boulder/issuance/crl.go

128 lines
3.3 KiB
Go

package issuance
import (
"crypto/rand"
"crypto/x509"
"fmt"
"math/big"
"time"
"github.com/zmap/zlint/v3/lint"
"github.com/letsencrypt/boulder/config"
"github.com/letsencrypt/boulder/crl/idp"
"github.com/letsencrypt/boulder/linter"
)
type CRLProfileConfig struct {
ValidityInterval config.Duration
MaxBackdate config.Duration
// LintConfig is a path to a zlint config file, which can be used to control
// the behavior of zlint's "customizable lints".
LintConfig string
// IgnoredLints is a list of lint names that we know will fail for this
// profile, and which we know it is safe to ignore.
IgnoredLints []string
}
type CRLProfile struct {
validityInterval time.Duration
maxBackdate time.Duration
lints lint.Registry
}
func NewCRLProfile(config CRLProfileConfig) (*CRLProfile, error) {
lifetime := config.ValidityInterval.Duration
if lifetime >= 10*24*time.Hour {
return nil, fmt.Errorf("crl lifetime cannot be more than 10 days, got %q", lifetime)
} else if lifetime <= 0*time.Hour {
return nil, fmt.Errorf("crl lifetime must be positive, got %q", lifetime)
}
if config.MaxBackdate.Duration < 0 {
return nil, fmt.Errorf("crl max backdate must be non-negative, got %q", config.MaxBackdate)
}
reg, err := linter.NewRegistry(config.IgnoredLints)
if err != nil {
return nil, fmt.Errorf("creating lint registry: %w", err)
}
if config.LintConfig != "" {
lintconfig, err := lint.NewConfigFromFile(config.LintConfig)
if err != nil {
return nil, fmt.Errorf("loading zlint config file: %w", err)
}
reg.SetConfiguration(lintconfig)
}
return &CRLProfile{
validityInterval: config.ValidityInterval.Duration,
maxBackdate: config.MaxBackdate.Duration,
lints: reg,
}, nil
}
type CRLRequest struct {
Number *big.Int
Shard int64
ThisUpdate time.Time
Entries []x509.RevocationListEntry
}
// crlURL combines the CRL URL base with a shard, and adds a suffix.
func (i *Issuer) crlURL(shard int) string {
return fmt.Sprintf("%s%d.crl", i.crlURLBase, shard)
}
func (i *Issuer) IssueCRL(prof *CRLProfile, req *CRLRequest) ([]byte, error) {
backdatedBy := i.clk.Now().Sub(req.ThisUpdate)
if backdatedBy > prof.maxBackdate {
return nil, fmt.Errorf("ThisUpdate is too far in the past (%s>%s)", backdatedBy, prof.maxBackdate)
}
if backdatedBy < 0 {
return nil, fmt.Errorf("ThisUpdate is in the future (%s>%s)", req.ThisUpdate, i.clk.Now())
}
template := &x509.RevocationList{
RevokedCertificateEntries: req.Entries,
Number: req.Number,
ThisUpdate: req.ThisUpdate,
NextUpdate: req.ThisUpdate.Add(-time.Second).Add(prof.validityInterval),
}
if i.crlURLBase == "" {
return nil, fmt.Errorf("CRL must contain an issuingDistributionPoint")
}
// Concat the base with the shard directly, since we require that the base
// end with a single trailing slash.
idp, err := idp.MakeUserCertsExt([]string{
i.crlURL(int(req.Shard)),
})
if err != nil {
return nil, fmt.Errorf("creating IDP extension: %w", err)
}
template.ExtraExtensions = append(template.ExtraExtensions, idp)
err = i.Linter.CheckCRL(template, prof.lints)
if err != nil {
return nil, err
}
crlBytes, err := x509.CreateRevocationList(
rand.Reader,
template,
i.Cert.Certificate,
i.Signer,
)
if err != nil {
return nil, err
}
return crlBytes, nil
}