diff options
Diffstat (limited to 'logsrvd/logsrvd_relay.c')
| -rw-r--r-- | logsrvd/logsrvd_relay.c | 1257 |
1 files changed, 1257 insertions, 0 deletions
diff --git a/logsrvd/logsrvd_relay.c b/logsrvd/logsrvd_relay.c new file mode 100644 index 0000000..f9e7f30 --- /dev/null +++ b/logsrvd/logsrvd_relay.c @@ -0,0 +1,1257 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2019-2022 Todd C. Miller <Todd.Miller@sudo.ws> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include <config.h> + +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netinet/tcp.h> +#include <arpa/inet.h> + +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#ifdef HAVE_STDBOOL_H +# include <stdbool.h> +#else +# include "compat/stdbool.h" +#endif /* HAVE_STDBOOL_H */ +#if defined(HAVE_STDINT_H) +# include <stdint.h> +#elif defined(HAVE_INTTYPES_H) +# include <inttypes.h> +#endif +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> + +#define NEED_INET_NTOP /* to expose sudo_inet_ntop in sudo_compat.h */ + +#include "sudo_compat.h" +#include "sudo_debug.h" +#include "sudo_event.h" +#include "sudo_eventlog.h" +#include "sudo_gettext.h" +#include "sudo_iolog.h" +#include "sudo_fatal.h" +#include "sudo_queue.h" +#include "sudo_util.h" + +#include "logsrvd.h" + +static void relay_client_msg_cb(int fd, int what, void *v); +static void relay_server_msg_cb(int fd, int what, void *v); +static void connect_cb(int sock, int what, void *v); +static bool start_relay(int sock, struct connection_closure *closure); + +/* + * Free a struct relay_closure container and its contents. + */ +void +relay_closure_free(struct relay_closure *relay_closure) +{ + struct connection_buffer *buf; + debug_decl(relay_closure_free, SUDO_DEBUG_UTIL); + +#if defined(HAVE_OPENSSL) + if (relay_closure->tls_client.ssl != NULL) { + sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, + "closing down TLSÂ connection to %s", + relay_closure->relay_name.name); + if (SSL_shutdown(relay_closure->tls_client.ssl) == 0) + SSL_shutdown(relay_closure->tls_client.ssl); + SSL_free(relay_closure->tls_client.ssl); + } +#endif + if (relay_closure->relays != NULL) + address_list_delref(relay_closure->relays); + sudo_rcstr_delref(relay_closure->relay_name.name); + sudo_ev_free(relay_closure->read_ev); + sudo_ev_free(relay_closure->write_ev); + sudo_ev_free(relay_closure->connect_ev); + free(relay_closure->read_buf.data); + while ((buf = TAILQ_FIRST(&relay_closure->write_bufs)) != NULL) { + TAILQ_REMOVE(&relay_closure->write_bufs, buf, entries); + free(buf->data); + free(buf); + } + if (relay_closure->sock != -1) { + shutdown(relay_closure->sock, SHUT_RDWR); + close(relay_closure->sock); + } + free(relay_closure); + + debug_return; +} + +/* + * Allocate a relay closure. + * Note that allocation of the events is deferred until we know the socket. + */ +static struct relay_closure * +relay_closure_alloc(void) +{ + struct relay_closure *relay_closure; + debug_decl(relay_closure_alloc, SUDO_DEBUG_UTIL); + + if ((relay_closure = calloc(1, sizeof(*relay_closure))) == NULL) + debug_return_ptr(NULL); + + /* We take a reference to relays so it doesn't change while connecting. */ + relay_closure->sock = -1; + relay_closure->relays = logsrvd_conf_relay_address(); + address_list_addref(relay_closure->relays); + TAILQ_INIT(&relay_closure->write_bufs); + + relay_closure->read_buf.size = 8 * 1024; + relay_closure->read_buf.data = malloc(relay_closure->read_buf.size); + if (relay_closure->read_buf.data == NULL) + goto bad; + + debug_return_ptr(relay_closure); +bad: + relay_closure_free(relay_closure); + debug_return_ptr(NULL); +} + +/* + * Allocate a new buffer, copy buf to it and insert on the write queue. + * On success the relay write event is enabled. + * The length parameter does not include space for the message's wire size. + */ +static bool +relay_enqueue_write(uint8_t *msgbuf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + struct connection_buffer *buf; + uint32_t msg_len; + bool ret = false; + debug_decl(relay_enqueue_write, SUDO_DEBUG_UTIL); + + /* Wire message size is used for length encoding, precedes message. */ + msg_len = htonl((uint32_t)len); + + sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, + "size + client message %zu bytes", len); + + if ((buf = get_free_buf(sizeof(msg_len) + len, closure)) == NULL) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, + "unable to allocate