src/submission/main.c

/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "submission-common.h"
#include "buffer.h"
#include "str.h"
#include "istream.h"
#include "ostream.h"
#include "array.h"
#include "base64.h"
#include "hostpid.h"
#include "path-util.h"
#include "process-title.h"
#include "restrict-access.h"
#include "fd-util.h"
#include "master-service.h"
#include "master-login.h"
#include "master-service-settings.h"
#include "master-interface.h"
#include "var-expand.h"
#include "mail-error.h"
#include "mail-user.h"
#include "mail-storage-service.h"
#include "smtp-server.h"
#include "smtp-client.h"

#include "submission-commands.h"

#include <stdio.h>
#include <unistd.h>

#define LMTP_MASTER_FIRST_LISTEN_FD 3

#define IS_STANDALONE() \
        (getenv(MASTER_IS_PARENT_ENV) == NULL)

struct smtp_server *smtp_server = NULL;
struct smtp_client *smtp_client = NULL;

static bool verbose_proctitle = FALSE;
static struct mail_storage_service_ctx *storage_service;
static struct master_login *master_login = NULL;

submission_client_created_func_t *hook_client_created = NULL;
bool submission_debug = FALSE;

submission_client_created_func_t *
submission_client_created_hook_set(submission_client_created_func_t *new_hook)
{
    submission_client_created_func_t *old_hook = hook_client_created;

    hook_client_created = new_hook;
    return old_hook;
}

void submission_refresh_proctitle(void)
{
    struct client *client;
    string_t *title = t_str_new(128);

    if (!verbose_proctitle)
        return;

    str_append_c(title, '[');
    switch (submission_client_count) {
    case 0:
        str_append(title, "idling");
        break;
    case 1:
        client = submission_clients;
        str_append(title, client->user->username);
        if (client->user->conn.remote_ip != NULL) {
            str_append_c(title, ' ');
            str_append(title,
                   net_ip2addr(client->user->conn.remote_ip));
        }
        str_append_c(title, ' ');
        str_append(title, client_state_get_name(client));
        break;
    default:
        str_printfa(title, "%u connections", submission_client_count);
        break;
    }
    str_append_c(title, ']');
    process_title_set(str_c(title));
}

static void submission_die(void)
{
    /* do nothing. submission connections typically die pretty quick anyway.
     */
}

static void
send_error(int fd_out, const char *hostname, const char *error_code,
       const char *error_msg)
{
    const char *msg;

    msg = t_strdup_printf("451 %s %s\r\n"
        "421 4.3.2 %s Shutting down due to fatal error\r\n",
        error_code, error_msg, hostname);
    if (write(fd_out, msg, strlen(msg)) < 0) {
        if (errno != EAGAIN && errno != EPIPE)
            i_error("write(client) failed: %m");
    }
}

static int
client_create_from_input(const struct mail_storage_service_input *input,
             int fd_in, int fd_out, const buffer_t *input_buf,
             const char **error_r)
{
    struct mail_storage_service_user *user;
    struct mail_user *mail_user;
    const struct submission_settings *set;
    const char *helo = NULL;
    const unsigned char *data;
    size_t data_len;

    if (mail_storage_service_lookup_next(storage_service, input,
                         &user, &mail_user, error_r) <= 0) {
        send_error(fd_out, my_hostname,
            "4.7.0", MAIL_ERRSTR_CRITICAL_MSG);
        return -1;
    }
    restrict_access_allow_coredumps(TRUE);

    set = mail_storage_service_user_get_set(user)[1];

    if (set->submission_relay_host == NULL ||
        *set->submission_relay_host == '\0') {
        *error_r = "No relay host configured for submission proxy "
            "(submission_relay_host is unset)";
        send_error(fd_out, set->hostname,
            "4.3.5", MAIL_ERRSTR_CRITICAL_MSG);
        mail_user_unref(&mail_user);
        mail_storage_service_user_unref(&user);
        return -1;
    }
    if (set->verbose_proctitle)
        verbose_proctitle = TRUE;

