Configure golangci-lint and fix warnings

signer/x509ops/x509ops.go

@@ -0,0 +1,987 @@
+package x509ops
+
+import (
+	"bufio"
+	"bytes"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha1" // #nosec G505 needed for protocol version 1
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/pem"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/big"
+	"os"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/longsleep/pkac"
+	log "github.com/sirupsen/logrus"
+
+	"git.cacert.org/cacert-gosigner/shared"
+)
+
+const crlLifetime = time.Hour * 24 * 7
+
+const (
+	pemTypeCertificate        = "CERTIFICATE"
+	pemTypeCertificateRequest = "CERTIFICATE REQUEST"
+	pemTypePrivateKey         = "PRIVATE KEY"
+)
+
+var (
+	oidPkcs9EmailAddress = []int{1, 2, 840, 113549, 1, 9, 1}
+)
+
+type Root struct {
+	Name                  string
+	privateKey            crypto.Signer
+	certificate           *x509.Certificate
+	databaseFile          string
+	serialNumberFile      string
+	crlNumberFile         string
+	crlFileName           string
+	crlHashDir            string
+	crlDistributionPoints []string
+	ocspServers           []string
+}
+
+func (x *Root) String() string {
+	return x.Name
+}
+
+func loadCertificate(certificateFile string) (*x509.Certificate, error) {
+	pemBytes, err := ioutil.ReadFile(certificateFile)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"could not load certificate %s: %w",
+			certificateFile,
+			err,
+		)
+	}
+
+	pemBlock, _ := pem.Decode(pemBytes)
+	if pemBlock.Type != pemTypeCertificate {
+		log.Warnf(
+			"PEM in %s is probably not a certificate. PEM block has type %s",
+			certificateFile,
+			pemBlock.Type,
+		)
+	}
+
+	certificate, err := x509.ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"could no parse certificate from %s: %w",
+			certificateFile,
+			err,
+		)
+	}
+
+	return certificate, nil
+}
+
+func loadPrivateKey(filename string) (crypto.Signer, error) {
+	pemBytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"could not load private key %s: %w",
+			filename,
+			err,
+		)
+	}
+
+	pemBlock, _ := pem.Decode(pemBytes)
+	if pemBlock == nil {
+		return nil, fmt.Errorf("no PEM data found in %s", filename)
+	}
+
+	if pemBlock.Type != pemTypePrivateKey {
+		log.Warnf(
+			"PEM in %s is probably not a private key. PEM block has type %s",
+			filename,
+			pemBlock.Type,
+		)
+	}
+
+	privateKey, err := x509.ParsePKCS8PrivateKey(pemBlock.Bytes)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"could no parse private key from %s: %w",
+			filename,
+			err,
+		)
+	}
+
+	return privateKey.(*rsa.PrivateKey), nil
+}
+
+func (x *Root) getNextSerialNumber() (*big.Int, error) {
+	// TODO: decide whether we should use 64 bit random serial numbers as
+	//       recommended by CAB forum baseline requirements
+	serialNumberFile := x.serialNumberFile
+
+	_, err := os.Stat(serialNumberFile)
+	if err != nil {
+		log.Warnf("serial number file %s does not exist: %v", x.serialNumberFile, err)
+
+		return big.NewInt(1), nil
+	}
+
+	data, err := ioutil.ReadFile(x.serialNumberFile)
+	if err != nil {
+		return nil, fmt.Errorf("could not read serial number file %s: %w", x.serialNumberFile, err)
+	}
+
+	result, err := stringAsBigInt(data)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse content of %s as serial number: %w", x.serialNumberFile, err)
+	}
+
