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package x509util
import (
"fmt"
"crypto/ed25519"
"crypto/x509"
"encoding/pem"
"io/ioutil"
)
// LoadTrustAnchors loads a list of PEM-encoded certificates from file
func LoadTrustAnchors(path string) ([]*x509.Certificate, *x509.CertPool, error) {
rest, err := ioutil.ReadFile(path)
if err != nil {
return nil, nil, fmt.Errorf("failed reading trust anchors: %v", err)
}
pool := x509.NewCertPool()
var anchors []*x509.Certificate
for len(rest) > 0 {
var block *pem.Block
block, rest = pem.Decode(rest)
if block == nil {
break
}
if block.Type != "CERTIFICATE" {
return nil, nil, fmt.Errorf("unexpected PEM block type: %s", block.Type)
}
certificate, err := x509.ParseCertificate(block.Bytes)
if err != nil {
return nil, nil, fmt.Errorf("invalid trust anchor before rest(%s): %v", rest, err)
}
anchors = append(anchors, certificate)
pool.AddCert(certificate)
}
if len(anchors) == 0 {
return nil, nil, fmt.Errorf("found no valid trust anchor in: %s", path)
}
return anchors, pool, nil
}
// LoadEd25519SigningKey loads an Ed25519 private key from a given path
func LoadEd25519SigningKey(path string) (ed25519.PrivateKey, error) {
data, err := ioutil.ReadFile(path)
if err != nil {
return nil, fmt.Errorf("failed reading private key: %v", err)
}
return ParseEd25519PrivateKey(data)
}
// ParseEd25519PrivateKey parses a PEM-encoded private key block
func ParseEd25519PrivateKey(data []byte) (ed25519.PrivateKey, error) {
block, rest := pem.Decode(data)
if block == nil {
return nil, fmt.Errorf("pem block: is empty")
}
if block.Type != "PRIVATE KEY" {
return nil, fmt.Errorf("bad pem block type: %v", block.Type)
}
if len(rest) != 0 {
return nil, fmt.Errorf("pem block: trailing data")
}
key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
fmt.Errorf("x509 parser failed: %v", err)
}
switch t := key.(type) {
case ed25519.PrivateKey:
return key.(ed25519.PrivateKey), nil
default:
return nil, fmt.Errorf("unexpected signing key type: %v", t)
}
}
// LoadChain loads a PEM-encoded certificate chain from a given path
func LoadChain(path string) ([]*x509.Certificate, error) {
blob, err := ioutil.ReadFile(path)
if err != nil {
return nil, fmt.Errorf("failed reading certificate chain: %v", err)
}
return ParseChain(blob)
}
// ParseChain parses a PEM-encoded certificate chain
func ParseChain(rest []byte) ([]*x509.Certificate, error) {
var chain []*x509.Certificate
for len(rest) > 0 {
var block *pem.Block
block, rest = pem.Decode(rest)
if block == nil {
break
}
if block.Type != "CERTIFICATE" {
return nil, fmt.Errorf("unexpected pem block type: %v", block.Type)
}
certificate, err := x509.ParseCertificate(block.Bytes)
if err != nil {
return nil, fmt.Errorf("failed parsing x509 certificate: %v", err)
}
chain = append(chain, certificate)
}
return chain, nil
}
// ParseDerChain parses a list of DER-encoded X.509 certificates, such that the
// first (zero-index) string is interpretted as an end-entity certificate and
// the remaining ones as the an intermediate CertPool.
func ParseDerChain(chain [][]byte) (*x509.Certificate, *x509.CertPool, error) {
certificates, err := ParseDerChainToList(chain)
if err != nil || len(certificates) == 0 {
return nil, nil, err
}
intermediatePool := x509.NewCertPool()
for _, certificate := range certificates[1:] {
intermediatePool.AddCert(certificate)
}
return certificates[0], intermediatePool, nil
}
// ParseDerChainToList parses a list of DER-encoded certificates
func ParseDerChainToList(chain [][]byte) ([]*x509.Certificate, error) {
ret := make([]*x509.Certificate, 0, len(chain))
for _, der := range chain {
c, err := x509.ParseCertificate(der)
if err != nil {
return nil, fmt.Errorf("certificate decoding failed: %v", err)
}
ret = append(ret, c)
}
return ret, nil
}
// VerifyChain checks whether the listed certificates are chained such
// that the first is signed by the second, the second by the third, etc.
func VerifyChain(chain []*x509.Certificate) error {
for i := 0; i < len(chain)-1; i++ {
if err := chain[i].CheckSignatureFrom(chain[i+1]); err != nil {
return err
}
}
return nil
}
|
