static int proxy_input_banner(struct imap_client *client,
struct ostream *output, const char *line)
{
const char *const *capabilities = NULL;
string_t *str;
int ret;
if (!str_begins(line, "* OK ")) {
client_log_err(&client->common, t_strdup_printf(
"proxy: Remote returned invalid banner: %s",
str_sanitize(line, 160)));
return -1;
}
str = t_str_new(128);
if (str_begins(line + 5, "[CAPABILITY ")) {
capabilities = t_strsplit(t_strcut(line + 5 + 12, ']'), " ");
if (str_array_icase_find(capabilities, "SASL-IR"))
client->proxy_sasl_ir = TRUE;
if (str_array_icase_find(capabilities, "LOGINDISABLED"))
client->proxy_logindisabled = TRUE;
i_free(client->proxy_backend_capability);
client->proxy_backend_capability =
i_strdup(t_strcut(line + 5 + 12, ']'));
if (str_array_icase_find(capabilities, "ID") &&
!client->common.proxy_not_trusted) {
client->proxy_sent_state |= IMAP_PROXY_SENT_STATE_ID;
proxy_write_id(client, str);
if (client->common.proxy_nopipelining) {
/* write login or starttls after I OK */
o_stream_nsend(output, str_data(str), str_len(str));
return 0;
}
}
}
if ((ret = proxy_write_starttls(client, str)) < 0) {
return -1;
} else if (ret == 0) {
if (proxy_write_login(client, str) < 0)
return -1;
}
o_stream_nsend(output, str_data(str), str_len(str));
return 0;
}
int imap_proxy_parse_line(struct client *client, const char *line)
{
struct imap_client *imap_client = (struct imap_client *)client;
struct ostream *output;
string_t *str;
const unsigned char *data;
unsigned int data_len;
const char *error;
int ret;
i_assert(!client->destroyed);
output = login_proxy_get_ostream(client->login_proxy);
if (!imap_client->proxy_seen_banner) {
/* this is a banner */
client->proxy_state = IMAP_PROXY_STATE_BANNER;
imap_client->proxy_seen_banner = TRUE;
if (proxy_input_banner(imap_client, output, line) < 0) {
client_proxy_failed(client, TRUE);
return -1;
}
return 0;
} else if (*line == '+') {
/* AUTHENTICATE started. finish it. */
if (client->proxy_sasl_client == NULL) {
/* used literals with LOGIN command, just ignore. */
return 0;
}
client->proxy_state = IMAP_PROXY_STATE_AUTH_CONTINUE;
str = t_str_new(128);
if (line[1] != ' ' ||
base64_decode(line+2, strlen(line+2), NULL, str) < 0) {
client_log_err(client,
"proxy: Server sent invalid base64 data in AUTHENTICATE response");
client_proxy_failed(client, TRUE);
return -1;
}
ret = dsasl_client_input(client->proxy_sasl_client,
str_data(str), str_len(str), &error);
if (ret == 0) {
ret = dsasl_client_output(client->proxy_sasl_client,
&data, &data_len, &error);
}
if (ret < 0) {
client_log_err(client, t_strdup_printf(
"proxy: Server sent invalid authentication data: %s",
error));
client_proxy_failed(client, TRUE);
return -1;
}
i_assert(ret == 0);
str_truncate(str, 0);
base64_encode(data, data_len, str);
str_append(str, "\r\n");
o_stream_nsend(output, str_data(str), str_len(str));
return 0;
} else if (strncmp(line, "S ", 2) == 0) {
if (strncmp(line, "S OK ", 5) != 0) {
/* STARTTLS failed */
client_log_err(client, t_strdup_printf(
"proxy: Remote STARTTLS failed: %s",
str_sanitize(line + 5, 160)));
client_proxy_failed(client, TRUE);
return -1;
}
/* STARTTLS successful, begin TLS negotiation. */
client->proxy_state = IMAP_PROXY_STATE_STARTTLS;
if (login_proxy_starttls(client->login_proxy) < 0) {
client_proxy_failed(client, TRUE);
return -1;
}
/* i/ostreams changed. */
output = login_proxy_get_ostream(client->login_proxy);
str = t_str_new(128);