    /* parse input data */
    data = NULL;
    data_len = 0;
    if (input_buf != NULL && input_buf->used > 0) {
        size_t len = input_buf->used, helo_len = 0;

        data = input_buf->data;

        if (len > 0) {
            if (*data == '\0') {
                helo_len = 1;
            } else {
                helo = t_strndup(data, len);
                helo_len = strlen(helo) + 1;
            }
        }

        /* NOTE: actually, pipelining the AUTH command is stricly
                 speaking not allowed, but we support it anyway.
         */
        if (len > helo_len) {
            data = data + helo_len;
            data_len = len - helo_len;
        }
    }

    (void)client_create(fd_in, fd_out, input->session_id, mail_user,
                user, set, helo, data, data_len);
    return 0;
}

static void main_stdio_run(const char *username)
{
    struct mail_storage_service_input input;
    buffer_t *input_buf;
    const char *value, *error, *input_base64;

    i_zero(&input);
    input.module = input.service = "submission";
    input.username = username != NULL ? username : getenv("USER");
    if (input.username == NULL && IS_STANDALONE())
        input.username = getlogin();
    if (input.username == NULL)
        i_fatal("USER environment missing");
    if ((value = getenv("IP")) != NULL)
        (void)net_addr2ip(value, &input.remote_ip);
    if ((value = getenv("LOCAL_IP")) != NULL)
        (void)net_addr2ip(value, &input.local_ip);

    input_base64 = getenv("CLIENT_INPUT");
    input_buf = input_base64 == NULL ? NULL :
        t_base64_decode_str(input_base64);

    if (client_create_from_input(&input, STDIN_FILENO, STDOUT_FILENO,
                     input_buf, &error) < 0)
        i_fatal("%s", error);
}

static void
login_client_connected(const struct master_login_client *login_client,
               const char *username, const char *const *extra_fields)
{
    struct mail_storage_service_input input;
    enum mail_auth_request_flags flags = login_client->auth_req.flags;
    const char *error;
    buffer_t input_buf;

    i_zero(&input);
    input.module = input.service = "submission";
    input.local_ip = login_client->auth_req.local_ip;
    input.remote_ip = login_client->auth_req.remote_ip;
    input.local_port = login_client->auth_req.local_port;
    input.remote_port = login_client->auth_req.remote_port;
    input.username = username;
    input.userdb_fields = extra_fields;
    input.session_id = login_client->session_id;
    if ((flags & MAIL_AUTH_REQUEST_FLAG_CONN_SECURED) != 0)
        input.conn_secured = TRUE;
    if ((flags & MAIL_AUTH_REQUEST_FLAG_CONN_SSL_SECURED) != 0)
        input.conn_ssl_secured = TRUE;

    buffer_create_from_const_data(&input_buf, login_client->data,
                      login_client->auth_req.data_size);
    if (client_create_from_input(&input, login_client->fd, login_client->fd,
                     &input_buf, &error) < 0) {
        int fd = login_client->fd;
        i_error("%s", error);
        i_close_fd(&fd);
        master_service_client_connection_destroyed(master_service);
    }
}

static void login_client_failed(const struct master_login_client *client,
                const char *errormsg)
{
    const char *msg;

    msg = t_strdup_printf("451 4.7.0 %s\r\n"
        "421 4.3.2 %s Shutting down due to fatal error\r\n",
        errormsg, my_hostname);
    if (write(client->fd, msg, strlen(msg)) < 0) {
        /* ignored */
    }
}

static void client_connected(struct master_service_connection *conn)
{
    /* when running standalone, we shouldn't even get here */
    i_assert(master_login != NULL);

    master_service_client_connection_accept(conn);
    master_login_add(master_login, conn->fd);
}

