Refactor code structure

Move X.509 and Openpgp operations into custom packages. Implement more
robust input reading. Do not convert []byte to string unnecessarily.

Finish implementation of X.509 CRL creation.
This commit is contained in:
Jan Dittberner 2021-01-05 19:59:43 +01:00
parent 2de9771472
commit 9f0916b14a
9 changed files with 715 additions and 493 deletions

View file

@ -2,18 +2,15 @@ package signer
import (
"bytes"
"crypto/rand"
"crypto/sha1"
"crypto/x509"
"crypto/x509/pkix"
"encoding/hex"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"os"
"path"
"time"
"os/exec"
"strings"
"unsafe"
log "github.com/sirupsen/logrus"
@ -21,20 +18,14 @@ import (
"git.cacert.org/cacert-gosigner/datastructures"
"git.cacert.org/cacert-gosigner/shared"
"git.cacert.org/cacert-gosigner/signer/x509_ops"
)
const crlLifetime = time.Hour * 24 * 7
var emptyDataSha1 [20]byte
func init() {
emptyDataSha1 = sha1.Sum([]byte{})
}
type CommandProcessorSettings struct {
CABaseDir string
XDeltaPath string
OpenPGPUidEmail string
CABaseDir string
XDeltaPath string
OpenPGPKeyRingDir string
OpenPGPUidEmail string
}
// The CommandProcessor takes parsed protocol data and executes the actual
@ -102,7 +93,36 @@ func (p *CommandProcessor) handleSignAction(
error,
) {
log.Debugf("handle sign call: %v", command)
return nil, errors.New("not implemented yet")
idSystem, err := p.checkIdentitySystem(
command.System, command.Root, command.Profile, command.MdAlgorithm)
if err != nil {
return nil, err
}
log.Debugf("identified id system: %+v", idSystem)
switch command.System {
case CsX509:
request := command.Content1
san := command.Content2
subject := command.Content3
if content, err := p.signX509Certificate(idSystem, command.Days, command.Spkac, request, san, subject); err != nil {
return nil, err
} else {
return datastructures.NewSignResponse(command.Version, content), nil
}
case CsOpenPGP:
pubKey := command.Content1
if content, err := p.signOpenpgpKey(idSystem, command.Days, pubKey); err != nil {
return nil, err
} else {
return datastructures.NewSignResponse(command.Version, content), nil
}
default:
return nil, fmt.Errorf("sign not implemented for crypto system %s", idSystem.System)
}
}
func (p *CommandProcessor) handleRevokeAction(
@ -128,7 +148,11 @@ func (p *CommandProcessor) handleRevokeAction(
case CsX509:
request := command.Content1
clientHash := command.Content3
return p.revokeX509(idSystem, request, clientHash)
if content, err := p.revokeX509(idSystem, request, clientHash); err != nil {
return nil, err
} else {
return datastructures.NewRevokeResponse(command.Version, content), nil
}
default:
return nil, fmt.Errorf("revoke not implemented for crypto system %s", idSystem.System)
}
@ -136,10 +160,9 @@ func (p *CommandProcessor) handleRevokeAction(
type IdSystemParameters struct {
System *CryptoSystem
Root *RootCredentials
RootId shared.CryptoSystemRootId
Profile string
MessageDigestAlgorithm x509.SignatureAlgorithm
Root interface{}
Profile interface{}
MessageDigestAlgorithm interface{}
}
func (p *CommandProcessor) checkIdentitySystem(
@ -158,7 +181,7 @@ func (p *CommandProcessor) checkIdentitySystem(
root, ok := p.CryptoSystems[systemId].Roots[rootId]
if !ok {
return nil, fmt.Errorf(
"unsupported root certificate %d for crypto system %s",
"unsupported root %d for crypto system %s",
rootId,
cryptoSystem,
)
@ -166,7 +189,7 @@ func (p *CommandProcessor) checkIdentitySystem(
profile, ok := p.CryptoSystems[systemId].Profiles[profileId]
if !ok {
return nil, fmt.Errorf(
"invalid CA profile %d for crypto system %s",
"invalid profile %d for crypto system %s",
profileId,
cryptoSystem,
)
@ -182,153 +205,111 @@ func (p *CommandProcessor) checkIdentitySystem(
