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runner-go/secret/encrypted.go

112 lines
2.6 KiB
Go

// Copyright 2019 Drone.IO Inc. All rights reserved.
// Use of this source code is governed by the Polyform License
// that can be found in the LICENSE file.
package secret
import (
"context"
"crypto/aes"
"crypto/cipher"
"encoding/base64"
"errors"
"git.awesome-for.me/liuzhiguo/runner-go/logger"
"git.awesome-for.me/liuzhiguo/runner-go/manifest"
"git.awesome-for.me/liuzhiguo/drone-go/drone"
)
// Encrypted returns a new encrypted secret provider. The
// encrypted secret provider finds and decrypts secrets stored
// inline in the (yaml) configuration.
func Encrypted() Provider {
return new(encrypted)
}
type encrypted struct{}
func (p *encrypted) Find(ctx context.Context, in *Request) (*drone.Secret, error) {
logger := logger.FromContext(ctx).
WithField("name", in.Name).
WithField("kind", "secret")
// lookup the named secret in the manifest. If the
// secret does not exist, return a nil variable,
// allowing the next secret controller in the chain
// to be invoked.
data, ok := getEncrypted(in.Conf, in.Name)
if !ok {
logger.Trace("secret: encrypted: no matching secret")
return nil, nil
}
// if the build event is a pull request and the source
// repository is a fork, the secret is not exposed to
// the pipeline, for security reasons.
if in.Repo.Private == false &&
in.Build.Event == drone.EventPullRequest &&
in.Build.Fork != "" {
logger.Trace("secret: encrypted: restricted from forks")
return nil, nil
}
decoded, err := base64.StdEncoding.DecodeString(string(data))
if err != nil {
logger.WithError(err).Debug("secret: encrypted: cannot decode")
return nil, err
}
decrypted, err := decrypt(decoded, []byte(in.Repo.Secret))
if err != nil {
logger.WithError(err).Debug("secret: encrypted: cannot decrypt")
return nil, err
}
logger.Trace("secret: encrypted: found matching secret")
return &drone.Secret{
Name: in.Name,
Data: string(decrypted),
}, nil
}
func getEncrypted(spec *manifest.Manifest, match string) (data string, ok bool) {
for _, resource := range spec.Resources {
secret, ok := resource.(*manifest.Secret)
if !ok {
continue
}
if secret.Name != match {
continue
}
if secret.Data == "" {
continue
}
return secret.Data, true
}
return
}
func decrypt(ciphertext []byte, key []byte) (plaintext []byte, err error) {
block, err := aes.NewCipher(key[:])
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
if len(ciphertext) < gcm.NonceSize() {
return nil, errors.New("malformed ciphertext")
}
return gcm.Open(nil,
ciphertext[:gcm.NonceSize()],
ciphertext[gcm.NonceSize():],
nil,
)
}