cmd/ca-signed: clean up the codebase

certlib/certlib.go

@@ -4,6 +4,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"errors"
+	"fmt"
 	"os"
 
 	"git.wntrmute.dev/kyle/goutils/certlib/certerr"
@@ -93,3 +94,18 @@ func LoadCertificates(path string) ([]*x509.Certificate, error) {
 
 	return ReadCertificates(in)
 }
+
+func PoolFromBytes(certBytes []byte) (*x509.CertPool, error) {
+	pool := x509.NewCertPool()
+
+	certs, err := ReadCertificates(certBytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read certificates: %w", err)
+	}
+
+	for _, cert := range certs {
+		pool.AddCert(cert)
+	}
+
+	return pool, nil
+}

cmd/ca-signed/main.go

@@ -1,157 +1,22 @@
 package main
 
 import (
+	"bytes"
 	"crypto/x509"
 	"embed"
-	"errors"
+	"flag"
 	"fmt"
 	"os"
-	"path/filepath"
-	"time"
 
 	"git.wntrmute.dev/kyle/goutils/certlib"
+	"git.wntrmute.dev/kyle/goutils/certlib/verify"
+	"git.wntrmute.dev/kyle/goutils/die"
+	"git.wntrmute.dev/kyle/goutils/lib"
 )
 
-// loadCertsFromFile attempts to parse certificates from a file that may be in
-// PEM or DER/PKCS#7 format. Returns the parsed certificates or an error.
-func loadCertsFromFile(path string) ([]*x509.Certificate, error) {
-	var certs []*x509.Certificate
-
-	data, err := os.ReadFile(path)
-	if err != nil {
-		return nil, err
-	}
-
-	if certs, err = certlib.ParseCertificatesPEM(data); err == nil {
-		return certs, nil
-	}
-
-	if certs, _, err = certlib.ParseCertificatesDER(data, ""); err == nil {
-		return certs, nil
-	}
-
-	return nil, err
-}
-
-func makePoolFromFile(path string) (*x509.CertPool, error) {
-	// Try PEM via helper (it builds a pool)
-	if pool, err := certlib.LoadPEMCertPool(path); err == nil && pool != nil {
-		return pool, nil
-	}
-
-	// Fallback: read as DER(s), add to a new pool
-	certs, err := loadCertsFromFile(path)
-	if err != nil || len(certs) == 0 {
-		return nil, fmt.Errorf("failed to load CA certificates from %s", path)
-	}
-	pool := x509.NewCertPool()
-	for _, c := range certs {
-		pool.AddCert(c)
-	}
-	return pool, nil
-}
-
 //go:embed testdata/*.pem
 var embeddedTestdata embed.FS
 