connection_buffer"); + goto done; + } + memcpy(buf->data, &msg_len, sizeof(msg_len)); + memcpy(buf->data + sizeof(msg_len), msgbuf, len); + buf->len = sizeof(msg_len) + len; + + if (sudo_ev_add(closure->evbase, relay_closure->write_ev, NULL, false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + goto done; + } + + TAILQ_INSERT_TAIL(&relay_closure->write_bufs, buf, entries); + buf = NULL; + + ret = true; + +done: + if (buf != NULL) { + free(buf->data); + free(buf); + } + debug_return_bool(ret); +} + +/* + * Format a ClientMessage and store the wire format message in buf. + * Returns true on success, false on failure. + */ +static bool +fmt_client_message(struct connection_closure *closure, ClientMessage *msg) +{ + struct relay_closure *relay_closure = closure->relay_closure; + struct connection_buffer *buf = NULL; + uint32_t msg_len; + bool ret = false; + size_t len; + debug_decl(fmt_client_message, SUDO_DEBUG_UTIL); + + len = client_message__get_packed_size(msg); + if (len > MESSAGE_SIZE_MAX) { + sudo_warnx(U_("client message too large: %zu"), len); + goto done; + } + + /* Wire message size is used for length encoding, precedes message. */ + msg_len = htonl((uint32_t)len); + len += sizeof(msg_len); + + sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, + "size + client message %zu bytes", len); + + if ((buf = get_free_buf(len, closure)) == NULL) { + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, + "unable to allocate connection_buffer"); + goto done; + } + memcpy(buf->data, &msg_len, sizeof(msg_len)); + client_message__pack(msg, buf->data + sizeof(msg_len)); + buf->len = len; + TAILQ_INSERT_TAIL(&relay_closure->write_bufs, buf, entries); + + ret = true; + +done: + debug_return_bool(ret); +} + +static bool +fmt_client_hello(struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + ClientMessage client_msg = CLIENT_MESSAGE__INIT; + ClientHello hello_msg = CLIENT_HELLO__INIT; + bool ret; + debug_decl(fmt_client_hello, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: sending ClientHello", __func__); + hello_msg.client_id = (char *)"Sudo Logsrvd " PACKAGE_VERSION; + + client_msg.u.hello_msg = &hello_msg; + client_msg.type_case = CLIENT_MESSAGE__TYPE_HELLO_MSG; + ret = fmt_client_message(closure, &client_msg); + if (ret) { + if (sudo_ev_add(closure->evbase, relay_closure->read_ev, NULL, false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + ret = false; + } + if (sudo_ev_add(closure->evbase, relay_closure->write_ev, NULL, false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + ret = false; + } + } + + debug_return_bool(ret); +} + +#if defined(HAVE_OPENSSL) +/* Wrapper for start_relay() called via tls_connect_cb() */ +static bool +tls_client_start_fn(struct tls_client_closure *tls_client) +{ + sudo_ev_free(tls_client->tls_connect_ev); + tls_client->tls_connect_ev = NULL; + return start_relay(SSL_get_fd(tls_client->ssl), tls_client->parent_closure); +} + +/* Perform TLS connection to the relay host. */ +static bool +connect_relay_tls(struct connection_closure *closure) +{ + struct tls_client_closure *tls_client = &closure->relay_closure->tls_client; + SSL_CTX *ssl_ctx = logsrvd_relay_tls_ctx(); + debug_decl(connect_relay_tls, SUDO_DEBUG_UTIL); + + /* Populate struct tls_client_closure. */ + tls_client->parent_closure = closure; + tls_client->evbase = closure->evbase; + tls_client->tls_connect_ev = sudo_ev_alloc(closure->relay_closure->sock, + SUDO_EV_WRITE, tls_connect_cb, tls_client); + if (tls_client->tls_connect_ev == NULL) + goto bad; + tls_client->peer_name = &closure->relay_closure->relay_name; + tls_client->connect_timeout = *logsrvd_conf_relay_connect_timeout(); + tls_client->start_fn = tls_client_start_fn; + if (!tls_ctx_client_setup(ssl_ctx, closure->relay_closure->sock, tls_client)) + goto bad; + + debug_return_bool(true); +bad: + debug_return_bool(false); +} +#endif /* HAVE_OPENSSL */ + +/* + * Try to connect to the next relay host. + * Returns 0 on success, -1 on error, setting errno. + * If there is no next relay, errno is set to ENOENT. + */ +static int +connect_relay_next(struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + struct server_address *relay; + int ret, sock = -1; + char *addr; + debug_decl(connect_relay_next, SUDO_DEBUG_UTIL); + + /* Get next relay or return ENOENT none are left. */ + if (relay_closure->relay_addr != NULL) { + relay = TAILQ_NEXT(relay_closure->relay_addr, entries); + } else { + relay = TAILQ_FIRST(relay_closure->relays); + } + if (relay == NULL) { + errno = ENOENT; + goto bad; + } + relay_closure->relay_addr = relay; + + sock = socket(relay->sa_un.sa.sa_family, SOCK_STREAM, 0); + if (sock == -1) { + sudo_warn("socket"); + goto bad; + } + if (logsrvd_conf_relay_tcp_keepalive()) { + int keepalive = 1; + if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &keepalive, + sizeof(keepalive)) == -1) { + sudo_warn("SO_KEEPALIVE"); + } + } + ret = fcntl(sock, F_GETFL, 0); + if (ret == -1 || fcntl(sock, F_SETFL, ret | O_NONBLOCK) == -1) { + sudo_warn("fcntl(O_NONBLOCK)"); + goto bad; + } + + ret = connect(sock, &relay->sa_un.sa, relay->sa_size); + if (ret == -1 && errno != EINPROGRESS) + goto bad; + + switch (relay->sa_un.sa.sa_family) { + case AF_INET: + addr = (char *)&relay->sa_un.sin.sin_addr; + break; +#ifdef HAVE_STRUCT_IN6_ADDR + case AF_INET6: + addr = (char *)&relay->sa_un.sin6.sin6_addr; + break; +#endif + default: + errno = EAFNOSUPPORT; + sudo_warn("connect"); + goto bad; + } + inet_ntop(relay->sa_un.sa.sa_family, addr, + relay_closure->relay_name.ipaddr, + sizeof(relay_closure->relay_name.ipaddr)); + relay_closure->relay_name.name = sudo_rcstr_addref(relay->sa_host); + + if (ret == 0) { + if (relay_closure->sock != -1) { + shutdown(relay_closure->sock, SHUT_RDWR); + close(relay_closure->sock); + } + relay_closure->sock = sock; +#if defined(HAVE_OPENSSL) + /* Relay connection succeeded, start TLS handshake. */ + if (relay_closure->relay_addr->tls) { + if (!connect_relay_tls(closure)) + goto bad; + } else +#endif + { + /* Connection succeeded without blocking. */ + if (!start_relay(sock, closure)) + goto bad; + } + } else { + /* Connection will be completed in connect_cb(). */ + relay_closure->connect_ev = sudo_ev_alloc(sock, SUDO_EV_WRITE, + connect_cb, closure); + if (relay_closure->connect_ev == NULL) + goto bad; + if (sudo_ev_add(closure->evbase, relay_closure->connect_ev, + logsrvd_conf_relay_connect_timeout(), false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + goto bad; + } + if (relay_closure->sock != -1) { + shutdown(relay_closure->sock, SHUT_RDWR); + close(relay_closure->sock); + } + relay_closure->sock = sock; + closure->state = CONNECTING; + } + debug_return_int(ret); + +bad: + /* Connection or system error. */ + if (sock != -1) { + shutdown(sock, SHUT_RDWR); + close(sock); + } + sudo_rcstr_delref(relay_closure->relay_name.name); + relay_closure->relay_name.name = NULL; + sudo_ev_free(relay_closure->connect_ev); + relay_closure->connect_ev = NULL; + debug_return_int(-1); +} + +static void +connect_cb(int sock, int what, void *v) +{ + struct connection_closure *closure = v; + struct relay_closure *relay_closure = closure->relay_closure; + int errnum, optval, ret; + socklen_t optlen = sizeof(optval); + debug_decl(connect_cb, SUDO_DEBUG_UTIL); + + if (what == SUDO_EV_TIMEOUT) { + errnum = ETIMEDOUT; + } else { + ret = getsockopt(sock, SOL_SOCKET, SO_ERROR, &optval, &optlen); + errnum = ret == 0 ? optval : errno; + } + if (errnum == 0) { + closure->state = INITIAL; +#if defined(HAVE_OPENSSL) + /* Relay connection succeeded, start TLS handshake. */ + if (relay_closure->relay_addr->tls) { + if (!connect_relay_tls(closure)) { + closure->errstr = _("TLS handshake with relay host failed"); + if (!schedule_error_message(closure->errstr, closure)) + connection_close(closure); + } + } else +#endif + { + /* Relay connection succeeded, start talking to the client. */ + if (!start_relay(sock, closure)) { + closure->errstr = _("unable to allocate memory"); + if (!schedule_error_message(closure->errstr, closure)) + connection_close(closure); + } + } + } else { + /* Connection failed, try next relay (if any). */ + int res; + sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO, + "unable to connect to relay %s (%s): %s", + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr, + strerror(errnum)); + while ((res = connect_relay_next(closure)) == -1) { + if (errno == ENOENT || errno == EINPROGRESS) { + /* Out of relays or connecting asynchronously. */ + break; + } + } + if (res == -1 && errno != EINPROGRESS) { + closure->errstr = _("unable to connect to relay host"); + if (!schedule_error_message(closure->errstr, closure)) + connection_close(closure); + } + } + + debug_return; +} + +/* Connect to the first available relay host. */ +bool +connect_relay(struct connection_closure *closure) +{ + struct