From 9ac47d37a59142a66ac13f58bef197117ff53141 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Wed, 24 Mar 2021 11:42:39 +0100
Subject: [PATCH] Revert "resolved: gracefully handle with packets with too
 large RR count"

This reverts commit 18674159ebbf622a9e6e5a45cc36b38f74dae315.

There are multiple reports that this breaks lookups for people, and reverting
this commit, even on the main branch (approx. v248-rc4), fixes the issue.

https://github.com/systemd/systemd/issues/18917#issuecomment-799421587
https://bodhi.fedoraproject.org/updates/FEDORA-2021-1c1a870ceb
---
 src/resolve/resolved-dns-packet.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index abc978ab83..15c8123f6a 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -2271,18 +2271,6 @@ static int dns_packet_extract_answer(DnsPacket *p, DnsAnswer **ret_answer) {
                 bool cache_flush = false;
                 size_t start;
 
-                if (p->rindex == p->size) {
-                        /* If we reached the end of the packet already, but there are still more RRs
-                         * declared, then that's a corrupt packet. Let's accept the packet anyway, since it's
-                         * apparently a common bug in routers. Let's however suppress OPT support in this
-                         * case, so that we force the rest of the logic into lowest DNS baseline support. Or
-                         * to say this differently: if the DNS server doesn't even get the RR counts right,
-                         * it's highly unlikely it gets EDNS right. */
-                        log_debug("More resource records declared in packet than included, suppressing OPT.");
-                        bad_opt = true;
-                        break;
-                }
-
                 r = dns_packet_read_rr(p, &rr, &cache_flush, &start);
                 if (r < 0)
                         return r;
@@ -2382,10 +2370,8 @@ static int dns_packet_extract_answer(DnsPacket *p, DnsAnswer **ret_answer) {
                 previous = dns_resource_record_ref(rr);
         }
 
-        if (bad_opt) {
+        if (bad_opt)
                 p->opt = dns_resource_record_unref(p->opt);
-                p->opt_start = p->opt_size = SIZE_MAX;
-        }
 
         *ret_answer = TAKE_PTR(answer);
 
-- 
2.30.2