src/pop3-login/pop3-proxy.c

	pop3-proxy.c revision d67848ba944a3172c4834c591ddc921fa4ff16b1
/* Copyright (c) 2004-2008 Dovecot authors, see the included COPYING file */

#include "common.h"
#include "ioloop.h"
#include "istream.h"
#include "ostream.h"
#include "base64.h"
#include "safe-memset.h"
#include "str.h"
#include "str-sanitize.h"
#include "client.h"
#include "pop3-proxy.h"

static void proxy_input(struct istream *input, struct ostream *output,
            struct pop3_client *client)
{
    string_t *str;
    const char *line;

    if (input == NULL) {
        if (client->io != NULL) {
            /* remote authentication failed, we're just
               freeing the proxy */
            return;
        }

        if (client->destroyed) {
            /* we came here from client_destroy() */
            return;
        }

        /* failed for some reason, probably server disconnected */
        client_send_line(client,
                 "-ERR [IN-USE] Temporary login failure.");
        client_destroy_success(client, NULL);
        return;
    }

    i_assert(!client->destroyed);

    switch (i_stream_read(input)) {
    case -2:
        /* buffer full */
        client_syslog(&client->common,
                  "proxy: Remote input buffer full");
        client_destroy_internal_failure(client);
        return;
    case -1:
        /* disconnected */
        client_destroy_success(client, "Proxy: Remote disconnected");
        return;
    }

    line = i_stream_next_line(input);
    if (line == NULL)
        return;

    switch (client->proxy_state) {
    case 0:
        /* this is a banner */
        if (strncmp(line, "+OK", 3) != 0) {
            client_syslog(&client->common, t_strdup_printf(
                "proxy: Remote returned invalid banner: %s",
                str_sanitize(line, 160)));
            client_destroy_internal_failure(client);
            return;
        }

        /* send USER command */
        str = t_str_new(128);
        str_append(str, "USER ");
        str_append(str, client->proxy_user);
        str_append(str, "\r\n");
        (void)o_stream_send(output, str_data(str), str_len(str));

        client->proxy_state++;
        return;
    case 1:
        if (strncmp(line, "+OK", 3) != 0)
            break;

        /* USER successful, send PASS */
        str = t_str_new(128);
        str_append(str, "PASS ");
        str_append(str, client->proxy_password);
        str_append(str, "\r\n");
        (void)o_stream_send(output, str_data(str),
                    str_len(str));

        safe_memset(client->proxy_password, 0,
                strlen(client->proxy_password));
        i_free(client->proxy_password);
        client->proxy_password = NULL;

        client->proxy_state++;
        return;
    case 2:
        if (strncmp(line, "+OK", 3) != 0)
            break;

        /* Login successful. Send this line to client. */
        line = t_strconcat(line, "\r\n", NULL);
        (void)o_stream_send_str(client->output, line);

        str = t_str_new(128);
        str_printfa(str, "proxy(%s): started proxying to %s:%u",
                client->common.virtual_user,
                login_proxy_get_host(client->proxy),
                login_proxy_get_port(client->proxy));
        if (strcmp(client->common.virtual_user,
               client->proxy_user) != 0) {
            /* remote username is different, log it */
            str_append_c(str, '/');
            str_append(str, client->proxy_user);
        }

        login_proxy_detach(client->proxy, client->common.input,
                   client->output);

        client->proxy = NULL;
        client->common.input = NULL;
        client->output = NULL;
        client->common.fd = -1;
        client_destroy_success(client, str_c(str));
        return;
    }

    /* Login failed. Pass through the error message to client
       (see imap-proxy code for potential problems with this) */
    if (strncmp(line, "-ERR ", 5) != 0)
        client_send_line(client, "-ERR "AUTH_FAILED_MSG);
    else
        client_send_line(client, line);

    /* allow client input again */
    i_assert(client->io == NULL);
    client->io = io_add(client->common.fd, IO_READ,
                client_input, client);

    login_proxy_free(client->proxy);
    client->proxy = NULL;

    if (client->proxy_password != NULL) {
        safe_memset(client->proxy_password, 0,
                strlen(client->proxy_password));
        i_free(client->proxy_password);
        client->proxy_password = NULL;
    }

    i_free(client->proxy_user);
    client->proxy_user = NULL;
}

int pop3_proxy_new(struct pop3_client *client, const char *host,
           unsigned int port, const char *user, const char *password)
{
    i_assert(user != NULL);
    i_assert(!client->destroyed);

    if (password == NULL) {
        client_syslog(&client->common, "proxy: password not given");
        return -1;
    }

    i_assert(client->refcount > 1);
    connection_queue_add(1);

    if (client->destroyed) {
        /* connection_queue_add() decided that we were the oldest
           connection and killed us. */
        return -1;
    }

    client->proxy = login_proxy_new(&client->common, host, port,
                    proxy_input, client);
    if (client->proxy == NULL)
        return -1;

    client->proxy_state = 0;
    client->proxy_user = i_strdup(user);
    client->proxy_password = i_strdup(password);

    /* disable input until authentication is finished */
    if (client->io != NULL)
        io_remove(&client->io);
    return 0;
}