cmd: refactor cert utils into certlib

cmd/ski/main.go

@@ -1,29 +1,19 @@
 package main
 
 import (
-	"bytes"
-	"crypto/ecdsa"
-	"crypto/rsa"
-	"crypto/sha1" // #nosec G505
-	"crypto/x509"
-	"crypto/x509/pkix"
-	"encoding/asn1"
-	"encoding/pem"
+
+	// #nosec G505
+
 	"flag"
 	"fmt"
 	"io"
 	"os"
 
-	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/ski"
 	"git.wntrmute.dev/kyle/goutils/die"
 	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-const (
-	keyTypeRSA   = "RSA"
-	keyTypeECDSA = "ECDSA"
-)
-
 func usage(w io.Writer) {
 	fmt.Fprintf(w, `ski: print subject key info for PEM-encoded files
 
@@ -42,117 +32,6 @@ func init() {
 	flag.Usage = func() { usage(os.Stderr) }
 }
 
-func parse(path string) ([]byte, string, string) {
-	data, err := os.ReadFile(path)
-	die.If(err)
-
-	data = bytes.TrimSpace(data)
-	p, rest := pem.Decode(data)
-	if len(rest) > 0 {
-		_, _ = lib.Warnx("trailing data in PEM file")
-	}
-
-	if p == nil {
-		die.With("no PEM data found")
-	}
-
-	data = p.Bytes
-
-	var (
-		public []byte
-		kt     string
-		ft     string
-	)
-
-	switch p.Type {
-	case "PRIVATE KEY", "RSA PRIVATE KEY", "EC PRIVATE KEY":
-		public, kt = parseKey(data)
-		ft = "private key"
-	case "CERTIFICATE":
-		public, kt = parseCertificate(data)
-		ft = "certificate"
-	case "CERTIFICATE REQUEST":
-		public, kt = parseCSR(data)
-		ft = "certificate request"
-	default:
-		die.With("unknown PEM type %s", p.Type)
-	}
-
-	return public, kt, ft
-}
-
-func parseKey(data []byte) ([]byte, string) {
-	priv, err := certlib.ParsePrivateKeyDER(data)
-	if err != nil {
-		die.If(err)
-	}
-
-	var kt string
-	switch priv.Public().(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown private key type %T", priv)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(priv.Public())
-	die.If(err)
-
-	return public, kt
-}
-
-func parseCertificate(data []byte) ([]byte, string) {
-	cert, err := x509.ParseCertificate(data)
-	die.If(err)
-
-	pub := cert.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func parseCSR(data []byte) ([]byte, string) {
-	// Use certlib to support both PEM and DER and to centralize validation.
-	csr, _, err := certlib.ParseCSR(data)
-	die.If(err)
-
-	pub := csr.PublicKey
-	var kt string
-	switch pub.(type) {
-	case *rsa.PublicKey:
-		kt = keyTypeRSA
-	case *ecdsa.PublicKey:
-		kt = keyTypeECDSA
-	default:
-		die.With("unknown public key type %T", pub)
-	}
-
-	public, err := x509.MarshalPKIXPublicKey(pub)
-	die.If(err)
-	return public, kt
-}
-
-func dumpHex(in []byte, mode lib.HexEncodeMode) string {
-	return lib.HexEncode(in, mode)
-}
-
-type subjectPublicKeyInfo struct {
-	Algorithm        pkix.AlgorithmIdentifier
-	SubjectPublicKey asn1.BitString
-}
-
 func main() {
 	var help, shouldMatch bool
 	var displayModeString string
@@ -168,27 +47,22 @@ func main() {
 		os.Exit(0)
 	}
 
-	var ski string
+	var matchSKI string
 	for _, path := range flag.Args() {
-		public, kt, ft := parse(path)
+		keyInfo, err := ski.ParsePEM(path)
+		die.If(err)
 
-		var subPKI subjectPublicKeyInfo
-		_, err := asn1.Unmarshal(public, &subPKI)
-		if err != nil {
-			_, _ = lib.Warn(err, "failed to get subject PKI")
-			continue
+		keySKI, err := keyInfo.SKI(displayMode)
+		die.If(err)
+
+		if matchSKI == "" {
+			matchSKI = keySKI
 		}
 
-		pubHash := sha1.Sum(subPKI.SubjectPublicKey.Bytes) // #nosec G401 this is the standard
-		pubHashString := dumpHex(pubHash[:], displayMode)
-		if ski == "" {
-			ski = pubHashString
-		}
-
-		if shouldMatch && ski != pubHashString {
+		if shouldMatch && matchSKI != keySKI {
 			_, _ = lib.Warnx("%s: SKI mismatch (%s != %s)",
-				path, ski, pubHashString)
+				path, matchSKI, keySKI)
 		}
-		fmt.Printf("%s  %s (%s %s)\n", path, pubHashString, kt, ft)
+		fmt.Printf("%s  %s (%s %s)\n", path, keySKI, keyInfo.KeyType, keyInfo.FileType)
 	}
 }