1 files changed, 60 insertions, 0 deletions
diff --git a/debian/patches/0036-CVE-2022-2795.patch b/debian/patches/0036-CVE-2022-2795.patch
new file mode 100644
index 0000000..c978c73
--- /dev/null
+++ b/debian/patches/0036-CVE-2022-2795.patch
@@ -0,0 +1,60 @@
+From bf2ea6d8525bfd96a84dad221ba9e004adb710a8 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <michal@isc.org>
+Date: Thu, 8 Sep 2022 11:11:30 +0200
+Subject: [PATCH] Bound the amount of work performed for delegations
+
+Limit the amount of database lookups that can be triggered in
+fctx_getaddresses() (i.e. when determining the name server addresses to
+query next) by setting a hard limit on the number of NS RRs processed
+for any delegation encountered.  Without any limit in place, named can
+be forced to perform large amounts of database lookups per each query
+received, which severely impacts resolver performance.
+
+The limit used (20) is an arbitrary value that is considered to be big
+enough for any sane DNS delegation.
+
+(cherry picked from commit 3a44097fd6c6c260765b628cd1d2c9cb7efb0b2a)
+---
+ lib/dns/resolver.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
+index d2cf14bbc8b..73a0ee9f779 100644
+--- a/lib/dns/resolver.c
++++ b/lib/dns/resolver.c
+@@ -195,6 +195,12 @@
+  */
+ #define NS_FAIL_LIMIT 4
+ #define NS_RR_LIMIT   5
++/*
++ * IP address lookups are performed for at most NS_PROCESSING_LIMIT NS RRs in
++ * any NS RRset encountered, to avoid excessive resource use while processing
++ * large delegations.
++ */
++#define NS_PROCESSING_LIMIT 20
+ 
+ /* Number of hash buckets for zone counters */
+ #ifndef RES_DOMAIN_BUCKETS
+@@ -3711,6 +3717,7 @@ fctx_getaddresses(fetchctx_t *fctx, bool badcache) {
+ 	bool need_alternate = false;
+ 	bool all_spilled = true;
+ 	unsigned int no_addresses = 0;
++	unsigned int ns_processed = 0;
+ 
+ 	FCTXTRACE5("getaddresses", "fctx->depth=", fctx->depth);
+ 
+@@ -3902,6 +3909,11 @@ normal_nses:
+ 
+ 		dns_rdata_reset(&rdata);
+ 		dns_rdata_freestruct(&ns);
++
++		if (++ns_processed >= NS_PROCESSING_LIMIT) {
++			result = ISC_R_NOMORE;
++			break;
++		}
+ 	}
+ 	if (result != ISC_R_NOMORE) {
+ 		return (result);
+-- 
+GitLab
+