324 lines
9.6 KiB
Go
324 lines
9.6 KiB
Go
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/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// Package keyutil contains utilities for managing public/private key pairs.
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package keyutil
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import (
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"crypto"
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"crypto/ecdsa"
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"crypto/elliptic"
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cryptorand "crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"encoding/pem"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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)
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const (
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// ECPrivateKeyBlockType is a possible value for pem.Block.Type.
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ECPrivateKeyBlockType = "EC PRIVATE KEY"
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// RSAPrivateKeyBlockType is a possible value for pem.Block.Type.
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RSAPrivateKeyBlockType = "RSA PRIVATE KEY"
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// PrivateKeyBlockType is a possible value for pem.Block.Type.
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PrivateKeyBlockType = "PRIVATE KEY"
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// PublicKeyBlockType is a possible value for pem.Block.Type.
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PublicKeyBlockType = "PUBLIC KEY"
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)
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// MakeEllipticPrivateKeyPEM creates an ECDSA private key
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func MakeEllipticPrivateKeyPEM() ([]byte, error) {
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privateKey, err := ecdsa.GenerateKey(elliptic.P256(), cryptorand.Reader)
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if err != nil {
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return nil, err
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}
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derBytes, err := x509.MarshalECPrivateKey(privateKey)
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if err != nil {
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return nil, err
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}
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privateKeyPemBlock := &pem.Block{
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Type: ECPrivateKeyBlockType,
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Bytes: derBytes,
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}
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return pem.EncodeToMemory(privateKeyPemBlock), nil
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}
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// WriteKey writes the pem-encoded key data to keyPath.
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// The key file will be created with file mode 0600.
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// If the key file already exists, it will be overwritten.
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// The parent directory of the keyPath will be created as needed with file mode 0755.
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func WriteKey(keyPath string, data []byte) error {
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if err := os.MkdirAll(filepath.Dir(keyPath), os.FileMode(0755)); err != nil {
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return err
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}
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return ioutil.WriteFile(keyPath, data, os.FileMode(0600))
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}
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// LoadOrGenerateKeyFile looks for a key in the file at the given path. If it
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// can't find one, it will generate a new key and store it there.
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func LoadOrGenerateKeyFile(keyPath string) (data []byte, wasGenerated bool, err error) {
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loadedData, err := ioutil.ReadFile(keyPath)
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// Call verifyKeyData to ensure the file wasn't empty/corrupt.
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if err == nil && verifyKeyData(loadedData) {
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return loadedData, false, err
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}
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if !os.IsNotExist(err) {
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return nil, false, fmt.Errorf("error loading key from %s: %v", keyPath, err)
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}
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generatedData, err := MakeEllipticPrivateKeyPEM()
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if err != nil {
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return nil, false, fmt.Errorf("error generating key: %v", err)
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}
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if err := WriteKey(keyPath, generatedData); err != nil {
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return nil, false, fmt.Errorf("error writing key to %s: %v", keyPath, err)
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}
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return generatedData, true, nil
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}
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// MarshalPrivateKeyToPEM converts a known private key type of RSA or ECDSA to
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// a PEM encoded block or returns an error.
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func MarshalPrivateKeyToPEM(privateKey crypto.PrivateKey) ([]byte, error) {
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switch t := privateKey.(type) {
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case *ecdsa.PrivateKey:
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derBytes, err := x509.MarshalECPrivateKey(t)
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if err != nil {
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return nil, err
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}
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block := &pem.Block{
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Type: ECPrivateKeyBlockType,
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Bytes: derBytes,
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}
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return pem.EncodeToMemory(block), nil
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case *rsa.PrivateKey:
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block := &pem.Block{
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Type: RSAPrivateKeyBlockType,
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Bytes: x509.MarshalPKCS1PrivateKey(t),
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}
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return pem.EncodeToMemory(block), nil
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default:
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return nil, fmt.Errorf("private key is not a recognized type: %T", privateKey)
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}
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}
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// PrivateKeyFromFile returns the private key in rsa.PrivateKey or ecdsa.PrivateKey format from a given PEM-encoded file.
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// Returns an error if the file could not be read or if the private key could not be parsed.
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func PrivateKeyFromFile(file string) (interface{}, error) {
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data, err := ioutil.ReadFile(file)
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if err != nil {
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return nil, err
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}
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key, err := ParsePrivateKeyPEM(data)
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if err != nil {
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return nil, fmt.Errorf("error reading private key file %s: %v", file, err)
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}
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return key, nil
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}
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// PublicKeysFromFile returns the public keys in rsa.PublicKey or ecdsa.PublicKey format from a given PEM-encoded file.
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// Reads public keys from both public and private key files.
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func PublicKeysFromFile(file string) ([]interface{}, error) {
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data, err := ioutil.ReadFile(file)
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if err != nil {
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return nil, err
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}
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keys, err := ParsePublicKeysPEM(data)
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if err != nil {
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return nil, fmt.Errorf("error reading public key file %s: %v", file, err)
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}
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return keys, nil
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}
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// verifyKeyData returns true if the provided data appears to be a valid private key.
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func verifyKeyData(data []byte) bool {
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if len(data) == 0 {
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return false
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}
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_, err := ParsePrivateKeyPEM(data)
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return err == nil
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}
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// ParsePrivateKeyPEM returns a private key parsed from a PEM block in the supplied data.
