When following a CNAME chain, if any lookup is insecure the whole must be too

[exim.git] / src / src / dns.c

diff --git a/src/src/dns.c b/src/src/dns.c
index 6efb88d5843b4f96ee04cef42597b44644ce1ead..542354db394e0c41a28583c5831450661a9ee52e 100644 (file)
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -455,6 +455,14 @@ return h->ad ? TRUE : FALSE;
 #endif
 }
 
+static void
+dns_set_insecure(dns_answer * dnsa)
+{
+HEADER * h = (HEADER *)dnsa->answer;
+h->ad = 0;
+}
+
+
 
 
 
@@ -607,7 +615,7 @@ if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
   /* For an SRV lookup, skip over the first two components (the service and
   protocol names, which both start with an underscore). */
 
-  if (type == T_SRV)
+  if (type == T_SRV || type == T_TLSA)
     {
     while (*checkname++ != '.');
     while (*checkname++ != '.');
@@ -752,7 +760,8 @@ int
 dns_lookup(dns_answer *dnsa, uschar *name, int type, uschar **fully_qualified_name)
 {
 int i;
-uschar *orig_name = name;
+const uschar *orig_name = name;
+BOOL secure_so_far = TRUE;
 
 /* Loop to follow CNAME chains so far, but no further... */
 
@@ -807,7 +816,12 @@ for (i = 0; i < 10; i++)
 
   /* If any data records of the correct type were found, we are done. */
 
-  if (type_rr.data != NULL) return DNS_SUCCEED;
+  if (type_rr.data != NULL)
+    {
+    if (!secure_so_far)        /* mark insecure if any element of CNAME chain was */
+      dns_set_insecure(dnsa);
+    return DNS_SUCCEED;
+    }
 
   /* If there are no data records, we need to re-scan the DNS using the
   domain given in the CNAME record, which should exist (otherwise we should
@@ -820,6 +834,9 @@ for (i = 0; i < 10; i++)
   if (datalen < 0) return DNS_FAIL;
   name = data;
 
+  if (!dns_is_secure(dnsa))
+    secure_so_far = FALSE;
+
   DEBUG(D_dns) debug_printf("CNAME found: change to %s\n", name);
   }       /* Loop back to do another lookup */