mirror of https://github.com/status-im/consul.git
74 lines
2.5 KiB
Go
74 lines
2.5 KiB
Go
// Copyright (c) HashiCorp, Inc.
|
|
// SPDX-License-Identifier: MPL-2.0
|
|
|
|
package connect
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"encoding/binary"
|
|
"fmt"
|
|
"regexp"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
var invalidDNSNameChars = regexp.MustCompile(`[^a-z0-9]`)
|
|
|
|
// CompactUID returns a crypto random Unique Identifier string consiting of 8
|
|
// characters of base36 encoded random value. This has roughly 41 bits of
|
|
// entropy so is suitable for infrequently occuring events with low probability
|
|
// of collision. It is not suitable for UUIDs for very frequent events. It's
|
|
// main purpose is to assign unique values to CA certificate Common Names which
|
|
// need to be unique in some providers - see CACN - but without using up large
|
|
// amounts of the limited 64 character Common Name. It also makes the values
|
|
// more easily digestable by humans considering there are likely to be few of
|
|
// them ever in use.
|
|
func CompactUID() (string, error) {
|
|
// 48 bits (6 bytes) is enough to fill 8 bytes in base36 but it's simpler to
|
|
// have a whole uint8 to convert from.
|
|
var raw [8]byte
|
|
_, err := rand.Read(raw[:])
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
i := binary.LittleEndian.Uint64(raw[:])
|
|
return truncateTo(strconv.FormatInt(int64(i), 36), 8), nil
|
|
}
|
|
|
|
// CACN returns the common name for a CA certificate.
|
|
// A uniqueID is requires because some providers (e.g.
|
|
// Vault) cache by subject and so produce incorrect results - for example they
|
|
// won't cross-sign an older CA certificate with the same common name since they
|
|
// think they already have a valid cert for that CN and just return the current
|
|
// root.
|
|
//
|
|
// This can be generated by any means but will be truncated to 8 chars and
|
|
// sanitised to DNS-safe chars. CompactUID generates suitable UIDs for this
|
|
// specific purpose.
|
|
//
|
|
// Format is:
|
|
//
|
|
// {provider}-{uniqueID_first8}.{pri|sec}.ca.<trust_domain_first_8>.consul
|
|
//
|
|
// trust domain is truncated to keep the whole name short
|
|
func CACN(provider, uniqueID, trustDomain string, primaryDC bool) string {
|
|
providerSan := invalidDNSNameChars.ReplaceAllString(strings.ToLower(provider), "")
|
|
typ := "pri"
|
|
if !primaryDC {
|
|
typ = "sec"
|
|
}
|
|
// 32 = 7 bytes for ".consul", 8 bytes for trust domain, 8 bytes for
|
|
// ".pri.ca.", 9 bytes for "-{uniqueID-8-b36}"
|
|
uidSAN := invalidDNSNameChars.ReplaceAllString(strings.ToLower(uniqueID), "")
|
|
return fmt.Sprintf("%s-%s.%s.ca.%s.consul", typ, truncateTo(uidSAN, 8),
|
|
truncateTo(providerSan, 64-32), truncateTo(trustDomain, 8))
|
|
}
|
|
|
|
func truncateTo(s string, n int) string {
|
|
if len(s) > n {
|
|
return s[:n]
|
|
}
|
|
return s
|
|
}
|