+	return result, err
+}
+
+func (x *Root) getNextCRLNumber() (*big.Int, error) {
+	_, err := os.Stat(x.crlNumberFile)
+	if err != nil {
+		log.Warnf("CRL number file %s does not exist: %v", x.crlNumberFile, err)
+
+		return big.NewInt(1), nil
+	}
+
+	data, err := ioutil.ReadFile(x.crlNumberFile)
+	if err != nil {
+		return nil, fmt.Errorf("could not read CRL number file %s: %w", x.crlNumberFile, err)
+	}
+
+	result, err := stringAsBigInt(data)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse content of %s as CRL number: %w", x.crlNumberFile, err)
+	}
+
+	return result, nil
+}
+
+func (x *Root) bumpCRLNumber(current *big.Int) error {
+	serial := current.Int64() + 1
+	crlNumberFile := x.crlNumberFile
+
+	outFile, err := ioutil.TempFile(path.Dir(crlNumberFile), "*.txt")
+	if err != nil {
+		return fmt.Errorf("could not create temporary crl number file: %w", err)
+	}
+
+	defer func() { _ = outFile.Close() }()
+
+	_, err = outFile.WriteString(fmt.Sprintf(
+		"%s\n",
+		strings.ToUpper(strconv.FormatInt(serial, 16)),
+	))
+	if err != nil {
+		return fmt.Errorf("could not write new CRL number %d to %s: %w", serial, outFile.Name(), err)
+	}
+
+	if err = outFile.Close(); err != nil {
+		return fmt.Errorf("could not close temporary file %s: %w", outFile.Name(), err)
+	}
+
+	if err = os.Rename(crlNumberFile, fmt.Sprintf("%s.old", crlNumberFile)); err != nil {
+		return fmt.Errorf("could not rename %s to %s.old: %w", crlNumberFile, crlNumberFile, err)
+	}
+
+	if err = os.Rename(outFile.Name(), crlNumberFile); err != nil {
+		return fmt.Errorf("could not rename %s to %s: %w", outFile.Name(), crlNumberFile, err)
+	}
+
+	return nil
+}
+
+func (x *Root) bumpSerialNumber(current *big.Int) error {
+	serial := current.Int64() + 1
+
+	outFile, err := ioutil.TempFile(path.Dir(x.serialNumberFile), "*.txt")
+	if err != nil {
+		return fmt.Errorf("could not open temporary serial number file: %w", err)
+	}
+
+	defer func() { _ = outFile.Close() }()
+
+	_, err = outFile.WriteString(fmt.Sprintf(
+		"%s\n",
+		strings.ToUpper(strconv.FormatInt(serial, 16)),
+	))
+	if err != nil {
+		return fmt.Errorf("could not write new serial number %d to %s: %w", serial, outFile.Name(), err)
+	}
+
+	if err = outFile.Close(); err != nil {
+		return fmt.Errorf("could not close temporary file %s: %w", outFile.Name(), err)
+	}
+
+	if _, err = os.Stat(x.serialNumberFile); err == nil {
+		if err = os.Rename(x.serialNumberFile, fmt.Sprintf("%s.old", x.serialNumberFile)); err != nil {
+			return fmt.Errorf("could not rename %s to %s.old: %w", x.serialNumberFile, x.serialNumberFile, err)
+		}
+	}
+
+	if err = os.Rename(outFile.Name(), x.serialNumberFile); err != nil {
+		return fmt.Errorf("could not rename %s to %s: %w", outFile.Name(), x.serialNumberFile, err)
+	}
+
+	return nil
+}
+
+func (x *Root) loadRevokedCertificatesFromDatabase() ([]pkix.RevokedCertificate, error) {
+	databaseFile := x.databaseFile
+
+	_, err := os.Stat(databaseFile)
+	if err != nil {
+		log.Warnf("openssl certificate database file %s does not exist: %v", databaseFile, err)
+
+		return []pkix.RevokedCertificate{}, nil
+	}
+
+	file, err := os.Open(databaseFile)
+	if err != nil {
+		return nil, fmt.Errorf("could not open openssl certificate database file %s: %w", databaseFile, err)
+	}
+
+	defer func() { _ = file.Close() }()
+
+	result := make([]pkix.RevokedCertificate, 0)
