ok i had similiar issues and ended up patching the sasl auth system
inside postfix to include login username & IP ADDRESS
this gave a single log file entry (syslog, file whatever postfix was
configured to do) showing that the account had been accessed for sending
an email
example :
mail19 10-24 08:13:38 {postfix.in} [5814] (1222052179) Oct 24
08:13:38 mail19 postfix/smtpd[5814]: 09B192D2C2B:
client=174-138-211-141.cpe.distributel.net[174.138.211.141],
sasl_method=PLAIN, [email protected]
from there i have my own custom logging system but i am sure fail2ban
etc would work as well
basically i cutoff the user after 100 sent emails / hour, this is easily
done by placing the counts in the sasl auth database and using the pgsql
(in my case) statement to include
also it tracks bad login's
example :
www-1 10-24 08:13:29 {postfix.in/smtpd[53113] (1222051970)
xsasl_cyrus_server_first: sasl_method LOGIN
www-1 10-24 08:13:29 {postfix.in/smtpd[53113] (1222051971)
xsasl_cyrus_server_auth_response: uncoded server challenge: Username:
www-1 10-24 08:13:30 {postfix.in/smtpd[53113] (1222052015)
xsasl_cyrus_server_next: decoded response: [email protected]
www-1 10-24 08:13:30 {postfix.in/smtpd[53113] (1222052016)
xsasl_cyrus_server_auth_response: uncoded server challenge: Password:
www-1 10-24 08:13:32 {postfix.in/smtpd[53113] (1222052035)
xsasl_cyrus_server_next: decoded response: c@15
www-1 10-24 08:13:32 {postfix.in/smtpd[53113] (1222052036) SASL
authentication info: sql plugin: no result found
www-1 10-24 08:13:32 {postfix.in/smtpd[53113] (1222052037)
warning: unknown[183.182.107.110]: SASL LOGIN authentication failed:
authentication failure
the above is good info for blacklisting ip's
the relative code patched was in smtpd.conf (below)
# cat smtpd.conf
#Local Password Database
#pwcheck_method: saslauthd
#mech_list: login plain
#saslauthd_path: /var/run/saslauthd
#Postygres
pwcheck_method: auxprop
mech_list: PLAIN LOGIN
auxprop_plugin: sql
sql_engine: pgsql
sql_hostnames: pg.scom.ca:5433
sql_database: scom_billing
sql_user: pgsql
sql_passwd: xxxxxx
sql_select: SELECT password FROM email_users WHERE username = '%u@%r'
and password <> 'alias' and currentcount_bad < 30 and status = True
#Logging?
log_level: 7
note currentcount_bad etc
note this does require knowledge of 'c' programming but it gets around
the long requested username & ip address log entry in one line?
also dont forget to clear the counter via crontab once an hour so it
does not block prematurely.
note the postfix version : postfix-3.6-20200523
postfix-3.6-20200523/src/smtpd
in smtpd_sasl_glue.c
here's the full file :
# cat smtpd_sasl_glue.c
/*++
/* NAME
/* smtpd_sasl_glue 3
/* SUMMARY
/* Postfix SMTP server, SASL support interface
/* SYNOPSIS
/* #include "smtpd_sasl_glue.h"
/*
/* void smtpd_sasl_state_init(state)
/* SMTPD_STATE *state;
/*
/* void smtpd_sasl_initialize()
/*
/* void smtpd_sasl_activate(state, sasl_opts_name, sasl_opts_val)
/* SMTPD_STATE *state;
/* const char *sasl_opts_name;
/* const char *sasl_opts_val;
/*
/* char *smtpd_sasl_authenticate(state, sasl_method, init_response)
/* SMTPD_STATE *state;
/* const char *sasl_method;
/* const char *init_response;
/*
/* void smtpd_sasl_logout(state)
/* SMTPD_STATE *state;
/*
/* void smtpd_sasl_login(state, sasl_username, sasl_method)
/* SMTPD_STATE *state;
/* const char *sasl_username;
/* const char *sasl_method;
/*
/* void smtpd_sasl_deactivate(state)
/* SMTPD_STATE *state;
/*
/* int smtpd_sasl_is_active(state)
/* SMTPD_STATE *state;
/*
/* int smtpd_sasl_set_inactive(state)
/* SMTPD_STATE *state;
/* DESCRIPTION
/* This module encapsulates most of the detail specific to SASL
/* authentication.
