lego/challenge/tlsalpn01/tls_alpn_challenge.go

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2019-03-11 16:56:48 +00:00
package tlsalpn01
import (
"crypto/rsa"
"crypto/sha256"
"crypto/tls"
"crypto/x509/pkix"
"encoding/asn1"
"fmt"
2019-03-11 16:56:48 +00:00
"github.com/go-acme/lego/acme"
"github.com/go-acme/lego/acme/api"
"github.com/go-acme/lego/certcrypto"
"github.com/go-acme/lego/challenge"
"github.com/go-acme/lego/log"
)
// idPeAcmeIdentifierV1 is the SMI Security for PKIX Certification Extension OID referencing the ACME extension.
// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-05#section-5.1
var idPeAcmeIdentifierV1 = asn1.ObjectIdentifier{1, 3, 6, 1, 5, 5, 7, 1, 31}
type ValidateFunc func(core *api.Core, domain string, chlng acme.Challenge) error
type Challenge struct {
core *api.Core
validate ValidateFunc
provider challenge.Provider
}
func NewChallenge(core *api.Core, validate ValidateFunc, provider challenge.Provider) *Challenge {
return &Challenge{
core: core,
validate: validate,
provider: provider,
}
}
func (c *Challenge) SetProvider(provider challenge.Provider) {
c.provider = provider
}
// Solve manages the provider to validate and solve the challenge.
func (c *Challenge) Solve(authz acme.Authorization) error {
domain := authz.Identifier.Value
log.Infof("[%s] acme: Trying to solve TLS-ALPN-01", challenge.GetTargetedDomain(authz))
chlng, err := challenge.FindChallenge(challenge.TLSALPN01, authz)
if err != nil {
return err
}
// Generate the Key Authorization for the challenge
keyAuth, err := c.core.GetKeyAuthorization(chlng.Token)
if err != nil {
return err
}
err = c.provider.Present(domain, chlng.Token, keyAuth)
if err != nil {
return fmt.Errorf("[%s] acme: error presenting token: %v", challenge.GetTargetedDomain(authz), err)
}
defer func() {
err := c.provider.CleanUp(domain, chlng.Token, keyAuth)
if err != nil {
log.Warnf("[%s] acme: error cleaning up: %v", challenge.GetTargetedDomain(authz), err)
}
}()
chlng.KeyAuthorization = keyAuth
return c.validate(c.core, domain, chlng)
}
// ChallengeBlocks returns PEM blocks (certPEMBlock, keyPEMBlock) with the acmeValidation-v1 extension
// and domain name for the `tls-alpn-01` challenge.
func ChallengeBlocks(domain, keyAuth string) ([]byte, []byte, error) {
// Compute the SHA-256 digest of the key authorization.
zBytes := sha256.Sum256([]byte(keyAuth))
value, err := asn1.Marshal(zBytes[:sha256.Size])
if err != nil {
return nil, nil, err
}
// Add the keyAuth digest as the acmeValidation-v1 extension
// (marked as critical such that it won't be used by non-ACME software).
// Reference: https://tools.ietf.org/html/draft-ietf-acme-tls-alpn-05#section-3
extensions := []pkix.Extension{
{
Id: idPeAcmeIdentifierV1,
Critical: true,
Value: value,
},
}
// Generate a new RSA key for the certificates.
tempPrivateKey, err := certcrypto.GeneratePrivateKey(certcrypto.RSA2048)
if err != nil {
return nil, nil, err
}
rsaPrivateKey := tempPrivateKey.(*rsa.PrivateKey)
// Generate the PEM certificate using the provided private key, domain, and extra extensions.
tempCertPEM, err := certcrypto.GeneratePemCert(rsaPrivateKey, domain, extensions)
if err != nil {
return nil, nil, err
}
// Encode the private key into a PEM format. We'll need to use it to generate the x509 keypair.
rsaPrivatePEM := certcrypto.PEMEncode(rsaPrivateKey)
return tempCertPEM, rsaPrivatePEM, nil
}
// ChallengeCert returns a certificate with the acmeValidation-v1 extension
// and domain name for the `tls-alpn-01` challenge.
func ChallengeCert(domain, keyAuth string) (*tls.Certificate, error) {
tempCertPEM, rsaPrivatePEM, err := ChallengeBlocks(domain, keyAuth)
if err != nil {
return nil, err
}
cert, err := tls.X509KeyPair(tempCertPEM, rsaPrivatePEM)
if err != nil {
return nil, err
}
return &cert, nil
}