136 lines
3.7 KiB
Go
136 lines
3.7 KiB
Go
package gmi
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import (
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"crypto"
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"crypto/ed25519"
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"crypto/rand"
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"crypto/tls"
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"crypto/x509"
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"math/big"
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"net"
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"path/filepath"
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"strings"
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"time"
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)
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// CertificateStore maps hostnames to certificates.
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// The zero value of CertificateStore is an empty store ready to use.
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type CertificateStore struct {
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store map[string]tls.Certificate
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}
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// Add adds a certificate for the given hostname to the store.
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// It tries to parse the certificate if it is not already parsed.
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func (c *CertificateStore) Add(hostname string, cert tls.Certificate) {
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if c.store == nil {
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c.store = map[string]tls.Certificate{}
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}
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// Parse certificate if not already parsed
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if cert.Leaf == nil {
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parsed, err := x509.ParseCertificate(cert.Certificate[0])
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if err == nil {
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cert.Leaf = parsed
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}
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}
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c.store[hostname] = cert
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}
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// Lookup returns the certificate for the given hostname.
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func (c *CertificateStore) Lookup(hostname string) (*tls.Certificate, error) {
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cert, ok := c.store[hostname]
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if !ok {
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return nil, ErrCertificateUnknown
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}
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// Ensure that the certificate is not expired
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if cert.Leaf != nil && cert.Leaf.NotAfter.Before(time.Now()) {
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return &cert, ErrCertificateExpired
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}
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return &cert, nil
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}
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// Load loads certificates from the given path.
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// The path should lead to a directory containing certificates and private keys
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// in the form hostname.crt and hostname.key.
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// For example, the hostname "localhost" would have the corresponding files
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// localhost.crt (certificate) and localhost.key (private key).
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func (c *CertificateStore) Load(path string) error {
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matches, err := filepath.Glob(filepath.Join(path, "*.crt"))
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if err != nil {
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return err
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}
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for _, crtPath := range matches {
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keyPath := strings.TrimSuffix(crtPath, ".crt") + ".key"
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cert, err := tls.LoadX509KeyPair(crtPath, keyPath)
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if err != nil {
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continue
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}
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hostname := strings.TrimSuffix(filepath.Base(crtPath), ".crt")
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c.Add(hostname, cert)
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}
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return nil
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}
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// NewCertificate creates and returns a new parsed certificate.
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func NewCertificate(host string, duration time.Duration) (tls.Certificate, error) {
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crt, priv, err := newX509KeyPair(host, duration)
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if err != nil {
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return tls.Certificate{}, err
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}
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var cert tls.Certificate
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cert.Leaf = crt
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cert.Certificate = append(cert.Certificate, crt.Raw)
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cert.PrivateKey = priv
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return cert, nil
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}
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// newX509KeyPair creates and returns a new certificate and private key.
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func newX509KeyPair(host string, duration time.Duration) (*x509.Certificate, crypto.PrivateKey, error) {
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// Generate an ED25519 private key
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_, priv, err := ed25519.GenerateKey(rand.Reader)
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if err != nil {
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return nil, nil, err
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}
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public := priv.Public()
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// ED25519 keys should have the DigitalSignature KeyUsage bits set
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// in the x509.Certificate template
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keyUsage := x509.KeyUsageDigitalSignature
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serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
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serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
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if err != nil {
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return nil, nil, err
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}
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notBefore := time.Now()
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notAfter := notBefore.Add(duration)
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template := x509.Certificate{
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SerialNumber: serialNumber,
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NotBefore: notBefore,
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NotAfter: notAfter,
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KeyUsage: keyUsage,
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ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
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BasicConstraintsValid: true,
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}
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hosts := strings.Split(host, ",")
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for _, h := range hosts {
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if ip := net.ParseIP(h); ip != nil {
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template.IPAddresses = append(template.IPAddresses, ip)
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} else {
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template.DNSNames = append(template.DNSNames, h)
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}
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}
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crt, err := x509.CreateCertificate(rand.Reader, &template, &template, public, priv)
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if err != nil {
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return nil, nil, err
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}
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cert, err := x509.ParseCertificate(crt)
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if err != nil {
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return nil, nil, err
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}
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return cert, priv, nil
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}
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