src/pop3-login/client.c

	client.c revision 46ec792dd4ccf6c34706c4774228301fafde6aa9
/* Copyright (c) 2002-2009 Dovecot authors, see the included COPYING file */

#include "common.h"
#include "base64.h"
#include "buffer.h"
#include "ioloop.h"
#include "istream.h"
#include "ostream.h"
#include "randgen.h"
#include "safe-memset.h"
#include "str.h"
#include "strescape.h"
#include "client.h"
#include "client-authenticate.h"
#include "auth-client.h"
#include "ssl-proxy.h"
#include "pop3-proxy.h"
#include "hostpid.h"

/* Disconnect client when it sends too many bad commands */
#define CLIENT_MAX_BAD_COMMANDS 10

const char *login_protocol = "pop3";
const char *login_process_name = "pop3-login";
unsigned int login_default_port = 110;

static bool cmd_stls(struct pop3_client *client)
{
    client_cmd_starttls(&client->common);
    return TRUE;
}

static bool cmd_quit(struct pop3_client *client)
{
    client_send_line(&client->common, CLIENT_CMD_REPLY_OK, "Logging out");
    client_destroy(&client->common, "Aborted login");
    return TRUE;
}

static bool client_command_execute(struct pop3_client *client, const char *cmd,
                   const char *args)
{
    cmd = t_str_ucase(cmd);
    if (strcmp(cmd, "CAPA") == 0)
        return cmd_capa(client, args);
    if (strcmp(cmd, "USER") == 0)
        return cmd_user(client, args);
    if (strcmp(cmd, "PASS") == 0)
        return cmd_pass(client, args);
    if (strcmp(cmd, "AUTH") == 0)
        return cmd_auth(client, args);
    if (strcmp(cmd, "APOP") == 0)
        return cmd_apop(client, args);
    if (strcmp(cmd, "STLS") == 0)
        return cmd_stls(client);
    if (strcmp(cmd, "QUIT") == 0)
        return cmd_quit(client);

    client_send_line(&client->common, CLIENT_CMD_REPLY_BAD,
             "Unknown command.");
    return FALSE;
}

static void pop3_client_input(struct client *client)
{
    struct pop3_client *pop3_client = (struct pop3_client *)client;
    char *line, *args;

    i_assert(!client->authenticating);

    if (!client_read(client))
        return;

    client_ref(client);

    o_stream_cork(client->output);
    /* if a command starts an authentication, stop processing further
       commands until the authentication is finished. */
    while (!client->output->closed && !client->authenticating &&
           (line = i_stream_next_line(client->input)) != NULL) {
        args = strchr(line, ' ');
        if (args != NULL)
            *args++ = '\0';

        if (client_command_execute(pop3_client, line,
                       args != NULL ? args : ""))
            client->bad_counter = 0;
        else if (++client->bad_counter > CLIENT_MAX_BAD_COMMANDS) {
            client_send_line(client, CLIENT_CMD_REPLY_BYE,
                "Too many invalid bad commands.");
            client_destroy(client,
                       "Disconnected: Too many bad commands");
        }
    }

    if (client_unref(client))
        o_stream_uncork(client->output);
}

static struct client *pop3_client_alloc(pool_t pool)
{
    struct pop3_client *pop3_client;

    pop3_client = p_new(pool, struct pop3_client, 1);
    return &pop3_client->common;
}

static void pop3_client_create(struct client *client ATTR_UNUSED)
{
}

static void pop3_client_destroy(struct client *client)
{
    struct pop3_client *pop3_client = (struct pop3_client *)client;

    i_free_and_null(pop3_client->last_user);
    i_free_and_null(pop3_client->apop_challenge);
}

static char *get_apop_challenge(struct pop3_client *client)
{
    struct auth_connect_id *id = &client->auth_id;
    unsigned char buffer[16];
        buffer_t *buf;

    if (!auth_client_reserve_connection(auth_client, "APOP", id))
        return NULL;

    random_fill(buffer, sizeof(buffer));
    buf = buffer_create_static_hard(pool_datastack_create(),
            MAX_BASE64_ENCODED_SIZE(sizeof(buffer)) + 1);
    base64_encode(buffer, sizeof(buffer), buf);
    buffer_append_c(buf, '\0');

    return i_strdup_printf("<%x.%x.%lx.%s@%s>",
                   id->server_pid, id->connect_uid,
                   (unsigned long)ioloop_time,
                   (const char *)buf->data, my_hostname);
}

static void pop3_client_send_greeting(struct client *client)
{
    struct pop3_client *pop3_client = (struct pop3_client *)client;

    client->io = io_add(client->fd, IO_READ, client_input, client);

    pop3_client->apop_challenge = get_apop_challenge(pop3_client);
    if (pop3_client->apop_challenge == NULL) {
        client_send_line(client, CLIENT_CMD_REPLY_OK,
                 client->set->login_greeting);
    } else {
        client_send_line(client, CLIENT_CMD_REPLY_OK,
            t_strconcat(client->set->login_greeting, " ",
                    pop3_client->apop_challenge, NULL));
    }
    client->greeting_sent = TRUE;
}

static void pop3_client_starttls(struct client *client ATTR_UNUSED)
{
}

static void
pop3_client_send_line(struct client *client, enum client_cmd_reply reply,
              const char *text)
{
    const char *prefix = "-ERR";

    switch (reply) {
    case CLIENT_CMD_REPLY_OK:
        prefix = "+OK";
        break;
    case CLIENT_CMD_REPLY_AUTH_FAIL_TEMP:
        prefix = "-ERR [IN-USE]";
        break;
    case CLIENT_CMD_REPLY_AUTH_FAILED:
    case CLIENT_CMD_REPLY_AUTHZ_FAILED:
    case CLIENT_CMD_REPLY_AUTH_FAIL_REASON:
    case CLIENT_CMD_REPLY_AUTH_FAIL_NOSSL:
    case CLIENT_CMD_REPLY_BAD:
    case CLIENT_CMD_REPLY_BYE:
        break;
    case CLIENT_CMD_REPLY_STATUS:
    case CLIENT_CMD_REPLY_STATUS_BAD:
        /* can't send status notifications */
        return;
    }

    T_BEGIN {
        string_t *line = t_str_new(256);

        str_append(line, prefix);
        str_append_c(line, ' ');
        str_append(line, text);
        str_append(line, "\r\n");

        client_send_raw_data(client, str_data(line),
                     str_len(line));
    } T_END;
}


void clients_init(void)
{
    /* Nothing to initialize for POP3 */
}

void clients_deinit(void)
{
    clients_destroy_all();
}

struct client_vfuncs client_vfuncs = {
    pop3_client_alloc,
    pop3_client_create,
    pop3_client_destroy,
    pop3_client_send_greeting,
    pop3_client_starttls,
    pop3_client_input,
    pop3_client_send_line,
    pop3_client_auth_handle_reply,
    NULL,
    NULL,
    pop3_proxy_reset,
    pop3_proxy_parse_line
};