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.Split(scanner.Text(), "\t")
+		if line[0] == "R" {
+			serialNumber, err := stringAsBigInt([]byte(line[3]))
+			if err != nil {
+				return nil, fmt.Errorf("could not parse serial number %s as big int: %w", line[3], err)
+			}
+
+			revokeTs, err := strconv.ParseInt(line[2][:len(line[2])-1], 10, 64)
+			if err != nil {
+				return nil, fmt.Errorf("could not parse serial number: %w", err)
+			}
+
+			result = append(result, pkix.RevokedCertificate{
+				SerialNumber:   serialNumber,
+				RevocationTime: time.Unix(revokeTs, 0),
+				Extensions:     nil,
+			})
+		}
+	}
+
+	return result, nil
+}
+
+func (x *Root) recordRevocation(certificate *x509.Certificate) (*pkix.RevokedCertificate, error) {
+	_, err := os.Stat(x.databaseFile)
+	if err != nil {
+		return nil, fmt.Errorf("openssl certificate database file %s does not exist: %w", x.databaseFile, err)
+	}
+
+	inFile, err := os.Open(x.databaseFile)
+	if err != nil {
+		return nil, fmt.Errorf("could not open openssl certificate database file %s: %w", x.databaseFile, err)
+	}
+
+	defer func() { _ = inFile.Close() }()
+
+	outFile, err := ioutil.TempFile(path.Dir(x.databaseFile), "*.txt")
+
+	defer func() { _ = outFile.Close() }()
+
+	if err != nil {
+		return nil, fmt.Errorf("could not open temporary database file: %w", err)
+	}
+
+	scanner := bufio.NewScanner(inFile)
+	writer := bufio.NewWriter(outFile)
+
+	found := false
+	revocationTime := time.Now()
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.Split(line, "\t")
+
+		serialNumber, err := stringAsBigInt([]byte(parts[3]))
+		if err != nil {
+			return nil, fmt.Errorf("could not parse serial number %s as big int: %w", parts[3], err)
+		}
+
+		if serialNumber == certificate.SerialNumber {
+			line = strings.Join(
+				[]string{"R", parts[1], strconv.FormatInt(revocationTime.Unix(), 10) + "Z", parts[3], parts[4]},
+				"\t",
+			)
+			found = true
+		}
+
+		if _, err = writer.WriteString(fmt.Sprintf("%s\n", line)); err != nil {
+			return nil, fmt.Errorf("could not write '%s' to %s: %w", line, outFile.Name(), err)
+		}
+	}
+
+	if err = outFile.Close(); err != nil {
+		return nil, fmt.Errorf("could not close temporary file %s: %w", outFile.Name(), err)
+	}
+
+	if err = inFile.Close(); err != nil {
+		return nil, fmt.Errorf("could not close %s: %w", x.databaseFile, err)
+	}
+
+	if err = os.Rename(x.databaseFile, fmt.Sprintf("%s.old", x.databaseFile)); err != nil {
+		return nil, fmt.Errorf("could not rename %s to %s.old: %w", x.databaseFile, x.databaseFile, err)
+	}
+
+	if err = os.Rename(outFile.Name(), x.databaseFile); err != nil {
+		return nil, fmt.Errorf("could not rename temporary file %s to %s: %w", outFile.Name(), x.databaseFile, err)
+	}
+
+	if !found {
+		log.Warnf("entry not found in database")
+	}
+
+	return &pkix.RevokedCertificate{
+		SerialNumber:   certificate.SerialNumber,
+		RevocationTime: revocationTime,
+	}, nil
+}
+
+func (x *Root) RevokeCertificate(request []byte) (*pkix.RevokedCertificate, error) {
+	pemBlock, _ := pem.Decode(request)
+	if pemBlock.Type != pemTypeCertificate {
+		log.Warnf(
+			"PEM structure is probably not a certificate. PEM block has type %s",
+			pemBlock.Type,
+		)
+		log.Trace(request)
+	}
+
+	certificate, err := x509.ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"could no parse certificate: %w",
