add info command

README.md

@@ -58,6 +58,13 @@ gossl key --bits 2048 --out private.key
 gossl key --bits 2048 --out private.key --withpub
 ```
 
+### info
+`info` displays information about x509 certificate. Thanks [grantae](https://github.com/grantae) for great [certinfo](https://github.com/grantae/certinfo) tool which is used here.
+
+```bash
+gossl info cert.pem
+```
+
 ### cert
 `cert` command generates x509 SSL/TLS Certificate Request (CSR), Root CA and Certificate with provided private key.
 
@@ -136,3 +143,5 @@ gossl ssh-copy --pubkey /home/user/.ssh/id_rsa.pub --password passw@rd123 remote
 1. Add generate command for generating private key, root ca and x509 certificates in one command
 2. Add cert template format read from yaml file
 3. Add certificate converter command like DER to PEM etc.
+4. Add test for info command
+5. Add test for CertFromFile function at utils package

commands/info/info.go

@@ -0,0 +1,59 @@
+package info
+
+import (
+	"errors"
+	"fmt"
+	"log"
+
+	"github.com/yakuter/gossl/pkg/utils"
+
+	"github.com/grantae/certinfo"
+	"github.com/urfave/cli/v2"
+)
+
+// Remote commands
+const (
+	CmdInfo = "info"
+)
+
+func Command() *cli.Command {
+	return &cli.Command{
+		Name:        CmdInfo,
+		HelpName:    CmdInfo,
+		Action:      Action,
+		ArgsUsage:   `[cert file path]`,
+		Usage:       `displays information about certificate.`,
+		Description: `Displays information about x509 certificate.`,
+		Flags:       Flags(),
+	}
+}
+
+func Flags() []cli.Flag {
+	return []cli.Flag{}
+}
+
+func Action(c *cli.Context) error {
+	if c.Args().Len() == 0 {
+		err := errors.New("cert file argument is not found")
+		log.Printf("%v", err)
+		return err
+	}
+
+	// Get certificate from file
+	certFilePath := c.Args().First()
+	cert, err := utils.CertFromFile(certFilePath)
+	if err != nil {
+		log.Printf("Failed to get cert from file %s CAs error: %v", certFilePath, err)
+		return err
+	}
+
+	// Print the certificate
+	result, err := certinfo.CertificateText(cert)
+	if err != nil {
+		log.Printf("Failed to get cert info from cert error: %v", err)
+		return err
+	}
+
+	fmt.Println(result)
+	return nil
+}

commands/verify/verify.go

@@ -3,13 +3,14 @@ package verify
 import (
 	"crypto/tls"
 	"crypto/x509"
-	"encoding/pem"
 	"errors"
 	"fmt"
 	"log"
 	"net/http"
 	"os"
 
+	"github.com/yakuter/gossl/pkg/utils"
+
 	"github.com/urfave/cli/v2"
 )
 
@@ -79,7 +80,7 @@ func Action(c *cli.Context) error {
 
 	// Verify cert file
 	if c.IsSet(flagCertFile) {
-		cert, err := x509Cert(c.String(flagCertFile))
+		cert, err := utils.CertFromFile(c.String(flagCertFile))
 		if err != nil {
 			log.Printf("Failed to get cert from file %s CAs error: %v", c.String(flagCertFile), err)
 			return err
@@ -124,32 +125,6 @@ func rootCAs(caFilePath string) (*x509.CertPool, error) {
 	return roots, nil
 }
 
-func x509Cert(certFilePath string) (*x509.Certificate, error) {
-	// Read cert file
-	certFileBytes, err := os.ReadFile(certFilePath)
-	if err != nil {
-		log.Printf("Failed to read cert file %q error: %v", certFilePath, err)
-		return nil, err
-	}
-
-	// Decode PEM encoded cert file
-	block, _ := pem.Decode(certFileBytes)
-	if block == nil {
-		err = errors.New("block is nil")
-		log.Printf("Failed to decode PEM encoded cert file %q error: %v", certFilePath, err)
-		return nil, err
-	}
-
-	// Parse x509 certificate
-	cert, err := x509.ParseCertificate(block.Bytes)
-	if err != nil {
-		log.Printf("Failed to parse x509 certificate from cert file %q error: %v", certFilePath, err)
-		return nil, err
-	}
-
-	return cert, nil
-}
-
 func verifyCertWithCA(c *cli.Context, cert *x509.Certificate, roots *x509.CertPool) error {
 	// Set verification options
 	opts := x509.VerifyOptions{

main.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/yakuter/gossl/commands/cert"
 	"github.com/yakuter/gossl/commands/help"
+	"github.com/yakuter/gossl/commands/info"
 	"github.com/yakuter/gossl/commands/key"
 	"github.com/yakuter/gossl/commands/ssh"
 	"github.com/yakuter/gossl/commands/ssh_copy"
@@ -33,9 +34,10 @@ func main() {
 func Commands(reader io.Reader) []*cli.Command {
 	return []*cli.Command{
 		help.Command(),
-		verify.Command(),
 		key.Command(),
 		cert.Command(reader),
+		info.Command(),
+		verify.Command(),
 		ssh.Command(),
 		ssh_copy.Command(ssh_copy.StdinPasswordReader{}),
 	}

pkg/utils/utils.go

@@ -109,6 +109,32 @@ func PrivateKeyFromPEMFile(keyFilePath string) (*rsa.PrivateKey, error) {
 	return key, nil
 }
 
+func CertFromFile(certFilePath string) (*x509.Certificate, error) {
+	// Read cert file
+	certFileBytes, err := os.ReadFile(certFilePath)
+	if err != nil {
+		log.Printf("Failed to read cert file %q error: %v", certFilePath, err)
+		return nil, err
+	}
+
+	// Decode PEM encoded cert file
+	block, _ := pem.Decode(certFileBytes)
+	if block == nil {
+		err = errors.New("block is nil")
+		log.Printf("Failed to decode PEM encoded cert file %q error: %v", certFilePath, err)
+		return nil, err
+	}
+
+	// Parse x509 certificate
+	cert, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		log.Printf("Failed to parse x509 certificate from cert file %q error: %v", certFilePath, err)
+		return nil, err
+	}
+
+	return cert, nil
+}
+
 func ReadInputs(questions []string, reader io.Reader) ([]string, error) {
 	answers := make([]string, len(questions))
 	scanner := bufio.NewScanner(reader)