Merge pull request #21 from lukehinds/getleaf

Get Leaf command

cmd/getleaf.go

+/*
+Copyright © 2020 Luke Hinds <lhinds@redhat.com>
+
+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"
+	"crypto"
+	"crypto/rand"
+	"crypto/x509"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/google/trillian"
+	tclient "github.com/google/trillian/client"
+	tcrypto "github.com/google/trillian/crypto"
+	"github.com/google/trillian/merkle/rfc6962"
+	"github.com/projectrekor/rekor-cli/log"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+)
+
+func GenerateRand(length int) string {
+	b := make([]byte, length)
+	if _, err := rand.Read(b); err != nil {
+		return ""
+	}
+	return hex.EncodeToString(b)
+}
+
+type getLeafResponse struct {
+	Leaf *trillian.GetLeavesByIndexResponse
+	Key  []byte
+}
+
+var getleafCmd = &cobra.Command{
+	Use:   "getleaf",
+	Short: "Rekor Get Leaf Command",
+	Long:  `Get Leaf entry by Index`,
+	Run: func(cmd *cobra.Command, args []string) {
+		log := log.Logger
+		rekorServer := viper.GetString("rekor_server")
+		leafIndex, _ := cmd.PersistentFlags().GetInt64("index")
+		outfile, _ := cmd.PersistentFlags().GetString("outfile")
+		u := rekorServer + "/api/v1/getleaf"
+
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+
+		request, err := http.NewRequestWithContext(ctx, "GET", u, nil)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		request.URL.RawQuery += fmt.Sprintf("leafindex=%d", leafIndex)
+
+		client := &http.Client{}
+		response, err := client.Do(request)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer response.Body.Close()
+
+		content, err := ioutil.ReadAll(response.Body)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		resp := getLeafResponse{}
+
+		if err := json.Unmarshal(content, &resp); err != nil {
+			log.Fatal(err)
+		}
+
+		pub, err := x509.ParsePKIXPublicKey(resp.Key)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		verifier := tclient.NewLogVerifier(rfc6962.DefaultHasher, pub, crypto.SHA256)
+		_, err = tcrypto.VerifySignedLogRoot(verifier.PubKey, verifier.SigHash, resp.Leaf.SignedLogRoot)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		fileContent := resp.Leaf.Leaves[0].LeafValue
+
+		err = ioutil.WriteFile(outfile, fileContent, 0644)
+		if err != nil {
+			log.Fatal(err)
+		}
+		log.Info("Leaf contents saved to ", outfile)
+
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(getleafCmd)
+	getleafCmd.PersistentFlags().Int64("index", -1, "")
+	getleafCmd.PersistentFlags().String("outfile", GenerateRand(20)+".txt", "file name to output leaf content")
+}