feat: implement 'replaces' field in newOrder and draft-ietf-acme-ari-03 CertID changes (#2114)

Author: beautifulentropy

.golangci.yml

@@ -226,6 +226,6 @@ issues:
     - path: providers/dns/hosttech/internal/client_test.go
       text: 'Duplicate words \(0\) found'
     - path: cmd/cmd_renew.go
-      text: 'cyclomatic complexity 15 of func `renewForDomains` is high'
+      text: 'cyclomatic complexity \d+ of func `renewForDomains` is high'
     - path: providers/dns/cpanel/cpanel.go
       text: 'cyclomatic complexity 13 of func `\(\*DNSProvider\)\.CleanUp` is high'

README.md

@@ -16,7 +16,7 @@ Let's Encrypt client and ACME library written in Go.
 - ACME v2 [RFC 8555](https://www.rfc-editor.org/rfc/rfc8555.html)
   - Support [RFC 8737](https://www.rfc-editor.org/rfc/rfc8737.html): TLS Application‑Layer Protocol Negotiation (ALPN) Challenge Extension
   - Support [RFC 8738](https://www.rfc-editor.org/rfc/rfc8738.html): certificates for IP addresses
-  - Support [draft-ietf-acme-ari-02](https://datatracker.ietf.org/doc/draft-ietf-acme-ari/): Renewal Information (ARI) Extension
+  - Support [draft-ietf-acme-ari-03](https://datatracker.ietf.org/doc/draft-ietf-acme-ari/): Renewal Information (ARI) Extension
 - Register with CA
 - Obtain certificates, both from scratch or with an existing CSR
 - Renew certificates

acme/api/order.go

@@ -13,6 +13,10 @@ import (
 type OrderOptions struct {
 	NotBefore time.Time
 	NotAfter  time.Time
+	// A string uniquely identifying a previously-issued certificate which this
+	// order is intended to replace.
+	// - https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-5
+	ReplacesCertID string
 }
 
 type OrderService service
@@ -45,6 +49,10 @@ func (o *OrderService) NewWithOptions(domains []string, opts *OrderOptions) (acm
 		if !opts.NotBefore.IsZero() {
 			orderReq.NotBefore = opts.NotBefore.Format(time.RFC3339)
 		}
+
+		if o.core.GetDirectory().RenewalInfo != "" {
+			orderReq.Replaces = opts.ReplacesCertID
+		}
 	}
 
 	var order acme.Order

acme/commons.go

@@ -181,6 +181,12 @@ type Order struct {
 	// certificate (optional, string):
 	// A URL for the certificate that has been issued in response to this order
 	Certificate string `json:"certificate,omitempty"`
+
+	// replaces (optional, string):
+	// replaces (string, optional): A string uniquely identifying a
+	// previously-issued certificate which this order is intended to replace.
+	// - https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-5
+	Replaces string `json:"replaces,omitempty"`
 }
 
 // Authorization the ACME authorization object.
@@ -329,11 +335,11 @@ type RenewalInfoResponse struct {
 }
 
 // RenewalInfoUpdateRequest is the JWS payload for POST requests made to the renewalInfo endpoint.
-// - (4.2. RenewalInfo Objects) https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-02#section-4.2
+// - (4.2. RenewalInfo Objects) https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-4.2
 type RenewalInfoUpdateRequest struct {
 	// CertID is a composite string in the format: base64url(AKI) || '.' || base64url(Serial), where AKI is the
 	// certificate's authority key identifier and Serial is the certificate's serial number. For details, see:
-	// https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-02#section-4.1
+	// https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-4.1
 	CertID string `json:"certID"`
 	// Replaced is required and indicates whether or not the client considers the certificate to have been replaced.
 	// A certificate is considered replaced when its revocation would not disrupt any ongoing services,

certificate/certificates.go

@@ -63,6 +63,10 @@ type ObtainRequest struct {
 	Bundle                         bool
 	PreferredChain                 string
 	AlwaysDeactivateAuthorizations bool
+	// A string uniquely identifying a previously-issued certificate which this
+	// order is intended to replace.
+	// - https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-5
+	ReplacesCertID string
 }
 