int main(int argc, char *argv[])
{
    static const struct setting_parser_info *set_roots[] = {
        &submission_setting_parser_info,
        NULL
    };
    struct master_login_settings login_set;
    enum master_service_flags service_flags = 0;
    enum mail_storage_service_flags storage_service_flags = 0;
    struct smtp_server_settings smtp_server_set;
    struct smtp_client_settings smtp_client_set;
    const char *username = NULL, *auth_socket_path = "auth-master";
    const char *error;
    int c;

    i_zero(&login_set);
    login_set.postlogin_timeout_secs = MASTER_POSTLOGIN_TIMEOUT_DEFAULT;
    login_set.request_auth_token = TRUE;

    if (IS_STANDALONE() && getuid() == 0 &&
        net_getpeername(1, NULL, NULL) == 0) {
        printf("421 5.3.5 The submission binary must not be started "
               "from inetd, use submission-login instead.\r\n");
        return 1;
    }

    if (IS_STANDALONE()) {
        service_flags |= MASTER_SERVICE_FLAG_STANDALONE |
            MASTER_SERVICE_FLAG_STD_CLIENT;
    } else {
        service_flags |= MASTER_SERVICE_FLAG_KEEP_CONFIG_OPEN;
    }

    master_service = master_service_init("submission", service_flags,
                         &argc, &argv, "a:Dt:u:");
    while ((c = master_getopt(master_service)) > 0) {
        switch (c) {
        case 'a':
            auth_socket_path = optarg;
            break;
        case 't':
            if (str_to_uint(optarg,
                    &login_set.postlogin_timeout_secs) < 0 ||
                login_set.postlogin_timeout_secs == 0)
                i_fatal("Invalid -t parameter: %s", optarg);
            break;
        case 'u':
            storage_service_flags |=
                MAIL_STORAGE_SERVICE_FLAG_USERDB_LOOKUP;
            username = optarg;
            break;
        case 'D':
            submission_debug = TRUE;
            break;
        default:
            return FATAL_DEFAULT;
        }
    }

    if (t_abspath(auth_socket_path, &login_set.auth_socket_path,
              &error) < 0) {
        i_fatal("t_abspath(%s) failed: %s", auth_socket_path,
            error);
    }
    if (argv[optind] != NULL) {
        if (t_abspath(argv[optind],
                  &login_set.postlogin_socket_path, &error) < 0) {
            i_fatal("t_abspath(%s) failed: %s",
                argv[optind], error);
        }
    }
    login_set.callback = login_client_connected;
    login_set.failure_callback = login_client_failed;

    master_service_init_finish(master_service);
    master_service_set_die_callback(master_service, submission_die);

    storage_service =
        mail_storage_service_init(master_service,
                      set_roots, storage_service_flags);

    /* initialize SMTP server */
    i_zero(&smtp_server_set);
    smtp_server_set.capabilities = SMTP_CAPABILITY_DSN;
    smtp_server_set.protocol = SMTP_PROTOCOL_SMTP;
    smtp_server_set.max_pipelined_commands = 5;
    smtp_server_set.debug = submission_debug;
    smtp_server = smtp_server_init(&smtp_server_set);
    smtp_server_command_register(smtp_server, "BURL", cmd_burl, 0);

    /* initialize SMTP client */
    i_zero(&smtp_client_set);
    smtp_client_set.my_hostname = my_hostdomain();
    smtp_client_set.debug = submission_debug;
    smtp_client = smtp_client_init(&smtp_client_set);

    /* fake that we're running, so we know if client was destroyed
       while handling its initial input */
    io_loop_set_running(current_ioloop);

    if (IS_STANDALONE()) {
        T_BEGIN {
            main_stdio_run(username);
        } T_END;
    } else {
        master_login = master_login_init(master_service, &login_set);
        io_loop_set_running(current_ioloop);
    }

    if (io_loop_is_running(current_ioloop))
        master_service_run(master_service, client_connected);
    clients_destroy_all();

    smtp_client_deinit(&smtp_client);
    smtp_server_deinit(&smtp_server);

    if (master_login != NULL)
        master_login_deinit(&master_login);
    mail_storage_service_deinit(&storage_service);
    master_service_deinit(&master_service);
    return 0;
}