mirror of
https://gitea.com/Lydanne/buildx.git
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265 lines
7.6 KiB
Go
265 lines
7.6 KiB
Go
package signed
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import (
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"crypto"
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"crypto/ecdsa"
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"crypto/rsa"
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"crypto/sha256"
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"crypto/x509"
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"encoding/pem"
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"fmt"
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"math/big"
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"github.com/agl/ed25519"
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"github.com/sirupsen/logrus"
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"github.com/theupdateframework/notary/tuf/data"
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)
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const (
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minRSAKeySizeBit = 2048 // 2048 bits = 256 bytes
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minRSAKeySizeByte = minRSAKeySizeBit / 8
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)
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// Verifiers serves as a map of all verifiers available on the system and
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// can be injected into a verificationService. For testing and configuration
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// purposes, it will not be used by default.
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var Verifiers = map[data.SigAlgorithm]Verifier{
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data.RSAPSSSignature: RSAPSSVerifier{},
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data.RSAPKCS1v15Signature: RSAPKCS1v15Verifier{},
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data.PyCryptoSignature: RSAPyCryptoVerifier{},
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data.ECDSASignature: ECDSAVerifier{},
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data.EDDSASignature: Ed25519Verifier{},
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}
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// Ed25519Verifier used to verify Ed25519 signatures
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type Ed25519Verifier struct{}
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// Verify checks that an ed25519 signature is valid
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func (v Ed25519Verifier) Verify(key data.PublicKey, sig []byte, msg []byte) error {
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if key.Algorithm() != data.ED25519Key {
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return ErrInvalidKeyType{}
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}
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var sigBytes [ed25519.SignatureSize]byte
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if len(sig) != ed25519.SignatureSize {
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logrus.Debugf("signature length is incorrect, must be %d, was %d.", ed25519.SignatureSize, len(sig))
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return ErrInvalid
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}
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copy(sigBytes[:], sig)
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var keyBytes [ed25519.PublicKeySize]byte
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pub := key.Public()
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if len(pub) != ed25519.PublicKeySize {
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logrus.Errorf("public key is incorrect size, must be %d, was %d.", ed25519.PublicKeySize, len(pub))
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return ErrInvalidKeyLength{msg: fmt.Sprintf("ed25519 public key must be %d bytes.", ed25519.PublicKeySize)}
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}
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n := copy(keyBytes[:], key.Public())
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if n < ed25519.PublicKeySize {
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logrus.Errorf("failed to copy the key, must have %d bytes, copied %d bytes.", ed25519.PublicKeySize, n)
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return ErrInvalid
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}
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if !ed25519.Verify(&keyBytes, msg, &sigBytes) {
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logrus.Debugf("failed ed25519 verification")
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return ErrInvalid
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}
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return nil
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}
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func verifyPSS(key interface{}, digest, sig []byte) error {
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rsaPub, ok := key.(*rsa.PublicKey)
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if !ok {
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logrus.Debugf("value was not an RSA public key")
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return ErrInvalid
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}
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if rsaPub.N.BitLen() < minRSAKeySizeBit {
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logrus.Debugf("RSA keys less than 2048 bits are not acceptable, provided key has length %d.", rsaPub.N.BitLen())
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return ErrInvalidKeyLength{msg: fmt.Sprintf("RSA key must be at least %d bits.", minRSAKeySizeBit)}
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}
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if len(sig) < minRSAKeySizeByte {
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logrus.Debugf("RSA keys less than 2048 bits are not acceptable, provided signature has length %d.", len(sig))
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return ErrInvalid
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}
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opts := rsa.PSSOptions{SaltLength: sha256.Size, Hash: crypto.SHA256}
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if err := rsa.VerifyPSS(rsaPub, crypto.SHA256, digest[:], sig, &opts); err != nil {
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logrus.Debugf("failed RSAPSS verification: %s", err)
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return ErrInvalid
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}
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return nil
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}
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func getRSAPubKey(key data.PublicKey) (crypto.PublicKey, error) {
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algorithm := key.Algorithm()
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var pubKey crypto.PublicKey
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switch algorithm {
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case data.RSAx509Key:
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pemCert, _ := pem.Decode([]byte(key.Public()))
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if pemCert == nil {
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logrus.Debugf("failed to decode PEM-encoded x509 certificate")
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return nil, ErrInvalid
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}
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cert, err := x509.ParseCertificate(pemCert.Bytes)
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if err != nil {
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logrus.Debugf("failed to parse x509 certificate: %s\n", err)
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return nil, ErrInvalid
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}
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pubKey = cert.PublicKey
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case data.RSAKey:
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var err error
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pubKey, err = x509.ParsePKIXPublicKey(key.Public())
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if err != nil {
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logrus.Debugf("failed to parse public key: %s\n", err)
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return nil, ErrInvalid
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}
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default:
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// only accept RSA keys
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logrus.Debugf("invalid key type for RSAPSS verifier: %s", algorithm)
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return nil, ErrInvalidKeyType{}
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}
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return pubKey, nil
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}
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// RSAPSSVerifier checks RSASSA-PSS signatures
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type RSAPSSVerifier struct{}
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// Verify does the actual check.