 // ObtainForCSRRequest The request to obtain a certificate matching the CSR passed into it.
@@ -79,6 +83,10 @@ type ObtainForCSRRequest struct {
 	Bundle                         bool
 	PreferredChain                 string
 	AlwaysDeactivateAuthorizations bool
+	// A string uniquely identifying a previously-issued certificate which this
+	// order is intended to replace.
+	// - https://datatracker.ietf.org/doc/html/draft-ietf-acme-ari-03#section-5
+	ReplacesCertID string
 }
 
 type resolver interface {
@@ -124,8 +132,9 @@ func (c *Certifier) Obtain(request ObtainRequest) (*Resource, error) {
 	}
 
 	orderOpts := &api.OrderOptions{
-		NotBefore: request.NotBefore,
-		NotAfter:  request.NotAfter,
+		NotBefore:      request.NotBefore,
+		NotAfter:       request.NotAfter,
+		ReplacesCertID: request.ReplacesCertID,
 	}
 
 	order, err := c.core.Orders.NewWithOptions(domains, orderOpts)
@@ -189,8 +198,9 @@ func (c *Certifier) ObtainForCSR(request ObtainForCSRRequest) (*Resource, error)
 	}
 
 	orderOpts := &api.OrderOptions{
-		NotBefore: request.NotBefore,
-		NotAfter:  request.NotAfter,
+		NotBefore:      request.NotBefore,
+		NotAfter:       request.NotAfter,
+		ReplacesCertID: request.ReplacesCertID,
 	}
 
 	order, err := c.core.Orders.NewWithOptions(domains, orderOpts)

certificate/renewal.go

@@ -2,12 +2,12 @@ package certificate
 
 import (
 	"crypto/x509"
+	"encoding/asn1"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
 	"math/rand"
-	"strings"
 	"time"
 
 	"github.com/go-acme/lego/v4/acme"
@@ -65,7 +65,7 @@ func (r *RenewalInfoResponse) ShouldRenewAt(now time.Time, willingToSleep time.D
 //
 // https://datatracker.ietf.org/doc/draft-ietf-acme-ari
 func (c *Certifier) GetRenewalInfo(req RenewalInfoRequest) (*RenewalInfoResponse, error) {
-	certID, err := makeARICertID(req.Cert)
+	certID, err := MakeARICertID(req.Cert)
 	if err != nil {
 		return nil, fmt.Errorf("error making certID: %w", err)
 	}
@@ -84,39 +84,32 @@ func (c *Certifier) GetRenewalInfo(req RenewalInfoRequest) (*RenewalInfoResponse
 	return &info, nil
 }
 
-// UpdateRenewalInfo sends an update to the ACME server's renewal info endpoint to indicate that the client has successfully replaced a certificate.
-// A certificate is considered replaced when its revocation would not disrupt any ongoing services,
-// for instance because it has been renewed and the new certificate is in use, or because it is no longer in use.
-//
-// Note: this endpoint is part of a draft specification, not all ACME servers will implement it.
-// This method will return api.ErrNoARI if the server does not advertise a renewal info endpoint.
-//
-// https://datatracker.ietf.org/doc/draft-ietf-acme-ari
-func (c *Certifier) UpdateRenewalInfo(req RenewalInfoRequest) error {
-	certID, err := makeARICertID(req.Cert)
-	if err != nil {
-		return fmt.Errorf("error making certID: %w", err)
+// MakeARICertID constructs a certificate identifier as described in draft-ietf-acme-ari-03, section 4.1.
+func MakeARICertID(leaf *x509.Certificate) (string, error) {
+	if leaf == nil {
+		return "", errors.New("leaf certificate is nil")
 	}
 
-	_, err = c.core.Certificates.UpdateRenewalInfo(acme.RenewalInfoUpdateRequest{
-		CertID:   certID,
-		Replaced: true,
-	})
+	// Marshal the Serial Number into DER.
+	der, err := asn1.Marshal(leaf.SerialNumber)
 	if err != nil {
-		return err
+		return "", err
 	}
 
-	return nil
-}
-
-// makeARICertID constructs a certificate identifier as described in draft-ietf-acme-ari-02, section 4.1.
-func makeARICertID(leaf *x509.Certificate) (string, error) {
-	if leaf == nil {
-		return "", errors.New("leaf certificate is nil")
+	// Check if the DER encoded bytes are sufficient (at least 3 bytes: tag,
+	// length, and value).
+	if len(der) < 3 {
+		return "", errors.New("invalid DER encoding of serial number")
 	}
 
