104 lines
2.3 KiB
Go
104 lines
2.3 KiB
Go
// This shows an example of how to generate a SSH RSA Private/Public key pair and save it locally
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package utils
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import (
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"crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"encoding/pem"
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"io/ioutil"
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"log"
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"golang.org/x/crypto/ssh"
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)
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func GenerateSSHKeys(sshPrivKeyFile string, sshPubKeyFile string) {
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savePrivateFileTo := sshPrivKeyFile
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savePublicFileTo := sshPubKeyFile
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bitSize := 4096
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privateKey, err := generatePrivateKey(bitSize)
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if err != nil {
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log.Fatal(err.Error())
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}
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publicKeyBytes, err := generatePublicKey(&privateKey.PublicKey)
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if err != nil {
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log.Fatal(err.Error())
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}
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privateKeyBytes := encodePrivateKeyToPEM(privateKey)
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err = writeKeyToFile(privateKeyBytes, savePrivateFileTo)
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if err != nil {
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log.Fatal(err.Error())
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}
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err = writeKeyToFile([]byte(publicKeyBytes), savePublicFileTo)
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if err != nil {
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log.Fatal(err.Error())
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}
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}
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// generatePrivateKey creates a RSA Private Key of specified byte size
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func generatePrivateKey(bitSize int) (*rsa.PrivateKey, error) {
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// Private Key generation
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privateKey, err := rsa.GenerateKey(rand.Reader, bitSize)
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if err != nil {
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return nil, err
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}
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// Validate Private Key
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err = privateKey.Validate()
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if err != nil {
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return nil, err
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}
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log.Println("Private Key generated")
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return privateKey, nil
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}
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// encodePrivateKeyToPEM encodes Private Key from RSA to PEM format
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func encodePrivateKeyToPEM(privateKey *rsa.PrivateKey) []byte {
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// Get ASN.1 DER format
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privDER := x509.MarshalPKCS1PrivateKey(privateKey)
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// pem.Block
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privBlock := pem.Block{
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Type: "RSA PRIVATE KEY",
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Headers: nil,
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Bytes: privDER,
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}
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// Private key in PEM format
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privatePEM := pem.EncodeToMemory(&privBlock)
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return privatePEM
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}
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// generatePublicKey take a rsa.PublicKey and return bytes suitable for writing to .pub file
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// returns in the format "ssh-rsa ..."
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func generatePublicKey(privatekey *rsa.PublicKey) ([]byte, error) {
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publicRsaKey, err := ssh.NewPublicKey(privatekey)
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if err != nil {
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return nil, err
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}
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pubKeyBytes := ssh.MarshalAuthorizedKey(publicRsaKey)
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log.Println("Public key generated")
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return pubKeyBytes, nil
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}
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// writePemToFile writes keys to a file
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func writeKeyToFile(keyBytes []byte, saveFileTo string) error {
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err := ioutil.WriteFile(saveFileTo, keyBytes, 0600)
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if err != nil {
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return err
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}
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log.Printf("Key saved to: %s", saveFileTo)
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return nil
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}
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