/* * librdkafka - The Apache Kafka C/C++ library * * Copyright (c) 2015 Magnus Edenhill * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include "rdkafka_int.h" #include "rdkafka_transport.h" #include "rdkafka_transport_int.h" #include "rdkafka_sasl.h" #include static mtx_t rd_kafka_sasl_kinit_lock; /** * Send auth message with framing. * This is a blocking call. */ static int rd_kafka_sasl_send (rd_kafka_transport_t *rktrans, const void *payload, int len, char *errstr, int errstr_size) { struct msghdr msg = RD_ZERO_INIT; struct iovec iov[1]; int32_t hdr; char *frame; int total_len = sizeof(hdr) + len; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SASL", "Send SASL frame to broker (%d bytes)", len); frame = rd_malloc(total_len); hdr = htobe32(len); memcpy(frame, &hdr, sizeof(hdr)); if (payload) memcpy(frame+sizeof(hdr), payload, len); msg.msg_iov = iov; msg.msg_iovlen = 1; iov[0].iov_base = frame; iov[0].iov_len = total_len; /* Simulate blocking behaviour on non-blocking socket.. * FIXME: This isn't optimal but is highly unlikely to stall since * the socket buffer will most likely not be exceeded. */ do { int r; r = rd_kafka_transport_sendmsg(rktrans, &msg, errstr, errstr_size); if (r == -1) { rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SASL", "SASL send of %d bytes failed: %s", total_len, errstr); free(frame); return -1; } if (r == total_len) break; /* Avoid busy-looping */ rd_usleep(10*1000, NULL); /* Shave off written bytes */ total_len -= r; iov[0].iov_base = ((char *)(iov[0].iov_base)) + r; iov[0].iov_len = total_len; } while (total_len > 0); free(frame); return 0; } /** * Handle received frame from broker. */ static int rd_kafka_sasl_handle_recv (rd_kafka_transport_t *rktrans, rd_kafka_buf_t *rkbuf, char *errstr, int errstr_size) { int r; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SASL", "Received SASL frame from broker (%"PRIdsz" bytes)", rkbuf ? rkbuf->rkbuf_len : 0); if (rktrans->rktrans_sasl.complete && (!rkbuf || rkbuf->rkbuf_len == 0)) goto auth_successful; do { sasl_interact_t *interact = NULL; const char *out; unsigned int outlen; r = sasl_client_step(rktrans->rktrans_sasl.conn, rkbuf && rkbuf->rkbuf_len > 0 ? rkbuf->rkbuf_rbuf : NULL, rkbuf ? rkbuf->rkbuf_len : 0, &interact, &out, &outlen); if (rkbuf) { rd_kafka_buf_destroy(rkbuf); rkbuf = NULL; } if (r >= 0) { /* Note: outlen may be 0 here for an empty response */ if (rd_kafka_sasl_send(rktrans, out, outlen, errstr, errstr_size) == -1) return -1; } if (r == SASL_INTERACT) rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SASL", "SASL_INTERACT: %lu %s, %s, %s, %p", interact->id, interact->challenge, interact->prompt, interact->defresult, interact->result); } while (r == SASL_INTERACT); if (r == SASL_CONTINUE) return 0; /* Wait for more data from broker */ else if (r != SASL_OK) { rd_snprintf(errstr, errstr_size, "SASL handshake failed (step): %s", sasl_errdetail(rktrans->rktrans_sasl.conn)); return -1; } /* Authentication successful */ auth_successful: if (rktrans->rktrans_rkb->rkb_rk->rk_conf.debug & RD_KAFKA_DBG_SECURITY) { const char *user, *mech, *authsrc; if (sasl_getprop(rktrans->rktrans_sasl.conn, SASL_USERNAME, (const void **)&user) != SASL_OK) user = "(unknown)"; if (sasl_getprop(rktrans->rktrans_sasl.conn, SASL_MECHNAME, (const void **)&mech) != SASL_OK) mech = "(unknown)"; if (sasl_getprop(rktrans->rktrans_sasl.conn, SASL_AUTHSOURCE, (const void **)&authsrc) != SASL_OK) authsrc = "(unknown)"; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "SASL", "Authenticated as %s using %s (%s)", user, mech, authsrc); } rd_kafka_broker_connect_up(rktrans->rktrans_rkb); return 