void userauth_finish(struct ssh *ssh, int authenticated, const char *method, const char *submethod) { Authctxt *authctxt = ssh->authctxt; char *methods; int partial = 0; if (!authctxt->valid && authenticated) fatal("INTERNAL ERROR: authenticated invalid user %s", authctxt->user); if (authenticated && authctxt->postponed) fatal("INTERNAL ERROR: authenticated and postponed"); /* Special handling for root */ if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed(ssh, method)) { authenticated = 0; #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); #endif } if (authenticated && options.num_auth_methods != 0) { if (!auth2_update_methods_lists(authctxt, method, submethod)) { authenticated = 0; partial = 1; } } /* Log before sending the reply */ auth_log(authctxt, authenticated, partial, method, submethod); /* Update information exposed to session */ if (authenticated || partial) auth2_update_session_info(authctxt, method, submethod); if (authctxt->postponed) return; #ifdef USE_PAM if (options.use_pam && authenticated) { int r; if (!PRIVSEP(do_pam_account())) { /* if PAM returned a message, send it to the user */ if (sshbuf_len(loginmsg) > 0) { if ((r = sshbuf_put(loginmsg, "\0", 1)) != 0) fatal("%s: buffer error: %s", __func__, ssh_err(r)); userauth_send_banner(sshbuf_ptr(loginmsg)); packet_write_wait(); } fatal("Access denied for user %s by PAM account " "configuration", authctxt->user); } } #endif if (authenticated == 1) { /* turn off userauth */ ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); packet_start(SSH2_MSG_USERAUTH_SUCCESS); packet_send(); packet_write_wait(); /* now we can break out */ authctxt->success = 1; ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); } else { /* Allow initial try of "none" auth without failure penalty */ if (!partial && !authctxt->server_caused_failure && (authctxt->attempt > 1 || strcmp(method, "none") != 0)) authctxt->failures++; if (authctxt->failures >= options.max_authtries) { #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); #endif auth_maxtries_exceeded(authctxt); } methods = authmethods_get(authctxt); debug3("%s: failure partial=%d next methods=\"%s\"", __func__, partial, methods); packet_start(SSH2_MSG_USERAUTH_FAILURE); packet_put_cstring(methods); packet_put_char(partial); packet_send(); packet_write_wait(); free(methods); } }
int mm_answer_pwnamallow(int sock, Buffer *m) { struct ssh *ssh = active_state; /* XXX */ char *username; struct passwd *pwent; int allowed = 0; u_int i; debug3("%s", __func__); if (authctxt->attempt++ != 0) fatal("%s: multiple attempts for getpwnam", __func__); username = buffer_get_string(m, NULL); pwent = getpwnamallow(username); authctxt->user = xstrdup(username); setproctitle("%s [priv]", pwent ? username : "******"); free(username); buffer_clear(m); if (pwent == NULL) { buffer_put_char(m, 0); authctxt->pw = fakepw(); goto out; } allowed = 1; authctxt->pw = pwent; authctxt->valid = 1; buffer_put_char(m, 1); buffer_put_string(m, pwent, sizeof(struct passwd)); buffer_put_cstring(m, pwent->pw_name); buffer_put_cstring(m, "*"); #ifdef HAVE_STRUCT_PASSWD_PW_GECOS buffer_put_cstring(m, pwent->pw_gecos); #endif #ifdef HAVE_STRUCT_PASSWD_PW_CLASS buffer_put_cstring(m, pwent->pw_class); #endif buffer_put_cstring(m, pwent->pw_dir); buffer_put_cstring(m, pwent->pw_shell); out: ssh_packet_set_log_preamble(ssh, "%suser %s", authctxt->valid ? "authenticating" : "invalid ", authctxt->user); buffer_put_string(m, &options, sizeof(options)); #define M_CP_STROPT(x) do { \ if (options.x != NULL) \ buffer_put_cstring(m, options.x); \ } while (0) #define M_CP_STRARRAYOPT(x, nx) do { \ for (i = 0; i < options.nx; i++) \ buffer_put_cstring(m, options.x[i]); \ } while (0) /* See comment in servconf.h */ COPY_MATCH_STRING_OPTS(); #undef M_CP_STROPT #undef M_CP_STRARRAYOPT /* Create valid auth method lists */ if (auth2_setup_methods_lists(authctxt) != 0) { /* * The monitor will continue long enough to let the child * run to it's packet_disconnect(), but it must not allow any * authentication to succeed. */ debug("%s: no valid authentication method lists", __func__); } debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed); mm_request_send(sock, MONITOR_ANS_PWNAM, m); /* Allow service/style information on the auth context */ monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); #ifdef USE_PAM if (options.use_pam) monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1); #endif return (0); }
