From 33a2d90852227b3172198c78b6387f284bc2ff0f Mon Sep 17 00:00:00 2001 From: Alex Simenduev Date: Mon, 26 Jun 2023 17:57:11 +0300 Subject: [PATCH] Fix a bug that wrongly trims domains when there is an overlap with DC name (#17160) * Fix a bug that wrongly trims domains when there is an overlap with DC name Before this change, when DC name and domain/alt-domain overlap, the domain name incorrectly trimmed from the query. Example: Given: datacenter = dc-test, alt-domain = test.consul. Querying for "test-node.node.dc-test.consul" will faile, because the code was trimming "test.consul" instead of just ".consul" This change, fixes the issue by adding dot (.) before trimming * trimDomain: ensure domain trimmed without modyfing original domains * update changelog --------- Co-authored-by: Dhia Ayachi --- .changelog/17160.txt | 3 +++ agent/dns.go | 2 +- agent/dns_test.go | 39 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 1 deletion(-) create mode 100644 .changelog/17160.txt diff --git a/.changelog/17160.txt b/.changelog/17160.txt new file mode 100644 index 0000000000..666a6e8f25 --- /dev/null +++ b/.changelog/17160.txt @@ -0,0 +1,3 @@ +```release-note:bug +Fix a bug that wrongly trims domains when there is an overlap with DC name. +``` diff --git a/agent/dns.go b/agent/dns.go index cb1e3c310d..5804dc97dd 100644 --- a/agent/dns.go +++ b/agent/dns.go @@ -1055,7 +1055,7 @@ func (d *DNSServer) trimDomain(query string) string { longer, shorter = shorter, longer } - if strings.HasSuffix(query, longer) { + if strings.HasSuffix(query, "."+strings.TrimLeft(longer, ".")) { return strings.TrimSuffix(query, longer) } return strings.TrimSuffix(query, shorter) diff --git a/agent/dns_test.go b/agent/dns_test.go index 46a7e758c7..ef5364964d 100644 --- a/agent/dns_test.go +++ b/agent/dns_test.go @@ -7071,6 +7071,45 @@ func TestDNS_AltDomains_Overlap(t *testing.T) { } } +func TestDNS_AltDomain_DCName_Overlap(t *testing.T) { + if testing.Short() { + t.Skip("too slow for testing.Short") + } + + // this tests the DC name overlap with the consul domain/alt-domain + // we should get response when DC suffix is a prefix of consul alt-domain + t.Parallel() + a := NewTestAgent(t, ` + datacenter = "dc-test" + node_name = "test-node" + alt_domain = "test.consul." + `) + defer a.Shutdown() + testrpc.WaitForLeader(t, a.RPC, "dc-test") + + questions := []string{ + "test-node.node.dc-test.consul.", + "test-node.node.dc-test.test.consul.", + } + + for _, question := range questions { + m := new(dns.Msg) + m.SetQuestion(question, dns.TypeA) + + c := new(dns.Client) + in, _, err := c.Exchange(m, a.DNSAddr()) + if err != nil { + t.Fatalf("err: %v", err) + } + + require.Len(t, in.Answer, 1) + + aRec, ok := in.Answer[0].(*dns.A) + require.True(t, ok) + require.Equal(t, aRec.A.To4().String(), "127.0.0.1") + } +} + func TestDNS_PreparedQuery_AllowStale(t *testing.T) { if testing.Short() { t.Skip("too slow for testing.Short")