/*
/* smtpd_sasl_state_init() performs minimal server state
/* initialization to support external authentication (e.g.,
/* XCLIENT) without having to enable SASL in main.cf. This
/* should always be called at process startup.
/*
/* smtpd_sasl_initialize() initializes the SASL library. This
/* routine should be called once at process start-up. It may
/* need access to the file system for run-time loading of
/* plug-in modules. There is no corresponding cleanup routine.
/*
/* smtpd_sasl_activate() performs per-connection initialization.
/* This routine should be called once at the start of every
/* connection. The sasl_opts_name and sasl_opts_val parameters
/* are the postfix configuration parameters setting the security
/* policy of the SASL authentication.
/*
/* smtpd_sasl_authenticate() implements the authentication
/* dialog. The result is zero in case of success, -1 in case
/* of failure. smtpd_sasl_authenticate() updates the following
/* state structure members:
/* .IP sasl_method
/* The authentication method that was successfully applied.
/* This member is a null pointer in the absence of successful
/* authentication.
/* .IP sasl_username
/* The username that was successfully authenticated.
/* This member is a null pointer in the absence of successful
/* authentication.
/* .PP
/* smtpd_sasl_login() records the result of successful external
/* authentication, i.e. without invoking smtpd_sasl_authenticate(),
/* but produces an otherwise equivalent result.
/*
/* smtpd_sasl_logout() cleans up after smtpd_sasl_authenticate().
/* This routine exists for the sake of symmetry.
/*
/* smtpd_sasl_deactivate() performs per-connection cleanup.
/* This routine should be called at the end of every connection.
/*
/* smtpd_sasl_is_active() is a predicate that returns true
/* if the SMTP server session state is between smtpd_sasl_activate()
/* and smtpd_sasl_deactivate().
/*
/* smtpd_sasl_set_inactive() initializes the SMTP session
/* state before the first smtpd_sasl_activate() call.
/*
/* Arguments:
/* .IP state
/* SMTP session context.
/* .IP sasl_opts_name
/* Security options parameter name.
/* .IP sasl_opts_val
/* Security options parameter value.
/* .IP sasl_method
/* A SASL mechanism name
/* .IP init_reply
/* An optional initial client response.
/* DIAGNOSTICS
/* All errors are fatal.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Initial implementation by:
/* Till Franke
/* SuSE Rhein/Main AG
/* 65760 Eschborn, Germany
/*
/* Adopted by:
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <stdlib.h>
#include <string.h>
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
#include <stringops.h>
/* Global library. */
#include <mail_params.h>
/* XSASL library. */
#include <xsasl.h>
char saslx[256];
/* Application-specific. */
#include "smtpd.h"
#include "smtpd_sasl_glue.h"
#include "smtpd_chat.h"
#include "pfilter.h" /* for blacklistd(8) */
#ifdef USE_SASL_AUTH
/*
* Silly little macros.
*/
#define STR(s) vstring_str(s)
/*
* SASL server implementation handle.
*/
static XSASL_SERVER_IMPL *smtpd_sasl_impl;
/* smtpd_sasl_initialize - per-process initialization */
void smtpd_sasl_initialize(void)
{
/*
* Sanity check.
*/
if (smtpd_sasl_impl)
msg_panic("smtpd_sasl_initialize: repeated call");
/*
* Initialize the SASL library.
*/
if ((smtpd_sasl_impl = xsasl_server_init(var_smtpd_sasl_type,
var_smtpd_sasl_path)) == 0)
msg_fatal("SASL per-process initialization failed");
}
/* smtpd_sasl_activate - per-connection initialization */
void smtpd_sasl_activate(SMTPD_STATE *state, const char *sasl_opts_name,
const char *sasl_opts_val)
{
const char *mechanism_list;
XSASL_SERVER_CREATE_ARGS create_args;
int tls_flag;
/*
* Sanity check.
