); if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) fatal("kexgss_server: BN_bin2bn failed"); memset(kbuf, 0, klen); xfree(kbuf); switch (kex->kex_type) { case KEX_GSS_GRP1_SHA1: case KEX_GSS_GRP14_SHA1: kex_dh_hash( kex->client_version_string, kex->server_version_string, buffer_ptr(&kex->peer), buffer_len(&kex->peer), buffer_ptr(&kex->my), buffer_len(&kex->my), NULL, 0, /* Change this if we start sending host keys */ dh_client_pub, dh->pub_key, shared_secret, &hash, &hashlen ); break; case KEX_GSS_GEX_SHA1: kexgex_hash( kex->evp_md, kex->client_version_string, kex->server_version_string, buffer_ptr(&kex->peer), buffer_len(&kex->peer), buffer_ptr(&kex->my), buffer_len(&kex->my), NULL, 0, min, nbits, max, dh->p, dh->g, dh_client_pub, dh->pub_key, shared_secret, &hash, &hashlen ); break; default: fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type); } BN_clear_free(dh_client_pub); if (kex->session_id == NULL) { kex->session_id_len = hashlen; kex->session_id = xmalloc(kex->session_id_len); memcpy(kex->session_id, hash, kex->session_id_len); } gssbuf.value = hash; gssbuf.length = hashlen; if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok)))) fatal("Couldn't get MIC"); packet_start(SSH2_MSG_KEXGSS_COMPLETE); packet_put_bignum2(dh->pub_key); packet_put_string(msg_tok.value,msg_tok.length); if (send_tok.length != 0) { packet_put_char(1); /* true */ packet_put_string(send_tok.value, send_tok.length); } else { packet_put_char(0); /* false */ } packet_send(); gss_release_buffer(&min_status, &send_tok); gss_release_buffer(&min_status, &msg_tok); if (gss_kex_context == NULL) gss_kex_context = ctxt; else ssh_gssapi_delete_ctx(&ctxt); DH_free(dh); kex_derive_keys(kex, hash, hashlen, shared_secret); BN_clear_free(shared_secret); kex_finish(kex); /* If this was a rekey, then save out any delegated credentials we * just exchanged. */ if (options.gss_store_rekey) ssh_gssapi_rekey_creds(); }
static int input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) { Authctxt *authctxt = ssh->authctxt; Gssctxt *gssctxt; gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; gss_buffer_desc recv_tok; OM_uint32 maj_status, min_status, flags; u_char *p; size_t len; int r; if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) fatal("No authentication or GSSAPI context"); gssctxt = authctxt->methoddata; if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || (r = sshpkt_get_end(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); recv_tok.value = p; recv_tok.length = len; maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, &send_tok, &flags)); free(p); if (GSS_ERROR(maj_status)) { if (send_tok.length != 0) { if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK)) != 0 || (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 || (r = sshpkt_send(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); } authctxt->postponed = 0; ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); userauth_finish(ssh, 0, "gssapi-with-mic", NULL); } else { if (send_tok.length != 0) { if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN)) != 0 || (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 || (r = sshpkt_send(ssh)) != 0) fatal("%s: %s", __func__, ssh_err(r)); } if (maj_status == GSS_S_COMPLETE) { ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); if (flags & GSS_C_INTEG_FLAG) ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC, &input_gssapi_mic); else ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, &input_gssapi_exchange_complete); } } gss_release_buffer(&min_status, &send_tok); return 0; }