-	return fmt.Sprintf("%s.%s",
-		strings.TrimRight(base64.URLEncoding.EncodeToString(leaf.AuthorityKeyId), "="),
-		strings.TrimRight(base64.URLEncoding.EncodeToString(leaf.SerialNumber.Bytes()), "="),
-	), nil
+	// Extract only the integer bytes from the DER encoded Serial Number
+	// Skipping the first 2 bytes (tag and length).
+	serial := base64.RawURLEncoding.EncodeToString(der[2:])
+
+	// Convert the Authority Key Identifier to base64url encoding without
+	// padding.
+	aki := base64.RawURLEncoding.EncodeToString(leaf.AuthorityKeyId)
+
+	// Construct the final identifier by concatenating AKI and Serial Number.
+	return fmt.Sprintf("%s.%s", aki, serial), nil
 }

certificate/renewal_test.go

@@ -3,8 +3,6 @@ package certificate
 import (
 	"crypto/rand"
 	"crypto/rsa"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 	"time"
@@ -13,40 +11,28 @@ import (
 	"github.com/go-acme/lego/v4/acme/api"
 	"github.com/go-acme/lego/v4/certcrypto"
 	"github.com/go-acme/lego/v4/platform/tester"
-	"github.com/go-jose/go-jose/v4"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
 const (
 	ariLeafPEM = `-----BEGIN CERTIFICATE-----
-MIIDMDCCAhigAwIBAgIIPqNFaGVEHxwwDQYJKoZIhvcNAQELBQAwIDEeMBwGA1UE
-AxMVbWluaWNhIHJvb3QgY2EgM2ExMzU2MB4XDTIyMDMxNzE3NTEwOVoXDTI0MDQx
-NjE3NTEwOVowFjEUMBIGA1UEAxMLZXhhbXBsZS5jb20wggEiMA0GCSqGSIb3DQEB
-AQUAA4IBDwAwggEKAoIBAQCgm9K/c+il2Pf0f8qhgxn9SKqXq88cOm9ov9AVRbPA
-OWAAewqX2yUAwI4LZBGEgzGzTATkiXfoJ3cN3k39cH6tBbb3iSPuEn7OZpIk9D+e
-3Q9/hX+N/jlWkaTB/FNA+7aE5IVWhmdczYilXa10V9r+RcvACJt0gsipBZVJ4jfJ
-HnWJJGRZzzxqG/xkQmpXxZO7nOPFc8SxYKWdfcgp+rjR2ogYhSz7BfKoVakGPbpX
-vZOuT9z4kkHra/WjwlkQhtHoTXdAxH3qC2UjMzO57Tx+otj0CxAv9O7CTJXISywB
-vEVcmTSZkHS3eZtvvIwPx7I30ITRkYk/tLl1MbyB3SiZAgMBAAGjeDB2MA4GA1Ud
-DwEB/wQEAwIFoDAdBgNVHSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwDAYDVR0T
-AQH/BAIwADAfBgNVHSMEGDAWgBQ4zzDRUaXHVKqlSTWkULGU4zGZpTAWBgNVHREE
-DzANggtleGFtcGxlLmNvbTANBgkqhkiG9w0BAQsFAAOCAQEAx0aYvmCk7JYGNEXe
-+hrOfKawkHYzWvA92cI/Oi6h+oSdHZ2UKzwFNf37cVKZ37FCrrv5pFP/xhhHvrNV
-EnOx4IaF7OrnaTu5miZiUWuvRQP7ZGmGNFYbLTEF6/dj+WqyYdVaWzxRqHFu1ptC
-TXysJCeyiGnR+KOOjOOQ9ZlO5JUK3OE4hagPLfaIpDDy6RXQt3ss0iNLuB1+IOtp
-1URpvffLZQ8xPsEgOZyPWOcabTwJrtqBwily+lwPFn2mChUx846LwQfxtsXU/lJg
-HX2RteNJx7YYNeX3Uf960mgo5an6vE8QNAsIoNHYrGyEmXDhTRe9mCHyiW2S7fZq
-o9q12g==
+MIIBQzCB66ADAgECAgUAh2VDITAKBggqhkjOPQQDAjAVMRMwEQYDVQQDEwpFeGFt
+cGxlIENBMCIYDzAwMDEwMTAxMDAwMDAwWhgPMDAwMTAxMDEwMDAwMDBaMBYxFDAS
+BgNVBAMTC2V4YW1wbGUuY29tMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEeBZu
+7cbpAYNXZLbbh8rNIzuOoqOOtmxA1v7cRm//AwyMwWxyHz4zfwmBhcSrf47NUAFf
+qzLQ2PPQxdTXREYEnKMjMCEwHwYDVR0jBBgwFoAUaYhba4dGQEHhs3uEe6CuLN4B
+yNQwCgYIKoZIzj0EAwIDRwAwRAIge09+S5TZAlw5tgtiVvuERV6cT4mfutXIlwTb
++FYN/8oCIClDsqBklhB9KAelFiYt9+6FDj3z4KGVelYM5MdsO3pK
 -----END CERTIFICATE-----`
-	ariLeafCertID = "OM8w0VGlx1SqpUk1pFCxlOMxmaU.PqNFaGVEHxw"
+	ariLeafCertID = "aYhba4dGQEHhs3uEe6CuLN4ByNQ.AIdlQyE"
 )
 
 func Test_makeCertID(t *testing.T) {
 	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
 	require.NoError(t, err)
 
