Add step-kms-plugin attest command

cmd/attest.go

@@ -0,0 +1,93 @@
+// Copyright 2022 Smallstep Labs, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package cmd
+
+import (
+	"context"
+	"encoding/pem"
+	"fmt"
+	"os"
+
+	"github.com/smallstep/step-kms-plugin/internal/flagutil"
+	"github.com/spf13/cobra"
+	"go.step.sm/crypto/kms"
+	"go.step.sm/crypto/kms/apiv1"
+	"go.step.sm/crypto/pemutil"
+)
+
+// attestCmd represents the attest command
+var attestCmd = &cobra.Command{
+	Use:   "attest <uri>",
+	Short: "create an attestation certificate",
+	Long: `This command, if the KMS supports it, it prints an attestation certificate or an endorsement key.
+	
+Currently this command is only supported on YubiKeys.`,
+	Example: `  # Get the attestation certificate from a YubiKey:
+  step-kms-plugin attest "yubikey:slot-id=9c"`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		if len(args) != 1 {
+			return showUsageErr(cmd)
+		}
+
+		flags := cmd.Flags()
+		kuri := flagutil.MustString(flags, "kms")
+		if kuri == "" {
+			kuri = args[0]
+		}
+
+		km, err := kms.New(context.Background(), apiv1.Options{
+			URI: kuri,
+		})
+		if err != nil {
+			return fmt.Errorf("failed to load key manager: %w", err)
+		}
+		defer km.Close()
+
+		attester, ok := km.(apiv1.Attester)
+		if !ok {
+			return fmt.Errorf("%s does not implement an Attester", kuri)
+		}
+
+		resp, err := attester.CreateAttestation(&apiv1.CreateAttestationRequest{
+			Name: args[0],
+		})
+		if err != nil {
+			return fmt.Errorf("failed to attest: %w", err)
+		}
+
+		switch {
+		case resp.Certificate != nil:
+			return pem.Encode(os.Stdout, &pem.Block{
+				Type:  "CERTIFICATE",
+				Bytes: resp.Certificate.Raw,
+			})
+		case resp.PublicKey != nil:
+			block, err := pemutil.Serialize(resp.PublicKey)
+			if err != nil {
+				return err
+			}
+			return pem.Encode(os.Stdout, block)
+		default:
+			return fmt.Errorf("failed to create attestation: unsupported response")
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(attestCmd)
+	attestCmd.SilenceUsage = true
+
+	flags := attestCmd.Flags()
+	flags.SortFlags = false
+}

cmd/key.go

@@ -4,7 +4,7 @@
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//     http://www.apache.org/licenses/LICENSE-2.0
+//	http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,

go.mod

@@ -5,7 +5,7 @@ go 1.18
 require (
 	github.com/spf13/cobra v1.5.0
 	github.com/spf13/pflag v1.0.5
-	go.step.sm/crypto v0.17.0
+	go.step.sm/crypto v0.18.1-0.20220826194421-b8cbff2a2b3e
 	golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3
 )
 

go.sum

@@ -325,8 +325,8 @@ go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqe
 go.step.sm/cli-utils v0.7.3 h1:IA12IaiXVCI18yOFVQuvMpyvjL8wuwUn1yO+KhAVAr0=
 go.step.sm/cli-utils v0.7.3/go.mod h1:RJRwbBLqzs5nrepQLAV9FuT3fVpWz66tKzLIB7Izpfk=
 go.step.sm/crypto v0.9.0/go.mod h1:+CYG05Mek1YDqi5WK0ERc6cOpKly2i/a5aZmU1sfGj0=
-go.step.sm/crypto v0.17.0 h1:qaLUbWygcMRMxrsz91jL5ytHIsIMABFYX6TkU+V8Pq8=
-go.step.sm/crypto v0.17.0/go.mod h1:2oZdJ4ZUqPv5q8wz6yN4Qfsdcu2+eRaob4q1E5Azavs=
+go.step.sm/crypto v0.18.1-0.20220826194421-b8cbff2a2b3e h1:aoy9vRtiegR+Afz0QcMkGr9NKQklDuuRyS1E8b5N6dw=
+go.step.sm/crypto v0.18.1-0.20220826194421-b8cbff2a2b3e/go.mod h1:qZ+pNU1nV+THwP7TPTNCRMRr9xrRURhETTAK7U5psfw=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=