-// loadCertsFromBytes attempts to parse certificates from bytes that may be in
-// PEM or DER/PKCS#7 format.
-func loadCertsFromBytes(data []byte) ([]*x509.Certificate, error) {
-	certs, err := certlib.ParseCertificatesPEM(data)
-	if err == nil {
-		return certs, nil
-	}
-
-	certs, _, err = certlib.ParseCertificatesDER(data, "")
-	if err == nil {
-		return certs, nil
-	}
-
-	return nil, err
-}
-
-func makePoolFromBytes(data []byte) (*x509.CertPool, error) {
-	certs, err := loadCertsFromBytes(data)
-	if err != nil || len(certs) == 0 {
-		return nil, errors.New("failed to load CA certificates from embedded bytes")
-	}
-	pool := x509.NewCertPool()
-	for _, c := range certs {
-		pool.AddCert(c)
-	}
-	return pool, nil
-}
-
-// isSelfSigned returns true if the given certificate is self-signed.
-// It checks that the subject and issuer match and that the certificate's
-// signature verifies against its own public key.
-func isSelfSigned(cert *x509.Certificate) bool {
-	if cert == nil {
-		return false
-	}
-	// Quick check: subject and issuer match
-	if cert.Subject.String() != cert.Issuer.String() {
-		return false
-	}
-	// Cryptographic check: the certificate is signed by itself
-	if err := cert.CheckSignatureFrom(cert); err != nil {
-		return false
-	}
-	return true
-}
-
-func verifyAgainstCA(caPool *x509.CertPool, path string) (bool, string) {
-	certs, err := loadCertsFromFile(path)
-	if err != nil || len(certs) == 0 {
-		return false, ""
-	}
-
-	leaf := certs[0]
-	ints := x509.NewCertPool()
-	if len(certs) > 1 {
-		for _, ic := range certs[1:] {
-			ints.AddCert(ic)
-		}
-	}
-
-	opts := x509.VerifyOptions{
-		Roots:         caPool,
-		Intermediates: ints,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	if _, err = leaf.Verify(opts); err != nil {
-		return false, ""
-	}
-
-	return true, leaf.NotAfter.Format("2006-01-02")
-}
-
-func verifyAgainstCABytes(caPool *x509.CertPool, certData []byte) (bool, string) {
-	certs, err := loadCertsFromBytes(certData)
-	if err != nil || len(certs) == 0 {
-		return false, ""
-	}
-
-	leaf := certs[0]
-	ints := x509.NewCertPool()
-	if len(certs) > 1 {
-		for _, ic := range certs[1:] {
-			ints.AddCert(ic)
-		}
-	}
-
-	opts := x509.VerifyOptions{
-		Roots:         caPool,
-		Intermediates: ints,
-		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
-	}
-	if _, err = leaf.Verify(opts); err != nil {
-		return false, ""
-	}
-
-	return true, leaf.NotAfter.Format("2006-01-02")
-}
-
 type testCase struct {
 	name     string
 	caFile   string
@@ -170,18 +35,25 @@ func (tc testCase) Run() error {
 		return fmt.Errorf("selftest: failed to read embedded %s: %w", tc.certFile, err)
 	}
 
-	pool, err := makePoolFromBytes(caBytes)
+	pool, err := certlib.PoolFromBytes(caBytes)
 	if err != nil || pool == nil {
 		return fmt.Errorf("selftest: failed to build CA pool for %s: %w", tc.caFile, err)
 	}
 
-	ok, exp := verifyAgainstCABytes(pool, certBytes)
+	cert, _, err := certlib.ReadCertificate(certBytes)
+	if err != nil {
+		return fmt.Errorf("selftest: failed to parse certificate from %s: %w", tc.certFile, err)
+	}
+
+	_, err = verify.CertWith(cert, pool, nil, false)
+	ok := err == nil
+
 	if ok != tc.expectOK {
 		return fmt.Errorf("%s: unexpected result: got %v, want %v", tc.name, ok, tc.expectOK)
 	}
 
 	if ok {
-		fmt.Printf("%s: OK (expires %s)\n", tc.name, exp)
+		fmt.Printf("%s: OK (expires %s)\n", tc.name, cert.NotAfter.Format(lib.DateShortFormat))
 	}
 
 	fmt.Printf("%s: INVALID (as expected)\n", tc.name)
@@ -237,14 +109,16 @@ func selftest() int {
 			failures++
 			continue
 		}
-		certs, err := loadCertsFromBytes(b)
+
+		certs, err := certlib.ReadCertificates(b)
 		if err != nil || len(certs) == 0 {
 			fmt.Fprintf(os.Stderr, "selftest: failed to parse cert(s) from %s: %v\n", root, err)
 			failures++
 			continue
 		}
+
 		leaf := certs[0]
-		if isSelfSigned(leaf) {
+		if len(leaf.AuthorityKeyId) == 0 || bytes.Equal(leaf.AuthorityKeyId, leaf.SubjectKeyId) {
 			fmt.Printf("%s: SELF-SIGNED (as expected)\n", root)
 		} else {
 			fmt.Printf("%s: expected SELF-SIGNED, but was not detected as such\n", root)
@@ -260,66 +134,58 @@ func selftest() int {
 	return 1
 }
 