+			err,
+		)
+	}
+
+	return x.recordRevocation(certificate)
+}
+
+func (x *Root) GenerateCrl(algorithm x509.SignatureAlgorithm) ([]byte, *[20]byte, error) {
+	certificatesToRevoke, err := x.loadRevokedCertificatesFromDatabase()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	nextCrlNumber, err := x.getNextCRLNumber()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	crlTemplate := &x509.RevocationList{
+		SignatureAlgorithm:  algorithm,
+		RevokedCertificates: certificatesToRevoke,
+		Number:              nextCrlNumber,
+		ThisUpdate:          time.Now(),
+		NextUpdate:          time.Now().Add(crlLifetime),
+		ExtraExtensions:     nil,
+	}
+
+	defer func() {
+		if err = x.bumpCRLNumber(nextCrlNumber); err != nil {
+			log.Errorf("could not bump CRL number: %v", err)
+		}
+	}()
+
+	crlBytes, err := x509.CreateRevocationList(
+		rand.Reader,
+		crlTemplate,
+		x.certificate,
+		x.privateKey,
+	)
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not create new CRL: %w", err)
+	}
+
+	if err = ioutil.WriteFile(x.crlFileName, crlBytes, 0600); err != nil {
+		return nil, nil, fmt.Errorf("could not write new CRL to %s: %w", x.crlFileName, err)
+	}
+
+	// sha1 is implied by protocol version 1
+	// #nosec G401
+	newCrlHash := sha1.Sum(crlBytes)
+	hashedCrlFileName := path.Join(
+		x.crlHashDir,
+		fmt.Sprintf("%s.crl", hex.EncodeToString(newCrlHash[:])),
+	)
+
+	if err = ioutil.WriteFile(hashedCrlFileName, crlBytes, 0600); err != nil {
+		return nil, nil, fmt.Errorf("could not write new CRL to %s: %w", hashedCrlFileName, err)
+	}
+
+	return crlBytes, &newCrlHash, nil
+}
+
+func (x *Root) DeleteOldCRLs(keepHashes ...string) error {
+	log.Debugf("will look for CRLs in %s", x.crlHashDir)
+
+	found, err := filepath.Glob(path.Join(x.crlHashDir, "*.crl"))
+	if err != nil {
+		log.Warnf("could not match files: %v", err)
+
+		return nil
+	}
+
+nextFound:
+	for _, filename := range found {
+		for _, keepHash := range keepHashes {
+			if x.GetCrlFileName(keepHash) == filename {
+				continue nextFound
+			}
+		}
+		if err := os.Remove(filename); err != nil {
+			return fmt.Errorf("could not delete %s: %w", filename, err)
+		}
+	}
+
+	return nil
+}
+
+func (x *Root) GetCrlFileName(hash string) string {
+	return path.Join(x.crlHashDir, fmt.Sprintf("%s.crl", hash))
+}
+
+func (x *Root) checkPreconditions() {
+	results := []bool{
+		x.checkFile(x.databaseFile, "database"),
+		x.checkFile(x.serialNumberFile, "serial number"),
+		x.checkFile(x.crlNumberFile, "CRL serial number"),
+		x.checkFile(x.crlFileName, "CRL"),
+		x.checkDir(x.crlHashDir, "directory for hash indexed CRLs"),
+	}
+	for _, success := range results {
+		if !success {
+			log.Warnf("preconditions for %s failed, operations may fail too", x)
+
+			break
+		}
+	}
+}
+
+func (x *Root) checkFile(path, prefix string) bool {
+	ok := true
+
+	if s, e := os.Stat(path); e != nil {
+		log.Warnf("%s file %s of %s has issues: %v", prefix, path, x, e)
+
+		ok = false
+	} else if s.IsDir() {
+		log.Warnf("%s file %s of %s is a directory", prefix, path, x)
+
+		ok = false
+	}
+
+	return ok
+}
+
+func (x *Root) checkDir(path, prefix string) bool {
+	ok := true
+
+	if s, e := os.Stat(path); e != nil {
+		log.Warnf("%s %s of %s has issues: %v", prefix, path, x, e)
+
+		if err := os.MkdirAll(path, 0755); err != nil {
