lugu/qiloop

package cert

import (
    "bufio"
    "crypto/rand"
    "crypto/rsa"
    "crypto/tls"
    "crypto/x509"
    "encoding/pem"
    "fmt"
    "io"
    "math/big"
    "os"
    "os/user"
    "strings"
)

func GenerateCertificate() (tls.Certificate, error) {

    key, err := rsa.GenerateKey(rand.Reader, 1024)
    if err != nil {
        panic(err)
    }
    template := x509.Certificate{SerialNumber: big.NewInt(1)}
    certDER, err := x509.CreateCertificate(rand.Reader, &template,
        &template, &key.PublicKey, key)
    if err != nil {
        panic(err)
    }
    keyPEM := pem.EncodeToMemory(&pem.Block{
        Type:  "RSA PRIVATE KEY",
        Bytes: x509.MarshalPKCS1PrivateKey(key),
    })
    certPEM := pem.EncodeToMemory(&pem.Block{
        Type:  "CERTIFICATE",
        Bytes: certDER,
    })

    return tls.X509KeyPair(certPEM, keyPEM)
}

func Certificate() (cert tls.Certificate, err error) {
    certFile, keyFile, err := getCertFiles()
    if err != nil {
        return cert, err
    }
    return tls.LoadX509KeyPair(certFile, keyFile)
}

func getCertConf() (string, error) {
    filename := os.Getenv("QILOOP_CERT_CONF")
    if filename != "" {
        return filename, nil
    }
    usr, err := user.Current()
    if err != nil {
        return "", fmt.Errorf("cannot get home directory")
    }
    return usr.HomeDir + "/.qi-cert.conf", nil
}

// getCertFiles returns the public and an X509 certificate and the
// associated private RSA key
func getCertFiles() (string, string, error) {
    filename, err := getCertConf()
    if err != nil {
        return "", "", err
    }
    file, err := os.Open(filename)
    if err != nil {
        return "", "", err
    }
    defer file.Close()
    r := bufio.NewReader(file)
    cert, err := r.ReadString('\n')
    if err != nil {
        return "", "", fmt.Errorf("cannot read cert from $HOME/.qi-cert.conf")
    }
    key, err := r.ReadString('\n')
    if err != io.EOF && err != nil {
        return "", "", fmt.Errorf("cannot read key from $HOME/.qi-cert.conf")
    }
    return strings.TrimSpace(cert), strings.TrimSpace(key), nil
}