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// Recognizes PEM blocks for "EC PRIVATE KEY", "RSA PRIVATE KEY", or "PRIVATE KEY"
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func ParsePrivateKeyPEM(keyData []byte) (interface{}, error) {
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var privateKeyPemBlock *pem.Block
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for {
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privateKeyPemBlock, keyData = pem.Decode(keyData)
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if privateKeyPemBlock == nil {
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break
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}
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switch privateKeyPemBlock.Type {
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case ECPrivateKeyBlockType:
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// ECDSA Private Key in ASN.1 format
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if key, err := x509.ParseECPrivateKey(privateKeyPemBlock.Bytes); err == nil {
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return key, nil
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}
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case RSAPrivateKeyBlockType:
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// RSA Private Key in PKCS#1 format
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if key, err := x509.ParsePKCS1PrivateKey(privateKeyPemBlock.Bytes); err == nil {
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return key, nil
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}
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case PrivateKeyBlockType:
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// RSA or ECDSA Private Key in unencrypted PKCS#8 format
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if key, err := x509.ParsePKCS8PrivateKey(privateKeyPemBlock.Bytes); err == nil {
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return key, nil
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}
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}
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// tolerate non-key PEM blocks for compatibility with things like "EC PARAMETERS" blocks
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// originally, only the first PEM block was parsed and expected to be a key block
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}
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// we read all the PEM blocks and didn't recognize one
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return nil, fmt.Errorf("data does not contain a valid RSA or ECDSA private key")
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}
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// ParsePublicKeysPEM is a helper function for reading an array of rsa.PublicKey or ecdsa.PublicKey from a PEM-encoded byte array.
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// Reads public keys from both public and private key files.
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func ParsePublicKeysPEM(keyData []byte) ([]interface{}, error) {
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var block *pem.Block
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keys := []interface{}{}
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for {
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// read the next block
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block, keyData = pem.Decode(keyData)
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if block == nil {
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break
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}
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// test block against parsing functions
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if privateKey, err := parseRSAPrivateKey(block.Bytes); err == nil {
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keys = append(keys, &privateKey.PublicKey)
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continue
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}
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if publicKey, err := parseRSAPublicKey(block.Bytes); err == nil {
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keys = append(keys, publicKey)
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continue
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}
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if privateKey, err := parseECPrivateKey(block.Bytes); err == nil {
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keys = append(keys, &privateKey.PublicKey)
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continue
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}
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if publicKey, err := parseECPublicKey(block.Bytes); err == nil {
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keys = append(keys, publicKey)
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continue
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}
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// tolerate non-key PEM blocks for backwards compatibility
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// originally, only the first PEM block was parsed and expected to be a key block
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}
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if len(keys) == 0 {
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return nil, fmt.Errorf("data does not contain any valid RSA or ECDSA public keys")
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}
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return keys, nil
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}
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// parseRSAPublicKey parses a single RSA public key from the provided data
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func parseRSAPublicKey(data []byte) (*rsa.PublicKey, error) {
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var err error
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// Parse the key
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var parsedKey interface{}
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if parsedKey, err = x509.ParsePKIXPublicKey(data); err != nil {
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if cert, err := x509.ParseCertificate(data); err == nil {
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parsedKey = cert.PublicKey
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} else {
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return nil, err
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}
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}
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// Test if parsed key is an RSA Public Key
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var pubKey *rsa.PublicKey
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var ok bool
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if pubKey, ok = parsedKey.(*rsa.PublicKey); !ok {
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return nil, fmt.Errorf("data doesn't contain valid RSA Public Key")
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}
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return pubKey, nil
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}
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// parseRSAPrivateKey parses a single RSA private key from the provided data
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func parseRSAPrivateKey(data []byte) (*rsa.PrivateKey, error) {
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var err error
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// Parse the key
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var parsedKey interface{}
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if parsedKey, err = x509.ParsePKCS1PrivateKey(data); err != nil {
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if parsedKey, err = x509.ParsePKCS8PrivateKey(data); err != nil {
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return nil, err
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}
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}
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// Test if parsed key is an RSA Private Key
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var privKey *rsa.PrivateKey
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var ok bool
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if privKey, ok = parsedKey.(*rsa.PrivateKey); !ok {
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return nil, fmt.Errorf("data doesn't contain valid RSA Private Key")
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}
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return privKey, nil
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}
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// parseECPublicKey parses a single ECDSA public key from the provided data
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func parseECPublicKey(data []byte) (*ecdsa.PublicKey, error) {
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var err error
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// Parse the key
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var parsedKey interface{}
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if parsedKey, err = x509.ParsePKIXPublicKey(data); err != nil {
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if cert, err := x509.ParseCertificate(data); err == nil {
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parsedKey = cert.PublicKey
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} else {
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return nil, err
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}
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}
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// Test if parsed key is an ECDSA Public Key
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var pubKey *ecdsa.PublicKey
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var ok bool
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if pubKey, ok = parsedKey.(*ecdsa.PublicKey); !ok {
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return nil, fmt.Errorf("data doesn't contain valid ECDSA Public Key")
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}
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return pubKey, nil
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}
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// parseECPrivateKey parses a single ECDSA private key from the provided data
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func parseECPrivateKey(data []byte) (*ecdsa.PrivateKey, error) {
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var err error
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// Parse the key
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var parsedKey interface{}
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if parsedKey, err = x509.ParseECPrivateKey(data); err != nil {
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return nil, err
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}
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// Test if parsed key is an ECDSA Private Key
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var privKey *ecdsa.PrivateKey
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var ok bool
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if privKey, ok = parsedKey.(*ecdsa.PrivateKey); !ok {
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return nil, fmt.Errorf("data doesn't contain valid ECDSA Private Key")
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}
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return privKey, nil
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}
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