/*ARGSUSED*/ static int input_userauth_request(int type, u_int32_t seq, struct ssh *ssh) { Authctxt *authctxt = ssh->authctxt; Authmethod *m = NULL; char *user, *service, *method, *style = NULL; int authenticated = 0; double tstart = monotime_double(); if (authctxt == NULL) fatal("input_userauth_request: no authctxt"); user = packet_get_cstring(NULL); service = packet_get_cstring(NULL); method = packet_get_cstring(NULL); debug("userauth-request for user %s service %s method %s", user, service, method); debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); if ((style = strchr(user, ':')) != NULL) *style++ = 0; if (authctxt->attempt++ == 0) { /* setup auth context */ authctxt->pw = PRIVSEP(getpwnamallow(user)); authctxt->user = xstrdup(user); if (authctxt->pw && strcmp(service, "ssh-connection")==0) { authctxt->valid = 1; debug2("%s: setting up authctxt for %s", __func__, user); } else { /* Invalid user, fake password information */ authctxt->pw = fakepw(); #ifdef SSH_AUDIT_EVENTS PRIVSEP(audit_event(SSH_INVALID_USER)); #endif } #ifdef USE_PAM if (options.use_pam) PRIVSEP(start_pam(authctxt)); #endif ssh_packet_set_log_preamble(ssh, "%suser %s", authctxt->valid ? "authenticating " : "invalid ", user); setproctitle("%s%s", authctxt->valid ? user : "******", use_privsep ? " [net]" : ""); authctxt->service = xstrdup(service); authctxt->style = style ? xstrdup(style) : NULL; if (use_privsep) mm_inform_authserv(service, style); userauth_banner(); if (auth2_setup_methods_lists(authctxt) != 0) packet_disconnect("no authentication methods enabled"); } else if (strcmp(user, authctxt->user) != 0 || strcmp(service, authctxt->service) != 0) { packet_disconnect("Change of username or service not allowed: " "(%s,%s) -> (%s,%s)", authctxt->user, authctxt->service, user, service); } /* reset state */ auth2_challenge_stop(ssh); #ifdef GSSAPI /* XXX move to auth2_gssapi_stop() */ ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); #endif auth2_authctxt_reset_info(authctxt); authctxt->postponed = 0; authctxt->server_caused_failure = 0; /* try to authenticate user */ m = authmethod_lookup(authctxt, method); if (m != NULL && authctxt->failures < options.max_authtries) { debug2("input_userauth_request: try method %s", method); authenticated = m->userauth(ssh); } if (!authctxt->authenticated) ensure_minimum_time_since(tstart, user_specific_delay(authctxt->user)); userauth_finish(ssh, authenticated, method, NULL); free(service); free(user); free(method); return 0; }
void monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) { struct ssh *ssh = active_state; /* XXX */ struct mon_table *ent; int authenticated = 0, partial = 0; debug3("preauth child monitor started"); close(pmonitor->m_recvfd); close(pmonitor->m_log_sendfd); pmonitor->m_log_sendfd = pmonitor->m_recvfd = -1; authctxt = _authctxt; memset(authctxt, 0, sizeof(*authctxt)); authctxt->loginmsg = &loginmsg; mon_dispatch = mon_dispatch_proto20; /* Permit requests for moduli and signatures */ monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); /* The first few requests do not require asynchronous access */ while (!authenticated) { partial = 0; auth_method = "unknown"; auth_submethod = NULL; auth2_authctxt_reset_info(authctxt); authenticated = (monitor_read(pmonitor, mon_dispatch, &ent) == 1); /* Special handling for multiple required authentications */ if (options.num_auth_methods != 0) { if (authenticated && !auth2_update_methods_lists(authctxt, auth_method, auth_submethod)) { debug3("%s: method %s: partial", __func__, auth_method); authenticated = 0; partial = 1; } } if (authenticated) { if (!(ent->flags & MON_AUTHDECIDE)) fatal("%s: unexpected authentication from %d", __func__, ent->type); if (authctxt->pw->pw_uid == 0 && !auth_root_allowed(auth_method)) authenticated = 0; #ifdef USE_PAM /* PAM needs to perform account checks after auth */ if (options.use_pam && authenticated) { Buffer m; buffer_init(&m); mm_request_receive_expect(pmonitor->m_sendfd, MONITOR_REQ_PAM_ACCOUNT, &m); authenticated = mm_answer_pam_account(pmonitor->m_sendfd, &m); buffer_free(&m); } #endif } if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) { auth_log(authctxt, authenticated, partial, auth_method, auth_submethod); if (!partial && !authenticated) authctxt->failures++; if (authenticated || partial) { auth2_update_session_info(authctxt, auth_method, auth_submethod); } } } if (!authctxt->valid) fatal("%s: authenticated invalid user", __func__); if (strcmp(auth_method, "unknown") == 0) fatal("%s: authentication method name unknown", __func__); debug("%s: %s has been authenticated by privileged process", __func__, authctxt->user); ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); mm_get_keystate(pmonitor); /* Drain any buffered messages from the child */ while (pmonitor->m_log_recvfd != -1 && monitor_read_log(pmonitor) == 0) ; close(pmonitor->m_sendfd); close(pmonitor->m_log_recvfd); pmonitor->m_sendfd = pmonitor->m_log_recvfd = -1; }