DNS: do not skip initial two components of SRV & TLSA lookups before checking name syntax.

The introduction of DKIM added _ to the permitted chars, so those components will pass.

1 files changed, 3 insertions, 20 deletions

diff --git a/src/src/dns.c b/src/src/dns.c
index 44654353c..4750f1b52 100644
--- a/src/src/dns.c
+++ b/src/src/dns.c
@@ -818,34 +818,17 @@ regex has substrings that are used - the default uses a conditional.
 
 This test is omitted for PTR records. These occur only in calls from the dnsdb
 lookup, which constructs the names itself, so they should be OK. Besides,
-bitstring labels don't conform to normal name syntax. (But the aren't used any
-more.)
-
-For SRV records, we omit the initial _smtp._tcp. components at the start.
-The check has been seen to bite on the destination of a SRV lookup that
-initiall hit a CNAME, for which the next name had only two components.
-RFC2782 makes no mention of the possibiility of CNAMES, but the Wikipedia
-article on SRV says they are not a valid configuration. */
+bitstring labels don't conform to normal name syntax. (But they aren't used any
+more.) */
 
 #ifndef STAND_ALONE   /* Omit this for stand-alone tests */
 
 if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
   {
-  const uschar *checkname = name;
   int ovector[3*(EXPAND_MAXN+1)];
 
   dns_pattern_init();
-
-  /* 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 || type == T_TLSA)
-    {
-    while (*checkname && *checkname++ != '.') ;
-    while (*checkname && *checkname++ != '.') ;
-    }
-
-  if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),
+  if (pcre_exec(regex_check_dns_names, NULL, CCS name, Ustrlen(name),
       0, PCRE_EOPT, ovector, nelem(ovector)) < 0)
     {
     DEBUG(D_dns)