vendor.github.com.pion.webrtc.v3.certificate.go Maven / Gradle / Ivy
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// SPDX-FileCopyrightText: 2023 The Pion community
// SPDX-License-Identifier: MIT
//go:build !js
// +build !js
package webrtc
import (
"crypto"
"crypto/ecdsa"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"crypto/x509/pkix"
"encoding/base64"
"encoding/pem"
"fmt"
"math/big"
"strings"
"time"
"github.com/pion/dtls/v2/pkg/crypto/fingerprint"
"github.com/pion/webrtc/v3/pkg/rtcerr"
)
// Certificate represents a x509Cert used to authenticate WebRTC communications.
type Certificate struct {
privateKey crypto.PrivateKey
x509Cert *x509.Certificate
statsID string
}
// NewCertificate generates a new x509 compliant Certificate to be used
// by DTLS for encrypting data sent over the wire. This method differs from
// GenerateCertificate by allowing to specify a template x509.Certificate to
// be used in order to define certificate parameters.
func NewCertificate(key crypto.PrivateKey, tpl x509.Certificate) (*Certificate, error) {
var err error
var certDER []byte
switch sk := key.(type) {
case *rsa.PrivateKey:
pk := sk.Public()
tpl.SignatureAlgorithm = x509.SHA256WithRSA
certDER, err = x509.CreateCertificate(rand.Reader, &tpl, &tpl, pk, sk)
if err != nil {
return nil, &rtcerr.UnknownError{Err: err}
}
case *ecdsa.PrivateKey:
pk := sk.Public()
tpl.SignatureAlgorithm = x509.ECDSAWithSHA256
certDER, err = x509.CreateCertificate(rand.Reader, &tpl, &tpl, pk, sk)
if err != nil {
return nil, &rtcerr.UnknownError{Err: err}
}
default:
return nil, &rtcerr.NotSupportedError{Err: ErrPrivateKeyType}
}
cert, err := x509.ParseCertificate(certDER)
if err != nil {
return nil, &rtcerr.UnknownError{Err: err}
}
return &Certificate{privateKey: key, x509Cert: cert, statsID: fmt.Sprintf("certificate-%d", time.Now().UnixNano())}, nil
}
// Equals determines if two certificates are identical by comparing both the
// secretKeys and x509Certificates.
func (c Certificate) Equals(o Certificate) bool {
switch cSK := c.privateKey.(type) {
case *rsa.PrivateKey:
if oSK, ok := o.privateKey.(*rsa.PrivateKey); ok {
if cSK.N.Cmp(oSK.N) != 0 {
return false
}
return c.x509Cert.Equal(o.x509Cert)
}
return false
case *ecdsa.PrivateKey:
if oSK, ok := o.privateKey.(*ecdsa.PrivateKey); ok {
if cSK.X.Cmp(oSK.X) != 0 || cSK.Y.Cmp(oSK.Y) != 0 {
return false
}
return c.x509Cert.Equal(o.x509Cert)
}
return false
default:
return false
}
}
// Expires returns the timestamp after which this certificate is no longer valid.
func (c Certificate) Expires() time.Time {
if c.x509Cert == nil {
return time.Time{}
}
return c.x509Cert.NotAfter
}
// GetFingerprints returns the list of certificate fingerprints, one of which
// is computed with the digest algorithm used in the certificate signature.
func (c Certificate) GetFingerprints() ([]DTLSFingerprint, error) {
fingerprintAlgorithms := []crypto.Hash{crypto.SHA256}
res := make([]DTLSFingerprint, len(fingerprintAlgorithms))
i := 0
for _, algo := range fingerprintAlgorithms {
name, err := fingerprint.StringFromHash(algo)
if err != nil {
// nolint
return nil, fmt.Errorf("%w: %v", ErrFailedToGenerateCertificateFingerprint, err)
}
value, err := fingerprint.Fingerprint(c.x509Cert, algo)
if err != nil {
// nolint
return nil, fmt.Errorf("%w: %v", ErrFailedToGenerateCertificateFingerprint, err)
}
res[i] = DTLSFingerprint{
Algorithm: name,
Value: value,
}
}
return res[:i+1], nil
}
// GenerateCertificate causes the creation of an X.509 certificate and
// corresponding private key.