relay_closure *relay_closure; + int res; + debug_decl(connect_relay, SUDO_DEBUG_UTIL); + + relay_closure = closure->relay_closure = relay_closure_alloc(); + if (relay_closure == NULL) + debug_return_bool(false); + + while ((res = connect_relay_next(closure)) == -1) { + if (errno == ENOENT || errno == EINPROGRESS) { + /* Out of relays or connecting asynchronously. */ + break; + } + } + + if (res == -1 && errno != EINPROGRESS) + debug_return_bool(false); + + /* Switch to relay client message handlers. */ + closure->cms = &cms_relay; + debug_return_bool(true); +} + +/* + * Respond to a ServerHello message from the relay. + * Returns true on success, false on error. + */ +static bool +handle_server_hello(ServerHello *msg, struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + debug_decl(handle_server_hello, SUDO_DEBUG_UTIL); + + if (closure->state != INITIAL) { + sudo_warnx(U_("unexpected state %d for %s"), closure->state, + relay_closure->relay_name.ipaddr); + closure->errstr = _("state machine error"); + debug_return_bool(false); + } + + /* Check that ServerHello is valid. */ + if (msg->server_id == NULL || msg->server_id[0] == '\0') { + sudo_warnx(U_("%s: invalid ServerHello, missing server_id"), + relay_closure->relay_name.ipaddr); + closure->errstr = _("invalid ServerHello"); + debug_return_bool(false); + } + + sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, + "relay server %s (%s) ID %s", relay_closure->relay_name.name, + relay_closure->relay_name.ipaddr, msg->server_id); + + /* TODO: handle redirect */ + + debug_return_bool(true); +} + +/* + * Respond to a CommitPoint message from the relay. + * Returns true on success, false on error. + */ +static bool +handle_commit_point(TimeSpec *commit_point, struct connection_closure *closure) +{ + debug_decl(handle_commit_point, SUDO_DEBUG_UTIL); + + if (closure->state < RUNNING) { + sudo_warnx(U_("unexpected state %d for %s"), closure->state, + closure->relay_closure->relay_name.ipaddr); + closure->errstr = _("state machine error"); + debug_return_bool(false); + } + + /* Pass commit point from relay to client. */ + debug_return_bool(schedule_commit_point(commit_point, closure)); +} + +/* + * Respond to a LogId message from the relay. + * Always returns true. + */ +static bool +handle_log_id(char *id, struct connection_closure *closure) +{ + char *new_id; + bool ret = false; + int len; + debug_decl(handle_log_id, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO, + "log ID %s from relay %s (%s)", id, + closure->relay_closure->relay_name.name, + closure->relay_closure->relay_name.ipaddr); + + /* No client connection when replaying a journaled entry. */ + if (closure->write_ev == NULL) + debug_return_bool(true); + + /* Generate a new log ID that includes the relay host. */ + len = asprintf(&new_id, "%s/%s", id, + closure->relay_closure->relay_name.name); + if (len != -1) { + if (fmt_log_id_message(id, closure)) { + if (sudo_ev_add(closure->evbase, closure->write_ev, + logsrvd_conf_relay_timeout(), false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + } else { + ret = true; + } + } + free(new_id); + } + + debug_return_bool(ret); +} + +/* + * Respond to a ServerError message from the relay. + * Always returns false. + */ +static bool +handle_server_error(char *errmsg, struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + debug_decl(handle_server_error, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, + "error message received from relay %s (%s): %s", + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr, + errmsg); + + /* Server will drop connection after the error message. */ + sudo_ev_del(closure->evbase, closure->relay_closure->read_ev); + sudo_ev_del(closure->evbase, closure->relay_closure->write_ev); + + if (!schedule_error_message(errmsg, closure)) + debug_return_bool(false); + + debug_return_bool(true); +} + +/* + * Respond to a ServerAbort message from the server. + * Always returns false. + */ +static bool +handle_server_abort(char *errmsg, struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + debug_decl(handle_server_abort, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, + "abort message received from relay %s (%s): %s", + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr, + errmsg); + + if (!schedule_error_message(errmsg, closure)) + debug_return_bool(false); + + debug_return_bool(true); +} + +/* + * Respond to a ServerMessage from