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/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
#include "login-common.h"
#include "buffer.h"
#include "ioloop.h"
#include "istream.h"
#include "ostream.h"
#include "safe-memset.h"
#include "str.h"
#include "imap-parser.h"
#include "imap-id.h"
#include "imap-resp-code.h"
#include "master-service.h"
#include "master-service-ssl-settings.h"
#include "master-auth.h"
#include "imap-login-client.h"
#include "client-authenticate.h"
#include "auth-client.h"
#include "imap-proxy.h"
#include "imap-quote.h"
#include "imap-login-commands.h"
#include "imap-login-settings.h"
#if LOGIN_MAX_INBUF_SIZE < 1024+2
# error LOGIN_MAX_INBUF_SIZE too short to fit all ID command parameters
#endif
/* Disconnect client when it sends too many bad commands */
#define CLIENT_MAX_BAD_COMMANDS 3
/* Skip incoming data until newline is found,
returns TRUE if newline was found. */
bool client_skip_line(struct imap_client *client)
{
const unsigned char *data;
size_t i, data_size;
data = i_stream_get_data(client->common.input, &data_size);
for (i = 0; i < data_size; i++) {
if (data[i] == '\n') {
i_stream_skip(client->common.input, i+1);
return TRUE;
}
}
return FALSE;
}
bool client_handle_parser_error(struct imap_client *client,
struct imap_parser *parser)
{
const char *msg;
enum imap_parser_error parse_error;
msg = imap_parser_get_error(parser, &parse_error);
switch (parse_error) {
case IMAP_PARSE_ERROR_NONE:
i_unreached();
case IMAP_PARSE_ERROR_LITERAL_TOO_BIG:
client_send_reply(&client->common,
IMAP_CMD_REPLY_BYE, msg);
client_destroy(&client->common, msg);
return FALSE;
default:
break;
}
client_send_reply(&client->common, IMAP_CMD_REPLY_BAD, msg);
client->cmd_finished = TRUE;
client->skip_line = TRUE;
return TRUE;
}
static bool is_login_cmd_disabled(struct client *client)
{
if (client->secured) {
if (sasl_server_find_available_mech(client, "PLAIN") == NULL) {
/* no PLAIN authentication, can't use LOGIN command */
return TRUE;
}
return FALSE;
}
if (client->set->disable_plaintext_auth)
return TRUE;
if (strcmp(client->ssl_set->ssl, "required") == 0)
return TRUE;
return FALSE;
}
static const char *get_capability(struct client *client)
{
struct imap_client *imap_client = (struct imap_client *)client;
string_t *cap_str = t_str_new(256);
bool explicit_capability = FALSE;
if (*imap_client->set->imap_capability == '\0')
str_append(cap_str, CAPABILITY_BANNER_STRING);
else if (*imap_client->set->imap_capability != '+') {
explicit_capability = TRUE;
str_append(cap_str, imap_client->set->imap_capability);
} else {
str_append(cap_str, CAPABILITY_BANNER_STRING);
str_append_c(cap_str, ' ');
str_append(cap_str, imap_client->set->imap_capability + 1);
}
if (!explicit_capability) {
if (imap_client->set->imap_literal_minus)
str_append(cap_str, " LITERAL-");
else
str_append(cap_str, " LITERAL+");
}
if (client_is_tls_enabled(client) && !client->tls)
str_append(cap_str, " STARTTLS");
if (is_login_cmd_disabled(client))
str_append(cap_str, " LOGINDISABLED");
client_authenticate_get_capabilities(client, cap_str);
return str_c(cap_str);
}
static int cmd_capability(struct imap_client *imap_client,
const struct imap_arg *args ATTR_UNUSED)
{
struct client *client = &imap_client->common;
/* Client is required to send CAPABILITY after STARTTLS, so the
capability resp-code workaround checks only pre-STARTTLS
CAPABILITY commands. */
if (!client->starttls)
imap_client->client_ignores_capability_resp_code = TRUE;
client_send_raw(client, t_strconcat(
"* CAPABILITY ", get_capability(client), "\r\n", NULL));
client_send_reply(client, IMAP_CMD_REPLY_OK,
"Pre-login capabilities listed, post-login capabilities have more.");
