Support for DelegationUsage extension

This special cases the DelegationUsage extension, copying it to the
output when signing. It also adds support for a flag
delegation_enabled in certificate specifications. I have manually
confirmed this works.

Author: Watson Ladd

cli/testdata/csr.json

@@ -18,5 +18,6 @@
                 "1.2.3.4.5": "abc"
             }
         }
-    ]
-}
+    ],
+    "delegation_enabled": true
+}

csr/csr.go

@@ -37,7 +37,7 @@ type Name struct {
 	L            string            `json:"L,omitempty" yaml:"L,omitempty"`   // Locality
 	O            string            `json:"O,omitempty" yaml:"O,omitempty"`   // OrganisationName
 	OU           string            `json:"OU,omitempty" yaml:"OU,omitempty"` // OrganisationalUnitName
-    E            string            `json:"E,omitempty" yaml:"E,omitempty"`
+	E            string            `json:"E,omitempty" yaml:"E,omitempty"`
 	SerialNumber string            `json:"SerialNumber,omitempty" yaml:"SerialNumber,omitempty"`
 	OID          map[string]string `json:"OID,omitempty", yaml:"OID,omitempty"`
 }
@@ -136,14 +136,15 @@ type CAConfig struct {
 // A CertificateRequest encapsulates the API interface to the
 // certificate request functionality.
 type CertificateRequest struct {
-	CN           string           `json:"CN" yaml:"CN"`
-	Names        []Name           `json:"names" yaml:"names"`
-	Hosts        []string         `json:"hosts" yaml:"hosts"`
-	KeyRequest   *KeyRequest      `json:"key,omitempty" yaml:"key,omitempty"`
-	CA           *CAConfig        `json:"ca,omitempty" yaml:"ca,omitempty"`
-	SerialNumber string           `json:"serialnumber,omitempty" yaml:"serialnumber,omitempty"`
-	Extensions   []pkix.Extension `json:"extensions,omitempty" yaml:"extensions,omitempty"`
-	CRL          string           `json:"crl_url,omitempty" yaml:"crl_url,omitempty"`
+	CN                string           `json:"CN" yaml:"CN"`
+	Names             []Name           `json:"names" yaml:"names"`
+	Hosts             []string         `json:"hosts" yaml:"hosts"`
+	KeyRequest        *KeyRequest      `json:"key,omitempty" yaml:"key,omitempty"`
+	CA                *CAConfig        `json:"ca,omitempty" yaml:"ca,omitempty"`
+	SerialNumber      string           `json:"serialnumber,omitempty" yaml:"serialnumber,omitempty"`
+	DelegationEnabled bool             `json:"delegation_enabled,omitempty" yaml:"delegation_enabled,omitempty"`
+	Extensions        []pkix.Extension `json:"extensions,omitempty" yaml:"extensions,omitempty"`
+	CRL               string           `json:"crl_url,omitempty" yaml:"crl_url,omitempty"`
 }
 
 // New returns a new, empty CertificateRequest with a
@@ -196,9 +197,9 @@ func (cr *CertificateRequest) Name() (pkix.Name, error) {
 			}
 			name.ExtraNames = append(name.ExtraNames, pkix.AttributeTypeAndValue{Type: oid, Value: v})
 		}
-        if n.E != "" {
-            name.ExtraNames = append(name.ExtraNames, pkix.AttributeTypeAndValue{Type: asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: n.E})
-        }
+		if n.E != "" {
+			name.ExtraNames = append(name.ExtraNames, pkix.AttributeTypeAndValue{Type: asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: n.E})
+		}
 	}
 	name.SerialNumber = cr.SerialNumber
 	return name, nil
@@ -430,6 +431,10 @@ func Generate(priv crypto.Signer, req *CertificateRequest) (csr []byte, err erro
 		}
 	}
 
