MSVSphere Packaging Team
1 year ago
parent
a7c33f0154
commit
294087c110
@ -0,0 +1,37 @@
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From e73ecbf039c3b2cd33dd2926691a8a346c9ca574 Mon Sep 17 00:00:00 2001
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From: Matthijs Mekking <matthijs@isc.org>
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Date: Tue, 2 Aug 2022 14:21:40 +0200
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Subject: [PATCH 1/3] Don't enable serve-stale on duplicate queries
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When checking if we should enable serve-stale, add an early out case
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when the result is an error signalling a duplicate query or a query
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that would be dropped.
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(cherry picked from commit 059a4c2f4d9d3cff371842f43208d021509314fa)
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(cherry picked from commit dd7dde5743715dc0dec2defbb92b1a8637977bf9)
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---
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lib/ns/query.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/lib/ns/query.c b/lib/ns/query.c
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index 4f61374e2c..c169e22bf4 100644
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--- a/lib/ns/query.c
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+++ b/lib/ns/query.c
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@@ -7205,6 +7205,14 @@ query_usestale(query_ctx_t *qctx, isc_result_t result) {
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return (false);
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}
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+ if (result == DNS_R_DUPLICATE || result == DNS_R_DROP) {
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+ /*
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+ * Don't enable serve-stale if the result signals a duplicate
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+ * query or query that is being dropped.
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+ */
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+ return (false);
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+ }
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+
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qctx_clean(qctx);
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qctx_freedata(qctx);
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--
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2.40.1
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@ -0,0 +1,72 @@
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From 589c06568e3036bfe713d42b53c8e88005ce17e4 Mon Sep 17 00:00:00 2001
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From: Evan Hunt <each@isc.org>
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Date: Thu, 25 May 2023 23:53:50 -0700
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Subject: [PATCH 2/3] Stale answer lookups could loop when over recursion quota
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When a query was aborted because of the recursion quota being exceeded,
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but triggered a stale answer response and a stale data refresh query,
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it could cause named to loop back where we are iterating and following
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a delegation. Having no good answer in cache, we would fall back to
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using serve-stale again, use the stale data, try to refresh the RRset,
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and loop back again, without ever terminating until crashing due to
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stack overflow.
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This happens because in the functions 'query_notfound()' and
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'query_delegation_recurse()', we check whether we can fall back to
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serving stale data. We shouldn't do so if we are already refreshing
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an RRset due to having prioritized stale data in cache.
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In other words, we need to add an extra check to 'query_usestale()' to
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disallow serving stale data if we are currently refreshing a stale
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RRset.
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As an additional mitigation to prevent looping, we now use the result
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code ISC_R_ALREADYRUNNING rather than ISC_R_FAILURE when a recursion
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loop is encountered, and we check for that condition in
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'query_usestale()' as well.
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(cherry picked from commit 0101e28f91fb36b6a16a0049d3b3e2b7846f23f0)
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---
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lib/ns/query.c | 17 ++++++++++++++---
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1 file changed, 14 insertions(+), 3 deletions(-)
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diff --git a/lib/ns/query.c b/lib/ns/query.c
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index c169e22bf4..1eb662ea4d 100644
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--- a/lib/ns/query.c
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+++ b/lib/ns/query.c
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@@ -6229,7 +6229,7 @@ ns_query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qname,
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if (recparam_match(&client->query.recparam, qtype, qname, qdomain)) {
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ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_QUERY,
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ISC_LOG_INFO, "recursion loop detected");
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- return (ISC_R_FAILURE);
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+ return (ISC_R_ALREADYRUNNING);
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}
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recparam_update(&client->query.recparam, qtype, qname, qdomain);
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@@ -7205,10 +7205,21 @@ query_usestale(query_ctx_t *qctx, isc_result_t result) {
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return (false);
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}
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- if (result == DNS_R_DUPLICATE || result == DNS_R_DROP) {
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+ if (qctx->refresh_rrset) {
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+ /*
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+ * This is a refreshing query, we have already prioritized
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+ * stale data, so don't enable serve-stale again.
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+ */
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+ return (false);
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+ }
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+
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+ if (result == DNS_R_DUPLICATE || result == DNS_R_DROP ||
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+ result == ISC_R_ALREADYRUNNING)
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+ {
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/*
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* Don't enable serve-stale if the result signals a duplicate
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- * query or query that is being dropped.
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+ * query or a query that is being dropped or can't proceed
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+ * because of a recursion loop.
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*/
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return (false);
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}
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--
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2.40.1
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@ -0,0 +1,60 @@
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From c20e9d30bae58d3120aa7c6a0e5dcae0e7e93dbd Mon Sep 17 00:00:00 2001
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From: Matthijs Mekking <matthijs@isc.org>
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Date: Thu, 1 Jun 2023 10:03:48 +0200
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Subject: [PATCH 3/3] Fix serve-stale hang at shutdown
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The 'refresh_rrset' variable is used to determine if we can detach from
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the client. This can cause a hang on shutdown. To fix this, move setting
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of the 'nodetach' variable up to where 'refresh_rrset' is set (in
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query_lookup(), and thus not in ns_query_done()), and set it to false
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when actually refreshing the RRset, so that when this lookup is
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completed, the client will be detached.
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(cherry picked from commit c003c5bc3c68f3e513654b6689e1f60280d14844)
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---
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lib/ns/query.c | 13 ++++++++-----
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1 file changed, 8 insertions(+), 5 deletions(-)
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diff --git a/lib/ns/query.c b/lib/ns/query.c
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index 1eb662ea4d..4fe3e30f45 100644
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--- a/lib/ns/query.c
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+++ b/lib/ns/query.c
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@@ -5644,6 +5644,7 @@ query_refresh_rrset(query_ctx_t *orig_qctx) {
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qctx.client->query.dboptions &= ~(DNS_DBFIND_STALETIMEOUT |
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DNS_DBFIND_STALEOK |
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DNS_DBFIND_STALEENABLED);
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+ qctx.client->nodetach = false;
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/*
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* We'll need some resources...
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@@ -5868,7 +5869,14 @@ query_lookup(query_ctx_t *qctx) {
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"%s stale answer used, an attempt to "
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"refresh the RRset will still be made",
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namebuf);
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+
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qctx->refresh_rrset = STALE(qctx->rdataset);
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+
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+ /*
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+ * If we are refreshing the RRSet, we must not
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+ * detach from the client in query_send().
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+ */
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+ qctx->client->nodetach = qctx->refresh_rrset;
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}
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} else {
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/*
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@@ -11469,12 +11477,7 @@ ns_query_done(query_ctx_t *qctx) {
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/*
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* Client may have been detached after query_send(), so
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* we test and store the flag state here, for safety.
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- * If we are refreshing the RRSet, we must not detach from the client
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- * in the query_send(), so we need to override the flag.
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*/
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- if (qctx->refresh_rrset) {
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- qctx->client->nodetach = true;
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- }
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nodetach = qctx->client->nodetach;
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query_send(qctx->client);
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--
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2.40.1
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