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Index: src/query.c
===================================================================
--- src/query.c (revision 14)
+++ src/query.c (working copy)
@@ -63,6 +63,10 @@
qu->cname_dgram= 0;
qu->cname_dglen= qu->cname_begin= 0;
+ /* Patch to allow CNAME chains */
+ /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+ /* Allow CNAME chains up to some sane limit */
+ qu->cname_alias_hops_left = 10;
adns__vbuf_init(&qu->search_vb);
qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
Index: src/internal.h
===================================================================
--- src/internal.h (revision 14)
+++ src/internal.h (working copy)
@@ -231,6 +231,11 @@
int cname_dglen, cname_begin;
/* If non-0, has been allocated using . */
+ /* Patch to allow CNAME chains */
+ /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+ int cname_alias_hops_left;
+ /* The number of cname alias hops we will allow */
+
vbuf search_vb;
int search_origlen, search_pos, search_doneabs;
/* Used by the searching algorithm. The query domain in textual form
Index: src/reply.c
===================================================================
--- src/reply.c (revision 14)
+++ src/reply.c (working copy)
@@ -190,12 +190,17 @@
if (qu->flags & adns_qf_cname_forbid) {
adns__query_fail(qu,adns_s_prohibitedcname);
return;
- } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */
+ }
+
+ /* Patch to allow CNAME chains */
+ /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+ else if (qu->cname_dgram && --(qu->cname_alias_hops_left) <= 0) { /* Don't follow "too long" CNAME chains */
adns__debug(ads,serv,qu,"allegedly canonical name %s"
- " is actually alias for %s", qu->answer->cname,
+ " is actually alias for %s and aliases too deep",
+ qu->answer->cname,
adns__diag_domain(ads,serv,qu, &qu->vb,
dgram,dglen,rdstart));
- adns__query_fail(qu,adns_s_prohibitedcname);
+ adns__query_fail(qu,adns_s_norecurse);
return;
} else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */
adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR",
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