88 lines
2.2 KiB
Go
88 lines
2.2 KiB
Go
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/*
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Package ca implements a disk file-backed certificate authority with a built-in
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CRL signer. The certificate authority can issue new certificates (including the
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creation of intermediate CAs) and revoke existing certificates, resulting in a
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fresh CRL.
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*/
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package ca
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import (
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"crypto/rand"
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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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"path/filepath"
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"time"
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"src.lwithers.me.uk/go/rsa/pkg/pemfile"
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)
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const (
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crlFilename = "crl.pem"
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crlKeyFilename = "crl-signer-key.pem"
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crlCertFilename = "crl-signer-cert.pem"
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)
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func (ca *CA) loadCRLState() error {
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var err error
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ca.crl, err = pemfile.ReadCRL(filepath.Join(ca.dir, crlFilename))
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if err != nil {
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return err
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}
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ca.crlKey, err = pemfile.ReadKey(filepath.Join(ca.dir, crlKeyFilename))
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if err != nil {
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return err
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}
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ca.crlCert, err = pemfile.ReadCert(filepath.Join(ca.dir, crlCertFilename))
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return err
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}
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func (ca *CA) Revoke(serial *big.Int) (*x509.RevocationList, error) {
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// if the certificate is already revoked, update its revocation time
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var found bool
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for i := range ca.crl.RevokedCertificates {
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if ca.crl.RevokedCertificates[i].SerialNumber.Cmp(serial) == 0 {
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ca.crl.RevokedCertificates[i].RevocationTime = time.Now()
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found = true
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break
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}
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}
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// otherwise, add a new entry
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if !found {
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n := big.NewInt(0)
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n.SetBytes(serial.Bytes())
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ca.crl.RevokedCertificates = append(ca.crl.RevokedCertificates,
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pkix.RevokedCertificate{
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SerialNumber: n,
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RevocationTime: time.Now(),
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})
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}
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// increment issue number
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ca.crl.Number.Add(ca.crl.Number, big.NewInt(1))
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ca.crl.ThisUpdate = time.Now()
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// create new DER-form certificate
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der, err := x509.CreateRevocationList(rand.Reader, ca.crl, ca.crlCert, ca.crlKey)
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if err != nil {
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return nil, fmt.Errorf("failed to sign new CRL: %w", err)
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}
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// ensure we can parse it
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newCRL, err := x509.ParseRevocationList(der)
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if err != nil {
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return nil, fmt.Errorf("failed to parse newly-signed CRL: %w", err)
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}
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// save to disk
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if err := pemfile.Write(filepath.Join(ca.dir, crlFilename), pemfile.TypeX509CRL, der); err != nil {
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return nil, fmt.Errorf("failed to save CRL: %w", err)
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}
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// update in-memory copy
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ca.crl = newCRL
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return ca.crl, nil
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}
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