0
0
mirror of https://github.com/slackhq/nebula.git synced 2024-12-22 04:08:31 +00:00
slackhq_nebula/cert/cert_v1.go
2024-10-10 18:00:22 -05:00

497 lines
12 KiB
Go

package cert
import (
"bytes"
"crypto/ecdh"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/elliptic"
"crypto/rand"
"crypto/sha256"
"encoding/binary"
"encoding/hex"
"encoding/json"
"encoding/pem"
"fmt"
"math/big"
"net"
"net/netip"
"time"
"github.com/slackhq/nebula/pkclient"
"golang.org/x/crypto/curve25519"
"google.golang.org/protobuf/proto"
)
const publicKeyLen = 32
type certificateV1 struct {
details detailsV1
signature []byte
}
type detailsV1 struct {
Name string
Ips []netip.Prefix
Subnets []netip.Prefix
Groups []string
NotBefore time.Time
NotAfter time.Time
PublicKey []byte
IsCA bool
Issuer string
Curve Curve
}
type m map[string]interface{}
func (nc *certificateV1) Version() Version {
return Version1
}
func (nc *certificateV1) Curve() Curve {
return nc.details.Curve
}
func (nc *certificateV1) Groups() []string {
return nc.details.Groups
}
func (nc *certificateV1) IsCA() bool {
return nc.details.IsCA
}
func (nc *certificateV1) Issuer() string {
return nc.details.Issuer
}
func (nc *certificateV1) Name() string {
return nc.details.Name
}
func (nc *certificateV1) Networks() []netip.Prefix {
return nc.details.Ips
}
func (nc *certificateV1) NotAfter() time.Time {
return nc.details.NotAfter
}
func (nc *certificateV1) NotBefore() time.Time {
return nc.details.NotBefore
}
func (nc *certificateV1) PublicKey() []byte {
return nc.details.PublicKey
}
func (nc *certificateV1) Signature() []byte {
return nc.signature
}
func (nc *certificateV1) UnsafeNetworks() []netip.Prefix {
return nc.details.Subnets
}
func (nc *certificateV1) Fingerprint() (string, error) {
b, err := nc.Marshal()
if err != nil {
return "", err
}
sum := sha256.Sum256(b)
return hex.EncodeToString(sum[:]), nil
}
func (nc *certificateV1) CheckSignature(key []byte) bool {
b, err := proto.Marshal(nc.getRawDetails())
if err != nil {
return false
}
switch nc.details.Curve {
case Curve_CURVE25519:
return ed25519.Verify(key, b, nc.signature)
case Curve_P256:
x, y := elliptic.Unmarshal(elliptic.P256(), key)
pubKey := &ecdsa.PublicKey{Curve: elliptic.P256(), X: x, Y: y}
hashed := sha256.Sum256(b)
return ecdsa.VerifyASN1(pubKey, hashed[:], nc.signature)
default:
return false
}
}
func (nc *certificateV1) Expired(t time.Time) bool {
return nc.details.NotBefore.After(t) || nc.details.NotAfter.Before(t)
}
func (nc *certificateV1) VerifyPrivateKey(curve Curve, key []byte) error {
if curve != nc.details.Curve {
return fmt.Errorf("curve in cert and private key supplied don't match")
}
if nc.details.IsCA {
switch curve {
case Curve_CURVE25519:
// the call to PublicKey below will panic slice bounds out of range otherwise
if len(key) != ed25519.PrivateKeySize {
return fmt.Errorf("key was not 64 bytes, is invalid ed25519 private key")
}
if !ed25519.PublicKey(nc.details.PublicKey).Equal(ed25519.PrivateKey(key).Public()) {
return fmt.Errorf("public key in cert and private key supplied don't match")
}
case Curve_P256:
privkey, err := ecdh.P256().NewPrivateKey(key)
if err != nil {
return fmt.Errorf("cannot parse private key as P256: %w", err)
}
pub := privkey.PublicKey().Bytes()
if !bytes.Equal(pub, nc.details.PublicKey) {
return fmt.Errorf("public key in cert and private key supplied don't match")
}
default:
return fmt.Errorf("invalid curve: %s", curve)
}
return nil
}
var pub []byte
switch curve {
case Curve_CURVE25519:
var err error
pub, err = curve25519.X25519(key, curve25519.Basepoint)
if err != nil {
return err
}
case Curve_P256:
privkey, err := ecdh.P256().NewPrivateKey(key)
if err != nil {
return err
}
pub = privkey.PublicKey().Bytes()
default:
return fmt.Errorf("invalid curve: %s", curve)
}
if !bytes.Equal(pub, nc.details.PublicKey) {