+			log.Warnf("could not create %s %s of %s: %v", prefix, path, x, err)
+		}
+
+		ok = false
+	} else if !s.IsDir() {
+		log.Warnf("%s %s of %s is not a directory", prefix, path, x)
+
+		ok = false
+	}
+
+	return ok
+}
+
+type SigningRequestParameters struct {
+	Request                 []byte
+	Subject                 []byte
+	SubjectAlternativeNames []byte
+	Days                    uint16
+	IsSpkac                 bool
+}
+
+func (x *Root) SignCertificate(
+	profile *Profile,
+	algorithm x509.SignatureAlgorithm,
+	params *SigningRequestParameters,
+) ([]byte, error) {
+	var publicKey interface{}
+
+	// nolint:nestif
+	if params.IsSpkac {
+		var err error
+
+		const spkacPrefix = "SPKAC="
+
+		if !bytes.Equal([]byte(spkacPrefix), params.Request[:len(spkacPrefix)]) {
+			return nil, fmt.Errorf("request does not contain a valid SPKAC string")
+		}
+
+		derBytes, err := base64.StdEncoding.DecodeString(string(params.Request[len(spkacPrefix):]))
+		if err != nil {
+			return nil, fmt.Errorf("could not decode SPKAC bytes: %w", err)
+		}
+
+		publicKey, err = pkac.ParseSPKAC(derBytes)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse SPKAC: %w", err)
+		}
+	} else {
+		csrBlock, _ := pem.Decode(params.Request)
+		if csrBlock.Type != pemTypeCertificateRequest {
+			return nil, fmt.Errorf(
+				"unexpected PEM block '%s' instead of '%s'",
+				csrBlock.Type,
+				pemTypeCertificateRequest,
+			)
+		}
+		csr, err := x509.ParseCertificateRequest(csrBlock.Bytes)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse CSR: %w", err)
+		}
+		publicKey = csr.PublicKey
+	}
+
+	nextSerialNumber, err := x.getNextSerialNumber()
+	if err != nil {
+		return nil, fmt.Errorf("could not get next serial number: %w", err)
+	}
+
+	// copy profile
+	notBefore := time.Now()
+	notAfter := notBefore.Add(time.Hour * 24 * time.Duration(params.Days))
+	certificate := &x509.Certificate{
+		KeyUsage:              profile.prototype.KeyUsage,
+		ExtKeyUsage:           profile.prototype.ExtKeyUsage,
+		SignatureAlgorithm:    algorithm,
+		CRLDistributionPoints: x.crlDistributionPoints,
+		OCSPServer:            x.ocspServers,
+		SerialNumber:          nextSerialNumber,
+		NotBefore:             notBefore,
+		NotAfter:              notAfter,
+	}
+
+	// check subject
+	subject, err := profile.parseSubject(params.Subject)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse subject: %w", err)
+	}
+
+	certificate.Subject = *subject
+
+	// check altNames
+	err = profile.parseAltNames(certificate, params.SubjectAlternativeNames)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse subject alternative names: %w", err)
+	}
+
+	moveEmailsFromSubjectToAlternativeNames(certificate)
+
+	log.Tracef("prepared for signing: %+v", certificate)
+
+	certBytes, err := x509.CreateCertificate(rand.Reader, certificate, x.certificate, publicKey, x.privateKey)
+	if err != nil {
+		return nil, fmt.Errorf("could not sign certificate: %w", err)
+	}
+
+	parsedCertificate, err := x509.ParseCertificate(certBytes)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse signed certificate: %w", err)
+	}
+
+	if err = x.bumpSerialNumber(nextSerialNumber); err != nil {
+		return nil, fmt.Errorf("could not bump serial number: %w", err)
+	}
+
+	err = x.recordIssuedCertificate(parsedCertificate)
+	if err != nil {