*/
if (smtpd_sasl_is_active(state))
msg_panic("smtpd_sasl_activate: already active");
/*
* Initialize SASL-specific state variables. Use long-lived storage for
* base 64 conversion results, rather than local variables, to avoid
* memory leaks when a read or write routine returns abnormally after
* timeout or I/O error.
*/
state->sasl_reply = vstring_alloc(20);
state->sasl_mechanism_list = 0;
/*
* Set up a new server context for this connection.
*/
#ifdef USE_TLS
tls_flag = state->tls_context != 0;
#else
tls_flag = 0;
#endif
#define ADDR_OR_EMPTY(addr, unknown) (strcmp(addr, unknown) ? addr : "")
#define REALM_OR_NULL(realm) (*(realm) ? (realm) : (char *) 0)
if ((state->sasl_server =
XSASL_SERVER_CREATE(smtpd_sasl_impl, &create_args,
stream = state->client,
addr_family = state->addr_family,
server_addr = ADDR_OR_EMPTY(state->dest_addr,
SERVER_ADDR_UNKNOWN),
server_port = ADDR_OR_EMPTY(state->dest_port,
SERVER_PORT_UNKNOWN),
client_addr = ADDR_OR_EMPTY(state->addr,
CLIENT_ADDR_UNKNOWN),
client_port = ADDR_OR_EMPTY(state->port,
CLIENT_PORT_UNKNOWN),
service = var_smtpd_sasl_service,
user_realm =
REALM_OR_NULL(var_smtpd_sasl_realm),
security_options = sasl_opts_val,
tls_flag = tls_flag)) == 0)
msg_fatal("SASL per-connection initialization failed");
/*
* Get the list of authentication mechanisms.
*/
if ((mechanism_list =
xsasl_server_get_mechanism_list(state->sasl_server)) == 0)
msg_fatal("no SASL authentication mechanisms");
state->sasl_mechanism_list = mystrdup(mechanism_list);
}
/* smtpd_sasl_state_init - initialize state to allow extern
authentication. */
void smtpd_sasl_state_init(SMTPD_STATE *state)
{
/* Initialization to support external authentication (e.g.,
XCLIENT). */
state->sasl_username = 0;
state->sasl_method = 0;
state->sasl_sender = 0;
}
/* smtpd_sasl_deactivate - per-connection cleanup */
void smtpd_sasl_deactivate(SMTPD_STATE *state)
{
if (state->sasl_reply) {
vstring_free(state->sasl_reply);
state->sasl_reply = 0;
}
if (state->sasl_mechanism_list) {
myfree(state->sasl_mechanism_list);
state->sasl_mechanism_list = 0;
}
if (state->sasl_username) {
myfree(state->sasl_username);
state->sasl_username = 0;
}
if (state->sasl_method) {
myfree(state->sasl_method);
state->sasl_method = 0;
}
if (state->sasl_sender) {
myfree(state->sasl_sender);
state->sasl_sender = 0;
}
if (state->sasl_server) {
xsasl_server_free(state->sasl_server);
state->sasl_server = 0;
}
}
/* smtpd_sasl_authenticate - per-session authentication */
int smtpd_sasl_authenticate(SMTPD_STATE *state,
const char *sasl_method,
const char *init_response)
{
int status;
const char *sasl_username;
saslx[0]=0;
if ( init_response != 0 ) {
strncpy ( saslx, init_response, 254 );
saslx[255]=0;
}
/*
* SASL authentication protocol start-up. Process any initial client
* response that was sent along in the AUTH command.
*/
for (status = xsasl_server_first(state->sasl_server, sasl_method,
init_response, state->sasl_reply);
status == XSASL_AUTH_MORE;
status = xsasl_server_next(state->sasl_server, STR(state->buffer),
state->sasl_reply)) {
/*
* Send a server challenge.
*/
smtpd_chat_reply(state, "334 %s", STR(state->sasl_reply));
/*
* Receive the client response. "*" means that the client gives up.
