src/pop3-login/pop3-proxy.c

	pop3-proxy.c revision ad9da7356677de3b1176bbed0ec8a04e7a33ea03
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik/* Copyright (c) 2004-2012 Dovecot authors, see the included COPYING file */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "login-common.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "ioloop.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "istream.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "ostream.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "base64.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "safe-memset.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "str.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "str-sanitize.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "client.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik#include "pop3-proxy.h"
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnikstatic void proxy_free_password(struct client *client)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik{
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    if (client->proxy_password == NULL)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        return;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    safe_memset(client->proxy_password, 0, strlen(client->proxy_password));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    i_free_and_null(client->proxy_password);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik}
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnikstatic void get_plain_auth(struct client *client, string_t *dest)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik{
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    string_t *str;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str = t_str_new(128);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str_append(str, client->proxy_user);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str_append_c(str, '\0');
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str_append(str, client->proxy_master_user);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str_append_c(str, '\0');
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str_append(str, client->proxy_password);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    base64_encode(str_data(str), str_len(str), dest);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik}
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnikstatic void proxy_send_login(struct pop3_client *client, struct ostream *output)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik{
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    string_t *str;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    if (client->proxy_xclient) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* remote supports XCLIENT, send it */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        (void)o_stream_send_str(output, t_strdup_printf(
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            "XCLIENT ADDR=%s PORT=%u\r\n",
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            net_ip2addr(&client->common.ip),
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client->common.remote_port));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    str = t_str_new(128);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    if (client->common.proxy_master_user == NULL) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* send USER command */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        str_append(str, "USER ");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        str_append(str, client->common.proxy_user);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        str_append(str, "\r\n");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    } else {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* master user login - use AUTH PLAIN. */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        str_append(str, "AUTH PLAIN\r\n");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    (void)o_stream_send(output, str_data(str), str_len(str));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    client->common.proxy_state = POP3_PROXY_LOGIN1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik}
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnikint pop3_proxy_parse_line(struct client *client, const char *line)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik{
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    struct pop3_client *pop3_client = (struct pop3_client *)client;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    struct ostream *output;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    enum login_proxy_ssl_flags ssl_flags;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    string_t *str;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    i_assert(!client->destroyed);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    output = login_proxy_get_ostream(client->login_proxy);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    switch (client->proxy_state) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    case POP3_PROXY_BANNER:
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* this is a banner */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (strncmp(line, "+OK", 3) != 0) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client_log_err(client, t_strdup_printf(
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                "proxy: Remote returned invalid banner: %s",
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                str_sanitize(line, 160)));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client_proxy_failed(client, TRUE);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            return -1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        pop3_client->proxy_xclient =
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            strncmp(line+3, " [XCLIENT]", 10) == 0;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        ssl_flags = login_proxy_get_ssl_flags(client->login_proxy);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if ((ssl_flags & PROXY_SSL_FLAG_STARTTLS) == 0) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            proxy_send_login(pop3_client, output);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        } else {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            (void)o_stream_send_str(output, "STLS\r\n");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client->proxy_state = POP3_PROXY_STARTTLS;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        return 0;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    case POP3_PROXY_STARTTLS:
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (strncmp(line, "+OK", 3) != 0) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client_log_err(client, t_strdup_printf(
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                "proxy: Remote STLS failed: %s",
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                str_sanitize(line, 160)));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client_proxy_failed(client, TRUE);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            return -1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (login_proxy_starttls(client->login_proxy) < 0) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            client_proxy_failed(client, TRUE);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            return -1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* i/ostreams changed. */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        output = login_proxy_get_ostream(client->login_proxy);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        proxy_send_login(pop3_client, output);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        return 1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    case POP3_PROXY_LOGIN1:
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        str = t_str_new(128);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (client->proxy_master_user == NULL) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            if (strncmp(line, "+OK", 3) != 0)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                break;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            /* USER successful, send PASS */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            str_append(str, "PASS ");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            str_append(str, client->proxy_password);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            str_append(str, "\r\n");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        } else {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            if (*line != '+')
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                break;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            /* AUTH successful, send the authentication data */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            get_plain_auth(client, str);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            str_append(str, "\r\n");
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        (void)o_stream_send(output, str_data(str), str_len(str));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        proxy_free_password(client);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        client->proxy_state = POP3_PROXY_LOGIN2;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        return 0;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    case POP3_PROXY_LOGIN2:
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (strncmp(line, "+OK", 3) != 0)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            break;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        /* Login successful. Send this line to client. */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        line = t_strconcat(line, "\r\n", NULL);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        (void)o_stream_send_str(client->output, line);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        client_proxy_finish_destroy_client(client);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        return 1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    /* Login failed. Pass through the error message to client.
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       If the backend server isn't Dovecot, the error message may
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       be different from Dovecot's "user doesn't exist" error. This
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       would allow an attacker to find out what users exist in the
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       system.
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       The optimal way to handle this would be to replace the
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       backend's "password failed" error message with Dovecot's
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       AUTH_FAILED_MSG, but this would require a new setting and
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       the sysadmin to actually bother setting it properly.
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       So for now we'll just forward the error message. This
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       shouldn't be a real problem since of course everyone will
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik       be using only Dovecot as their backend :) */
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    if (strncmp(line, "-ERR ", 5) != 0) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        client_send_line(client, CLIENT_CMD_REPLY_AUTH_FAILED,
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik                 AUTH_FAILED_MSG);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    } else {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        client_send_raw(client, t_strconcat(line, "\r\n", NULL));
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    if (client->set->auth_verbose) {
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        if (strncmp(line, "-ERR ", 5) == 0)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik            line += 5;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik        client_proxy_log_failure(client, line);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    }
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    client->proxy_auth_failed = TRUE;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    client_proxy_failed(client, FALSE);
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    return -1;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik}
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnikvoid pop3_proxy_reset(struct client *client)
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik{
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik    client->proxy_state = POP3_PROXY_BANNER;
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik}
49a5412cbc98e630de17359c29cb8d6ce0e16168Lukas Slebodnik