return &IdSystemParameters{
System: cryptoSystem,
Root: root,
RootId: rootId,
Profile: profile,
MessageDigestAlgorithm: mdAlgorithm,
}, nil
}
func (p *CommandProcessor) revokeX509(
system *IdSystemParameters,
request string,
clientHash string,
) (*datastructures.SignerResponse, error) {
clientHashBytes, err := hex.DecodeString(clientHash)
if err != nil {
return nil, fmt.Errorf("could not parse '%s' as hex bytes", clientHash)
}
func (p *CommandProcessor) revokeX509(system *IdSystemParameters, request []byte, clientHash []byte) ([]byte, error) {
x509Root := system.Root.(*x509_ops.Root)
signatureAlgorithm := system.MessageDigestAlgorithm.(x509.SignatureAlgorithm)
log.Debugf("revoke X.509 for root %s (%d)", system.Root, system.RootId)
log.Debugf("hash bytes from client %x", clientHashBytes)
log.Debugf("revoke X.509 for root %s", x509Root)
log.Debugf("hash bytes from client %x", clientHash)
crlFileName := fmt.Sprintf("revoke-root%d.crl", system.RootId)
stat, err := os.Stat(crlFileName)
if err != nil {
log.Debugf("CRL file %s does not exist", crlFileName)
} else if stat.IsDir() {
return nil, fmt.Errorf("CRL filename %s points to a directory", crlFileName)
}
currentHash := emptyDataSha1
if stat != nil {
crlData, err := ioutil.ReadFile(crlFileName)
if err != nil {
log.Warnf("could not read current CRL, assuming empty CRL")
}
currentHash = sha1.Sum(crlData)
}
log.Debugf("hash bytes on signer %x", currentHash)
crlIsCurrent := false
if bytes.Equal(clientHashBytes, currentHash[:]) {
log.Debug("client CRL hash and current CRL hash on signer match")
err := p.deleteOldCrl(system.RootId, clientHash)
if err != nil {
log.Warnf("could not delete old CRLs: %v", err)
}
if !bytes.Equal(clientHashBytes, emptyDataSha1[:]) {
crlIsCurrent = true
} else {
log.Debugf("client has an empty CRL, the signer too")
}
}
var (
err error
crlBytes []byte
newHash *[20]byte
)
if len(request) > 0 {
_, err = revokeCertificate(request, system.System, system.RootId)
_, err = x509Root.RevokeCertificate(request)
if err != nil {
return nil, fmt.Errorf("could not revoke certificate / create CRL: %v", err)
}
}
var crlBytes []byte
crlBytes, err = generateCrl(system.MessageDigestAlgorithm, system.System, system.RootId)
crlBytes, newHash, err = x509Root.GenerateCrl(signatureAlgorithm)
if err != nil {
return nil, fmt.Errorf("could not generate a new CRL for root %d: %v", system.RootId, err)
return nil, fmt.Errorf("could not generate a new CRL for root %s: %v", x509Root, err)
}
log.Debugf("crlIsCurrent: %v, crlBytes: %d", crlIsCurrent, len(crlBytes))
log.Debugf("crlBytes: %d", len(crlBytes))
log.Tracef("New CRL\n%s", pem.EncodeToMemory(&pem.Block{
Type: "X509 CRL",
Bytes: crlBytes,
}))
var content []byte
oldCrlFile := x509Root.GetCrlFileName(string(clientHash))
newCrlFile := x509Root.GetCrlFileName(hex.EncodeToString(newHash[:]))
err = ioutil.WriteFile(crlFileName, crlBytes, 0644)
if err != nil {
return nil, fmt.Errorf("could not write new CRL to %s: %v", crlFileName, err)
statOld, oldErr := os.Stat(oldCrlFile)
statNew, newErr := os.Stat(newCrlFile)
if oldErr == nil && newErr == nil && !statOld.IsDir() && !statNew.IsDir() {
content, err = p.buildXDelta(oldCrlFile, newCrlFile)
if err != nil {
log.Warnf("could not generate xdelta: %v", err)
}
log.Tracef("xdelte produced %d bytes", len(content))
}
if content == nil {
content = pem.EncodeToMemory(&pem.Block{
Type: "X509 CRL",
Bytes: crlBytes,
})
log.Tracef("sending %d PEM CRL bytes", len(content))
}
return nil, errors.New("not implemented yet")
return content, nil
}
func (p *CommandProcessor) deleteOldCrl(id shared.CryptoSystemRootId, hash string) error {
