Symptoms:
Host www.kk.org has both AAAA and CNAME -- ignoring CNAME.
Host www.kk.org has both AAAA and CNAME -- ignoring CNAME.
Host www.kk.org has both AAAA and CNAME -- ignoring CNAME.
Host www.kk.org lookup failed: Timeout (131072).
Cause:
Polipo sends two DNS queries in paralell for A (ipv4) and AAAA
(ipv6). Here's what causes the above error:
polipo: query 1: A
polipo: query 2: AAAA
dns: response to 2: no error, but also no answers
(i.e. domain exists but is not an IPV6 address)
dns: response to 1: CNAME (a redirect to a different domain name)
Fix:
Don't allow responses to an AAAA query to override CNAME if the
AAAA response doesn't actually include an address.
The fix itself only affects a single if statement. The remaining
bulk of the patch is needed to correct the same issue in an
assertion further down.
diff --git a/dns.c b/dns.c
index 8d4ac75..d126857 100644
diff --git a/dns.c b/dns.c
index 8d4ac75..8c8f160 100644
--- a/dns.c
+++ b/dns.c
@@ -1181,7 +1181,8 @@ dnsReplyHandler(int abort, FdEventHandlerPtr event)
} else
releaseAtom(value);
} else if(af == 0) {
- if(query->inet4 || query->inet6) {
+ if((query->inet4 && query->inet4->length > 0) ||
+ (query->inet6 && query->inet6->length > 0)) {
do_log(L_WARN, "Host %s has both %s and CNAME -- "
"ignoring CNAME.\n", scrub(query->name->string),
query->inet4 ? "A" : "AAAA");
@@ -1206,24 +1207,29 @@ dnsReplyHandler(int abort, FdEventHandlerPtr event)
if(object->flags & OBJECT_INITIAL) {
assert(!object->headers);
+
+ if (query->inet4 && query->inet4->length == 0) {
+ releaseAtom(query->inet4);
+ query->inet4 = NULL;
+ }
+ if (query->inet6 && query->inet6->length == 0) {
+ releaseAtom(query->inet6);
+ query->inet6 = NULL;
+ }
+
if(cname) {
- assert(query->inet4 == NULL && query->inet6 == NULL);
+ assert(!query->inet4 && !query->inet6);
object->headers = cname;
object->expires = current_time.tv_sec + ttl;
- } else if((!query->inet4 || query->inet4->length == 0) &&
- (!query->inet6 || query->inet6->length == 0)) {
- releaseAtom(query->inet4);
- releaseAtom(query->inet6);
+ } else if(!query->inet4 && !query->inet6) {
object->expires = current_time.tv_sec + dnsNegativeTtl;
abortObject(object, 500, retainAtom(message));
- } else if(!query->inet4 || query->inet4->length == 0) {
+ } else if(!query->inet4) {
object->headers = query->inet6;
object->expires = query->ttl6;
- releaseAtom(query->inet4);
- } else if(!query->inet6 || query->inet6->length == 0) {
+ } else if(!query->inet6) {
object->headers = query->inet4;
object->expires = query->ttl4;
- releaseAtom(query->inet6);
} else {
/* need to merge results */
char buf[1024];
------------------------------------------------------------------------------
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