return fmt.Errorf("public key in cert and private key supplied don't match")
}
return nil
}
// getRawDetails marshals the raw details into protobuf ready struct
func (nc *certificateV1) getRawDetails() *RawNebulaCertificateDetails {
rd := &RawNebulaCertificateDetails{
Name: nc.details.Name,
Groups: nc.details.Groups,
NotBefore: nc.details.NotBefore.Unix(),
NotAfter: nc.details.NotAfter.Unix(),
PublicKey: make([]byte, len(nc.details.PublicKey)),
IsCA: nc.details.IsCA,
Curve: nc.details.Curve,
}
for _, ipNet := range nc.details.Ips {
mask := net.CIDRMask(ipNet.Bits(), ipNet.Addr().BitLen())
rd.Ips = append(rd.Ips, addr2int(ipNet.Addr()), ip2int(mask))
}
for _, ipNet := range nc.details.Subnets {
mask := net.CIDRMask(ipNet.Bits(), ipNet.Addr().BitLen())
rd.Subnets = append(rd.Subnets, addr2int(ipNet.Addr()), ip2int(mask))
}
copy(rd.PublicKey, nc.details.PublicKey[:])
// I know, this is terrible
rd.Issuer, _ = hex.DecodeString(nc.details.Issuer)
return rd
}
func (nc *certificateV1) String() string {
if nc == nil {
return "Certificate {}\n"
}
s := "NebulaCertificate {\n"
s += "\tDetails {\n"
s += fmt.Sprintf("\t\tName: %v\n", nc.details.Name)
if len(nc.details.Ips) > 0 {
s += "\t\tIps: [\n"
for _, ip := range nc.details.Ips {
s += fmt.Sprintf("\t\t\t%v\n", ip.String())
}
s += "\t\t]\n"
} else {
s += "\t\tIps: []\n"
}
if len(nc.details.Subnets) > 0 {
s += "\t\tSubnets: [\n"
for _, ip := range nc.details.Subnets {
s += fmt.Sprintf("\t\t\t%v\n", ip.String())
}
s += "\t\t]\n"
} else {
s += "\t\tSubnets: []\n"
}
if len(nc.details.Groups) > 0 {
s += "\t\tGroups: [\n"
for _, g := range nc.details.Groups {
s += fmt.Sprintf("\t\t\t\"%v\"\n", g)
}
s += "\t\t]\n"
} else {
s += "\t\tGroups: []\n"
}
s += fmt.Sprintf("\t\tNot before: %v\n", nc.details.NotBefore)
s += fmt.Sprintf("\t\tNot After: %v\n", nc.details.NotAfter)
s += fmt.Sprintf("\t\tIs CA: %v\n", nc.details.IsCA)
s += fmt.Sprintf("\t\tIssuer: %s\n", nc.details.Issuer)
s += fmt.Sprintf("\t\tPublic key: %x\n", nc.details.PublicKey)
s += fmt.Sprintf("\t\tCurve: %s\n", nc.details.Curve)
s += "\t}\n"
fp, err := nc.Fingerprint()
if err == nil {
s += fmt.Sprintf("\tFingerprint: %s\n", fp)
}
s += fmt.Sprintf("\tSignature: %x\n", nc.Signature())
s += "}"
return s
}
func (nc *certificateV1) MarshalForHandshakes() ([]byte, error) {
pubKey := nc.details.PublicKey
nc.details.PublicKey = nil
rawCertNoKey, err := nc.Marshal()
if err != nil {
return nil, err
}
nc.details.PublicKey = pubKey
return rawCertNoKey, nil
}
func (nc *certificateV1) Marshal() ([]byte, error) {
rc := RawNebulaCertificate{
Details: nc.getRawDetails(),
Signature: nc.signature,
}
return proto.Marshal(&rc)
}
func (nc *certificateV1) MarshalPEM() ([]byte, error) {
b, err := nc.Marshal()
if err != nil {
return nil, err
}
return pem.EncodeToMemory(&pem.Block{Type: CertificateBanner, Bytes: b}), nil
}
func (nc *certificateV1) MarshalJSON() ([]byte, error) {
fp, _ := nc.Fingerprint()
jc := m{
"details": m{
"name": nc.details.Name,
"ips": nc.details.Ips,
"subnets": nc.details.Subnets,
"groups": nc.details.Groups,
"notBefore": nc.details.NotBefore,
"notAfter": nc.details.NotAfter,
"publicKey": fmt.Sprintf("%x", nc.details.PublicKey),
"isCa": nc.details.IsCA,
"issuer": nc.details.Issuer,
"curve": nc.details.Curve.String(),
},
"fingerprint": fp,
"signature": fmt.Sprintf("%x", nc.Signature()),
}
return json.Marshal(jc)
}
func (nc *certificateV1) Copy() Certificate {
c := &certificateV1{
details: detailsV1{
Name: nc.details.Name,
Groups: make([]string, len(nc.details.Groups)),
Ips: make([]netip.Prefix, len(nc.details.Ips)),
Subnets: make([]netip.Prefix, len(nc.details.Subnets)),
NotBefore: nc.details.NotBefore,
NotAfter: nc.details.NotAfter,
PublicKey: make([]byte, len(nc.details.PublicKey)),
IsCA: nc.details.IsCA,
Issuer: nc.details.Issuer,
},
signature: make([]byte, len(nc.signature)),
