check_smtp: certificate check is no longer opt-in

This is a breaking change.
Testing whether a TLS certificate is still valid (expiration wise)
is now the default in check_smtp.
The reasoning is, that in most scenarios an expired certificate
will effectively mean that the service is not working anymore due to
the refusal of other software to talk to it.

There is a new cli parameter though to explicitly ignore that.
This commit is contained in:
Lorenz Kästle 2025-11-09 11:46:36 +01:00
parent 62035adf6c
commit bc2720abdd
2 changed files with 54 additions and 40 deletions

View file

@ -37,6 +37,7 @@
#include "base64.h"
#include "regex.h"
#include <bits/getopt_ext.h>
#include <ctype.h>
#include <string.h>
#include "check_smtp.d/config.h"
@ -347,9 +348,19 @@ int main(int argc, char **argv) {
switch (cert_check_result.errors) {
case ALL_OK: {
xasprintf(&sc_cert_check.output, "Certificate expiration. Remaining time %g days",
cert_check_result.remaining_seconds / 86400);
sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
if (cert_check_result.result_state != STATE_OK &&
config.ignore_certificate_expiration) {
xasprintf(&sc_cert_check.output,
"Remaining certificate lifetime: %d days. Expiration will be ignored",
(int)(cert_check_result.remaining_seconds / 86400));
sc_cert_check = mp_set_subcheck_state(sc_cert_check, STATE_OK);
} else {
xasprintf(&sc_cert_check.output, "Remaining certificate lifetime: %d days",
(int)(cert_check_result.remaining_seconds / 86400));
sc_cert_check =
mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
}
} break;
case NO_SERVER_CERTIFICATE_PRESENT: {
xasprintf(&sc_cert_check.output, "no server certificate present");
@ -366,12 +377,6 @@ int main(int argc, char **argv) {
};
mp_add_subcheck_to_check(&overall, sc_cert_check);
if (config.check_cert) {
smtp_quit(config, buffer, socket_descriptor, ssl_established);
my_close(socket_descriptor);
mp_exit(overall);
}
}
# endif /* USE_OPENSSL */
@ -584,37 +589,40 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
enum {
SNI_OPTION = CHAR_MAX + 1,
output_format_index,
ignore_certificate_expiration_index,
};
int option = 0;
static struct option longopts[] = {{"hostname", required_argument, 0, 'H'},
{"expect", required_argument, 0, 'e'},
{"critical", required_argument, 0, 'c'},
{"warning", required_argument, 0, 'w'},
{"timeout", required_argument, 0, 't'},
{"port", required_argument, 0, 'p'},
{"from", required_argument, 0, 'f'},
{"fqdn", required_argument, 0, 'F'},
{"authtype", required_argument, 0, 'A'},
{"authuser", required_argument, 0, 'U'},
{"authpass", required_argument, 0, 'P'},
{"command", required_argument, 0, 'C'},
{"response", required_argument, 0, 'R'},
{"verbose", no_argument, 0, 'v'},
{"version", no_argument, 0, 'V'},
{"use-ipv4", no_argument, 0, '4'},
{"use-ipv6", no_argument, 0, '6'},
{"help", no_argument, 0, 'h'},
{"lmtp", no_argument, 0, 'L'},
{"ssl", no_argument, 0, 's'},
{"tls", no_argument, 0, 's'},
{"starttls", no_argument, 0, 'S'},
{"sni", no_argument, 0, SNI_OPTION},
{"certificate", required_argument, 0, 'D'},
{"ignore-quit-failure", no_argument, 0, 'q'},
{"proxy", no_argument, 0, 'r'},
{"output-format", required_argument, 0, output_format_index},
{0, 0, 0, 0}};
static struct option longopts[] = {
{"hostname", required_argument, 0, 'H'},
{"expect", required_argument, 0, 'e'},
{"critical", required_argument, 0, 'c'},
{"warning", required_argument, 0, 'w'},
{"timeout", required_argument, 0, 't'},
{"port", required_argument, 0, 'p'},
{"from", required_argument, 0, 'f'},
{"fqdn", required_argument, 0, 'F'},
{"authtype", required_argument, 0, 'A'},
{"authuser", required_argument, 0, 'U'},
{"authpass", required_argument, 0, 'P'},
{"command", required_argument, 0, 'C'},
{"response", required_argument, 0, 'R'},
{"verbose", no_argument, 0, 'v'},
{"version", no_argument, 0, 'V'},
{"use-ipv4", no_argument, 0, '4'},
{"use-ipv6", no_argument, 0, '6'},
{"help", no_argument, 0, 'h'},
{"lmtp", no_argument, 0, 'L'},
{"ssl", no_argument, 0, 's'},
{"tls", no_argument, 0, 's'},
{"starttls", no_argument, 0, 'S'},
{"sni", no_argument, 0, SNI_OPTION},
{"certificate", required_argument, 0, 'D'},
{"ignore-quit-failure", no_argument, 0, 'q'},
{"proxy", no_argument, 0, 'r'},
{"ignore-certificate-expiration", no_argument, 0, ignore_certificate_expiration_index},
{"output-format", required_argument, 0, output_format_index},
{0, 0, 0, 0}};
check_smtp_config_wrapper result = {
.config = check_smtp_config_init(),
@ -766,7 +774,6 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
}
result.config.days_till_exp_warn = atoi(optarg);
}
result.config.check_cert = true;
result.config.ignore_send_quit_failure = true;
#else
usage(_("SSL support not available - install OpenSSL and recompile"));
@ -827,6 +834,9 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
result.config.output_format = parser.output_format;
break;
}
case ignore_certificate_expiration_index: {
result.config.ignore_certificate_expiration = true;
}
}
}
@ -1028,6 +1038,8 @@ void print_help(void) {
printf(" %s\n", _("Send LHLO instead of HELO/EHLO"));
printf(" %s\n", "-q, --ignore-quit-failure");
printf(" %s\n", _("Ignore failure when sending QUIT command to server"));
printf(" %s\n", "--ignore-certificate-expiration");
printf(" %s\n", _("Ignore certificate expiration"));
printf(UT_WARN_CRIT);

View file

@ -40,12 +40,13 @@ typedef struct {
bool use_proxy_prefix;
#ifdef HAVE_SSL
bool check_cert;
int days_till_exp_warn;
int days_till_exp_crit;
bool use_ssl;
bool use_starttls;
bool use_sni;
bool ignore_certificate_expiration;
#endif
bool output_format_is_set;
@ -80,12 +81,13 @@ check_smtp_config check_smtp_config_init() {
.use_proxy_prefix = false,
#ifdef HAVE_SSL
.check_cert = false,
.days_till_exp_warn = 0,
.days_till_exp_crit = 0,
.use_ssl = false,
.use_starttls = false,
.use_sni = false,
.ignore_certificate_expiration = false,
#endif
.output_format_is_set = false,