*/
if (!smtpd_chat_query_limit(state, var_smtpd_sasl_resp_limit)) {
smtpd_chat_reply(state, "500 5.5.6 SASL response limit
exceeded");
return (-1);
}
if (strcmp(STR(state->buffer), "*") == 0) {
msg_warn("%s: SASL %s authentication aborted",
state->namaddr, sasl_method);
smtpd_chat_reply(state, "501 5.7.0 Authentication aborted");
return (-1);
}
}
if (status != XSASL_AUTH_DONE) {
if ( saslx[0] != 0 ) {
msg_warn("Net : %s User Auth Failed for : %s",state->namaddr, saslx );
}
msg_warn("%s: SASL %s authentication failed: %s",
state->namaddr, sasl_method,
STR(state->sasl_reply));
/* RFC 4954 Section 6. */
if (status == XSASL_AUTH_TEMP)
smtpd_chat_reply(state, "454 4.7.0 Temporary authentication
failure: %s",
STR(state->sasl_reply));
else
smtpd_chat_reply(state, "535 5.7.8 Error: authentication
failed: %s",
STR(state->sasl_reply));
/* notify blacklistd of SASL authentication failure */
pfilter_notify(1, vstream_fileno(state->client));
return (-1);
}
/* RFC 4954 Section 6. */
smtpd_chat_reply(state, "235 2.7.0 Authentication successful");
if ( saslx[0] != 0 ) {
msg_warn("Net : %s User Auth Passed for : %s",state->namaddr, saslx );
}
if ((sasl_username = xsasl_server_get_username(state->sasl_server))
== 0)
msg_panic("cannot look up the authenticated SASL username");
state->sasl_username = mystrdup(sasl_username);
printable(state->sasl_username, '?');
state->sasl_method = mystrdup(sasl_method);
printable(state->sasl_method, '?');
return (0);
}
/* smtpd_sasl_logout - clean up after smtpd_sasl_authenticate */
void smtpd_sasl_logout(SMTPD_STATE *state)
{
if (state->sasl_username) {
myfree(state->sasl_username);
state->sasl_username = 0;
}
if (state->sasl_method) {
myfree(state->sasl_method);
state->sasl_method = 0;
}
}
/* smtpd_sasl_login - set login information */
void smtpd_sasl_login(SMTPD_STATE *state, const char *sasl_username,
const char *sasl_method)
{
if (state->sasl_username)
myfree(state->sasl_username);
state->sasl_username = mystrdup(sasl_username);
if (state->sasl_method)
myfree(state->sasl_method);
state->sasl_method = mystrdup(sasl_method);
}
#endif
Happy Monday !!!
Thanks - paul
Paul Kudla
Scom.ca Internet Services <http://www.scom.ca>
004-1009 Byron Street South
Whitby, Ontario - Canada
L1N 4S3
Toronto 416.642.7266
Main 1.866.411.7266
Fax 1.888.892.7266
Email [email protected]
On 10/23/2022 4:06 PM, Wietse Venema wrote:
Marek Podmaka:
On Sun, 23 Oct 2022 at 17:21, Markus Sch?nhaber
<[email protected]> wrote:
warning: access table static:HOLD: with smtpd_proxy_filter specified,
action HOLD is unavailable
I am using postfix-cluebringer to limit the number of sent messages
per SASL username (to slow down spam from hacked accounts) and putting
the excessive emails into the HOLD queue for manual checks.
As it is not directly possible, cluebringer just adds a custom header
to the message, and I use header_checks to actually HOLD the message
based on that header.
https://serverfault.com/questions/698324/postfix-how-to-use-policy-service-together-with-proxy-filter
Quoting from new text for
https://www.postfix.org/SMTPD_PROXY_README.html#pros_cons
One workaround is to combine a before-filter PREPEND action that
outputs a unique pattern (for example containing the MTA domain
name), with an after-filter header_checks rule that triggers a HOLD
action. The header can be removed with an smtp_header_checks IGNORE
action.
Wietse
