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package keys
import (
"bytes"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/sha256"
"encoding/json"
"errors"
"fmt"
"io"
"github.com/theupdateframework/go-tuf/data"
)
func NewDeprecatedEcdsaVerifier() Verifier {
return &ecdsaVerifierWithDeprecatedSupport{}
}
type ecdsaVerifierWithDeprecatedSupport struct {
key *data.PublicKey
// This will switch based on whether this is a PEM-encoded key
// or a deprecated hex-encoded key.
Verifier
}
func (p *ecdsaVerifierWithDeprecatedSupport) UnmarshalPublicKey(key *data.PublicKey) error {
p.key = key
pemVerifier := &EcdsaVerifier{}
if err := pemVerifier.UnmarshalPublicKey(key); err != nil {
// Try the deprecated hex-encoded verifier
hexVerifier := &deprecatedP256Verifier{}
if err := hexVerifier.UnmarshalPublicKey(key); err != nil {
return err
}
p.Verifier = hexVerifier
return nil
}
p.Verifier = pemVerifier
return nil
}
/*
Deprecated ecdsaVerifier that used hex-encoded public keys.
This MAY be used to verify existing metadata that used this
old format. This will be deprecated soon, ensure that repositories
are re-signed and clients receieve a fully compliant root.
*/
type deprecatedP256Verifier struct {
PublicKey data.HexBytes `json:"public"`
key *data.PublicKey
}
func (p *deprecatedP256Verifier) Public() string {
return p.PublicKey.String()
}
func (p *deprecatedP256Verifier) Verify(msg, sigBytes []byte) error {
x, y := elliptic.Unmarshal(elliptic.P256(), p.PublicKey)
k := &ecdsa.PublicKey{
Curve: elliptic.P256(),
X: x,
Y: y,
}
hash := sha256.Sum256(msg)
if !ecdsa.VerifyASN1(k, hash[:], sigBytes) {
return errors.New("tuf: deprecated ecdsa signature verification failed")
}
return nil
}
func (p *deprecatedP256Verifier) MarshalPublicKey() *data.PublicKey {
return p.key
}
func (p *deprecatedP256Verifier) UnmarshalPublicKey(key *data.PublicKey) error {
// Prepare decoder limited to 512Kb
dec := json.NewDecoder(io.LimitReader(bytes.NewReader(key.Value), MaxJSONKeySize))
// Unmarshal key value
if err := dec.Decode(p); err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
return fmt.Errorf("tuf: the public key is truncated or too large: %w", err)
}
return err
}
curve := elliptic.P256()
// Parse as uncompressed marshalled point.
x, _ := elliptic.Unmarshal(curve, p.PublicKey)
if x == nil {
return errors.New("tuf: invalid ecdsa public key point")
}
p.key = key
return nil
}
|
