1
0
2025-01-25 16:11:19 -05:00

477 lines
12 KiB
Go

package main
import (
`bytes`
`crypto`
`crypto/ecdh`
`crypto/ecdsa`
`crypto/ed25519`
`crypto/elliptic`
`crypto/rand`
`crypto/rsa`
`crypto/x509`
`crypto/x509/pkix`
`encoding/binary`
`encoding/pem`
`errors`
`fmt`
`log`
`math/big`
`os`
`path/filepath`
`github.com/brunoga/deep`
`github.com/google/uuid`
)
/*
getKeyFpath returns a (relative) path for a key PEM file (PKCS#8).
This is used both when fetching from embed.FS and when generating new keys.
*/
func getKeyFpath(pairType, keyType string) (path string) {
path = filepath.Join("_testdata", fmt.Sprintf("%s_%s_key.pem", pairType, keyType))
return
}
/*
getCertFpath returns a (relative) path for a cert PEM file.
This is used both when fetching from embed.FS and when generating new certs.
*/
func getCertFpath(pairType, keyType string) (path string) {
path = filepath.Join("_testdata", fmt.Sprintf("%s_%s_cert.pem", pairType, keyType))
return
}
/*
getChainFpath returns a (relative) path for a chained cert PEM file.
This is used both when fetching from embed.FS and when generating new certs.
*/
func getChainFpath(pairType, keyType string) (path string) {
path = filepath.Join("_testdata", fmt.Sprintf("%s_%s_cert_chained.pem", pairType, keyType))
return
}
/*
getCsrFpath returns a (relative) path for a CSR PEM file.
This is used both when fetching from embed.FS and when generating new CSRs.
*/
func getCsrFpath(pairType, keyType string) (path string) {
path = filepath.Join("_testdata", fmt.Sprintf("%s_%s_csr.pem", pairType, keyType))
return
}
/*
getKeypair takes cert type t and key type kt and returns the crypto.Private and crypto.Public keys for it.
It assumes that loadKeys() at the *least* has already been called.
*/
func getKeypair(t, kt string) (priv crypto.PrivateKey, pub crypto.PublicKey) {
priv = pairs[t].privKeys[kt]
switch k := priv.(type) {
case *ecdh.PrivateKey:
pub = k.Public()
case *ecdsa.PrivateKey:
pub = k.Public()
case ed25519.PrivateKey: // This is correct. Unlike other kt's, ed25519 doesn't use pointers.
pub = k.Public()
case *rsa.PrivateKey:
pub = k.Public()
}
return
}
/*
getSerial returns a (pseudo-)random certificate based on a UUIDv4 (RFC 4122 type 4).
This guarantees not only that renewals (if issued/implemented) are reasonably guaranteed
to be different from the past issuance but also that the serial issuance is non-sequential
(both are common modern requirements of modern browser-trusted CAs; see
https://cabforum.org/working-groups/server/baseline-requirements/documents/)
*/
func getSerial() (serial *big.Int) {
var b []byte
var n int64
var u uuid.UUID = uuid.New()
b = u[:]
n = int64(binary.BigEndian.Uint64(b))
// Serials must be positive.
if n < 0 {
n = -n
}
serial = big.NewInt(n)
return
}
// getTpl returns a version of certificate template tpl with a randomized serial.
func getTpl(tpl *x509.Certificate) (newTpl *x509.Certificate) {
newTpl = new(x509.Certificate)
*newTpl = *tpl
newTpl.SerialNumber = getSerial()
return
}
// getSubj returns a cert/CSR-specific pkix.Name from a given cn (commonName).
func getSubj(cn string) (newSubj pkix.Name) {
newSubj = deep.MustCopy(*pkixCommon)
newSubj.CommonName = cn
return
}
// loadKeys either loads from pems or generates and writes out the PEM keys.
func loadKeys() (err error) {
var b []byte
var t string
var kt string
var ok bool
var pemBlock *pem.Block
var keybuf *bytes.Buffer = new(bytes.Buffer)
// Load in any existing keys.