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func (v RSAPSSVerifier) Verify(key data.PublicKey, sig []byte, msg []byte) error {
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// will return err if keytype is not a recognized RSA type
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pubKey, err := getRSAPubKey(key)
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if err != nil {
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return err
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}
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digest := sha256.Sum256(msg)
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return verifyPSS(pubKey, digest[:], sig)
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}
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// RSAPKCS1v15Verifier checks RSA PKCS1v15 signatures
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type RSAPKCS1v15Verifier struct{}
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// Verify does the actual verification
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func (v RSAPKCS1v15Verifier) Verify(key data.PublicKey, sig []byte, msg []byte) error {
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// will return err if keytype is not a recognized RSA type
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pubKey, err := getRSAPubKey(key)
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if err != nil {
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return err
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}
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digest := sha256.Sum256(msg)
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rsaPub, ok := pubKey.(*rsa.PublicKey)
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if !ok {
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logrus.Debugf("value was not an RSA public key")
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return ErrInvalid
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}
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if rsaPub.N.BitLen() < minRSAKeySizeBit {
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logrus.Debugf("RSA keys less than 2048 bits are not acceptable, provided key has length %d.", rsaPub.N.BitLen())
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return ErrInvalidKeyLength{msg: fmt.Sprintf("RSA key must be at least %d bits.", minRSAKeySizeBit)}
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}
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if len(sig) < minRSAKeySizeByte {
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logrus.Debugf("RSA keys less than 2048 bits are not acceptable, provided signature has length %d.", len(sig))
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return ErrInvalid
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}
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if err = rsa.VerifyPKCS1v15(rsaPub, crypto.SHA256, digest[:], sig); err != nil {
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logrus.Errorf("Failed verification: %s", err.Error())
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return ErrInvalid
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}
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return nil
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}
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// RSAPyCryptoVerifier checks RSASSA-PSS signatures
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type RSAPyCryptoVerifier struct{}
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// Verify does the actual check.
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// N.B. We have not been able to make this work in a way that is compatible
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// with PyCrypto.
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func (v RSAPyCryptoVerifier) Verify(key data.PublicKey, sig []byte, msg []byte) error {
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digest := sha256.Sum256(msg)
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if key.Algorithm() != data.RSAKey {
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return ErrInvalidKeyType{}
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}
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k, _ := pem.Decode([]byte(key.Public()))
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if k == nil {
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logrus.Debugf("failed to decode PEM-encoded x509 certificate")
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return ErrInvalid
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}
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pub, err := x509.ParsePKIXPublicKey(k.Bytes)
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if err != nil {
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logrus.Debugf("failed to parse public key: %s\n", err)
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return ErrInvalid
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}
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return verifyPSS(pub, digest[:], sig)
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}
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// ECDSAVerifier checks ECDSA signatures, decoding the keyType appropriately
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type ECDSAVerifier struct{}
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// Verify does the actual check.
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func (v ECDSAVerifier) Verify(key data.PublicKey, sig []byte, msg []byte) error {
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algorithm := key.Algorithm()
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var pubKey crypto.PublicKey
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switch algorithm {
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case data.ECDSAx509Key:
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pemCert, _ := pem.Decode([]byte(key.Public()))
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if pemCert == nil {
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logrus.Debugf("failed to decode PEM-encoded x509 certificate for keyID: %s", key.ID())
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logrus.Debugf("certificate bytes: %s", string(key.Public()))
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return ErrInvalid
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}
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cert, err := x509.ParseCertificate(pemCert.Bytes)
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if err != nil {
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logrus.Debugf("failed to parse x509 certificate: %s\n", err)
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return ErrInvalid
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}
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pubKey = cert.PublicKey
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case data.ECDSAKey:
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var err error
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pubKey, err = x509.ParsePKIXPublicKey(key.Public())
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if err != nil {
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logrus.Debugf("Failed to parse private key for keyID: %s, %s\n", key.ID(), err)
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return ErrInvalid
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}
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default:
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// only accept ECDSA keys.
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logrus.Debugf("invalid key type for ECDSA verifier: %s", algorithm)
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return ErrInvalidKeyType{}
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}
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ecdsaPubKey, ok := pubKey.(*ecdsa.PublicKey)
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if !ok {
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logrus.Debugf("value isn't an ECDSA public key")
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return ErrInvalid
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}
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sigLength := len(sig)
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expectedOctetLength := 2 * ((ecdsaPubKey.Params().BitSize + 7) >> 3)
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if sigLength != expectedOctetLength {
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logrus.Debugf("signature had an unexpected length")
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return ErrInvalid
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}
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rBytes, sBytes := sig[:sigLength/2], sig[sigLength/2:]
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r := new(big.Int).SetBytes(rBytes)
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s := new(big.Int).SetBytes(sBytes)
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digest := sha256.Sum256(msg)
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if !ecdsa.Verify(ecdsaPubKey, digest[:], r, s) {
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logrus.Debugf("failed ECDSA signature validation")
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return ErrInvalid
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}
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return nil
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}
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