[SR-Dev] git:ser_core_cvs: dns: fix selecting neg. cname entry

Module: sip-router Branch: ser_core_cvs Commit: 25ba1f0f4cd2b059e3f2a27d619ca054122cf4cb URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=25ba1f0… Author: Andrei Pelinescu-Onciul <andrei(a)iptel.org> Committer: Andrei Pelinescu-Onciul <andrei(a)iptel.org> Date: Tue Mar 31 18:11:25 2009 +0000 dns: fix selecting neg. cname entry - do not select a neg. cache cname entry as a response, unless the request is for a cname. This fixes an unlikely bug: someone makes a specific cname request (from ser) for a name that doesn't resolve and then later when a normal non-cname request is made (e.g. A) the empty negative cname entry is selected, leading to a coredump. So far there is no code in ser that could trigger this bug. Only dns.lookup cname ... from sip-router could trigger it. --- dns_cache.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/dns_cache.c b/dns_cache.c index b0e7a4d..a5167c4 100644 --- a/dns_cache.c +++ b/dns_cache.c @@ -580,8 +580,11 @@ again: #endif #endif return e; - }else if ((e->type==T_CNAME) && (e->name_len==name->len) && - (strncasecmp(e->name, name->s, e->name_len)==0)){ + }else if ((e->type==T_CNAME) && !((e->rr_lst==0) || e->err_flags) && + (e->name_len==name->len) && + (strncasecmp(e->name, name->s, e->name_len)==0)){ + /*if CNAME matches and CNAME is entry is not a neg. cache entry + (could be produced by a specific CNAME lookup)*/ e->last_used=now; #ifdef DNS_LU_LST /* add it at the end */