the relay. + * Returns true on success, false on error. + */ +static bool +handle_server_message(uint8_t *buf, size_t len, struct connection_closure *closure) +{ + ServerMessage *msg; + bool ret = false; + debug_decl(handle_server_message, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unpacking ServerMessage", __func__); + msg = server_message__unpack(NULL, len, buf); + if (msg == NULL) { + sudo_warnx(U_("unable to unpack %s size %zu"), "ServerMessage", len); + debug_return_bool(false); + } + + switch (msg->type_case) { + case SERVER_MESSAGE__TYPE_HELLO: + if ((ret = handle_server_hello(msg->u.hello, closure))) { + /* Relay server said hello, start talking to client. */ + ret = start_protocol(closure); + } + break; + case SERVER_MESSAGE__TYPE_COMMIT_POINT: + ret = handle_commit_point(msg->u.commit_point, closure); + break; + case SERVER_MESSAGE__TYPE_LOG_ID: + ret = handle_log_id(msg->u.log_id, closure); + break; + case SERVER_MESSAGE__TYPE_ERROR: + ret = handle_server_error(msg->u.error, closure); + break; + case SERVER_MESSAGE__TYPE_ABORT: + ret = handle_server_abort(msg->u.abort, closure); + break; + default: + sudo_warnx(U_("unexpected type_case value %d in %s from %s"), + msg->type_case, "ServerMessage", + closure->relay_closure->relay_name.ipaddr); + closure->errstr = _("unrecognized ServerMessage type"); + break; + } + + server_message__free_unpacked(msg, NULL); + debug_return_bool(ret); +} + +/* + * Read and unpack a ServerMessage from the relay (read callback). + */ +static void +relay_server_msg_cb(int fd, int what, void *v) +{ + struct connection_closure *closure = v; + struct relay_closure *relay_closure = closure->relay_closure; + struct connection_buffer *buf = &relay_closure->read_buf; + ssize_t nread; + uint32_t msg_len; + debug_decl(relay_server_msg_cb, SUDO_DEBUG_UTIL); + + /* For TLS we may need to read as part of SSL_write(). */ + if (relay_closure->write_instead_of_read) { + relay_closure->write_instead_of_read = false; + relay_client_msg_cb(fd, what, v); + debug_return; + } + + if (what == SUDO_EV_TIMEOUT) { + sudo_warnx(U_("timed out reading from relay %s (%s)"), + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + closure->errstr = _("timeout reading from relay"); + goto send_error; + } + +#if defined(HAVE_OPENSSL) + if (relay_closure->tls_client.ssl != NULL) { + SSL *ssl = relay_closure->tls_client.ssl; + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: ServerMessage from relay %s (%s) [TLS]", __func__, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + nread = SSL_read(ssl, buf->data + buf->len, buf->size - buf->len); + if (nread <= 0) { + const char *errstr; + int err; + + switch (SSL_get_error(ssl, nread)) { + case SSL_ERROR_ZERO_RETURN: + /* ssl connection shutdown cleanly */ + nread = 0; + break; + case SSL_ERROR_WANT_READ: + /* ssl wants to read more, read event is always active */ + sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO, + "SSL_read returns SSL_ERROR_WANT_READ"); + debug_return; + case SSL_ERROR_WANT_WRITE: + /* ssl wants to write, schedule a write if not pending */ + sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO, + "SSL_read returns SSL_ERROR_WANT_WRITE"); + if (!sudo_ev_pending(relay_closure->write_ev, SUDO_EV_WRITE, NULL)) { + /* Enable a temporary write event. */ + if (sudo_ev_add(closure->evbase, relay_closure->write_ev, NULL, false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + closure->errstr = _("unable to allocate memory"); + goto send_error; + } + relay_closure->temporary_write_event = true; + } + /* Redirect write event to finish SSL_read() */ + relay_closure->read_instead_of_write = true; + debug_return; + case SSL_ERROR_SSL: + /* + * For TLS 1.3, if the cert verify function on the server + * returns an error, OpenSSL will send an internal error + * alert when we read ServerHello. Convert to a more useful + * message and hope that no actual internal error occurs. + */ + err = ERR_get_error(); +#if !defined(HAVE_WOLFSSL) + if (closure->state == INITIAL && + ERR_GET_REASON(err) == SSL_R_TLSV1_ALERT_INTERNAL_ERROR) { + errstr = _("relay host name does not match certificate"); + closure->errstr = errstr; + } else +#endif + { + errstr = ERR_reason_error_string(err); + closure->errstr = _("error reading from relay"); + } + sudo_warnx("%s: SSL_read: %s", + relay_closure->relay_name.ipaddr, + errstr ? errstr : strerror(errno)); + goto send_error; + case