0; } int rd_kafka_sasl_io_event (rd_kafka_transport_t *rktrans, int events, char *errstr, int errstr_size) { if (events & POLLIN) { rd_kafka_buf_t *rkbuf; int r; r = rd_kafka_transport_framed_recvmsg(rktrans, &rkbuf, errstr, errstr_size); if (r == -1) return -1; else if (r == 0) return 0; return rd_kafka_sasl_handle_recv(rktrans, rkbuf, errstr, errstr_size); } return 0; } static ssize_t render_callback (const char *key, char *buf, size_t size, void *opaque) { rd_kafka_broker_t *rkb = opaque; if (!strcmp(key, "broker.name")) { char *val, *t; size_t len; rd_kafka_broker_lock(rkb); rd_strdupa(&val, rkb->rkb_nodename); rd_kafka_broker_unlock(rkb); /* Just the broker name, no port */ if ((t = strchr(val, ':'))) len = (size_t)(t-val); else len = strlen(val); if (buf) memcpy(buf, val, RD_MIN(len, size)); return len; } else { rd_kafka_conf_res_t res; size_t destsize = size; /* Try config lookup. */ res = rd_kafka_conf_get(&rkb->rkb_rk->rk_conf, key, buf, &destsize); if (res != RD_KAFKA_CONF_OK) return -1; /* Dont include \0 in returned size */ return (destsize > 0 ? destsize-1 : destsize); } } /** * Execute kinit to refresh ticket. * * Returns 0 on success, -1 on error. * * Locality: any */ static int rd_kafka_sasl_kinit_refresh (rd_kafka_broker_t *rkb) { rd_kafka_t *rk = rkb->rkb_rk; int r; char *cmd; char errstr[128]; if (!rk->rk_conf.sasl.kinit_cmd || !strstr(rk->rk_conf.sasl.mechanisms, "GSSAPI")) return 0; /* kinit not configured */ /* Build kinit refresh command line using string rendering and config */ cmd = rd_string_render(rk->rk_conf.sasl.kinit_cmd, errstr, sizeof(errstr), render_callback, rkb); if (!cmd) { rd_rkb_log(rkb, LOG_ERR, "SASLREFRESH", "Failed to construct kinit command " "from sasl.kerberos.kinit.cmd template: %s", errstr); return -1; } /* Execute kinit */ rd_rkb_dbg(rkb, SECURITY, "SASLREFRESH", "Refreshing SASL keys with command: %s", cmd); mtx_lock(&rd_kafka_sasl_kinit_lock); r = system(cmd); mtx_unlock(&rd_kafka_sasl_kinit_lock); if (r == -1) { rd_rkb_log(rkb, LOG_ERR, "SASLREFRESH", "SASL key refresh failed: Failed to execute %s", cmd); rd_free(cmd); return -1; } else if (WIFSIGNALED(r)) { rd_rkb_log(rkb, LOG_ERR, "SASLREFRESH", "SASL key refresh failed: %s: received signal %d", cmd, WTERMSIG(r)); rd_free(cmd); return -1; } else if (WIFEXITED(r) && WEXITSTATUS(r) != 0) { rd_rkb_log(rkb, LOG_ERR, "SASLREFRESH", "SASL key refresh failed: %s: exited with code %d", cmd, WEXITSTATUS(r)); rd_free(cmd); return -1; } rd_free(cmd); rd_rkb_dbg(rkb, SECURITY, "SASLREFRESH", "SASL key refreshed"); return 0; } /** * Refresh timer callback * * Locality: kafka main thread */ static void rd_kafka_sasl_kinit_refresh_tmr_cb (rd_kafka_timers_t *rkts, void *arg) { rd_kafka_broker_t *rkb = arg; rd_kafka_sasl_kinit_refresh(rkb); } /** * * libsasl callbacks * */ static RD_UNUSED int rd_kafka_sasl_cb_getopt (void *context, const char *plugin_name, const char *option, const char **result, unsigned *len) { rd_kafka_transport_t *rktrans = context; if (!strcmp(option, "client_mech_list")) *result = "GSSAPI"; if (!strcmp(option, "canon_user_plugin")) *result = "INTERNAL"; if (*result && len) *len = strlen(*result); rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_GETOPT: plugin %s, option %s: returning %s", plugin_name, option, *result); return SASL_OK; } static int rd_kafka_sasl_cb_log (void *context, int level, const char *message){ rd_kafka_transport_t *rktrans = context; if (level >= LOG_DEBUG) rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "%s", message); else rd_rkb_log(rktrans->rktrans_rkb, level, "LIBSASL", "%s", message); return SASL_OK; } static int rd_kafka_sasl_cb_getsimple (void *context, int id, const char **result, unsigned *len) { rd_kafka_transport_t *rktrans = context; switch (id) { case SASL_CB_USER: case SASL_CB_AUTHNAME: *result = rktrans->rktrans_rkb->rkb_rk->rk_conf.sasl.username; break; default: *result = NULL; break; } if (len) *len = *result ? strlen(*result) : 0; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_GETSIMPLE: id 0x%x: returning %s", id, *result); return *result ? SASL_OK : SASL_FAIL; } static int rd_kafka_sasl_cb_getsecret (sasl_conn_t *conn, void *context, int id, sasl_secret_t **psecret) { rd_kafka_transport_t *rktrans = context; const char *password; password = rktrans->rktrans_rkb->rkb_rk->rk_conf.sasl.password; if (!password) { *psecret = NULL; } else { size_t passlen = strlen(password); *psecret = rd_realloc(*psecret, sizeof(**psecret) + passlen); (*psecret)->len = passlen; memcpy((*psecret)->data, password, passlen); } rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_GETSECRET: id 0x%x: returning %s", id, *psecret ? "(hidden)":"NULL"); return SASL_OK; } static int rd_kafka_sasl_cb_chalprompt (void *context, int id, const char *challenge, const char *prompt, const char *defres, const char **result, unsigned *len) { rd_kafka_transport_t *rktrans = context; *result = "min_chalprompt"; *len = strlen(*result); rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_CHALPROMPT: id 0x%x, challenge %s, prompt %s, " "default %s: returning %s", id, challenge, prompt, defres, *result); return SASL_OK; } static int rd_kafka_sasl_cb_getrealm (void *context, int id, const char **availrealms, const char **result) { rd_kafka_transport_t *rktrans = context; *result = *availrealms; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_GETREALM: id 0x%x: returning %s", id, *result); return SASL_OK; } static RD_UNUSED int rd_kafka_sasl_cb_canon (sasl_conn_t *conn, void *context, const char *in, unsigned inlen, unsigned flags, const char *user_realm, char *out, unsigned out_max, unsigned *out_len) { rd_kafka_transport_t *rktrans = context; if (strstr(rktrans->rktrans_rkb->rkb_rk->rk_conf. sasl.mechanisms, "GSSAPI")) { *out_len = rd_snprintf(out, out_max, "%s", rktrans->rktrans_rkb->rkb_rk-> rk_conf.sasl.principal); } else if (!strcmp(rktrans->rktrans_rkb->rkb_rk->rk_conf. sasl.mechanisms, "PLAIN")) { *out_len = rd_snprintf(out, out_max, "%.*s", inlen, in); } else out = NULL; rd_rkb_dbg(rktrans->rktrans_rkb, SECURITY, "LIBSASL", "CB_CANON: flags 0x%x, \"%.*s\" @ \"%s\": returning \"%.*s\"", flags, (int)inlen, in, user_realm, (int)(*out_len), out); return out ? SASL_OK : SASL_FAIL; } /** * Initialize and start SASL authentication. * * Returns 0 on successful init and -1 on error. * * Locality: broker thread */ int rd_kafka_sasl_client_new (rd_kafka_transport_t *rktrans, char *errstr, int errstr_size) { int r; rd_kafka_broker_t *rkb = rktrans->rktrans_rkb; rd_kafka_t *rk = rkb->rkb_rk; char *hostname, *t; sasl_callback_t callbacks[16] = { // { SASL_CB_GETOPT, (void *)rd_kafka_sasl_cb_getopt, rktrans }, { SASL_CB_LOG, (void *)rd_kafka_sasl_cb_log, rktrans }, { SASL_CB_AUTHNAME, (void *)rd_kafka_sasl_cb_getsimple, rktrans }, { SASL_CB_PASS, (void *)rd_kafka_sasl_cb_getsecret, rktrans }, { SASL_CB_ECHOPROMPT, (void *)rd_kafka_sasl_cb_chalprompt, rktrans }, { SASL_CB_GETREALM, (void *)rd_kafka_sasl_cb_getrealm, rktrans }, { SASL_CB_CANON_USER, (void *)rd_kafka_sasl_cb_canon, rktrans }, { SASL_CB_LIST_END } }; /* SASL_CB_USER is needed for PLAIN but breaks GSSAPI */ if (!strcmp(rk->rk_conf.sasl.service_name, "PLAIN")) { int endidx; /* Find end of callbacks array */ for (endidx = 0 ; callbacks[endidx].id != SASL_CB_LIST_END ; endidx++) ; callbacks[endidx].id = SASL_CB_USER; callbacks[endidx].proc = (void *)rd_kafka_sasl_cb_getsimple; endidx++; callbacks[endidx].id = SASL_CB_LIST_END; } rd_strdupa(&hostname, rktrans->rktrans_rkb->rkb_nodename); if ((t = strchr(hostname, ':'))) *t = '\0'; /* remove ":port" */ rd_rkb_dbg(rkb, SECURITY, "SASL", "Initializing SASL client: service name %s, " "hostname %s, mechanisms %s", rk->rk_conf.sasl.service_name, hostname, rk->rk_conf.sasl.mechanisms); /* Acquire or refresh ticket if kinit is configured */ rd_kafka_sasl_kinit_refresh(rkb); r = sasl_client_new(rk->rk_conf.sasl.service_name, hostname, NULL, NULL, /* no local & remote IP checks */ callbacks, 0, &rktrans->rktrans_sasl.conn); if (r != SASL_OK) { rd_snprintf(errstr, errstr_size, "%s", sasl_errstring(r, NULL, NULL)); return -1; } if (rk->rk_conf.debug & RD_KAFKA_DBG_SECURITY) { const char *avail_mechs; sasl_listmech(rktrans->rktrans_sasl.conn, NULL, NULL, " ", NULL, &avail_mechs, NULL, NULL); rd_rkb_dbg(rkb, SECURITY, "SASL", "My supported SASL mechanisms: %s", avail_mechs); } rd_kafka_transport_poll_set(rktrans, POLLIN); do { const char *out; unsigned int outlen; const char *mech = NULL; r = sasl_client_start(rktrans->rktrans_sasl.conn, rk->rk_conf.sasl.mechanisms, NULL, &out, &outlen, &mech); if (r >= 0) if (rd_kafka_sasl_send(rktrans, out, outlen, errstr, errstr_size)) return -1; } while (r == SASL_INTERACT); if (r == SASL_OK) { /* PLAIN is appearantly done here, but we still need to make sure * the PLAIN frame is sent and we get a response back (but we must * not pass the response to libsasl or it will fail). */ rktrans->rktrans_sasl.complete = 1; return 0; } else if (r != SASL_CONTINUE) { rd_snprintf(errstr, errstr_size, "SASL handshake failed (start (%d)): %s", r, sasl_errdetail(rktrans->rktrans_sasl.conn)); return -1; } return 0; } /** * Per handle SASL term. * * Locality: broker thread */ void rd_kafka_broker_sasl_term (rd_kafka_broker_t *rkb) { rd_kafka_t *rk = rkb->rkb_rk; if (!rk->rk_conf.sasl.kinit_cmd) return; rd_kafka_timer_stop(&rk->rk_timers, &rkb->rkb_sasl_kinit_refresh_tmr,1); } /** * Broker SASL init. * * Locality: broker thread */ void rd_kafka_broker_sasl_init (rd_kafka_broker_t *rkb) { rd_kafka_t *rk = rkb->rkb_rk; if (!rk->rk_conf.sasl.kinit_cmd || !strstr(rk->rk_conf.sasl.mechanisms, "GSSAPI")) return; /* kinit not configured, no need to start timer */ rd_kafka_timer_start(&rk->rk_timers, &rkb->rkb_sasl_kinit_refresh_tmr, rk->rk_conf.sasl.relogin_min_time * 1000, rd_kafka_sasl_kinit_refresh_tmr_cb, rkb); } int rd_kafka_sasl_conf_validate (rd_kafka_t *rk, char *errstr, size_t errstr_size) { rd_kafka_broker_t rkb; char *cmd; char tmperr[128]; if (strcmp(rk->rk_conf.sasl.mechanisms, "GSSAPI")) return 0; memset(&rkb, 0, sizeof(rkb)); strcpy(rkb.rkb_nodename, "ATestBroker:9092"); rkb.rkb_rk = rk; mtx_init(&rkb.rkb_lock, mtx_plain); cmd = rd_string_render(rk->rk_conf.sasl.kinit_cmd, tmperr, sizeof(tmperr), render_callback, &rkb); mtx_destroy(&rkb.rkb_lock); if (!cmd) { rd_snprintf(errstr, errstr_size, "Invalid sasl.kerberos.kinit.cmd value: %s", tmperr); return -1; } rd_free(cmd); return 0; } /** * Global SASL termination. * NOTE: Should not be called since the application may be using SASL too. */ void rd_kafka_sasl_global_term (void) { sasl_done(); mtx_destroy(&rd_kafka_sasl_kinit_lock); } /** * Global SASL init, called once per runtime. */ int rd_kafka_sasl_global_init (void) { int r; mtx_init(&rd_kafka_sasl_kinit_lock, mtx_plain); r = sasl_client_init(NULL); if (r != SASL_OK) { fprintf(stderr, "librdkafka: sasl_client_init() failed: %s\n", sasl_errstring(r, NULL, NULL)); return -1; } return 0; }