79 lines
1.9 KiB
Go
79 lines
1.9 KiB
Go
package tls
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import (
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"bytes"
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/tls"
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"crypto/x509"
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"crypto/x509/pkix"
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"encoding/pem"
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"math/big"
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"net"
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"time"
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)
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func Certificate(host ...string) (tls.Certificate, error) {
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priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
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if err != nil {
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return tls.Certificate{}, err
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}
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notBefore := time.Now()
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notAfter := notBefore.Add(time.Hour * 24 * 365)
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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 tls.Certificate{}, err
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}
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template := x509.Certificate{
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SerialNumber: serialNumber,
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Subject: pkix.Name{
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Organization: []string{"Acme Co"},
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},
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NotBefore: notBefore,
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NotAfter: notAfter,
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KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
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ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
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BasicConstraintsValid: true,
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}
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for _, h := range host {
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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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template.IsCA = true
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template.KeyUsage |= x509.KeyUsageCertSign
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derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
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if err != nil {
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return tls.Certificate{}, err
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}
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// create public key
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certOut := bytes.NewBuffer(nil)
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if err = pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
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return tls.Certificate{}, err
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}
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// create private key
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keyOut := bytes.NewBuffer(nil)
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b, err := x509.MarshalECPrivateKey(priv)
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if err != nil {
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return tls.Certificate{}, err
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}
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if err = pem.Encode(keyOut, &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}); err != nil {
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return tls.Certificate{}, err
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}
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return tls.X509KeyPair(certOut.Bytes(), keyOut.Bytes())
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}
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