for _, t = range pairTypes {
for _, kt = range keyTypes {
log.Printf("Loading %s key %s\n", t, kt)
if b, err = pems.ReadFile(getKeyFpath(t, kt)); err != nil {
if errors.Is(err, os.ErrNotExist) {
// Will generate missing below
pairs[t] = &Pair{
pairType: t,
keyBytes: make(map[string][]byte),
privKeys: make(map[string]crypto.PrivateKey),
certBytes: make(map[string][]byte),
certs: make(map[string]*x509.Certificate),
csrBytes: make(map[string][]byte),
csrs: make(map[string]*x509.CertificateRequest),
chainParentBytes: make(map[string][]byte),
chainParent: make(map[string]*x509.Certificate),
}
err = nil
continue
}
return
}
if _, ok = pairs[t]; !ok {
pairs[t] = &Pair{
pairType: t,
keyBytes: make(map[string][]byte),
privKeys: make(map[string]crypto.PrivateKey),
certBytes: make(map[string][]byte),
certs: make(map[string]*x509.Certificate),
csrBytes: make(map[string][]byte),
csrs: make(map[string]*x509.CertificateRequest),
}
}
pairs[t].keyBytes[kt] = b
if pairs[t].privKeys[kt], err = x509.ParsePKCS8PrivateKey(b); err != nil {
return
}
}
}
// Generate any missing keys.
for _, t = range pairTypes {
for _, kt = range keyTypes {
if _, ok = pairs[t].privKeys[kt]; !ok {
log.Printf("Generating %s key %s\n", t, kt)
keybuf.Reset()
switch kt {
case "ecdh":
if pairs[t].privKeys[kt], err = ecdh.X25519().GenerateKey(rand.Reader); err != nil {
return
}
case "ecdsa":
if pairs[t].privKeys[kt], err = ecdsa.GenerateKey(elliptic.P521(), rand.Reader); err != nil {
return
}
case "ed25519":
if _, pairs[t].privKeys[kt], err = ed25519.GenerateKey(rand.Reader); err != nil {
return
}
case "rsa":
if pairs[t].privKeys[kt], err = rsa.GenerateKey(rand.Reader, 4096); err != nil {
return
}
}
if b, err = x509.MarshalPKCS8PrivateKey(pairs[t].privKeys[kt]); err != nil {
log.Panicln(err)
}
pemBlock = &pem.Block{
Type: "PRIVATE KEY",
Headers: nil,
Bytes: b,
}
b = pem.EncodeToMemory(pemBlock)
pairs[t].keyBytes[kt] = b
if err = os.WriteFile(getKeyFpath(t, kt), b, 0o0600); err != nil {
return
}
}
}
}
return
}
// loadCerts combines all loadCert* functions in the proper order. It is expected that loadKeys has already been run.
func loadCerts() (err error) {
var b []byte
var t string
var kt string
var tkt [2]string
var chainMissing [][2]string = make([][2]string, 0, (len(certgenOrder)-1)*len(keyTypes))
if err = loadCertCa(); err != nil {
return
}
if err = loadCertIssued(); err != nil {
return
}
// And create chained certs of leaves so they fully validate.
for _, t = range certgenOrder {
if t == "inter" {
continue // Don't bother with chaining the intermediate. If we play around with multiple intermediates, we will.
}
for _, kt = range keyTypes {
pairs[t].chainParent[kt] = pairs[parents[t]].certs[kt]
log.Printf("Loading %s chain %s\n", t, kt)
if b, err = pems.ReadFile(getChainFpath(t, kt)); err != nil {
if errors.Is(err, os.ErrNotExist) {
err = nil
chainMissing = append(chainMissing, [2]string{t, kt})
continue
}
return
}
// Found
pairs[t].chainParentBytes[kt] = b
}
}
// "Generate" missing.
for _, tkt = range chainMissing {
t = tkt[0]
kt = tkt[1]
log.Printf("Building %s chain %s\n", t, kt)
b = append(pairs[t].certBytes[kt], pairs[parents[t]].certBytes[kt]...)
if err = os.WriteFile(getChainFpath(t, kt), b, 0o0600); err != nil {
return
}
}
return
}
// loadCertCa loads (or generates) the root CA/anchor. It is expected that loadKeys has already been run.
func loadCertCa() (err error) {
var b []byte
var kt string
var ok bool
var privKey crypto.PrivateKey
var pubKey crypto.PublicKey
var pemBlock *pem.Block
var ktTpl *x509.Certificate
for _, kt = range keyTypes {
log.Printf("Loading CA certificate %s\n", kt)
if b, err = pems.ReadFile(getCertFpath("ca", kt)); err != nil {
if errors.Is(err, os.ErrNotExist) {
// Will generate missing below.
err = nil
continue
}
return
}
// Assume the mapped Pair exists per loadKeys.
pairs["ca"].certBytes[kt] = b
pemBlock, _ = pem.Decode(b)
if pairs["ca"].certs[kt], err = x509.ParseCertificate(pemBlock.Bytes); err != nil {
return
}
}
// Generate missing CA certs.
for _, kt = range keyTypes {
log.Printf("Generating CA certificate %s\n", kt)
if _, ok = pairs["ca"].certs[kt]; !ok {
ktTpl = getTpl(certTpl["ca"])
privKey, pubKey = getKeypair("ca", kt)
// Specifying the same cert template for both the template and parent params creates a self-signed.