-	actual, err := makeARICertID(leaf)
+	actual, err := MakeARICertID(leaf)
 	require.NoError(t, err)
 	assert.Equal(t, ariLeafCertID, actual)
 }
@@ -145,85 +131,6 @@ func TestCertifier_GetRenewalInfo_errors(t *testing.T) {
 	}
 }
 
-func TestCertifier_UpdateRenewalInfo(t *testing.T) {
-	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
-	require.NoError(t, err)
-
-	key, err := rsa.GenerateKey(rand.Reader, 2048)
-	require.NoError(t, err, "Could not generate test key")
-
-	// Test with a fake API.
-	mux, apiURL := tester.SetupFakeAPI(t)
-	mux.HandleFunc("/renewalInfo", func(w http.ResponseWriter, r *http.Request) {
-		if r.Method != http.MethodPost {
-			http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
-			return
-		}
-
-		body, rsbErr := readSignedBody(r, key)
-		if rsbErr != nil {
-			http.Error(w, rsbErr.Error(), http.StatusBadRequest)
-			return
-		}
-
-		var req acme.RenewalInfoUpdateRequest
-		err = json.Unmarshal(body, &req)
-		assert.NoError(t, err)
-		assert.True(t, req.Replaced)
-		assert.Equal(t, ariLeafCertID, req.CertID)
-
-		w.WriteHeader(http.StatusOK)
-	})
-
-	core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
-	require.NoError(t, err)
-
-	certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
-
-	err = certifier.UpdateRenewalInfo(RenewalInfoRequest{leaf})
-	require.NoError(t, err)
-}
-
-func TestCertifier_UpdateRenewalInfo_errors(t *testing.T) {
-	leaf, err := certcrypto.ParsePEMCertificate([]byte(ariLeafPEM))
-	require.NoError(t, err)
-
-	key, err := rsa.GenerateKey(rand.Reader, 2048)
-	require.NoError(t, err, "Could not generate test key")
-
-	testCases := []struct {
-		desc    string
-		request RenewalInfoRequest
-	}{
-		{
-			desc:    "API error",
-			request: RenewalInfoRequest{leaf},
-		},
-	}
-
-	for _, test := range testCases {
-		test := test
-		t.Run(test.desc, func(t *testing.T) {
-			t.Parallel()
-
-			mux, apiURL := tester.SetupFakeAPI(t)
-
-			// Always returns an error.
-			mux.HandleFunc("/renewalInfo", func(w http.ResponseWriter, r *http.Request) {
-				http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
-			})
-
-			core, err := api.New(http.DefaultClient, "lego-test", apiURL+"/dir", "", key)
-			require.NoError(t, err)
-
-			certifier := NewCertifier(core, &resolverMock{}, CertifierOptions{KeyType: certcrypto.RSA2048})
-
-			err = certifier.UpdateRenewalInfo(test.request)
-			require.Error(t, err)
-		})
-	}
-}
-
 func TestRenewalInfoResponse_ShouldRenew(t *testing.T) {
 	now := time.Now().UTC()
 
@@ -289,26 +196,3 @@ func TestRenewalInfoResponse_ShouldRenew(t *testing.T) {
 		assert.Nil(t, rt)
 	})
 }
-
-func readSignedBody(r *http.Request, privateKey *rsa.PrivateKey) ([]byte, error) {
-	reqBody, err := io.ReadAll(r.Body)
-	if err != nil {
-		return nil, err
-	}
-
-	sigAlgs := []jose.SignatureAlgorithm{jose.RS256}
-	jws, err := jose.ParseSigned(string(reqBody), sigAlgs)
-	if err != nil {
-		return nil, err
-	}
-
-	body, err := jws.Verify(&jose.JSONWebKey{
-		Key:       privateKey.Public(),
-		Algorithm: "RSA",
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	return body, nil
-}