From fc667b98e0587dcebe19183b83f99059513dba0e Mon Sep 17 00:00:00 2001 From: Miek Gieben Date: Thu, 6 Dec 2018 21:18:11 +0000 Subject: Fix EDNS0 compliance (#2357) * Fix EDNS0 compliance Do SizeAndDo in the server (ScrubWriter) and remove all uses of this from the plugins. Also *always* do it. This is to get into compliance for https://dnsflagday.net/. The pkg/edns0 now exports the EDNS0 options we understand; this is exported to allow plugins add things there. The *rewrite* plugin used this to add custom EDNS0 option codes that the server needs to understand. This also needs a new release of miekg/dns because it triggered a race-condition that was basicly there forever. See: * https://github.com/miekg/dns/issues/857 * https://github.com/miekg/dns/pull/859 Running a test instance and pointing the https://ednscomp.isc.org/ednscomp to it shows the tests are now fixed: ~~~ EDNS Compliance Tester Checking: 'miek.nl' as at 2018-12-01T17:53:15Z miek.nl. @147.75.204.203 (drone.coredns.io.): dns=ok edns=ok edns1=ok edns@512=ok ednsopt=ok edns1opt=ok do=ok ednsflags=ok docookie=ok edns512tcp=ok optlist=ok miek.nl. @2604:1380:2002:a000::1 (drone.coredns.io.): dns=ok edns=ok edns1=ok edns@512=ok ednsopt=ok edns1opt=ok do=ok ednsflags=ok docookie=ok edns512tcp=ok optlist=ok All Ok Codes ok - test passed. ~~~ Signed-off-by: Miek Gieben Signed-off-by: Miek Gieben * typos in comments Signed-off-by: Miek Gieben --- plugin/rewrite/edns0.go | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'plugin/rewrite/edns0.go') diff --git a/plugin/rewrite/edns0.go b/plugin/rewrite/edns0.go index e97f04d95..34aaf3d67 100644 --- a/plugin/rewrite/edns0.go +++ b/plugin/rewrite/edns0.go @@ -10,6 +10,7 @@ import ( "strings" "github.com/coredns/coredns/plugin/metadata" + "github.com/coredns/coredns/plugin/pkg/edns" "github.com/coredns/coredns/request" "github.com/miekg/dns" @@ -159,6 +160,10 @@ func newEdns0LocalRule(mode, action, code, data string) (*edns0LocalRule, error) return nil, err } } + + // Add this code to the ones the server supports. + edns.SetSupportedOption(uint16(c)) + return &edns0LocalRule{mode: mode, action: action, code: uint16(c), data: decoded}, nil } @@ -172,6 +177,10 @@ func newEdns0VariableRule(mode, action, code, variable string) (*edns0VariableRu if !isValidVariable(variable) { return nil, fmt.Errorf("unsupported variable name %q", variable) } + + // Add this code to the ones the server supports. + edns.SetSupportedOption(uint16(c)) + return &edns0VariableRule{mode: mode, action: action, code: uint16(c), variable: variable}, nil } -- cgit v1.2.3