-// expiryString returns a YYYY-MM-DD date string to display for certificate
-// expiry. If an explicit exp string is provided, it is used. Otherwise, if a
-// leaf certificate is available, its NotAfter is formatted. As a last resort,
-// it falls back to today's date (should not normally happen).
-func expiryString(leaf *x509.Certificate, exp string) string {
-	if exp != "" {
-		return exp
-	}
-	if leaf != nil {
-		return leaf.NotAfter.Format("2006-01-02")
-	}
-	return time.Now().Format("2006-01-02")
-}
-
-// processCert verifies a single certificate file against the provided CA pool
-// and prints the result in the required format, handling self-signed
-// certificates specially.
-func processCert(caPool *x509.CertPool, certPath string) {
-	ok, exp := verifyAgainstCA(caPool, certPath)
-	name := filepath.Base(certPath)
-
-	// Try to load the leaf cert for self-signed detection and expiry fallback
-	var leaf *x509.Certificate
-	if certs, err := loadCertsFromFile(certPath); err == nil && len(certs) > 0 {
-		leaf = certs[0]
-	}
-
-	// Prefer the SELF-SIGNED label if applicable
-	if isSelfSigned(leaf) {
-		fmt.Printf("%s: SELF-SIGNED\n", name)
-		return
-	}
-
-	if ok {
-		fmt.Printf("%s: OK (expires %s)\n", name, expiryString(leaf, exp))
-		return
-	}
-	fmt.Printf("%s: INVALID\n", name)
-}
-
 func main() {
-	// Special selftest mode: single argument "selftest"
+	var skipVerify, useStrict bool
-	if len(os.Args) == 2 && os.Args[1] == "selftest" {
+
+	lib.StrictTLSFlag(&useStrict)
+	flag.BoolVar(&skipVerify, "k", false, "don't verify certificates")
+	flag.Parse()
+
+	tcfg, err := lib.BaselineTLSConfig(skipVerify, useStrict)
+	die.If(err)
+
+	args := flag.Args()
+
+	if len(args) == 1 && args[0] == "selftest" {
 		os.Exit(selftest())
 	}
 
-	if len(os.Args) < 3 {
+	if len(args) < 2 {
-		prog := filepath.Base(os.Args[0])
+		fmt.Println("No certificates to check.")
-		fmt.Fprintf(os.Stderr, "Usage:\n  %s ca.pem cert1.pem cert2.pem ...\n  %s selftest\n", prog, prog)
-		os.Exit(2)
-	}
-
-	caPath := os.Args[1]
-	caPool, err := makePoolFromFile(caPath)
-	if err != nil || caPool == nil {
-		fmt.Fprintf(os.Stderr, "failed to load CA certificate(s): %v\n", err)
 		os.Exit(1)
 	}
 
-	for _, certPath := range os.Args[2:] {
+	caFile := args[0]
-		processCert(caPool, certPath)
+	args = args[1:]
+
+	caCert, err := certlib.LoadCertificates(caFile)
+	die.If(err)
+
+	if len(caCert) != 1 {
+		die.With("only one CA certificate should be presented.")
+	}
+
+	roots := x509.NewCertPool()
+	roots.AddCert(caCert[0])
+
+	for _, arg := range args {
+		var cert *x509.Certificate
+
+		cert, err = lib.GetCertificate(arg, tcfg)
+		if err != nil {
+			lib.Warn(err, "while parsing certificate from %s", arg)
+			continue
+		}
+
+		if bytes.Equal(cert.AuthorityKeyId, caCert[0].AuthorityKeyId) {
+			fmt.Printf("%s: SELF-SIGNED\n", arg)
+			continue
+		}
+
+		if _, err := verify.CertWith(cert, roots, nil, false); err != nil {
+			fmt.Printf("%s: INVALID\n", arg)
+		} else {
+			fmt.Printf("%s: OK (expires %s)\n", arg, cert.NotAfter.Format(lib.DateShortFormat))
+		}
 	}
 }