mod_md: update to v2.4.26

- Using OCSP stapling information to trigger certificate renewals. Proposed
  by @frasertweedale.
- Added directive `MDCheckInterval` to control how often the server checks
  for detected revocations. Added proposals for configurations in the
  README.md chapter "Revocations".
- OCSP stapling: accept OCSP responses without a `nextUpdate` entry which is
  allowed in RFC 6960. Treat those as having an update interval of 12 hours.
  Added by @frasertweedale.
- Adapt OpenSSL usage to changes in their API. By Yann Ylavic.

Test Updates
- workarounds for using Pebble v2.5
- disable EAB tests for Pebble since v2.5 no longer
  supports HS256 FWT for EAB keys
- some stability improvemnets in error/warning checks



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1916861 13f79535-47bb-0310-9956-ffa450edef68

Author: icing

changes-entries/md_2.4.26.txt

@@ -0,0 +1,10 @@
+ * mod_md:
+   - Using OCSP stapling information to trigger certificate renewals. Proposed
+     by @frasertweedale.
+   - Added directive `MDCheckInterval` to control how often the server checks
+     for detected revocations. Added proposals for configurations in the
+     README.md chapter "Revocations".
+   - OCSP stapling: accept OCSP responses without a `nextUpdate` entry which is
+     allowed in RFC 6960. Treat those as having an update interval of 12 hours.
+     Added by @frasertweedale.
+   - Adapt OpenSSL usage to changes in their API. By Yann Ylavic.

docs/manual/mod/mod_md.xml

@@ -1512,4 +1512,29 @@ MDMessageCmd /etc/apache/md-message
         </usage>
     </directivesynopsis>
 
+    <directivesynopsis>
+        <name>MDCheckInterval</name>
+        <description>Determines how often certificates are checked</description>
+        <syntax>MDCheckInterval <var>duration</var></syntax>
+        <default>MDCheckInterval 12h</default>
+        <contextlist>
+            <context>server config</context>
+        </contextlist>
+        <compatibility>Available in version 2.4.60 and later</compatibility>
+        <usage>
+            <p>
+                The time between certificate checks. By default, the validity
+                and need for renewals is checked twice a day. This interval is
+                not followed precisely. Instead the module randomly applies
+                a +/-50% jitter to it. With the default of 12 hours, this
+                means the actual time between runs varies between 6 and 18
+                hours, jittered anew every run. This helps to mitigate
+                traffic peaks at ACME servers.
+            </p><p>
+                The minimum duration you may configure is 1 second. It is
+                not recommended to use such short times in production.
+            </p>
+        </usage>
+    </directivesynopsis>
+
 </modulesynopsis>

modules/md/md_ocsp.c

@@ -678,12 +678,6 @@ static apr_status_t ostat_on_resp(const md_http_response_t *resp, void *baton)
         md_result_log(update->result, MD_LOG_DEBUG);
         goto cleanup;
     }
-    if (!bnextup) {
-        rv = APR_EINVAL;
-        md_result_set(update->result, rv, "OCSP basicresponse reports not valid dates");
-        md_result_log(update->result, MD_LOG_DEBUG);
-        goto cleanup;
-    }
 
     /* Coming here, we have a response for our certid and it is either GOOD
      * or REVOKED. Both cases we want to remember and use in stapling. */
@@ -698,7 +692,14 @@ static apr_status_t ostat_on_resp(const md_http_response_t *resp, void *baton)
     new_der.free_data = md_openssl_free;
     nstat = (bstatus == V_OCSP_CERTSTATUS_GOOD)? MD_OCSP_CERT_ST_GOOD : MD_OCSP_CERT_ST_REVOKED;
     valid.start = bup? md_asn1_generalized_time_get(bup) : apr_time_now();
-    valid.end = md_asn1_generalized_time_get(bnextup);
+    if (bnextup) {
+        valid.end = md_asn1_generalized_time_get(bnextup);
+    }
+    else {
+        /* nextUpdate not set; default to 12 hours.
+         * Refresh attempts will be started some time earlier. */
+        valid.end = valid.start + apr_time_from_sec(MD_SECS_PER_DAY / 2);
+    }
 