return 1;
}
static int cmd_starttls(struct imap_client *client,
const struct imap_arg *args ATTR_UNUSED)
{
client_cmd_starttls(&client->common);
return 1;
}
static void
imap_client_notify_starttls(struct client *client,
bool success, const char *text)
{
if (success)
client_send_reply(client, IMAP_CMD_REPLY_OK, text);
else
client_send_reply(client, IMAP_CMD_REPLY_BAD, text);
}
static int cmd_noop(struct imap_client *client,
const struct imap_arg *args ATTR_UNUSED)
{
client_send_reply(&client->common, IMAP_CMD_REPLY_OK,
"NOOP completed.");
return 1;
}
static int cmd_logout(struct imap_client *client,
const struct imap_arg *args ATTR_UNUSED)
{
client_send_reply(&client->common, IMAP_CMD_REPLY_BYE, "Logging out");
client_send_reply(&client->common, IMAP_CMD_REPLY_OK,
"Logout completed.");
client_destroy(&client->common, CLIENT_UNAUTHENTICATED_LOGOUT_MSG);
return 1;
}
static int cmd_enable(struct imap_client *client,
const struct imap_arg *args ATTR_UNUSED)
{
client_send_raw(&client->common, "* ENABLED\r\n");
client_send_reply(&client->common, IMAP_CMD_REPLY_OK,
"ENABLE ignored in non-authenticated state.");
return 1;
}
static int client_command_execute(struct imap_client *client, const char *cmd,
const struct imap_arg *args)
{
struct imap_login_command *login_cmd;
login_cmd = imap_login_command_lookup(cmd);
if (login_cmd == NULL)
return -2;
return login_cmd->func(client, args);
}
static bool client_invalid_command(struct imap_client *client)
{
if (client->cmd_tag == NULL || *client->cmd_tag == '\0')
client->cmd_tag = "*";
if (++client->common.bad_counter >= CLIENT_MAX_BAD_COMMANDS) {
client_send_reply(&client->common, IMAP_CMD_REPLY_BYE,
"Too many invalid IMAP commands.");
client_destroy(&client->common, "Too many invalid commands");
return FALSE;
}
client_send_reply(&client->common, IMAP_CMD_REPLY_BAD,
"Error in IMAP command received by server.");
return TRUE;
}
static int client_parse_command(struct imap_client *client,
const struct imap_arg **args_r)
{
switch (imap_parser_read_args(client->parser, 0, 0, args_r)) {
case -1:
/* error */
if (!client_handle_parser_error(client, client->parser)) {
/* client destroyed */
return 0;
}
return -1;
case -2:
/* not enough data */
return 0;
default:
/* we read the entire line - skip over the CRLF */
if (!client_skip_line(client))
i_unreached();
return 1;
}
}
static bool client_handle_input(struct imap_client *client)
{
const char *tag, *name;
int ret;
i_assert(!client->common.authenticating);
if (client->cmd_finished) {
/* clear the previous command from memory. don't do this
immediately after handling command since we need the
cmd_tag to stay some time after authentication commands. */
client->cmd_tag = NULL;
client->cmd_name = NULL;
imap_parser_reset(client->parser);
/* remove \r\n */
if (client->skip_line) {
if (!client_skip_line(client))
return FALSE;
client->skip_line = FALSE;
}
client->cmd_finished = FALSE;
}
if (client->cmd_tag == NULL) {
ret = imap_parser_read_tag(client->parser, &tag);
if (ret == 0)
return FALSE; /* need more data */
if (ret < 0 || strlen(tag) > IMAP_TAG_MAX_LEN) {
/* the tag is invalid, don't allow it and don't
send it back. this attempts to prevent any
potentially dangerous replies in case someone tries
to access us using HTTP protocol. */
client->skip_line = TRUE;
client->cmd_finished = TRUE;
if (!client_invalid_command(client))
return FALSE;
return client_handle_input(client);
}
client->cmd_tag = tag;
}
if (client->cmd_name == NULL) {
ret = imap_parser_read_command_name(client->parser, &name);
if (ret == 0)
return FALSE; /* need more data */
if (ret < 0) {
client->skip_line = TRUE;
