src/imap-login/imap-proxy.c

	imap-proxy.c revision 45155bb1250cf5a120278f349465aded513a100f
/* Copyright (c) 2004-2008 Dovecot authors, see the included COPYING file */

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

static int proxy_input_line(struct imap_client *client,
                struct ostream *output, const char *line)
{
    string_t *str;
    const char *msg;

    i_assert(!client->destroyed);

    if (!client->proxy_login_sent) {
        /* this is a banner */
        if (strncmp(line, "* OK ", 5) != 0) {
            client_syslog(&client->common, t_strdup_printf(
                "proxy: Remote returned invalid banner: %s",
                str_sanitize(line, 160)));
            client_destroy_internal_failure(client);
            return -1;
        }

        /* send LOGIN command */
        str = t_str_new(128);
        str_append(str, "P LOGIN ");
        imap_quote_append_string(str, client->proxy_user, FALSE);
        str_append_c(str, ' ');
        imap_quote_append_string(str, client->proxy_password, FALSE);
        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_login_sent = TRUE;
        return 0;
    } else if (strncmp(line, "P OK ", 5) == 0) {
        /* Login successful. Send this line to client. */
        (void)o_stream_send_str(client->output, client->cmd_tag);
        (void)o_stream_send_str(client->output, line + 1);
        (void)o_stream_send(client->output, "\r\n", 2);

        msg = t_strdup_printf("proxy(%s): started proxying to %s:%u",
                      client->common.virtual_user,
                      login_proxy_get_host(client->proxy),
                      login_proxy_get_port(client->proxy));

        (void)client_skip_line(client);
        login_proxy_detach(client->proxy, client->input,
                   client->output);

        client->proxy = NULL;
        client->input = NULL;
        client->output = NULL;
        client->common.fd = -1;
        client_destroy(client, msg);
        return -1;
    } else if (strncmp(line, "P ", 2) == 0) {
        /* Login failed. Send our own failure reply so client can't
           figure out if user exists or not just by looking at the
           reply string. */
        client_send_tagline(client, "NO "AUTH_FAILED_MSG);

        /* 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;

        i_free(client->proxy_user);
        client->proxy_user = NULL;
        return -1;
    } else {
        /* probably some untagged reply */
        return 0;
    }
}

static void proxy_input(struct istream *input, struct ostream *output,
            struct imap_client *client)
{
    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, "* BYE Temporary login failure.");
        client_destroy(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(client, "Proxy: Remote disconnected");
        return;
    }

    while ((line = i_stream_next_line(input)) != NULL) {
        if (proxy_input_line(client, output, line) < 0)
            break;
    }
}

int imap_proxy_new(struct imap_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_login_sent = FALSE;
    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;
}