alist/server/sftp/hostkey.go

106 lines
2.8 KiB
Go

package sftp
import (
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"fmt"
"github.com/alist-org/alist/v3/cmd/flags"
"github.com/alist-org/alist/v3/pkg/utils"
"golang.org/x/crypto/ssh"
"os"
"path/filepath"
)
var SSHSigners []ssh.Signer
func InitHostKey() {
if SSHSigners != nil {
return
}
sshPath := filepath.Join(flags.DataDir, "ssh")
if !utils.Exists(sshPath) {
err := utils.CreateNestedDirectory(sshPath)
if err != nil {
utils.Log.Fatalf("failed to create ssh directory: %+v", err)
return
}
}
SSHSigners = make([]ssh.Signer, 0, 4)
if rsaKey, ok := LoadOrGenerateRSAHostKey(sshPath); ok {
SSHSigners = append(SSHSigners, rsaKey)
}
// TODO Add keys for other encryption algorithms
}
func LoadOrGenerateRSAHostKey(parentDir string) (ssh.Signer, bool) {
privateKeyPath := filepath.Join(parentDir, "ssh_host_rsa_key")
publicKeyPath := filepath.Join(parentDir, "ssh_host_rsa_key.pub")
privateKeyBytes, err := os.ReadFile(privateKeyPath)
if err == nil {
var privateKey *rsa.PrivateKey
privateKey, err = rsaDecodePrivateKey(privateKeyBytes)
if err == nil {
var ret ssh.Signer
ret, err = ssh.NewSignerFromKey(privateKey)
if err == nil {
return ret, true
}
}
}
_ = os.Remove(privateKeyPath)
_ = os.Remove(publicKeyPath)
privateKey, err := rsa.GenerateKey(rand.Reader, 4096)
if err != nil {
utils.Log.Fatalf("failed to generate RSA private key: %+v", err)
return nil, false
}
publicKey, err := ssh.NewPublicKey(&privateKey.PublicKey)
if err != nil {
utils.Log.Fatalf("failed to generate RSA public key: %+v", err)
return nil, false
}
ret, err := ssh.NewSignerFromKey(privateKey)
if err != nil {
utils.Log.Fatalf("failed to generate RSA signer: %+v", err)
return nil, false
}
privateBytes := rsaEncodePrivateKey(privateKey)
publicBytes := ssh.MarshalAuthorizedKey(publicKey)
err = os.WriteFile(privateKeyPath, privateBytes, 0600)
if err != nil {
utils.Log.Fatalf("failed to write RSA private key to file: %+v", err)
return nil, false
}
err = os.WriteFile(publicKeyPath, publicBytes, 0644)
if err != nil {
_ = os.Remove(privateKeyPath)
utils.Log.Fatalf("failed to write RSA public key to file: %+v", err)
return nil, false
}
return ret, true
}
func rsaEncodePrivateKey(privateKey *rsa.PrivateKey) []byte {
privateKeyBytes := x509.MarshalPKCS1PrivateKey(privateKey)
privateBlock := &pem.Block{
Type: "RSA PRIVATE KEY",
Headers: nil,
Bytes: privateKeyBytes,
}
return pem.EncodeToMemory(privateBlock)
}
func rsaDecodePrivateKey(bytes []byte) (*rsa.PrivateKey, error) {
block, _ := pem.Decode(bytes)
if block == nil {
return nil, fmt.Errorf("failed to parse PEM block containing the key")
}
privateKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
return nil, err
}
return privateKey, nil
}