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0d12e37c96
* Include EXC0014 and fix issues. * Include EXC0012 and fix issues. Signed-off-by: Fabian Kammel <fk@edgeless.systems> Co-authored-by: Otto Bittner <cobittner@posteo.net>
74 lines
2.1 KiB
Go
74 lines
2.1 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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// Package crypto provides functions to for cryptography and random numbers.
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package crypto
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import (
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"crypto/rand"
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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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"io"
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"math/big"
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"golang.org/x/crypto/hkdf"
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)
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const (
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// StateDiskKeyLength is key length in bytes for node state disk.
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StateDiskKeyLength = 32
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// DerivedKeyLengthDefault is the default length in bytes for KMS derived keys.
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DerivedKeyLengthDefault = 32
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// MasterSecretLengthDefault is the default length in bytes for CLI generated master secrets.
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MasterSecretLengthDefault = 32
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// MasterSecretLengthMin is the minimal length in bytes for user provided master secrets.
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MasterSecretLengthMin = 16
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// RNGLengthDefault is the number of bytes used for generating nonces.
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RNGLengthDefault = 32
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// HKDFInfoPrefix is the prefix used for the info parameter in HKDF.
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HKDFInfoPrefix = "key-"
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)
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// DeriveKey derives a key from a secret.
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func DeriveKey(secret, salt, info []byte, length uint) ([]byte, error) {
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hkdf := hkdf.New(sha256.New, secret, salt, info)
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key := make([]byte, length)
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if _, err := io.ReadFull(hkdf, key); err != nil {
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return nil, err
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}
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return key, nil
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}
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// GenerateCertificateSerialNumber generates a random serial number for an X.509 certificate.
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func GenerateCertificateSerialNumber() (*big.Int, error) {
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serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128)
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return rand.Int(rand.Reader, serialNumberLimit)
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}
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// GenerateRandomBytes reads length bytes from getrandom(2) if available, /dev/urandom otherwise.
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func GenerateRandomBytes(length int) ([]byte, error) {
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nonce := make([]byte, length)
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if _, err := rand.Read(nonce); err != nil {
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return nil, err
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}
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return nonce, nil
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}
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// PemToX509Cert takes a list of PEM encoded certificates, parses the first one and returns it.
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func PemToX509Cert(raw []byte) (*x509.Certificate, error) {
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decoded, _ := pem.Decode(raw)
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if decoded == nil {
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return nil, fmt.Errorf("decoding pem: no PEM data found")
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}
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cert, err := x509.ParseCertificate(decoded.Bytes)
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if err != nil {
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return nil, fmt.Errorf("parsing certificate: %w", err)
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}
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return cert, nil
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}
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