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cmd/devp2p: fix Route53 TXT record splitting (#20626)

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For longer records and subtree entries, the deployer created two
separate TXT records. This doesn't work as intended because the client
will receive the two records in arbitrary order. The fix is to encode
longer values as "string1""string2" instead of "string1", "string2".
This encoding creates a single record on AWS Route53.
This commit is contained in:
Felix Lange 2020-02-05 15:29:59 +01:00 committed by GitHub
parent a1313b5b1e
commit 976a0f5558
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 10 additions and 24 deletions
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28
cmd/devp2p/dns_route53.go
View File

@ -171,7 +171,7 @@ func (c *route53Client) computeChanges(name string, records map[string]string, e
}
prevRecords, exists := existing[path]
prevValue := combineTXT(prevRecords.values)
prevValue := strings.Join(prevRecords.values, "")
if !exists {
// Entry is unknown, push a new one
log.Info(fmt.Sprintf("Creating %s = %q", path, val))
@ -191,8 +191,8 @@ func (c *route53Client) computeChanges(name string, records map[string]string, e
continue
}
// Stale entry, nuke it.
log.Info(fmt.Sprintf("Deleting %s = %q", path, combineTXT(set.values)))
changes = append(changes, newTXTChange("DELETE", path, set.ttl, set.values))
log.Info(fmt.Sprintf("Deleting %s = %q", path, strings.Join(set.values, "")))
changes = append(changes, newTXTChange("DELETE", path, set.ttl, set.values...))
}
sortChanges(changes)
@ -263,7 +263,7 @@ func (c *route53Client) collectRecords(name string) (map[string]recordSet, error
}
// newTXTChange creates a change to a TXT record.
func newTXTChange(action, name string, ttl int64, values []string) *route53.Change {
func newTXTChange(action, name string, ttl int64, values ...string) *route53.Change {
var c route53.Change
var r route53.ResourceRecordSet
var rrs []*route53.ResourceRecord
@ -288,28 +288,16 @@ func isSubdomain(name, domain string) bool {
return strings.HasSuffix("."+name, "."+domain)
}
// combineTXT concatenates the given quoted strings into a single unquoted string.
func combineTXT(values []string) string {
result := ""
for _, v := range values {
if v[0] == '"' {
v = v[1 : len(v)-1]
}
result += v
}
return result
}
// splitTXT splits value into a list of quoted 255-character strings.
func splitTXT(value string) []string {
var result []string
func splitTXT(value string) string {
var result strings.Builder
for len(value) > 0 {
rlen := len(value)
if rlen > 253 {
rlen = 253
}
result = append(result, strconv.Quote(value[:rlen]))
result.WriteString(strconv.Quote(value[:rlen]))
value = value[rlen:]
}
return result
return result.String()
}

6
cmd/devp2p/dns_route53_test.go
View File

@ -28,8 +28,7 @@ import (
func TestRoute53ChangeSort(t *testing.T) {
testTree0 := map[string]recordSet{
"2kfjogvxdqtxxugbh7gs7naaai.n": {ttl: 3333, values: []string{
`"enr:-HW4QO1ml1DdXLeZLsUxewnthhUy8eROqkDyoMTyavfks9JlYQIlMFEUoM78PovJDPQrAkrb3LRJ-"`,
`"vtrymDguKCOIAWAgmlkgnY0iXNlY3AyNTZrMaEDffaGfJzgGhUif1JqFruZlYmA31HzathLSWxfbq_QoQ4"`,
`"enr:-HW4QO1ml1DdXLeZLsUxewnthhUy8eROqkDyoMTyavfks9JlYQIlMFEUoM78PovJDPQrAkrb3LRJ-""vtrymDguKCOIAWAgmlkgnY0iXNlY3AyNTZrMaEDffaGfJzgGhUif1JqFruZlYmA31HzathLSWxfbq_QoQ4"`,
}},
"fdxn3sn67na5dka4j2gok7bvqi.n": {ttl: treeNodeTTL, values: []string{`"enrtree-branch:"`}},
"n": {ttl: rootTTL, values: []string{`"enrtree-root:v1 e=2KFJOGVXDQTXXUGBH7GS7NAAAI l=FDXN3SN67NA5DKA4J2GOK7BVQI seq=0 sig=v_-J_q_9ICQg5ztExFvLQhDBGMb0lZPJLhe3ts9LAcgqhOhtT3YFJsl8BWNDSwGtamUdR-9xl88_w-X42SVpjwE"`}},
@ -116,8 +115,7 @@ func TestRoute53ChangeSort(t *testing.T) {
ResourceRecordSet: &route53.ResourceRecordSet{
Name: sp("2kfjogvxdqtxxugbh7gs7naaai.n"),
ResourceRecords: []*route53.ResourceRecord{
{Value: sp(`"enr:-HW4QO1ml1DdXLeZLsUxewnthhUy8eROqkDyoMTyavfks9JlYQIlMFEUoM78PovJDPQrAkrb3LRJ-"`)},
{Value: sp(`"vtrymDguKCOIAWAgmlkgnY0iXNlY3AyNTZrMaEDffaGfJzgGhUif1JqFruZlYmA31HzathLSWxfbq_QoQ4"`)},
{Value: sp(`"enr:-HW4QO1ml1DdXLeZLsUxewnthhUy8eROqkDyoMTyavfks9JlYQIlMFEUoM78PovJDPQrAkrb3LRJ-""vtrymDguKCOIAWAgmlkgnY0iXNlY3AyNTZrMaEDffaGfJzgGhUif1JqFruZlYmA31HzathLSWxfbq_QoQ4"`)},
},
TTL: ip(3333),
Type: sp("TXT"),