+	if req.DelegationEnabled {
+		tpl.ExtraExtensions = append(tpl.Extensions, helpers.DelegationExtension)
+	}
+
 	if req.Extensions != nil {
 		err = appendExtensionsToCSR(req.Extensions, &tpl)
 		if err != nil {

csr/csr_test.go

@@ -786,3 +786,50 @@ func TestExtractCertificateRequest(t *testing.T) {
 		t.Fatal("Bad Certificate Request!")
 	}
 }
+
+// TestDelegationCSR tests that we create requests with the DC extension
+func TestDelegationCSR(t *testing.T) {
+	var cr = &CertificateRequest{
+		CN: "Test Common Name",
+		Names: []Name{
+			{
+				C:  "US",
+				ST: "California",
+				L:  "San Francisco",
+				O:  "CloudFlare, Inc.",
+				OU: "Systems Engineering",
+			},
+			{
+				C:  "GB",
+				ST: "London",
+				L:  "London",
+				O:  "CloudFlare, Inc",
+				OU: "Systems Engineering",
+			},
+		},
+		DelegationEnabled: true,
+		Hosts:             []string{"cloudflare.com", "www.cloudflare.com"},
+		KeyRequest:        NewKeyRequest(),
+	}
+	csr, _, err := ParseRequest(cr)
+	if err != nil {
+		t.Fatal("could not generate csr")
+	}
+	unPem, _ := pem.Decode(csr)
+	if unPem == nil {
+		t.Fatal("Failed to decode pem")
+	}
+	res, err := x509.ParseCertificateRequest(unPem.Bytes)
+	if err != nil {
+		t.Fatalf("spat out nonsense as a csr: %v", err)
+	}
+	found := false
+	for _, ext := range res.Extensions {
+		if ext.Id.Equal(helpers.DelegationUsage) {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatal("generated csr has no extension")
+	}
+}

helpers/helpers.go

@@ -39,6 +39,16 @@ const OneYear = 8760 * time.Hour
 // OneDay is a time.Duration representing a day's worth of seconds.
 const OneDay = 24 * time.Hour
 
+// DelegationUsage  is the OID for the DelegationUseage extensions
+var DelegationUsage = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 44363, 44}
+
+// DelegationExtension
+var DelegationExtension = pkix.Extension{
+	Id:       DelegationUsage,
+	Critical: false,
+	Value:    []byte{0x05, 0x00}, // ASN.1 NULL
+}
+
 // InclusiveDate returns the time.Time representation of a date - 1
 // nanosecond. This allows time.After to be used inclusively.
 func InclusiveDate(year int, month time.Month, day int) time.Time {

signer/signer.go

@@ -20,6 +20,7 @@ import (
 	"github.com/cloudflare/cfssl/config"
 	"github.com/cloudflare/cfssl/csr"
 	cferr "github.com/cloudflare/cfssl/errors"
+	"github.com/cloudflare/cfssl/helpers"
 	"github.com/cloudflare/cfssl/info"
 )
 
@@ -45,7 +46,7 @@ type Extension struct {
 // Extensions provided in the signRequest are copied into the certificate, as
 // long as they are in the ExtensionWhitelist for the signer's policy.
 // Extensions requested in the CSR are ignored, except for those processed by
-// ParseCertificateRequest (mainly subjectAltName).
+// ParseCertificateRequest (mainly subjectAltName) and DelegationUsage.
 type SignRequest struct {
 	Hosts       []string    `json:"hosts"`
 	Request     string      `json:"certificate_request"`
@@ -240,6 +241,8 @@ func ParseCertificateRequest(s Signer, p *config.SigningProfile, csrBytes []byte
 			template.IsCA = constraints.IsCA
 			template.MaxPathLen = constraints.MaxPathLen
 			template.MaxPathLenZero = template.MaxPathLen == 0
+		} else if val.Id.Equal(helpers.DelegationUsage) {
+			template.ExtraExtensions = append(template.ExtraExtensions, val)
 		} else {
 			// If the profile has 'copy_extensions' to true then lets add it
 			if p.CopyExtensions {