if b, err = x509.CreateCertificate(
rand.Reader,
ktTpl,
ktTpl,
pubKey,
privKey,
); err != nil {
return
}
if pairs["ca"].certs[kt], err = x509.ParseCertificate(b); err != nil {
return
}
pemBlock = &pem.Block{
Type: "CERTIFICATE",
Headers: nil,
Bytes: b,
}
b = pem.EncodeToMemory(pemBlock)
pairs["ca"].certBytes[kt] = b
if err = os.WriteFile(getCertFpath("ca", kt), b, 0o0600); err != nil {
return
}
}
}
return
}
// loadCertIssued handles the intermediate, "server" leaf, and "user" leaf.
func loadCertIssued() (err error) {
var b []byte
var ok bool
var t string
var kt string
var tkt [2]string
var ktMap map[string]bool
var caCert *x509.Certificate
var caPrivKey crypto.PrivateKey
var certPrivKey crypto.PrivateKey
var certPubKey crypto.PublicKey
var pemBlock *pem.Block
var ktTpl *x509.Certificate
// map[<t>][<kt>]; map so we can condense dupes
var certMissing map[string]map[string]bool = make(map[string]map[string]bool)
var csrMissing [][2]string = make([][2]string, 0, len(certgenOrder)*len(keyTypes))
// CSRS
// Find existing CSRs and certs
for _, t = range certgenOrder {
for _, kt = range keyTypes {
log.Printf("Loading %s CSR %s\n", t, kt)
if b, err = pems.ReadFile(getCsrFpath(t, kt)); err != nil {
if errors.Is(err, os.ErrNotExist) {
err = nil
csrMissing = append(csrMissing, [2]string{t, kt})
continue
}
return
}
// Assume the mapped Pair exists per loadKeys.
pairs[t].csrBytes[kt] = b
pemBlock, _ = pem.Decode(b)
if pairs[t].csrs[kt], err = x509.ParseCertificateRequest(pemBlock.Bytes); err != nil {
return
}
log.Printf("Loading %s certificate %s\n", t, kt)
if b, err = pems.ReadFile(getCertFpath(t, kt)); err != nil {
if errors.Is(err, os.ErrNotExist) {
err = nil
if _, ok = certMissing[t]; !ok {
certMissing[t] = make(map[string]bool)
}
certMissing[t][kt] = true
continue
}
}
pairs[t].certBytes[kt] = b
pemBlock, _ = pem.Decode(b)
if pairs[t].certs[kt], err = x509.ParseCertificate(pemBlock.Bytes); err != nil {
return
}
}
}
// Generate missing CSRs.
for _, tkt = range csrMissing {
t = tkt[0]
kt = tkt[1]
log.Printf("Generating %s CSR %s\n", t, kt)
certPrivKey, certPubKey = getKeypair(t, kt)
if b, err = x509.CreateCertificateRequest(rand.Reader, csrs[t], certPrivKey); err != nil {
return
}
if pairs[t].csrs[kt], err = x509.ParseCertificateRequest(b); err != nil {
return
}
pemBlock = &pem.Block{
Type: "CERTIFICATE REQUEST",
Headers: nil,
Bytes: b,
}
b = pem.EncodeToMemory(pemBlock)
pairs[t].csrBytes[kt] = b
if err = os.WriteFile(getCsrFpath(t, kt), b, 0o0600); err != nil {
return
}
if _, ok = certMissing[t]; !ok {
certMissing[t] = make(map[string]bool)
}
certMissing[t][kt] = true
}
// Force re-gen of certs for above new CSRs and gen missing.
for _, t = range certgenOrder {
if ktMap, ok = certMissing[t]; !ok {
continue
}
for kt, _ = range ktMap {
log.Printf("Generating %s certificate %s\n", t, kt)
caCert = pairs[parents[t]].certs[kt]
caPrivKey = pairs[parents[t]].privKeys[kt]
_, certPubKey = getKeypair(t, kt)
ktTpl = getTpl(certTpl[t])
if b, err = x509.CreateCertificate(
rand.Reader,
ktTpl,
caCert,
certPubKey,
caPrivKey,
); err != nil {
return
}
if pairs[t].certs[kt], err = x509.ParseCertificate(b); err != nil {
return
}
pemBlock = &pem.Block{
Type: "CERTIFICATE",
Headers: nil,
Bytes: b,
}
b = pem.EncodeToMemory(pemBlock)
pairs[t].certBytes[kt] = b
if err = os.WriteFile(getCertFpath(t, kt), b, 0o0600); err != nil {
return
}
}
}
return
}