}
copy(c.signature, nc.signature)
copy(c.details.Groups, nc.details.Groups)
copy(c.details.PublicKey, nc.details.PublicKey)
for i, p := range nc.details.Ips {
c.details.Ips[i] = p
}
for i, p := range nc.details.Subnets {
c.details.Subnets[i] = p
}
return c
}
// unmarshalCertificateV1 will unmarshal a protobuf byte representation of a nebula cert
func unmarshalCertificateV1(b []byte, assertPublicKey bool) (*certificateV1, error) {
if len(b) == 0 {
return nil, fmt.Errorf("nil byte array")
}
var rc RawNebulaCertificate
err := proto.Unmarshal(b, &rc)
if err != nil {
return nil, err
}
if rc.Details == nil {
return nil, fmt.Errorf("encoded Details was nil")
}
if len(rc.Details.Ips)%2 != 0 {
return nil, fmt.Errorf("encoded IPs should be in pairs, an odd number was found")
}
if len(rc.Details.Subnets)%2 != 0 {
return nil, fmt.Errorf("encoded Subnets should be in pairs, an odd number was found")
}
nc := certificateV1{
details: detailsV1{
Name: rc.Details.Name,
Groups: make([]string, len(rc.Details.Groups)),
Ips: make([]netip.Prefix, len(rc.Details.Ips)/2),
Subnets: make([]netip.Prefix, len(rc.Details.Subnets)/2),
NotBefore: time.Unix(rc.Details.NotBefore, 0),
NotAfter: time.Unix(rc.Details.NotAfter, 0),
PublicKey: make([]byte, len(rc.Details.PublicKey)),
IsCA: rc.Details.IsCA,
Curve: rc.Details.Curve,
},
signature: make([]byte, len(rc.Signature)),
}
copy(nc.signature, rc.Signature)
copy(nc.details.Groups, rc.Details.Groups)
nc.details.Issuer = hex.EncodeToString(rc.Details.Issuer)
if len(rc.Details.PublicKey) < publicKeyLen && assertPublicKey {
return nil, fmt.Errorf("public key was fewer than 32 bytes; %v", len(rc.Details.PublicKey))
}
copy(nc.details.PublicKey, rc.Details.PublicKey)
var ip netip.Addr
for i, rawIp := range rc.Details.Ips {
if i%2 == 0 {
ip = int2addr(rawIp)
} else {
ones, _ := net.IPMask(int2ip(rawIp)).Size()
nc.details.Ips[i/2] = netip.PrefixFrom(ip, ones)
}
}
for i, rawIp := range rc.Details.Subnets {
if i%2 == 0 {
ip = int2addr(rawIp)
} else {
ones, _ := net.IPMask(int2ip(rawIp)).Size()
nc.details.Subnets[i/2] = netip.PrefixFrom(ip, ones)
}
}
return &nc, nil
}
func signV1(t *TBSCertificate, curve Curve, key []byte, client *pkclient.PKClient) (*certificateV1, error) {
c := &certificateV1{
details: detailsV1{
Name: t.Name,
Ips: t.Networks,
Subnets: t.UnsafeNetworks,
Groups: t.Groups,
NotBefore: t.NotBefore,
NotAfter: t.NotAfter,
PublicKey: t.PublicKey,
IsCA: t.IsCA,
Curve: t.Curve,
Issuer: t.issuer,
},
}
b, err := proto.Marshal(c.getRawDetails())
if err != nil {
return nil, err
}
var sig []byte
switch curve {
case Curve_CURVE25519:
signer := ed25519.PrivateKey(key)
sig = ed25519.Sign(signer, b)
case Curve_P256:
if client != nil {
sig, err = client.SignASN1(b)
} else {
signer := &ecdsa.PrivateKey{
PublicKey: ecdsa.PublicKey{
Curve: elliptic.P256(),
},
// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L95
D: new(big.Int).SetBytes(key),
}
// ref: https://github.com/golang/go/blob/go1.19/src/crypto/x509/sec1.go#L119
signer.X, signer.Y = signer.Curve.ScalarBaseMult(key)
// We need to hash first for ECDSA
// - https://pkg.go.dev/crypto/ecdsa#SignASN1
hashed := sha256.Sum256(b)
sig, err = ecdsa.SignASN1(rand.Reader, signer, hashed[:])
if err != nil {
return nil, err
}
}
default:
return nil, fmt.Errorf("invalid curve: %s", c.details.Curve)
}
c.signature = sig
return c, nil
}
func ip2int(ip []byte) uint32 {
if len(ip) == 16 {
return binary.BigEndian.Uint32(ip[12:16])
}
return binary.BigEndian.Uint32(ip)
}
func int2ip(nn uint32) net.IP {
ip := make(net.IP, net.IPv4len)
binary.BigEndian.PutUint32(ip, nn)
return ip
}
func addr2int(addr netip.Addr) uint32 {
b := addr.Unmap().As4()
return binary.BigEndian.Uint32(b[:])
}
func int2addr(nn uint32) netip.Addr {
ip := [4]byte{}
binary.BigEndian.PutUint32(ip[:], nn)
return netip.AddrFrom4(ip).Unmap()
}