refactor: move checksum calculation to utils

Signed-off-by: Suraj Shirvankar <[email protected]>

sztp-agent/pkg/secureagent/daemon.go

@@ -10,7 +10,6 @@ package secureagent
 
 import (
 	"bytes"
-	"crypto/sha256"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/asn1"
@@ -246,28 +245,17 @@ func (a *Agent) downloadAndValidateImage() error {
 
 		log.Printf("[INFO] Downloaded file: %s with size: %d", ARTIFACTS_PATH+a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.InfoTimestampReference+filepath.Base(item), size)
 		log.Println("[INFO] Verify the file checksum: ", ARTIFACTS_PATH+a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.InfoTimestampReference+filepath.Base(item))
-		// TODO: maybe need to move sha calculatinos to a function in util.go
 		switch a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.BootImage.ImageVerification[i].HashAlgorithm {
 		case "ietf-sztp-conveyed-info:sha-256":
-			f, err := os.Open(ARTIFACTS_PATH + a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.InfoTimestampReference + filepath.Base(item))
+			filePath := ARTIFACTS_PATH + a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.InfoTimestampReference + filepath.Base(item)
+			checksum, err := calculateSHA256File(filePath)
+			original := strings.ReplaceAll(a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.BootImage.ImageVerification[i].HashValue, ":", "")
 			if err != nil {
-				log.Panic(err)
-				return err
-			}
-			defer func() {
-				if err := f.Close(); err != nil {
-					log.Println("[ERROR] Error when closing:", err)
-				}
-			}()
-			h := sha256.New()
-			if _, err := io.Copy(h, f); err != nil {
-				return err
+				log.Println("[ERROR] Could not calculate checksum", err)
 			}
-			sum := fmt.Sprintf("%x", h.Sum(nil))
-			original := strings.ReplaceAll(a.BootstrapServerOnboardingInfo.IetfSztpConveyedInfoOnboardingInformation.BootImage.ImageVerification[i].HashValue, ":", "")
-			log.Println("calculated: " + sum)
+			log.Println("calculated: " + checksum)
 			log.Println("expected  : " + original)
-			if sum != original {
+			if checksum != original {
 				return errors.New("checksum mismatch")
 			}
 			log.Println("[INFO] Checksum verified successfully")

sztp-agent/pkg/secureagent/utils.go

@@ -9,8 +9,12 @@ Copyright (C) 2022 Red Hat.
 package secureagent
 
 import (
+	"crypto/sha256"
 	"encoding/json"
+	"fmt"
+	"io"
 	"log"
+	"os"
 	"strings"
 
 	"github.com/go-ini/ini"
@@ -63,3 +67,22 @@ func generateInputJSONContent() string {
 func replaceQuotes(input string) string {
 	return strings.ReplaceAll(input, "\"", "")
 }
+
+func calculateSHA256File(filePath string) (string, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		log.Panic(err)
+		return "", err
+	}
+	defer func() {
+		if err := f.Close(); err != nil {
+			log.Println("[ERROR] Error when closing:", err)
+		}
+	}()
+	h := sha256.New()
+	if _, err := io.Copy(h, f); err != nil {
+		return "", err
+	}
+	checkSum := fmt.Sprintf("%x", h.Sum(nil))
+	return checkSum, nil
+}

sztp-agent/pkg/secureagent/utils_test.go

@@ -5,6 +5,7 @@
 package secureagent
 
 import (
+	"os"
 	"testing"
 )
 
@@ -47,3 +48,31 @@ func Test_replaceQuotes(t *testing.T) {
 		})
 	}
 }
+
+func Test_calculateSHA256File(t *testing.T) {
+	content := []byte("temporary file's content")
+	file, err := os.CreateTemp("", "example")
+	if err != nil {
+		t.Fatal("Failed to create file", err)
+	}
+	defer func() {
+		_ = os.Remove(file.Name())
+	}()
+
+	if _, err := file.Write(content); err != nil {
+		t.Fatal("Failed to write to file", err)
+	}
+
+	if err := file.Close(); err != nil {
+		t.Fatal("Unable to close the file", err)
+	}
+
+	checksum, err := calculateSHA256File(file.Name())
+	if err != nil {
+		t.Fatal("Could not calculate SHA256", file.Name())
+	}
+	expected := "df3ae2e9b295f790e12e6cf440ffc461d4660f266b84865f14c5508cf68e6f3d"
+	if checksum != expected {
+		t.Errorf("Checksum did not match %s %s", checksum, expected)
+	}
+}