SSL_ERROR_SYSCALL: + if (nread == 0) { + /* EOF, handled below */ + sudo_warnx(U_("EOF from %s without proper TLS shutdown"), + relay_closure->relay_name.ipaddr); + break; + } + sudo_warn("%s: SSL_read", relay_closure->relay_name.ipaddr); + closure->errstr = _("error reading from relay"); + goto send_error; + default: + errstr = ERR_reason_error_string(ERR_get_error()); + sudo_warnx("%s: SSL_read: %s", + relay_closure->relay_name.ipaddr, + errstr ? errstr : strerror(errno)); + closure->errstr = _("error reading from relay"); + goto send_error; + } + } + } else +#endif + { + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: ServerMessage from relay %s (%s)", __func__, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + nread = read(fd, buf->data + buf->len, buf->size - buf->len); + } + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: received %zd bytes from relay %s (%s)", __func__, nread, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + switch (nread) { + case -1: + if (errno == EAGAIN || errno == EINTR) + debug_return; + sudo_warn("%s: read", relay_closure->relay_name.ipaddr); + closure->errstr = _("unable to read from relay"); + goto send_error; + case 0: + /* EOF from relay server, close the socket. */ + shutdown(relay_closure->sock, SHUT_RDWR); + close(relay_closure->sock); + relay_closure->sock = -1; + sudo_ev_del(closure->evbase, relay_closure->read_ev); + sudo_ev_del(closure->evbase, relay_closure->write_ev); + + if (closure->state != FINISHED) { + sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO, + "premature EOF from %s (%s) [state %d]", + relay_closure->relay_name.name, + relay_closure->relay_name.ipaddr, closure->state); + closure->errstr = _("relay server closed connection"); + goto send_error; + } + if (closure->sock == -1) + connection_close(closure); + debug_return; + default: + break; + } + buf->len += nread; + + while (buf->len - buf->off >= sizeof(msg_len)) { + /* Read wire message size (uint32_t in network byte order). */ + memcpy(&msg_len, buf->data + buf->off, sizeof(msg_len)); + msg_len = ntohl(msg_len); + + if (msg_len > MESSAGE_SIZE_MAX) { + sudo_warnx(U_("server message too large: %zu"), (size_t)msg_len); + closure->errstr = _("server message too large"); + goto send_error; + } + + if (msg_len + sizeof(msg_len) > buf->len - buf->off) { + /* Incomplete message, we'll read the rest next time. */ + if (!expand_buf(buf, msg_len + sizeof(msg_len))) { + closure->errstr = _("unable to allocate memory"); + goto send_error; + } + debug_return; + } + + /* Parse ServerMessage (could be zero bytes). */ + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: parsing ServerMessage, size %u", __func__, msg_len); + buf->off += sizeof(msg_len); + if (!handle_server_message(buf->data + buf->off, msg_len, closure)) + goto send_error; + buf->off += msg_len; + } + buf->len -= buf->off; + buf->off = 0; + debug_return; + +send_error: + /* + * Try to send client an error message before closing connection. + * If we are already in an error state, just give up. + */ + if (!schedule_error_message(closure->errstr, closure)) + goto close_connection; + debug_return; + +close_connection: + connection_close(closure); + debug_return; +} + +/* + * Forward a ClientMessage to the relay (write callback). + */ +static void +relay_client_msg_cb(int fd, int what, void *v) +{ + struct connection_closure *closure = v; + struct relay_closure *relay_closure = closure->relay_closure; + struct connection_buffer *buf; + ssize_t nwritten; + debug_decl(relay_client_msg_cb, SUDO_DEBUG_UTIL); + + /* For TLS we may need to write as part of SSL_read(). */ + if (relay_closure->read_instead_of_write) { + relay_closure->read_instead_of_write = false; + /* Delete write event if it was only due to SSL_read(). */ + if (relay_closure->temporary_write_event) { + relay_closure->temporary_write_event = false; + sudo_ev_del(closure->evbase, relay_closure->write_ev); + } + relay_server_msg_cb(fd, what, v); + debug_return; + } + + if (what == SUDO_EV_TIMEOUT) { + sudo_warnx(U_("timed out writing to relay %s (%s)"), + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + closure->errstr = _("timeout writing to relay"); + goto send_error; + } + + if ((buf = TAILQ_FIRST(&relay_closure->write_bufs)) == NULL) { + sudo_warnx(U_("missing write buffer for client %s"), + relay_closure->relay_name.ipaddr); + goto