Collectives™ on Stack Overflow

Find centralized, trusted content and collaborate around the technologies you use most.

Teams

Q&A for work

Connect and share knowledge within a single location that is structured and easy to search.

I am trying to make are tls cert for HTTPS server by golang x509 package

and i got this error

tls: failed to find any PEM data in certificate input

After some research, I create my Cert like this

func Generatecert()  {
    ca := &x509.Certificate{
        SerialNumber: big.NewInt(2023),
        Subject: pkix.Name{
            Organization:       []string{"Company"},
            OrganizationalUnit: []string{"lol"},
            Country:            []string{"US"},
            Province:           []string{""},
            Locality:           []string{"NY"},
            StreetAddress:      []string{"No street"},
            PostalCode:         []string{"77777"},
        NotBefore:             time.Now(),
        NotAfter:              time.Now().AddDate(10, 0, 0),
        SubjectKeyId:          []byte{1, 2, 3, 4, 5},
        BasicConstraintsValid: true,
        IsCA:                  true,
        ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth},
        KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
    certpubl, certpriv, err := ed25519.GenerateKey(rand.Reader)
    if err != nil {
        log.Println("key generate failed", err)
        return
    certCert, err := x509.CreateCertificate(rand.Reader, ca, ca, certpubl, certpriv)
    if err != nil {
        log.Println("create cert failed", err)
        return
    out := &bytes.Buffer{}
    //Encoding cert
    certtestpem := &pem.Block{Type: "CERTIFICATE", Bytes: certCert}
    pem.Encode(out, certtestpem)
    publicCert := out.Bytes()
    certDERBlock, publicCert := pem.Decode(publicCert)
    //Check Decoded cert
    print(certDERBlock.Type, "\n")
    if publicCert != nil {
        print("publicCert nil\n")
    //Encoding Private Key
    out.Reset()
    privatepem, _ := x509.MarshalPKCS8PrivateKey(certpriv)
    pem.Encode(out, &pem.Block{Type: "PRIVATE KEY", Bytes: privatepem})
    privitKey := out.Bytes()
    //check KeyPair
    _, err = tls.X509KeyPair(publicCert, privitKey)
    if err != nil {
        print(err.Error())
it show the error like under
CERTIFICATE
publicCert nil
tls: failed to find any PEM data in certificate input
I try Decode after pem.EncodeToMemory
the pem.Type are correct, but variable "publicCert" is nil, And I try add are \n begin of the cert, it did nothing, but the cert itself is not nil, Can Somebody Help me with this
What sould I do to make a working Tls???
                I don't have the problem you see. But this is not the code you are actually running, since this would not compile. Please provide a minimal but complete example instead which allows others to reproduce your problem.
– Steffen Ullrich
                Jan 12 at 17:44
Checking the content of publicCert at this stage shows the expect value. But the following statement will simply overwrite publicCert:
certDERBlock, publicCert := pem.Decode(publicCert)
This can be seen by checking publicCert after this statement. As documented publicCert will now show the data after the actual certificate.
It should be instead
certDERBlock, _ := pem.Decode(publicCert)
Checking the content of publicCert after this corrected statement shows the expected value again.
out.Reset()
privatepem, _ := x509.MarshalPKCS8PrivateKey(certpriv)
pem.Encode(out, &pem.Block{Type: "PRIVATE KEY", Bytes: privatepem})
privitKey := out.Bytes()
This will get the expected value into privitKey.  But, it will change publicCert since it is just a slice of out and out has been changed the the operations. Thus out will now contain at the beginning the privitKey and no longer the start of the certificate - and this is reflected in the value of publicCert.
See also the documentation for bytes.Buffer.Bytes
The slice is valid for use only until the next buffer modification (that is, only until the next call to a method like Read, Write, Reset, or Truncate)
So instead of just resetting the existing buffer
out.Reset()
it would be better to create a new buffer for privitKey and keep the existing one for publicCert
out = &bytes.Buffer{}
        
Thanks for contributing an answer to Stack Overflow!
Please be sure to answer the question. Provide details and share your research!
But avoid …
Asking for help, clarification, or responding to other answers.
Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.