+		return nil, fmt.Errorf("could not record signed certificate in database: %w", err)
+	}
+
+	pemBytes := pem.EncodeToMemory(&pem.Block{Type: pemTypeCertificate, Bytes: certBytes})
+	log.Tracef("signed new certificate\n%s", pemBytes)
+
+	return pemBytes, nil
+}
+
+// we move the email addresses to alt names because they are encoded to UTF-8
+// otherwise which is not compliant to RFC-5280
+func moveEmailsFromSubjectToAlternativeNames(certificate *x509.Certificate) {
+	extraNames := make([]pkix.AttributeTypeAndValue, 0)
+
+	for _, p := range certificate.Subject.ExtraNames {
+		if p.Type.Equal(oidPkcs9EmailAddress) {
+			email := p.Value.(string)
+
+			if certificate.EmailAddresses == nil {
+				certificate.EmailAddresses = []string{email}
+
+				continue
+			}
+
+			for _, e := range certificate.EmailAddresses {
+				if e == p.Value {
+					continue
+				}
+			}
+
+			certificate.EmailAddresses = append(certificate.EmailAddresses, email)
+		} else {
+			extraNames = append(extraNames, p)
+		}
+	}
+
+	certificate.Subject.ExtraNames = extraNames
+}
+
+func (x *Root) recordIssuedCertificate(certificate *x509.Certificate) error {
+	log.Tracef("recording %+v", certificate)
+
+	tempFile, err := ioutil.TempFile(path.Dir(x.databaseFile), "*.txt")
+	if err != nil {
+		return fmt.Errorf("could not create temporary file: %w", err)
+	}
+
+	defer func() { _ = tempFile.Close() }()
+
+	tempName := tempFile.Name()
+
+	dbExists := false
+
+	_, err = os.Stat(x.databaseFile)
+	if err != nil {
+		log.Warnf("openssl certificate database file %s does not exist: %v", x.databaseFile, err)
+	} else {
+		dbExists = true
+		inFile, err := os.Open(x.databaseFile)
+		defer func() { _ = inFile.Close() }()
+		if err != nil {
+			return fmt.Errorf("could not open openssl certificate database file %s: %w", x.databaseFile, err)
+		}
+		_, err = io.Copy(tempFile, inFile)
+		if err != nil {
+			return fmt.Errorf("could not copy %s to temporary file %s: %w", x.databaseFile, tempName, err)
+		}
+		if err = inFile.Close(); err != nil {
+			return fmt.Errorf("could not close %s: %w", x.databaseFile, err)
+		}
+	}
+
+	if err = tempFile.Close(); err != nil {
+		return fmt.Errorf("could not close temporary file %s: %w", tempName, err)
+	}
+
+	outFile, err := os.OpenFile(tempName, os.O_APPEND|os.O_WRONLY, 0644)
+	if err != nil {
+		return fmt.Errorf("could not open temporary file for writing %s: %w", tempName, err)
+	}
+
+	defer func() { _ = outFile.Close() }()
+
+	line := strings.Join(
+		// nolint:gomnd
+		[]string{
+			"V",
+			strconv.FormatInt(certificate.NotBefore.Unix(), 10) + "Z",
+			"",
+			strings.ToUpper(certificate.SerialNumber.Text(16)),
+			"unknown",
+			opensslFormatDN(certificate.Subject),
+		},
+		"\t",
+	)
+
+	_, err = fmt.Fprintln(outFile, line)
+	if err != nil {
+		return fmt.Errorf("could not write '%s' to %s: %w", line, tempName, err)
+	}
+
+	if err = outFile.Close(); err != nil {
+		return fmt.Errorf("could not close temporary file %s: %w", tempName, err)
+	}
+
+	if dbExists {
+		if err = os.Rename(x.databaseFile, fmt.Sprintf("%s.old", x.databaseFile)); err != nil {
+			return fmt.Errorf("could not rename %s to %s.old: %w", x.databaseFile, x.databaseFile, err)
+		}
+	}
+
+	if err = os.Rename(tempName, x.databaseFile); err != nil {
+		return fmt.Errorf("could not rename temporary file %s to %s: %w", tempName, x.databaseFile, err)
+	}
