96 lines
2.4 KiB
Go
96 lines
2.4 KiB
Go
package main
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import (
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"flag"
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"io/ioutil"
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"log"
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"os"
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"os/user"
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"path/filepath"
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"github.com/hashicorp/packer-plugin-sdk/communicator/sshkey"
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)
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type options struct {
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Type string
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Bits int
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Filename string
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}
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func (o *options) AddFlagSets(fs *flag.FlagSet) {
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fs.StringVar(&o.Type, "type", "rsa", `dsa | ecdsa | ed25519 | rsa
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Specifies the type of key to create. The possible values are 'dsa', 'ecdsa',
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'ed25519', or 'rsa'.
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`)
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fs.IntVar(&o.Bits, "bits", 0, `Specifies the number of bits in the key to create. By default maximum
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number will be picked. For RSA keys, the minimum size is 1024 bits and the
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default is 3072 bits. Generally, 3072 bits is considered sufficient. DSA
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keys must be exactly 1024 bits as specified by FIPS 186-2. For ECDSA keys,
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the bits flag determines the key length by selecting from one of three
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elliptic curve sizes: 256, 384 or 521 bits. Attempting to use bit lengths
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other than these three values for ECDSA keys will fail. Ed25519 keys have a
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fixed length and the bits flag will be ignored.
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`)
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defaultPath := ""
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user, err := user.Current()
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if err == nil {
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defaultPath = filepath.Join(user.HomeDir, ".ssh", "tests")
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}
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fs.StringVar(&o.Filename, "filename", defaultPath, `Specifies the filename of the key file.
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`)
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}
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func main() {
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log.SetFlags(0)
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log.SetPrefix("ssh-keygen: ")
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fs := flag.NewFlagSet("ssh-keygen", flag.ContinueOnError)
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cla := options{}
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cla.AddFlagSets(fs)
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if err := fs.Parse(os.Args[1:]); err != nil {
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log.Fatal(err)
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}
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algo, err := sshkey.AlgorithmString(cla.Type)
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if err != nil {
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log.Fatal(err)
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}
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log.Printf("Generating public/private %s key pair.", algo)
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keypair, err := sshkey.GeneratePair(algo, nil, cla.Bits)
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if err != nil {
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log.Fatal(err)
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}
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if isDir(cla.Filename) {
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cla.Filename = filepath.Join(cla.Filename, "id_"+algo.String())
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}
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if fileExists(cla.Filename) {
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log.Fatalf("%s already exists.", cla.Filename)
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}
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log.Printf("Saving private key to %s", cla.Filename)
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if err := ioutil.WriteFile(cla.Filename, keypair.Private, 0600); err != nil {
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log.Fatal(err)
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}
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publicFilename := cla.Filename + ".pub"
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log.Printf("Saving public key to %s", publicFilename)
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if err := ioutil.WriteFile(publicFilename, keypair.Public, 0644); err != nil {
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log.Fatal(err)
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}
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}
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func isDir(filename string) bool {
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info, err := os.Stat(filename)
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if err != nil {
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log.Fatal(err)
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}
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return info.IsDir()
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}
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func fileExists(filename string) bool {
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_, err := os.Stat(filename)
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return err == nil
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}
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