85 lines
1.9 KiB
Go
85 lines
1.9 KiB
Go
package signerverifier
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import (
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"context"
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"crypto"
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/x509"
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"encoding/pem"
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"fmt"
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"github.com/docker/attest/internal/util"
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"github.com/secure-systems-lab/go-securesystemslib/dsse"
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)
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type ECDSA256SignerVerifier struct {
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crypto.Signer
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}
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// implement keyid function.
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func (s *ECDSA256SignerVerifier) KeyID() (string, error) {
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keyid, err := KeyID(s.Signer.Public())
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if err != nil {
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return "", fmt.Errorf("error getting keyid: %w", err)
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}
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return keyid, nil
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}
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func (s *ECDSA256SignerVerifier) Public() crypto.PublicKey {
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return s.Signer.Public()
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}
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func (s *ECDSA256SignerVerifier) Sign(_ context.Context, data []byte) ([]byte, error) {
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return s.Signer.Sign(rand.Reader, data, crypto.SHA256)
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}
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func (s *ECDSA256SignerVerifier) Verify(_ context.Context, data []byte, sig []byte) error {
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pub, ok := s.Signer.Public().(*ecdsa.PublicKey)
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if !ok {
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return fmt.Errorf("public key is not ecdsa")
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}
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ok = ecdsa.VerifyASN1(pub, util.SHA256(data), sig)
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if !ok {
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return fmt.Errorf("payload signature is not valid")
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}
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return nil
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}
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func LoadKeyPair(priv []byte) (dsse.SignerVerifier, error) {
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privateKey, err := parsePriv(priv)
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if err != nil {
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return nil, err
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}
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return &ECDSA256SignerVerifier{
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Signer: privateKey,
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}, nil
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}
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func parsePriv(privkeyBytes []byte) (*ecdsa.PrivateKey, error) {
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p, _ := pem.Decode(privkeyBytes)
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if p == nil {
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return nil, fmt.Errorf("privkey file does not contain any PEM data")
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}
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if p.Type != "EC PRIVATE KEY" {
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return nil, fmt.Errorf("privkey file does not contain a priavte key")
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}
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privKey, err := x509.ParseECPrivateKey(p.Bytes)
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if err != nil {
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return nil, fmt.Errorf("error failed to parse public key: %w", err)
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}
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return privKey, nil
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}
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func GenKeyPair() (dsse.SignerVerifier, error) {
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signer, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
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if err != nil {
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return nil, err
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}
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return &ECDSA256SignerVerifier{
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Signer: signer,
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}, nil
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}
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