+
+	return nil
+}
+
+func opensslFormatDN(subject pkix.Name) string {
+	const (
+		oidSuffixCommonName         = 3
+		oidSuffixCountryName        = 6
+		oidSuffixLocalityName       = 7
+		oidSuffixProvinceName       = 8
+		oidSuffixOrganization       = 10
+		oidSuffixOrganizationalUnit = 11
+	)
+
+	var buf strings.Builder
+
+	for _, rdn := range subject.ToRDNSequence() {
+		if len(rdn) == 0 {
+			continue
+		}
+
+		for _, atv := range rdn {
+			value, ok := atv.Value.(string)
+			if !ok {
+				continue
+			}
+
+			t := atv.Type
+			if len(t) == 4 && t[:3].Equal([]int{2, 5, 4}) {
+				switch t[3] {
+				case oidSuffixCommonName:
+					buf.WriteString("/CN=")
+					buf.WriteString(value)
+				case oidSuffixCountryName:
+					buf.WriteString("/C=")
+					buf.WriteString(value)
+				case oidSuffixLocalityName:
+					buf.WriteString("/L=")
+					buf.WriteString(value)
+				case oidSuffixProvinceName:
+					buf.WriteString("/ST=")
+					buf.WriteString(value)
+				case oidSuffixOrganization:
+					buf.WriteString("/O=")
+					buf.WriteString(value)
+				case oidSuffixOrganizationalUnit:
+					buf.WriteString("/OU=")
+					buf.WriteString(value)
+				}
+			} else if t.Equal(oidPkcs9EmailAddress) {
+				buf.WriteString("/emailAddress=")
+				buf.WriteString(value)
+			}
+		}
+	}
+
+	return buf.String()
+}
+
+func NewRoot(
+	basedir, name, subdir string,
+	id shared.CryptoSystemRootID,
+	crlDistributionPoints, ocspServers []string,
+) *Root {
+	key, err := loadPrivateKey(path.Join(basedir, subdir, "private", "ca.key.pem"))
+	if err != nil {
+		log.Fatalf("could not load private key: %v", err)
+	}
+
+	cert, err := loadCertificate(path.Join(basedir, subdir, "ca.crt.pem"))
+	if err != nil {
+		log.Fatalf("could not load CA certificate: %v", err)
+	}
+
+	root := &Root{
+		Name:             name,
+		privateKey:       key,
+		certificate:      cert,
+		databaseFile:     path.Join(basedir, subdir, "index.txt"),
+		serialNumberFile: path.Join(basedir, subdir, "serial"),
+		crlNumberFile:    path.Join(basedir, subdir, "crlnumber"),
+		crlFileName:      fmt.Sprintf("revoke-root%d.crl", id),
+		crlHashDir: path.Join(
+			basedir,
+			"currentcrls",
+			fmt.Sprintf("%d", id),
+		),
+		crlDistributionPoints: crlDistributionPoints,
+		ocspServers:           ocspServers,
+	}
+	root.checkPreconditions()
+
+	return root
+}
+
+type AltNameType string
+
+const (
+	NameTypeDNS     AltNameType = "DNS"
+	NameTypeXMPPJid AltNameType = "otherName:1.3.6.1.5.5.7.8.5;UTF8" // from RFC 3920, 6120
+)
+
+type SubjectDnField string
+
+const (
+	SubjectDnFieldCountryName            SubjectDnField = "C"
+	SubjectDnFieldStateOrProvinceName    SubjectDnField = "ST"
+	SubjectDnFieldLocalityName           SubjectDnField = "L"
+	SubjectDnFieldOrganizationName       SubjectDnField = "O"
+	SubjectDnFieldOrganizationalUnitName SubjectDnField = "OU"
+	SubjectDnFieldCommonName             SubjectDnField = "CN"
+	SubjectDnFieldEmailAddress           SubjectDnField = "emailAddress"
+)
+
+type Profile struct {
+	name            string
+	prototype       *x509.Certificate
+	subjectDNFields []SubjectDnField
+	altNameTypes    []AltNameType
+	copyEmail       bool // whether to copy emailAddress values from subjectDN to email address subject alternative name
+}
+
+func (p *Profile) String() string {
+	return p.name
+}
+