     /* First, update the instance with a copy */
     apr_thread_mutex_lock(ostat->reg->mutex);

modules/md/md_reg.c

@@ -31,6 +31,7 @@
 #include "md_json.h"
 #include "md_result.h"
 #include "md_reg.h"
+#include "md_ocsp.h"
 #include "md_store.h"
 #include "md_status.h"
 #include "md_tailscale.h"
@@ -1321,3 +1322,38 @@ md_job_t *md_reg_job_make(md_reg_t *reg, const char *mdomain, apr_pool_t *p)
 {
     return md_job_make(p, reg->store, MD_SG_STAGING, mdomain, reg->min_delay);
 }
+
+static int get_cert_count(const md_t *md)
+{
+    if (md->cert_files && md->cert_files->nelts) {
+        return md->cert_files->nelts;
+    }
+    return md_pkeys_spec_count(md->pks);
+}
+
+int md_reg_has_revoked_certs(md_reg_t *reg, struct md_ocsp_reg_t *ocsp,
+                             const md_t *md, apr_pool_t *p)
+{
+    const md_pubcert_t *pubcert;
+    const md_cert_t *cert;
+    md_timeperiod_t ocsp_valid;
+    md_ocsp_cert_stat_t cert_stat;
+    apr_status_t rv = APR_SUCCESS;
+    int i;
+
+    if (!md->stapling || !ocsp)
+        return 0;
+
+    for (i = 0; i < get_cert_count(md); ++i) {
+        if (APR_SUCCESS != md_reg_get_pubcert(&pubcert, reg, md, i, p))
+            continue;
+        cert = APR_ARRAY_IDX(pubcert->certs, 0, const md_cert_t*);
+        if(!cert)
+            continue;
+        rv = md_ocsp_get_meta(&cert_stat, &ocsp_valid, ocsp, cert, p, md);
+        if (APR_SUCCESS == rv && cert_stat == MD_OCSP_CERT_ST_REVOKED) {
+            return 1;
+        }
+    }
+    return 0;
+}

modules/md/md_reg.h

@@ -23,6 +23,7 @@ struct md_pkey_t;
 struct md_cert_t;
 struct md_result_t;
 struct md_pkey_spec_t;
+struct md_ocsp_reg_t;
 
 #include "md_store.h"
 
@@ -310,4 +311,10 @@ apr_status_t md_reg_lock_global(md_reg_t *reg, apr_pool_t *p);
  */
 void md_reg_unlock_global(md_reg_t *reg, apr_pool_t *p);
 
+/**
+ * @return != 0 iff `md` has any certificates known to be REVOKED.
+ */
+int md_reg_has_revoked_certs(md_reg_t *reg, struct md_ocsp_reg_t *ocsp,
+                             const md_t *md, apr_pool_t *p);
+
 #endif /* mod_md_md_reg_h */

modules/md/md_version.h

@@ -27,15 +27,15 @@
  * @macro
  * Version number of the md module as c string
  */
-#define MOD_MD_VERSION "2.4.25"
+#define MOD_MD_VERSION "2.4.26"
 
 /**
  * @macro
  * Numerical representation of the version number of the md module
  * release. This is a 24 bit number with 8 bits for major number, 8 bits
  * for minor and 8 bits for patch. Version 1.2.3 becomes 0x010203.
  */
-#define MOD_MD_VERSION_NUM 0x020419
+#define MOD_MD_VERSION_NUM 0x02041a
 
 #define MD_ACME_DEF_URL         "https://acme-v02.api.letsencrypt.org/directory"
 #define MD_TAILSCALE_DEF_URL    "file://localhost/var/run/tailscale/tailscaled.sock"

modules/md/mod_md_config.c

@@ -84,6 +84,7 @@ static md_mod_conf_t defmc = {
     "crt.sh",                  /* default cert checker site name */
     "https://crt.sh?q=",       /* default cert checker site url */
     NULL,                      /* CA cert file to use */
+    apr_time_from_sec(MD_SECS_PER_DAY/2), /* default time between cert checks */
     apr_time_from_sec(5),      /* minimum delay for retries */
     13,                        /* retry_failover after 14 errors, with 5s delay ~ half a day */
     0,                         /* store locks, disabled by default */
@@ -624,6 +625,24 @@ static const char *md_config_set_base_server(cmd_parms *cmd, void *dc, const cha
     return set_on_off(&config->mc->manage_base_server, value, cmd->pool);
 }
 
+static const char *md_config_set_check_interval(cmd_parms *cmd, void *dc, const char *value)
+{
+    md_srv_conf_t *config = md_config_get(cmd->server);
+    const char *err = md_conf_check_location(cmd, MD_LOC_NOT_MD);
+    apr_time_t interval;
+
+    (void)dc;
+    if (err) return err;
+    if (md_duration_parse(&interval, value, "s") != APR_SUCCESS) {
+        return "unrecognized duration format";
+    }
+    if (interval < apr_time_from_sec(1)) {
+        return "check interval cannot be less than one second";
+    }
+    config->mc->check_interval = interval;
+    return NULL;
+}
+
 static const char *md_config_set_min_delay(cmd_parms *cmd, void *dc, const char *value)
 {
     md_srv_conf_t *config = md_config_get(cmd->server);
@@ -1304,7 +1323,8 @@ const command_rec md_cmds[] = {
                   "Configure locking of store for updates."),
     AP_INIT_TAKE1("MDMatchNames", md_config_set_match_mode, NULL, RSRC_CONF,
                   "Determines how DNS names are matched to vhosts."),
-
+    AP_INIT_TAKE1("MDCheckInterval", md_config_set_check_interval, NULL, RSRC_CONF,
+                  "Time between certificate checks."),
     AP_INIT_TAKE1(NULL, NULL, NULL, RSRC_CONF, NULL)
 };
 