func GenerateCertificate(secretKey crypto.PrivateKey) (*Certificate, error) {
// Max random value, a 130-bits integer, i.e 2^130 - 1
maxBigInt := new(big.Int)
/* #nosec */
maxBigInt.Exp(big.NewInt(2), big.NewInt(130), nil).Sub(maxBigInt, big.NewInt(1))
/* #nosec */
serialNumber, err := rand.Int(rand.Reader, maxBigInt)
if err != nil {
return nil, &rtcerr.UnknownError{Err: err}
}
return NewCertificate(secretKey, x509.Certificate{
Issuer: pkix.Name{CommonName: generatedCertificateOrigin},
NotBefore: time.Now().AddDate(0, 0, -1),
NotAfter: time.Now().AddDate(0, 1, -1),
SerialNumber: serialNumber,
Version: 2,
Subject: pkix.Name{CommonName: generatedCertificateOrigin},
})
}
// CertificateFromX509 creates a new WebRTC Certificate from a given PrivateKey and Certificate
//
// This can be used if you want to share a certificate across multiple PeerConnections
func CertificateFromX509(privateKey crypto.PrivateKey, certificate *x509.Certificate) Certificate {
return Certificate{privateKey, certificate, fmt.Sprintf("certificate-%d", time.Now().UnixNano())}
}
func (c Certificate) collectStats(report *statsReportCollector) error {
report.Collecting()
fingerPrintAlgo, err := c.GetFingerprints()
if err != nil {
return err
}
base64Certificate := base64.RawURLEncoding.EncodeToString(c.x509Cert.Raw)
stats := CertificateStats{
Timestamp: statsTimestampFrom(time.Now()),
Type: StatsTypeCertificate,
ID: c.statsID,
Fingerprint: fingerPrintAlgo[0].Value,
FingerprintAlgorithm: fingerPrintAlgo[0].Algorithm,
Base64Certificate: base64Certificate,
IssuerCertificateID: c.x509Cert.Issuer.String(),
}
report.Collect(stats.ID, stats)
return nil
}
// CertificateFromPEM creates a fresh certificate based on a string containing
// pem blocks fort the private key and x509 certificate
func CertificateFromPEM(pems string) (*Certificate, error) {
// decode & parse the certificate
block, more := pem.Decode([]byte(pems))
if block == nil || block.Type != "CERTIFICATE" {
return nil, errCertificatePEMFormatError
}
certBytes := make([]byte, base64.StdEncoding.DecodedLen(len(block.Bytes)))
n, err := base64.StdEncoding.Decode(certBytes, block.Bytes)
if err != nil {
return nil, fmt.Errorf("failed to decode ceritifcate: %w", err)
}
cert, err := x509.ParseCertificate(certBytes[:n])
if err != nil {
return nil, fmt.Errorf("failed parsing ceritifcate: %w", err)
}
// decode & parse the private key
block, _ = pem.Decode(more)
if block == nil || block.Type != "PRIVATE KEY" {
return nil, errCertificatePEMFormatError
}
privateKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
return nil, fmt.Errorf("unable to parse private key: %w", err)
}
x := CertificateFromX509(privateKey, cert)
return &x, nil
}
// PEM returns the certificate encoded as two pem block: once for the X509
// certificate and the other for the private key
func (c Certificate) PEM() (string, error) {
// First write the X509 certificate
var o strings.Builder
xcertBytes := make(
[]byte, base64.StdEncoding.EncodedLen(len(c.x509Cert.Raw)))
base64.StdEncoding.Encode(xcertBytes, c.x509Cert.Raw)
err := pem.Encode(&o, &pem.Block{Type: "CERTIFICATE", Bytes: xcertBytes})
if err != nil {
return "", fmt.Errorf("failed to pem encode the X certificate: %w", err)
}
// Next write the private key
privBytes, err := x509.MarshalPKCS8PrivateKey(c.privateKey)
if err != nil {
return "", fmt.Errorf("failed to marshal private key: %w", err)
}
err = pem.Encode(&o, &pem.Block{Type: "PRIVATE KEY", Bytes: privBytes})
if err != nil {
return "", fmt.Errorf("failed to encode private key: %w", err)
}
return o.String(), nil
}