client->cmd_finished = TRUE;
if (!client_invalid_command(client))
return FALSE;
return client_handle_input(client);
}
client->cmd_name = name;
}
return client->common.v.input_next_cmd(&client->common);
}
static bool imap_client_input_next_cmd(struct client *_client)
{
struct imap_client *client = (struct imap_client *)_client;
const struct imap_arg *args;
bool parsed;
int ret;
if (strcasecmp(client->cmd_name, "AUTHENTICATE") == 0) {
/* SASL-IR may need more space than input buffer's size,
so we'll handle it as a special case. */
ret = cmd_authenticate(client, &parsed);
if (ret == 0 && !parsed)
return FALSE;
} else if (strcasecmp(client->cmd_name, "ID") == 0) {
/* ID extensions allows max. 30 parameters,
each max. 1024 bytes long. that brings us over the input
buffer's size, so handle the parameters one at a time */
ret = cmd_id(client);
if (ret == 0)
return FALSE;
if (ret < 0)
ret = 1; /* don't send the error reply again */
} else {
ret = client_parse_command(client, &args);
if (ret < 0)
return TRUE;
if (ret == 0)
return FALSE;
ret = *client->cmd_tag == '\0' ? -1 :
client_command_execute(client, client->cmd_name, args);
}
client->cmd_finished = TRUE;
if (ret == -2 && strcasecmp(client->cmd_tag, "LOGIN") == 0) {
client_send_reply(&client->common, IMAP_CMD_REPLY_BAD,
"First parameter in line is IMAP's command tag, "
"not the command name. Add that before the command, "
"like: a login user pass");
} else if (ret < 0) {
if (!client_invalid_command(client))
return FALSE;
}
return ret != 0 && !client->common.destroyed;
}
static void imap_client_input(struct client *client)
{
struct imap_client *imap_client = (struct imap_client *)client;
if (!client_read(client))
return;
client_ref(client);
o_stream_cork(imap_client->common.output);
for (;;) {
if (!auth_client_is_connected(auth_client)) {
/* we're not currently connected to auth process -
don't allow any commands */
client_notify_status(client, FALSE,
AUTH_SERVER_WAITING_MSG);
timeout_remove(&client->to_auth_waiting);
client->input_blocked = TRUE;
break;
} else {
if (!client_handle_input(imap_client))
break;
}
}
o_stream_uncork(imap_client->common.output);
client_unref(&client);
}
static struct client *imap_client_alloc(pool_t pool)
{
struct imap_client *imap_client;
imap_client = p_new(pool, struct imap_client, 1);
return &imap_client->common;
}
static void imap_client_create(struct client *client, void **other_sets)
{
struct imap_client *imap_client = (struct imap_client *)client;
imap_client->set = other_sets[0];
imap_client->parser =
imap_parser_create(imap_client->common.input,
imap_client->common.output,
IMAP_LOGIN_MAX_LINE_LENGTH);
if (imap_client->set->imap_literal_minus)
imap_parser_enable_literal_minus(imap_client->parser);
client->io = io_add_istream(client->input, client_input, client);
}
static void imap_client_destroy(struct client *client)
{
struct imap_client *imap_client = (struct imap_client *)client;
i_free_and_null(imap_client->proxy_backend_capability);
imap_parser_unref(&imap_client->parser);
}
static void imap_client_notify_auth_ready(struct client *client)
{
string_t *greet;
greet = t_str_new(128);
str_append(greet, "* OK ");
str_printfa(greet, "[CAPABILITY %s] ", get_capability(client));
str_append(greet, client->set->login_greeting);
str_append(greet, "\r\n");
client_send_raw(client, str_c(greet));
client->banner_sent = TRUE;
}
static void imap_client_starttls(struct client *client)
{
struct imap_client *imap_client = (struct imap_client *)client;
imap_parser_unref(&imap_client->parser);
imap_client->parser =
imap_parser_create(imap_client->common.input,
imap_client->common.output,
IMAP_LOGIN_MAX_LINE_LENGTH);