modules/md/mod_md_config.h

@@ -75,6 +75,7 @@ struct md_mod_conf_t {
     const char *cert_check_name;       /* name of the linked certificate check site */
     const char *cert_check_url;        /* url "template for" checking a certificate */
     const char *ca_certs;              /* root certificates to use for connections */
+    apr_time_t check_interval;         /* duration between cert renewal checks */
     apr_time_t min_delay;              /* minimum delay for retries */
     int retry_failover;                /* number of errors to trigger CA failover */
     int use_store_locks;               /* use locks when updating store */

modules/md/mod_md_drive.c

@@ -100,15 +100,20 @@ static void process_drive_job(md_renew_ctx_t *dctx, md_job_t *job, apr_pool_t *p
     }
 
     if (md_will_renew_cert(md)) {
-        /* Renew the MDs credentials in a STAGING area. Might be invoked repeatedly 
+        /* Renew the MDs credentials in a STAGING area. Might be invoked repeatedly
          * without discarding previous/intermediate results.
          * Only returns SUCCESS when the renewal is complete, e.g. STAGING has a
          * complete set of new credentials.
          */
         ap_log_error( APLOG_MARK, APLOG_DEBUG, 0, dctx->s, APLOGNO(10052) 
                      "md(%s): state=%d, driving", job->mdomain, md->state);
 
-        if (!md_reg_should_renew(dctx->mc->reg, md, dctx->p)) {
+        if (md->stapling && dctx->mc->ocsp &&
+            md_reg_has_revoked_certs(dctx->mc->reg, dctx->mc->ocsp, md, dctx->p)) {
+            ap_log_error( APLOG_MARK, APLOG_DEBUG, 0, dctx->s, APLOGNO()
+                         "md(%s): has revoked certificates", job->mdomain);
+        }
+        else if (!md_reg_should_renew(dctx->mc->reg, md, dctx->p)) {
             ap_log_error( APLOG_MARK, APLOG_DEBUG, 0, dctx->s, APLOGNO(10053) 
                          "md(%s): no need to renew", job->mdomain);
             goto expiry;
@@ -180,10 +185,13 @@ int md_will_renew_cert(const md_t *md)
     return 1;
 }
 
-static apr_time_t next_run_default(void)
+static apr_time_t next_run_default(md_renew_ctx_t *dctx)
 {
-    /* we'd like to run at least twice a day by default */
-    return apr_time_now() + apr_time_from_sec(MD_SECS_PER_DAY / 2);
+    unsigned char c;
+    apr_time_t delay = dctx->mc->check_interval;
+
+    md_rand_bytes(&c, sizeof(c), dctx->p);
+    return apr_time_now() + delay + (delay * (c - 128) / 256);
 }
 
 static apr_status_t run_watchdog(int state, void *baton, apr_pool_t *ptemp)
@@ -211,7 +219,7 @@ static apr_status_t run_watchdog(int state, void *baton, apr_pool_t *ptemp)
              * and we schedule ourself at the earliest of all. A job may specify 0
              * as next_run to indicate that it wants to participate in the normal
              * regular runs. */
-            next_run = next_run_default();
+            next_run = next_run_default(dctx);
             for (i = 0; i < dctx->jobs->nelts; ++i) {
                 job = APR_ARRAY_IDX(dctx->jobs, i, md_job_t *);
 

test/modules/md/conftest.py

@@ -32,7 +32,8 @@ def env(pytestconfig) -> MDTestEnv:
     env.setup_httpd()
     env.apache_access_log_clear()
     env.httpd_error_log.clear_log()
-    return env
+    yield env
+    env.apache_stop()
 
 
 @pytest.fixture(autouse=True, scope="package")

test/modules/md/md_cert_util.py

@@ -166,10 +166,10 @@ def get_key_length(self):
 
     def get_san_list(self):
         text = OpenSSL.crypto.dump_certificate(OpenSSL.crypto.FILETYPE_TEXT, self.cert).decode("utf-8")
-        m = re.search(r"X509v3 Subject Alternative Name:\s*(.*)", text)
+        m = re.search(r"X509v3 Subject Alternative Name:(\s+critical)?\s*(.*)", text)
         sans_list = []
         if m:
-            sans_list = m.group(1).split(",")
+            sans_list = m.group(2).split(",")
 
         def _strip_prefix(s):
             return s.split(":")[1] if s.strip().startswith("DNS:") else s.strip()

test/modules/md/md_env.py

@@ -73,7 +73,11 @@ def has_acme_server(cls):
 