+func (p *Profile) parseSubject(subject []byte) (*pkix.Name, error) {
+	parts := strings.Split(string(subject), "/")
+	subjectDN := &pkix.Name{}
+
+	for _, part := range parts {
+		if len(strings.TrimSpace(part)) == 0 {
+			continue
+		}
+
+		handled := false
+		item := strings.SplitN(part, "=", 2)
+
+		for _, f := range p.subjectDNFields {
+			if !strings.EqualFold(item[0], string(f)) {
+				continue
+			}
+
+			value := item[1]
+			handled = true
+
+			switch f {
+			case SubjectDnFieldCountryName:
+				subjectDN.Country = append(subjectDN.Country, value)
+			case SubjectDnFieldStateOrProvinceName:
+				subjectDN.Province = append(subjectDN.Province, value)
+			case SubjectDnFieldLocalityName:
+				subjectDN.Locality = append(subjectDN.Locality, value)
+			case SubjectDnFieldOrganizationName:
+				subjectDN.Organization = append(subjectDN.Organization, value)
+			case SubjectDnFieldOrganizationalUnitName:
+				subjectDN.OrganizationalUnit = append(subjectDN.OrganizationalUnit, value)
+			case SubjectDnFieldCommonName:
+				subjectDN.CommonName = value
+			case SubjectDnFieldEmailAddress:
+				subjectDN.ExtraNames = append(subjectDN.ExtraNames, pkix.AttributeTypeAndValue{
+					Type:  oidPkcs9EmailAddress,
+					Value: value,
+				})
+			default:
+				log.Warnf("unhandled subject DN type %s", f)
+			}
+		}
+
+		if !handled {
+			return nil, fmt.Errorf("skipped part %s because it is not supported by profile %s", part, p)
+		}
+	}
+
+	log.Debugf("created subject DN %s", subjectDN)
+
+	return subjectDN, nil
+}
+
+func (p *Profile) parseAltNames(template *x509.Certificate, altNames []byte) error {
+	parts := strings.Split(string(altNames), ",")
+	for _, part := range parts {
+		if len(strings.TrimSpace(part)) == 0 {
+			continue
+		}
+
+		handled := false
+		item := strings.SplitN(part, ":", 3)
+
+		if item[0] == "otherName" {
+			item = []string{strings.Join(item[:2], ":"), item[2]}
+		} else {
+			item = []string{item[0], strings.Join(item[1:], ":")}
+		}
+
+		for _, f := range p.altNameTypes {
+			if item[0] != string(f) {
+				continue
+			}
+
+			value := item[1]
+			handled = true
+
+			switch f {
+			case NameTypeDNS:
+				if template.DNSNames == nil {
+					template.DNSNames = []string{value}
+				} else {
+					template.DNSNames = append(template.DNSNames, value)
+				}
+			case NameTypeXMPPJid:
+				// x509ops.Certificate has no support for otherName alternative names
+				log.Warnf("skipping %s because it cannot be supported", part)
+			default:
+				log.Warnf("unhandled alternative name type %s", f)
+			}
+		}
+
+		if !handled {
+			return fmt.Errorf("skipped alternative name %s because it is not supported by profile %s", part, p)
+		}
+	}
+
+	return nil
+}
+
+func NewProfile(
+	name string,
+	prototype *x509.Certificate,
+	subjectDnFields []SubjectDnField,
+	altNameTypes []AltNameType,
+	copyEmail bool,
+) *Profile {
+	return &Profile{
+		name:            name,
+		prototype:       prototype,
+		subjectDNFields: subjectDnFields,
+		altNameTypes:    altNameTypes,
+		copyEmail:       copyEmail,
+	}
+}
+
+func stringAsBigInt(data []byte) (*big.Int, error) {
+	dataString := strings.TrimSpace(string(data))
+
+	parseInt, err := strconv.ParseInt(dataString, 16, 64)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse %s as big int: %w", dataString, err)
+	}
+
+	return big.NewInt(parseInt), nil
+}