1 files changed, 67 insertions, 0 deletions

diff --git a/meta/recipes-connectivity/bind/bind/CVE-2022-2795.patch b/meta/recipes-connectivity/bind/bind/CVE-2022-2795.patch
new file mode 100644
index 0000000000..940c6776d3
--- /dev/null
+++ b/meta/recipes-connectivity/bind/bind/CVE-2022-2795.patch
@@ -0,0 +1,67 @@
+From 36c878a0124973f29b7ca49e6bb18310f9b2601f 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 1/3] 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)
+
+Upstream-Status: Backport
+CVE: CVE-2022-2795
+Reference to upstream patch:
+https://gitlab.isc.org/isc-projects/bind9/-/commit/bf2ea6d8525bfd96a84dad221ba9e004adb710a8
+
+Signed-off-by: Mathieu Dubois-Briand <mbriand@witekio.com>
+---
+ lib/dns/resolver.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
+index 8ae9a993bbd7..ac9a9ef5d009 100644
+--- a/lib/dns/resolver.c
++++ b/lib/dns/resolver.c
+@@ -180,6 +180,12 @@
+  */
+ #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
+@@ -3318,6 +3324,7 @@ 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);
+ 
+@@ -3504,6 +3511,11 @@ fctx_getaddresses(fetchctx_t *fctx, bool badcache) {
+ 
+                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);
+-- 
+2.34.1
+