Routing: in a dnslookup, fix fail_defer_domains to defer on missing MX record. Bug 1867

7 files changed, 34 insertions, 23 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 11b25f875..148329505 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -68,6 +68,9 @@ JH/16 DANE: treat a TLSA lookup response having all non-TLSA RRs, the same
 JH/17 Fakereject: previously logged as a norml message arrival "<="; now
       distinguished as "(=".
 
+JH/18 Bug 1867: make the fail_defer_domains option on a dnslookup router work
+      for missing MX records.  Previously it only worked for missing A records.
+
 
 Exim version 4.87
 -----------------
diff --git a/src/src/routers/dnslookup.c b/src/src/routers/dnslookup.c
index 83ba5f689..d2be40e0f 100644
--- a/src/src/routers/dnslookup.c
+++ b/src/src/routers/dnslookup.c
@@ -305,6 +305,22 @@ for (;;)
 
   if (rc != HOST_FIND_FAILED) break;
 
+  if (ob->fail_defer_domains)
+    switch(match_isinlist(fully_qualified_name,
+	  CUSS &ob->fail_defer_domains, 0,
+	  &domainlist_anchor, addr->domain_cache, MCL_DOMAIN, TRUE, NULL))
+      {
+      case DEFER:
+	addr->message = US"lookup defer for fail_defer_domains option";
+	return DEFER;
+
+      case OK:
+	DEBUG(D_route) debug_printf("%s router: matched fail_defer_domains\n",
+	  rblock->name);
+	addr->message = US"missing MX, or all MXs point to missing A records,"
+	  " and defer requested";
+	return DEFER;
+      }
   /* Check to see if the failure is the result of MX records pointing to
   non-existent domains, and if so, set an appropriate error message; the case
   of an MX or SRV record pointing to "." is another special case that we can
@@ -335,22 +351,6 @@ for (;;)
           addr->message);
         }
       }
-    if (ob->fail_defer_domains)
-      {
-      switch(match_isinlist(fully_qualified_name,
-	    CUSS &ob->fail_defer_domains, 0,
-	    &domainlist_anchor, addr->domain_cache, MCL_DOMAIN, TRUE, NULL))
-	{
-	case DEFER:
-	  addr->message = US"lookup defer for fail_defer_domains";
-	  return DEFER;
-
-	case OK:
-	  DEBUG(D_route) debug_printf("%s router: matched fail_defer_domains\n",
-	    rblock->name);
-	  return DEFER;
-	}
-      }
     return DECLINE;
     }
 
diff --git a/src/src/utf8.c b/src/src/utf8.c
index 84ad1dc18..e394db0a8 100644
--- a/src/src/utf8.c
+++ b/src/src/utf8.c
@@ -18,7 +18,7 @@ BOOL
 string_is_utf8(const uschar * s)
 {
 uschar c;
-while ((c = *s++)) if (c & 0x80) return TRUE;
+if (s) while ((c = *s++)) if (c & 0x80) return TRUE;
 return FALSE;
 }
 
diff --git a/test/confs/0099 b/test/confs/0099
index 8db58dcb0..8b4299130 100644
--- a/test/confs/0099
+++ b/test/confs/0099
@@ -19,7 +19,7 @@ begin routers
 
 bydns:
   driver = dnslookup
-  domains = mxt2.test.ex
+  domains = mxt2.test.ex : mxnonexist.test.ex
   transport = smtp
   fail_defer_domains = *
 
diff --git a/test/log/0099 b/test/log/0099
index 4b6439219..13a1916c1 100644
--- a/test/log/0099
+++ b/test/log/0099
@@ -25,4 +25,6 @@
 1999-03-02 09:44:33 10HmbC-0005vi-00 no IP address found for host nonexist.test.ex
 1999-03-02 09:44:33 10HmbC-0005vi-00 == userx@nonexist R=all defer (-32): lookup of host "nonexist.test.ex" failed in all router
 1999-03-02 09:44:33 10HmbD-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss for userx@mxt2.test.ex
-1999-03-02 09:44:33 10HmbD-0005vi-00 == userx@mxt2.test.ex R=bydns defer (-32): all relevant MX records point to non-existent hosts
+1999-03-02 09:44:33 10HmbD-0005vi-00 == userx@mxt2.test.ex R=bydns defer (-1): missing MX, or all MXs point to missing A records, and defer requested
+1999-03-02 09:44:33 10HmbE-0005vi-00 <= CALLER@test.ex U=CALLER P=local S=sss for userx@mxnonexist.test.ex
+1999-03-02 09:44:33 10HmbE-0005vi-00 == userx@mxnonexist.test.ex R=bydns defer (-1): missing MX, or all MXs point to missing A records, and defer requested
diff --git a/test/scripts/0000-Basic/0099 b/test/scripts/0000-Basic/0099
index c386e1e85..d6655dcf9 100644
--- a/test/scripts/0000-Basic/0099
+++ b/test/scripts/0000-Basic/0099
@@ -38,14 +38,18 @@ Test message
 ****
 dump retry
 #
-# one for a lookup-failure (in manualroute)
+# a lookup-failure (in manualroute)
 exim -odi userx@nonexist
 Test message
 ****
-# one for a lookup-failure (in dnslookup)
+# a lookup-failure (good MX, missing A) in dnslookup, deferred
 exim -odi userx@mxt2.test.ex
 Test message
 ****
+# a lookup-failure (missing MX) in dnslookup, deferred
+exim -odi userx@mxnonexist.test.ex
+Test message
+****
 dump retry
 #
 #
diff --git a/test/stdout/0099 b/test/stdout/0099
index 0f6f7f2fa..e14fa0a35 100644
--- a/test/stdout/0099
+++ b/test/stdout/0099
@@ -41,8 +41,10 @@ first failed = time last try = time2 next try = time2 + 900
   T:thisloop.test.ex:999 dd 65 Connection refused
 first failed = time last try = time2 next try = time2 + 900
 +++++++++++++++++++++++++++
-  R:mxt2.test.ex -32 0 all relevant MX records point to non-existent hosts
-first failed = time last try = time2 next try = time2 + 1800
+  R:mxnonexist.test.ex -1 0 missing MX, or all MXs point to missing A records, and defer requested
+first failed = time last try = time2 next try = time2 + 900
+  R:mxt2.test.ex -1 0 missing MX, or all MXs point to missing A records, and defer requested
+first failed = time last try = time2 next try = time2 + 900
   R:nonexist -32 0 lookup of host "nonexist.test.ex" failed in all router
 first failed = time last try = time2 next try = time2 + 1800
   T:thishost.test.ex:127.0.0.1:999 dd 65 Connection refused