inet_dns: FORMERR if more than one EDNS(0) option is present

erlang · Mar 2, 2023 · 99815ee · 99815ee
1 parent 07cf1c5
commit 99815ee
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/lib/kernel/src/inet_dns.erl b/lib/kernel/src/inet_dns.erl
@@ -230,6 +230,8 @@ decode_rr_section(Bin, N, Buffer, RRs) ->
            RR =
                case Type of
                    ?S_OPT ->
+                       % RFC 6891: 6.1.1. Return FORMERR if more than one EDNS(0) option
+                       lists:keymember(dns_rr_opt, 1, RRs) andalso throw(?DECODE_ERROR),
                        <<ExtRcode,Version,Z:16>> = TTL,
                        #dns_rr_opt{
                           domain           = Name,