From b964d4f8d8bc97f41eba5f2f18590be0efef1a52 Mon Sep 17 00:00:00 2001
From: Matthew R <matthew@staff.libraryofcode.org>
Date: Sun, 22 Dec 2019 16:49:21 -0500
Subject: [PATCH] add checkCertificate go

---
 src/go/checkCertificate.go | 96 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 src/go/checkCertificate.go

diff --git a/src/go/checkCertificate.go b/src/go/checkCertificate.go
new file mode 100644
index 0000000..6f3b4e1
--- /dev/null
+++ b/src/go/checkCertificate.go
@@ -0,0 +1,96 @@
+// ignore this error
+package main
+
+import (
+	"crypto/sha1"
+	"crypto/x509"
+	"encoding/hex"
+	"encoding/json"
+	"encoding/pem"
+	"encoding/xml"
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+// HandleError handles an error by panicing.
+func HandleError(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
+
+func main() {
+	type CertificateAbstract struct {
+		SignatureAlgorithm string
+		PublicKeyAlgorithm string
+		ExtendedKeyUsage   []string
+		PolicyIdentifiers  []string
+		FingerPrint        string
+	}
+	type CompleteCertificate struct {
+		XMLName xml.Name `xml:"CertificateParse"`
+		RawParse      *x509.Certificate
+		AbstractParse CertificateAbstract
+	}
+	certificateFile, err := ioutil.ReadFile(os.Args[1])
+	HandleError(err)
+	certificatePemDecode, _ := pem.Decode(certificateFile)
+	if certificatePemDecode == nil {
+		fmt.Println("Can't do that.")
+		os.Exit(1)
+	}
+	certificateParse, err := x509.ParseCertificate(certificatePemDecode.Bytes)
+	HandleError(err)
+	policyIdentifiers := []string{}
+	extendedKeyUsages := []string{}
+	for _, value := range certificateParse.PolicyIdentifiers {
+		policyIdentifiers = append(policyIdentifiers, value.String())
+	}
+	for _, value := range certificateParse.ExtKeyUsage {
+		switch value {
+		case 0:
+			extendedKeyUsages = append(extendedKeyUsages, "All/Any Usages")
+			break
+		case 1:
+			extendedKeyUsages = append(extendedKeyUsages, "TLS Web Server Authentication")
+			break
+		case 2:
+			extendedKeyUsages = append(extendedKeyUsages, "TLS Web Client Authentication")
+			break
+		case 3:
+			extendedKeyUsages = append(extendedKeyUsages, "Code Signing")
+			break
+		case 4:
+			extendedKeyUsages = append(extendedKeyUsages, "E-mail Protection (S/MIME)")
+		default:
+			break
+		}
+	}
+	sum := sha1.Sum(certificateParse.Raw)
+	certificateStruct := CompleteCertificate{
+		RawParse: certificateParse,
+		AbstractParse: CertificateAbstract{
+			SignatureAlgorithm: certificateParse.SignatureAlgorithm.String(),
+			PublicKeyAlgorithm: certificateParse.PublicKeyAlgorithm.String(),
+			PolicyIdentifiers:  policyIdentifiers,
+			ExtendedKeyUsage:   extendedKeyUsages,
+			FingerPrint:        hex.EncodeToString(sum[:]),
+		},
+	}
+	if len(os.Args) >= 3 {
+		if os.Args[2] == "json" {
+			data, err := json.MarshalIndent(certificateStruct, "", " ")
+			HandleError(err)
+			fmt.Printf("%v\n", string(data))
+		} else if os.Args[2] == "xml" {
+			data, err := xml.MarshalIndent(certificateStruct, "", " ")
+			HandleError(err)
+			fmt.Printf("%v\n", string(data))
+		}
+	} else {
+		data, err := json.MarshalIndent(certificateStruct, "", " ")
+		HandleError(err)
+		fmt.Printf("%v\n", string(data))
+	}
+}