if (proxy_write_login(imap_client, str) < 0) {
client_proxy_failed(client, TRUE);
return -1;
}
o_stream_nsend(output, str_data(str), str_len(str));
return 1;
} else if (strncmp(line, "L OK ", 5) == 0) {
/* Login successful. Send this line to client. */
client->proxy_state = IMAP_PROXY_STATE_LOGIN;
str = t_str_new(128);
client_send_login_reply(imap_client, str, line + 5);
o_stream_nsend(client->output, str_data(str), str_len(str));
(void)client_skip_line(imap_client);
client_proxy_finish_destroy_client(client);
return 1;
} else if (strncmp(line, "L ", 2) == 0) {
line += 2;
if (client->set->auth_verbose) {
const char *log_line = line;
if (strncasecmp(log_line, "NO ", 3) == 0)
log_line += 3;
client_proxy_log_failure(client, log_line);
}
#define STR_NO_IMAP_RESP_CODE_AUTHFAILED "NO ["IMAP_RESP_CODE_AUTHFAILED"]"
if (strncmp(line, STR_NO_IMAP_RESP_CODE_AUTHFAILED,
strlen(STR_NO_IMAP_RESP_CODE_AUTHFAILED)) == 0) {
/* the remote sent a generic "authentication failed"
error. replace it with our one, so that in case
the remote is sending a different error message
an attacker can't find out what users exist in
the system. */
client_send_reply_code(client, IMAP_CMD_REPLY_NO,
IMAP_RESP_CODE_AUTHFAILED,
AUTH_FAILED_MSG);
} else if (strncmp(line, "NO [", 4) == 0) {
/* remote sent some other resp-code. forward it. */
client_send_raw(client, t_strconcat(
imap_client->cmd_tag, " ", line, "\r\n", NULL));
} else {
/* there was no [resp-code], so remote isn't Dovecot
v1.2+. we could either forward the line as-is and
leak information about what users exist in this
system, or we could hide other errors than password
failures. since other errors are pretty rare,
it's safer to just hide them. they're still
available in logs though. */
client_send_reply_code(client, IMAP_CMD_REPLY_NO,
IMAP_RESP_CODE_AUTHFAILED,
AUTH_FAILED_MSG);
}
client->proxy_auth_failed = TRUE;
client_proxy_failed(client, FALSE);
return -1;
} else if (strncasecmp(line, "* CAPABILITY ", 13) == 0) {
i_free(imap_client->proxy_backend_capability);
imap_client->proxy_backend_capability = i_strdup(line + 13);
return 0;
} else if (strncmp(line, "C ", 2) == 0) {
/* Reply to CAPABILITY command we sent */
client->proxy_state = IMAP_PROXY_STATE_CAPABILITY;
if (strncmp(line, "C OK ", 5) == 0 &&
client->proxy_password != NULL) {
/* pipelining was disabled, send the login now. */
str = t_str_new(128);
if (proxy_write_login(imap_client, str) < 0)
return -1;
o_stream_nsend(output, str_data(str), str_len(str));
return 1;
}
return 0;
} else if (strncasecmp(line, "I ", 2) == 0) {
/* Reply to ID command we sent, ignore it unless
pipelining is disabled, in which case send
either STARTTLS or login */
client->proxy_state = IMAP_PROXY_STATE_ID;
if (client->proxy_nopipelining) {
str = t_str_new(128);
if ((ret = proxy_write_starttls(imap_client, str)) < 0) {
return -1;
} else if (ret == 0) {
if (proxy_write_login(imap_client, str) < 0)
return -1;
}
o_stream_nsend(output, str_data(str), str_len(str));
return 1;
}
return 0;
} else if (strncasecmp(line, "* ID ", 5) == 0) {
/* Reply to ID command we sent, ignore it */
return 0;
} else if (strncmp(line, "* ", 2) == 0) {
/* untagged reply. just forward it. */
client_send_raw(client, t_strconcat(line, "\r\n", NULL));
return 0;
} else {
/* tagged reply, shouldn't happen. */
client_log_err(client, t_strdup_printf(
"proxy: Unexpected input, ignoring: %s",
str_sanitize(line, 160)));
return 0;
}
}
