77 lines
2.2 KiB
Go
77 lines
2.2 KiB
Go
package certgen
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import (
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"crypto/rand"
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"crypto/rsa"
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"crypto/sha1"
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"crypto/tls"
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"crypto/x509"
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"crypto/x509/pkix"
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"fmt"
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"math/big"
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"net"
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"time"
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)
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// MakeServerTls generates a server TLS certificate using a CA to sign it
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// If ca is nil then the server will sign its own certificate
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// dnsNames and ipAddresses can be nil if they are not required on the certificate
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func MakeServerTls(ca *CertGen, bits int, name pkix.Name, serialNumber *big.Int, future Future, dnsNames []string, ipAddresses []net.IP) (*CertGen, error) {
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// generate rsa private key
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serverPrivKey, err := rsa.GenerateKey(rand.Reader, bits)
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if err != nil {
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return nil, fmt.Errorf("failed to generate server private key: %w", err)
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}
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// generate SubjectKeyId from sha1 hash of public key bytes
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pubKeyBytes := x509.MarshalPKCS1PublicKey(&serverPrivKey.PublicKey)
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pubKeyHash := sha1.Sum(pubKeyBytes)
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// base certificate data
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now := time.Now()
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cert := &x509.Certificate{
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SerialNumber: serialNumber,
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Subject: name,
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DNSNames: dnsNames,
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IPAddresses: ipAddresses,
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NotBefore: now,
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NotAfter: future(now),
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SubjectKeyId: pubKeyHash[:],
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ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
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KeyUsage: x509.KeyUsageDigitalSignature,
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}
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// use current certificate as CA if nil
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if ca == nil {
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ca = &CertGen{cert: cert, key: serverPrivKey}
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}
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// create certificate bytes
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serverBytes, err := x509.CreateCertificate(rand.Reader, cert, ca.cert, serverPrivKey.Public(), ca.key)
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if err != nil {
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return nil, fmt.Errorf("failed to generate server certificate bytes: %w", err)
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}
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// add the raw certificate bytes so `*x509.Certificate.Equal(*x509.Certificate)` is valid
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cert.Raw = serverBytes
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// get private key bytes
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privKeyBytes := x509.MarshalPKCS1PrivateKey(serverPrivKey)
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gen := &CertGen{cert: cert, certBytes: serverBytes, key: serverPrivKey, keyBytes: privKeyBytes}
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// generate pem blocks
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err = gen.generatePem()
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if err != nil {
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return nil, fmt.Errorf("failed to generate PEM encoding: %w", err)
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}
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// generate key pair
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caKeyPair, err := tls.X509KeyPair(gen.certPem, gen.keyPem)
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if err != nil {
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return nil, fmt.Errorf("failed to generate server key pair: %w", err)
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}
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gen.tlsCert = caKeyPair
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return gen, nil
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}
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