DANE: for hosts_try_dane (but not _require), on dnssec but no TLSA returned, fallback...

[exim.git] / src / src / transports / smtp.c

diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index dec52d047b0a9d9db34645f91d371ec66593f4d0..234467437c6a8ff4c86da5db8688767b59ceff9f 100644 (file)
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -1215,9 +1215,15 @@ return FALSE;
 
 
 #ifdef EXPERIMENTAL_DANE
+/* Lookup TLSA record for host/port.
+Return:  OK            success with dnssec; DANE mode
+         DEFER         Do not use this host now, may retry later
+        FAIL_FORCED    No TLSA record; DANE not usable
+        FAIL           Do not use this connection
+*/
+
 int
-tlsa_lookup(const host_item * host, dns_answer * dnsa,
-  BOOL dane_required, BOOL * dane)
+tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
 {
 /* move this out to host.c given the similarity to dns_lookup() ? */
 uschar buffer[300];
@@ -1228,25 +1234,24 @@ const uschar * fullname = buffer;
 
 switch (dns_lookup(dnsa, buffer, T_TLSA, &fullname))
   {
-  case DNS_AGAIN:
-    return DEFER; /* just defer this TLS'd conn */
-
-  default:
-  case DNS_FAIL:
-    if (dane_required)
-      return FAIL;
-    break;
-
   case DNS_SUCCEED:
     if (!dns_is_secure(dnsa))
       {
       log_write(0, LOG_MAIN, "DANE error: TLSA lookup not DNSSEC");
       return DEFER;
       }
-    *dane = TRUE;
-    break;
+    return OK;
+
+  case DNS_AGAIN:
+    return DEFER; /* just defer this TLS'd conn */
+
+  case DNS_NOMATCH:
+    return dane_required ? FAIL : FAIL_FORCED;
+
+  default:
+  case DNS_FAIL:
+    return dane_required ? FAIL : DEFER;
   }
-return OK;
 }
 #endif
 
@@ -1311,7 +1316,6 @@ we will veto this new message.  */
 static BOOL
 smtp_are_same_identities(uschar * message_id, smtp_compare_t * s_compare)
 {
-
 uschar * message_local_identity,
        * current_local_identity,
        * new_sender_address;
@@ -1545,26 +1549,26 @@ if (continue_hostname == NULL)
 
     if (host->dnssec == DS_YES)
       {
-      if(  (  dane_required
-          || verify_check_given_host(&ob->hosts_try_dane, host) == OK
-          )
-       && (rc = tlsa_lookup(host, &tlsa_dnsa, dane_required, &dane)) != OK
-       && dane_required        /* do not error on only dane-requested */
+      if(  dane_required
+       || verify_check_given_host(&ob->hosts_try_dane, host) == OK
        )
-       {
-       set_errno_nohost(addrlist, ERRNO_DNSDEFER,
-         string_sprintf("DANE error: tlsa lookup %s",
-           rc == DEFER ? "DEFER" : "FAIL"),
-         rc, FALSE);
-       return rc;
-       }
+       switch (rc = tlsa_lookup(host, &tlsa_dnsa, dane_required))
+         {
+         case OK:              dane = TRUE; break;
+         case FAIL_FORCED:     break;
+         default:              set_errno_nohost(addrlist, ERRNO_DNSDEFER,
+                                 string_sprintf("DANE error: tlsa lookup %s",
+                                   rc == DEFER ? "DEFER" : "FAIL"),
+                                 rc, FALSE);
+                               return rc;
+         }
       }
     else if (dane_required)
       {
       set_errno_nohost(addrlist, ERRNO_DNSDEFER,
        string_sprintf("DANE error: %s lookup not DNSSEC", host->name),
        FAIL, FALSE);
-      return  FAIL;
+      return FAIL;
       }
 
     if (dane)
@@ -1790,8 +1794,10 @@ if (  tls_offered
   if (!smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
       ob->command_timeout))
     {
-    if (errno != 0 || buffer2[0] == 0 ||
-         (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
+    if (  errno != 0
+       || buffer2[0] == 0
+       || (buffer2[0] == '4' && !ob->tls_tempfail_tryclear)
+       )
       {
       Ustrncpy(buffer, buffer2, sizeof(buffer));
       goto RESPONSE_FAILED;
@@ -1816,13 +1822,11 @@ if (  tls_offered
     if (rc != OK)
       {
 # ifdef EXPERIMENTAL_DANE
-      if (rc == DEFER && dane && !dane_required)
+      if (rc == DEFER && dane)
        {
-       log_write(0, LOG_MAIN, "DANE attempt failed;"
-         " trying CA-root TLS to %s [%s] (not in hosts_require_dane)",
+       log_write(0, LOG_MAIN,
+         "DANE attempt failed; no TLS connection to %s [%s]",
          host->name, host->address);
-       dane = FALSE;
-       goto TLS_NEGOTIATE;
        }
 # endif
 
@@ -2958,6 +2962,7 @@ writing RSET might have failed, or there may be other addresses whose hosts are
 specified in the transports, and therefore not visible at top level, in which
 case continue_more won't get set. */
 
+HDEBUG(D_transport|D_acl|D_v) debug_printf("  SMTP(close)>>\n");
 (void)close(inblock.sock);
 
 #ifndef DISABLE_EVENT
@@ -3960,9 +3965,9 @@ for (addr = addrlist; addr != NULL; addr = addr->next)
     else if (expired)
       {
       setflag(addr, af_pass_message);   /* This is not a security risk */
-      addr->message = (ob->delay_after_cutoff)?
-        US"retry time not reached for any host after a long failure period" :
-        US"all hosts have been failing for a long time and were last tried "
+      addr->message = ob->delay_after_cutoff
+        ? US"retry time not reached for any host after a long failure period"
+        : US"all hosts have been failing for a long time and were last tried "
           "after this message arrived";
 
       /* If we are already using fallback hosts, or there are no fallback hosts
@@ -3974,18 +3979,23 @@ for (addr = addrlist; addr != NULL; addr = addr->next)
       }
     else
       {
+      const char * s;
       if (hosts_retry == hosts_total)
-        addr->message = US"retry time not reached for any host";
+        s = "retry time not reached for any host%s";
       else if (hosts_fail == hosts_total)
-        addr->message = US"all host address lookups failed permanently";
+        s = "all host address lookups%s failed permanently";
       else if (hosts_defer == hosts_total)
-        addr->message = US"all host address lookups failed temporarily";
+        s = "all host address lookups%s failed temporarily";
       else if (hosts_serial == hosts_total)
-        addr->message = US"connection limit reached for all hosts";
+        s = "connection limit reached for all hosts%s";
       else if (hosts_fail+hosts_defer == hosts_total)
-        addr->message = US"all host address lookups failed";
-      else addr->message = US"some host address lookups failed and retry time "
-        "not reached for other hosts or connection limit reached";
+        s = "all host address lookups%s failed";
+      else
+        s = "some host address lookups failed and retry time "
+        "not reached for other hosts or connection limit reached%s";
+
+      addr->message = string_sprintf(s,
+       addr->domain ? string_sprintf(" for '%s'", addr->domain) : US"");
       }
     }
   }