close_connection; + } + + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: sending %u bytes to server %s (%s)", + __func__, buf->len - buf->off, relay_closure->relay_name.name, + relay_closure->relay_name.ipaddr); + +#if defined(HAVE_OPENSSL) + if (relay_closure->tls_client.ssl != NULL) { + SSL *ssl = relay_closure->tls_client.ssl; + nwritten = SSL_write(ssl, buf->data + buf->off, buf->len - buf->off); + if (nwritten <= 0) { + const char *errstr; + + switch (SSL_get_error(ssl, nwritten)) { + case SSL_ERROR_ZERO_RETURN: + /* ssl connection shutdown cleanly */ + shutdown(relay_closure->sock, SHUT_RDWR); + close(relay_closure->sock); + relay_closure->sock = -1; + sudo_ev_del(closure->evbase, relay_closure->read_ev); + sudo_ev_del(closure->evbase, relay_closure->write_ev); + + if (closure->state != FINISHED) { + sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO, + "premature EOF from %s (state %d)", + relay_closure->relay_name.ipaddr, closure->state); + closure->errstr = _("relay server closed connection"); + goto send_error; + } + debug_return; + case SSL_ERROR_WANT_READ: + /* ssl wants to read, read event always active */ + sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO, + "SSL_write returns SSL_ERROR_WANT_READ"); + /* Redirect read event to finish SSL_write() */ + relay_closure->write_instead_of_read = true; + debug_return; + case SSL_ERROR_WANT_WRITE: + /* ssl wants to write more, write event remains active */ + sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO, + "SSL_write returns SSL_ERROR_WANT_WRITE"); + debug_return; + case SSL_ERROR_SYSCALL: + sudo_warn("%s: SSL_write", + relay_closure->relay_name.ipaddr); + closure->errstr = _("error writing to relay"); + goto send_error; + default: + errstr = ERR_reason_error_string(ERR_get_error()); + sudo_warnx("%s: SSL_write: %s", + relay_closure->relay_name.ipaddr, + errstr ? errstr : strerror(errno)); + closure->errstr = _("error writing to relay"); + goto send_error; + } + } + } else +#endif + { + nwritten = write(fd, buf->data + buf->off, buf->len - buf->off); + if (nwritten == -1) { + if (errno == EAGAIN || errno == EINTR) + debug_return; + sudo_warn("%s: write", relay_closure->relay_name.ipaddr); + closure->errstr = _("error writing to relay"); + goto send_error; + } + } + buf->off += nwritten; + + if (buf->off == buf->len) { + /* sent entire message, move buf to free list */ + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: finished sending %u bytes to server", __func__, buf->len); + buf->off = 0; + buf->len = 0; + TAILQ_REMOVE(&relay_closure->write_bufs, buf, entries); + TAILQ_INSERT_TAIL(&closure->free_bufs, buf, entries); + if (TAILQ_EMPTY(&relay_closure->write_bufs)) + sudo_ev_del(closure->evbase, relay_closure->write_ev); + } + debug_return; + +send_error: + /* + * Try to send client an error message before closing connection. + * If we are already in an error state, just give up. + */ + if (!schedule_error_message(closure->errstr, closure)) + goto close_connection; + debug_return; + +close_connection: + connection_close(closure); + debug_return; +} + +/* Begin the conversation with the relay host. */ +static bool +start_relay(int sock, struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + debug_decl(start_relay, SUDO_DEBUG_UTIL); + + /* No longer need the connect event. */ + sudo_ev_free(relay_closure->connect_ev); + relay_closure->connect_ev = NULL; + + /* Allocate relay read/write events now that we know the socket. */ + relay_closure->read_ev = sudo_ev_alloc(sock, SUDO_EV_READ|SUDO_EV_PERSIST, + relay_server_msg_cb, closure); + relay_closure->write_ev = sudo_ev_alloc(sock, SUDO_EV_WRITE|SUDO_EV_PERSIST, + relay_client_msg_cb, closure); + if (relay_closure->read_ev == NULL || relay_closure->write_ev == NULL) + debug_return_bool(false); + + /* Start communication with the relay server by saying hello. */ + debug_return_bool(fmt_client_hello(closure)); +} + +/* + * Relay an AcceptMessage from the client to the relay server. + */ +static bool +relay_accept(AcceptMessage *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + debug_decl(relay_accept, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying AcceptMessage from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + debug_return_bool(relay_enqueue_write(buf, len, closure)); +} + +/* + * Relay a RejectMessage from the client to the relay server. + */ +static bool +relay_reject(RejectMessage *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + debug_decl(relay_reject, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying RejectMessage from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + debug_return_bool(relay_enqueue_write(buf, len, closure)); +} + +/* + * Relay an ExitMessage from the client to the relay server. + */ +static bool +relay_exit(ExitMessage *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + debug_decl(relay_exit, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying ExitMessage from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + debug_return_bool(relay_enqueue_write(buf, len, closure)); +} + +/* + * Relay a RestartMessage from the client to the relay server. + * We must rebuild the packed message because the log_id is modified. + */ +static bool +relay_restart(RestartMessage *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + struct sudo_event_base *evbase = closure->evbase; + ClientMessage client_msg = CLIENT_MESSAGE__INIT; + RestartMessage restart_msg = *msg; + char *cp; + bool ret; + debug_decl(relay_restart, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying RestartMessage from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + /* + * We prepend "relayhost/" to the log ID before relaying it to + * the client. Perform the reverse operation before passing the + * log ID to the relay host. + */ + if ((cp = strchr(restart_msg.log_id, '/')) != NULL) { + if (cp != restart_msg.log_id) + restart_msg.log_id = cp + 1; + } + + client_msg.u.restart_msg = &restart_msg; + client_msg.type_case = CLIENT_MESSAGE__TYPE_RESTART_MSG; + ret = fmt_client_message(closure, &client_msg); + if (ret) { + if (sudo_ev_add(evbase, relay_closure->write_ev, NULL, false) == -1) { + sudo_warnx("%s", U_("unable to add event to queue")); + ret = false; + } + } + + debug_return_bool(ret); +} + +/* + * Relay an AlertMessage from the client to the relay server. + */ +static bool +relay_alert(AlertMessage *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + bool ret; + debug_decl(relay_alert, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying AlertMessage from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + ret = relay_enqueue_write(buf, len, closure); + + debug_return_bool(ret); +} + +/* + * Relay a CommandSuspend from the client to the relay server. + */ +static bool +relay_suspend(CommandSuspend *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + bool ret; + debug_decl(relay_suspend, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying CommandSuspend from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + ret = relay_enqueue_write(buf, len, closure); + + debug_return_bool(ret); +} + +/* + * Relay a ChangeWindowSize from the client to the relay server. + */ +static bool +relay_winsize(ChangeWindowSize *msg, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + bool ret; + debug_decl(relay_winsize, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying ChangeWindowSize from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + ret = relay_enqueue_write(buf, len, closure); + + debug_return_bool(ret); +} + +/* + * Relay an IoBuffer from the client to the relay server. + */ +static bool +relay_iobuf(int iofd, IoBuffer *iobuf, uint8_t *buf, size_t len, + struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + const char *source = closure->journal_path ? closure->journal_path : + closure->ipaddr; + bool ret; + debug_decl(relay_iobuf, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, + "%s: relaying IoBuffer from %s to %s (%s)", __func__, source, + relay_closure->relay_name.name, relay_closure->relay_name.ipaddr); + + ret = relay_enqueue_write(buf, len, closure); + + debug_return_bool(ret); +} + +/* + * Shutdown relay connection when server is exiting. + */ +bool +relay_shutdown(struct connection_closure *closure) +{ + struct relay_closure *relay_closure = closure->relay_closure; + debug_decl(relay_shutdown, SUDO_DEBUG_UTIL); + + /* Close connection unless relay events are pending. */ + if (!sudo_ev_pending(relay_closure->read_ev, SUDO_EV_READ, NULL) && + !sudo_ev_pending(relay_closure->write_ev, SUDO_EV_WRITE, NULL) && + TAILQ_EMPTY(&relay_closure->write_bufs)) { + connection_close(closure); + } + + debug_return_bool(true); +} + +struct client_message_switch cms_relay = { + relay_accept, + relay_reject, + relay_exit, + relay_restart, + relay_alert, + relay_iobuf, + relay_suspend, + relay_winsize +}; |