path.Join(p.Settings.CABaseDir, "currentcrls", fmt.Sprintf("%d", id))
// TODO: implement
return errors.New("not implemented yet")
}
func generateCrl(
algorithm x509.SignatureAlgorithm,
system *CryptoSystem,
rootId shared.CryptoSystemRootId,
) ([]byte, error) {
caCertificate, err := system.loadCertificate(rootId)
func (p *CommandProcessor) buildXDelta(oldFile string, newFile string) ([]byte, error) {
patchFile, err := ioutil.TempFile(os.TempDir(), "*.patch")
if err != nil {
return nil, err
return nil, fmt.Errorf("could not create temporary file for patch: %v", err)
}
caPrivateKey, err := system.getPrivateKey(rootId)
if err != nil {
return nil, err
}
certificatesToRevoke, err := system.loadRevokedCertificatesFromDatabase(rootId)
if err != nil {
return nil, err
}
nextCrlNumber, err := system.getNextCRLNumber(rootId)
if err != nil {
return 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 = system.bumpCRLNumber(rootId, nextCrlNumber); err != nil {
log.Errorf("could not bump CRL number: %v", err)
if err := os.Remove(patchFile.Name()); err != nil {
log.Warnf("could not remove temporary file %s: %v", patchFile.Name(), err)
}
}()
return x509.CreateRevocationList(
rand.Reader,
crlTemplate,
caCertificate,
caPrivateKey,
)
}
func revokeCertificate(request string, system *CryptoSystem, rootId shared.CryptoSystemRootId) (*pkix.RevokedCertificate, error) {
pemBlock, _ := pem.Decode([]byte(request))
if pemBlock.Type != "CERTIFICATE" {
if pemBlock.Type != "CERTIFICATE" {
log.Warnf(
"PEM structure is probably not a certificate. PEM block has type %s",
pemBlock.Type,
if err = patchFile.Close(); err != nil {
return nil, fmt.Errorf("could not close temporary file: %v", err)
}
buf := bytes.NewBuffer([]byte{})
cmd := exec.Command(p.Settings.XDeltaPath, "delta", oldFile, newFile, patchFile.Name())
cmd.Stdout = buf
cmd.Stderr = buf
err = cmd.Run()
if err != nil {
switch err.(type) {
case *exec.ExitError:
if err.(*exec.ExitError).ExitCode() == 1 {
// xdelta delta exits with status code 1 if a delta has been found
break
}
return nil, fmt.Errorf(
"xdelta command '%s' did not work correctly: %v\noutput was:\n%s",
strings.Join(cmd.Args, " "),
err,
buf.String(),
)
default:
return nil, fmt.Errorf(
"xdelta command '%s' did not work correctly: %v\noutput was:\n%s",
strings.Join(cmd.Args, " "),
err,
buf.String(),
)
log.Trace(request)
}
}
certificate, err := x509.ParseCertificate(pemBlock.Bytes)
if err != nil {
return nil, fmt.Errorf(
"could no parse certificate: %v",
err,
)
}
return system.recordRevocation(rootId, certificate)
return ioutil.ReadFile(patchFile.Name())
}
func (p *CommandProcessor) signX509Certificate(system *IdSystemParameters, days uint16, spkac uint8, request []byte, san []byte, subject []byte) ([]byte, error) {
return nil, errors.New("signX509Certificate is not implemented yet")
}
func (p *CommandProcessor) signOpenpgpKey(system *IdSystemParameters, days uint16, pubKey []byte) ([]byte, error) {
return nil, errors.New("signOpenpgpKey is not implemented yet")
}
func NewCommandProcessorSettings() *CommandProcessorSettings {
@ -336,9 +317,18 @@ func NewCommandProcessorSettings() *CommandProcessorSettings {
if !ok {
caBasedir = "."
}
gpgUidEmail, ok := os.LookupEnv("SIGNER_GPG_KEYRING_DIR")
gpgKeyringDir, ok := os.LookupEnv("SIGNER_GPG_KEYRING_DIR")
if !ok {
gpgKeyringDir = "."
}
gpgUidEmail, ok := os.LookupEnv("SIGNER_GPG_ID")
if !ok {
gpgUidEmail = "gpg@cacert.org"
}
return &CommandProcessorSettings{CABaseDir: caBasedir, OpenPGPUidEmail: gpgUidEmail, XDeltaPath: "/usr/bin/xdelta"}
return &CommandProcessorSettings{
CABaseDir: caBasedir,
OpenPGPKeyRingDir: gpgKeyringDir,
OpenPGPUidEmail: gpgUidEmail,
XDeltaPath: "/usr/bin/xdelta",
}
}