/* CRLF is lost from buffer when streams are reopened. */
imap_client->skip_line = FALSE;
}
static void ATTR_NULL(3)
client_send_reply_raw(struct client *client,
const char *prefix, const char *resp_code,
const char *text, bool tagged)
{
struct imap_client *imap_client = (struct imap_client *)client;
T_BEGIN {
string_t *line = t_str_new(256);
if (tagged)
str_append(line, imap_client->cmd_tag);
else
str_append_c(line, '*');
str_append_c(line, ' ');
str_append(line, prefix);
str_append_c(line, ' ');
if (resp_code != NULL)
str_printfa(line, "[%s] ", resp_code);
str_append(line, text);
str_append(line, "\r\n");
client_send_raw_data(client, str_data(line), str_len(line));
} T_END;
}
void client_send_reply_code(struct client *client, enum imap_cmd_reply reply,
const char *resp_code, const char *text)
{
const char *prefix = "NO";
bool tagged = TRUE;
switch (reply) {
case IMAP_CMD_REPLY_OK:
prefix = "OK";
break;
case IMAP_CMD_REPLY_NO:
break;
case IMAP_CMD_REPLY_BAD:
prefix = "BAD";
break;
case IMAP_CMD_REPLY_BYE:
prefix = "BYE";
tagged = FALSE;
break;
}
client_send_reply_raw(client, prefix, resp_code, text, tagged);
}
void client_send_reply(struct client *client, enum imap_cmd_reply reply,
const char *text)
{
client_send_reply_code(client, reply, NULL, text);
}
static void
imap_client_notify_status(struct client *client, bool bad, const char *text)
{
if (bad)
client_send_reply_raw(client, "BAD", "ALERT", text, FALSE);
else
client_send_reply_raw(client, "OK", NULL, text, FALSE);
}
static void
imap_client_notify_disconnect(struct client *client,
enum client_disconnect_reason reason,
const char *text)
{
if (reason == CLIENT_DISCONNECT_INTERNAL_ERROR) {
client_send_reply_code(client, IMAP_CMD_REPLY_BYE,
IMAP_RESP_CODE_UNAVAILABLE, text);
} else {
client_send_reply_code(client, IMAP_CMD_REPLY_BYE, NULL, text);
}
}
static void imap_login_preinit(void)
{
login_set_roots = imap_login_setting_roots;
}
static const struct imap_login_command imap_login_commands[] = {
{ "LOGIN", cmd_login },
{ "CAPABILITY", cmd_capability },
{ "STARTTLS", cmd_starttls },
{ "NOOP", cmd_noop },
{ "LOGOUT", cmd_logout },
{ "ENABLE", cmd_enable }
};
static void imap_login_init(void)
{
imap_login_commands_init();
imap_login_commands_register(imap_login_commands,
N_ELEMENTS(imap_login_commands));
}
static void imap_login_deinit(void)
{
clients_destroy_all();
imap_login_commands_deinit();
}
static struct client_vfuncs imap_client_vfuncs = {
.alloc = imap_client_alloc,
.create = imap_client_create,
.destroy = imap_client_destroy,
.notify_auth_ready = imap_client_notify_auth_ready,
.notify_disconnect = imap_client_notify_disconnect,
.notify_status = imap_client_notify_status,
.notify_starttls = imap_client_notify_starttls,
.starttls = imap_client_starttls,
.input = imap_client_input,
.auth_result = imap_client_auth_result,
.proxy_reset = imap_proxy_reset,
.proxy_parse_line = imap_proxy_parse_line,
.proxy_failed = imap_proxy_failed,
.proxy_get_state = imap_proxy_get_state,
.send_raw_data = client_common_send_raw_data,
.input_next_cmd = imap_client_input_next_cmd,
.free = client_common_default_free,
};
static struct login_binary imap_login_binary = {
.protocol = "imap",
.process_name = "imap-login",
.default_port = 143,
.default_ssl_port = 993,
.event_category = {
.name = "imap",
},
.client_vfuncs = &imap_client_vfuncs,
.preinit = imap_login_preinit,
.init = imap_login_init,
.deinit = imap_login_deinit,
.sasl_support_final_reply = FALSE,
.anonymous_login_acceptable = TRUE,
};
int main(int argc, char *argv[])
{
return login_binary_run(&imap_login_binary, argc, argv);
}
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