cmd: continue lint fixes.

cmd/csrpubdump/main.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"flag"
+	"fmt"
+	"os"
+
+	"git.wntrmute.dev/kyle/goutils/die"
+)
+
+func main() {
+	flag.Parse()
+
+	for _, fileName := range flag.Args() {
+		in, err := os.ReadFile(fileName)
+		die.If(err)
+
+		if p, _ := pem.Decode(in); p != nil {
+			if p.Type != "CERTIFICATE REQUEST" {
+				die.With("INVALID FILE TYPE")
+			}
+			in = p.Bytes
+		}
+
+		csr, err := x509.ParseCertificateRequest(in)
+		die.If(err)
+
+		out, err := x509.MarshalPKIXPublicKey(csr.PublicKey)
+		die.If(err)
+
+		var t string
+		switch pub := csr.PublicKey.(type) {
+		case *rsa.PublicKey:
+			t = "RSA PUBLIC KEY"
+		case *ecdsa.PublicKey:
+			t = "EC PUBLIC KEY"
+		default:
+			die.With("unrecognised public key type %T", pub)
+		}
+
+		p := &pem.Block{
+			Type:  t,
+			Bytes: out,
+		}
+
+		err = os.WriteFile(fileName+".pub", pem.EncodeToMemory(p), 0o644)
+		die.If(err)
+		fmt.Fprintf(os.Stdout, "[+] wrote %s.\n", fileName+".pub")
+	}
+}