     @classmethod
     def has_acme_eab(cls):
-        return cls.get_acme_server() == 'pebble'
+        return False
+        # Pebble, since v2.5.0 no longer supports HS256 for EAB, which
+        # is the only thing mod_md supports. Issue opened at pebble:
+        # https://github.com/letsencrypt/pebble/issues/455
+        # return cls.get_acme_server() == 'pebble'
 
     @classmethod
     def is_pebble(cls) -> bool:
@@ -356,13 +360,14 @@ def check_md_credentials(self, domain):
         MDCertUtil.validate_privkey(self.store_domain_file(domain, 'privkey.pem'))
         cert = MDCertUtil(self.store_domain_file(domain, 'pubcert.pem'))
         cert.validate_cert_matches_priv_key(self.store_domain_file(domain, 'privkey.pem'))
-        # check SANs and CN
-        assert cert.get_cn() == domain
+        # No longer check CN, it may not be set or is not trusted anyway
+        # assert cert.get_cn() == domain, f'CN: expected "{domain}", got {cert.get_cn()}'
+        # check SANs
         # compare lists twice in opposite directions: SAN may not respect ordering
         san_list = list(cert.get_san_list())
         assert len(san_list) == len(domains)
-        assert set(san_list).issubset(domains)
-        assert set(domains).issubset(san_list)
+        assert set(san_list).issubset(domains), f'{san_list} not subset of {domains}'
+        assert set(domains).issubset(san_list), f'{domains} not subset of {san_list}'
         # check valid dates interval
         not_before = cert.get_not_before()
         not_after = cert.get_not_after()

test/modules/md/test_300_conf_validate.py

@@ -15,7 +15,8 @@
 class TestConf:
 
     @pytest.fixture(autouse=True, scope='class')
-    def _class_scope(self, env):
+    def _class_scope(self, env, acme):
+        acme.start(config='default')
         env.clear_store()
 
     # test case: just one MDomain definition
@@ -413,7 +414,7 @@ def test_md_300_025(self, env, ca, url):
     def test_md_300_026(self, env):
         assert env.apache_stop() == 0
         conf = MDConf(env)
-        domain = f"t300_026.{env.http_tld}"
+        domain = f"t300-026.{env.http_tld}"
         conf.add(f"""
             MDomain {domain}
             """)
@@ -460,11 +461,12 @@ def test_md_300_027(self, env, cas, should_work):
     def test_md_300_028(self, env):
         assert env.apache_stop() == 0
         conf = MDConf(env)
-        domaina = f"t300_028a.{env.http_tld}"
-        domainb = f"t300_028b.{env.http_tld}"
-        dalias = f"t300_028alias.{env.http_tld}"
+        domaina = f"t300-028a.{env.http_tld}"
+        domainb = f"t300-028b.{env.http_tld}"
+        dalias = f"t300-028alias.{env.http_tld}"
         conf.add_vhost(port=env.http_port, domains=[domaina, domainb, dalias], with_ssl=False)
         conf.add(f"""
+            MDMembers manual
             MDomain {domaina} 
             MDomain {domainb} {dalias}
             """)
@@ -481,23 +483,28 @@ def test_md_300_028(self, env):
             </VirtualHost>
             """)
         conf.install()
-        # This does not work as we have both MDs match domaina's vhost
+        # This does not work as we have both MDs match domain's vhost
         assert env.apache_fail() == 0
         env.httpd_error_log.ignore_recent(
-            lognos = [
-                "AH10238"   # 2 MDs match the same vhost
+            lognos=[
+                "AH10238",   # 2 MDs match the same vhost
             ]
         )
         # It works, if we only match on ServerNames
         conf.add("MDMatchNames servernames")
         conf.install()
         assert env.apache_restart() == 0
+        env.httpd_error_log.ignore_recent(
+            lognos=[
+                "AH10040",  # ServerAlias not covered
+            ]
+        )
 
     # wildcard and specfic MD overlaps
     def test_md_300_029(self, env):
         assert env.apache_stop() == 0
         conf = MDConf(env)
-        domain = f"t300_029.{env.http_tld}"
+        domain = f"t300-029.{env.http_tld}"
         subdomain = f"sub.{domain}"
         conf.add_vhost(port=env.http_port, domains=[domain, subdomain], with_ssl=False)
         conf.add(f"""
@@ -531,4 +538,10 @@ def test_md_300_029(self, env):
         conf.add("MDMatchNames servernames")
         conf.install()
         assert env.apache_restart() == 0
+        time.sleep(2)
+        assert env.apache_stop() == 0
+        # we need dns-01 challenge for the wildcard, which is not configured
+        env.httpd_error_log.ignore_recent(matches=[
+            r'.*None of offered challenge types.*are supported.*'
+        ])