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// Copyright 2015, 2018, 2019 Opsmate, Inc. All rights reserved.
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package pkcs12
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"crypto/x509/pkix"
"encoding/asn1"
"errors"
"hash"
"io"
"golang.org/x/crypto/pbkdf2"
"software.sslmate.com/src/go-pkcs12/internal/rc2"
)
var (
oidPBEWithSHAAnd3KeyTripleDESCBC = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 12, 1, 3})
oidPBEWithSHAAnd128BitRC2CBC = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 12, 1, 5})
oidPBEWithSHAAnd40BitRC2CBC = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 12, 1, 6})
oidPBES2 = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 5, 13})
oidPBKDF2 = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 5, 12})
oidHmacWithSHA1 = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 2, 7})
oidHmacWithSHA256 = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 2, 9})
oidHmacWithSHA512 = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 2, 11})
oidAES128CBC = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 1, 2})
oidAES192CBC = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 1, 22})
oidAES256CBC = asn1.ObjectIdentifier([]int{2, 16, 840, 1, 101, 3, 4, 1, 42})
)
// pbeCipher is an abstraction of a PKCS#12 cipher.
type pbeCipher interface {
// create returns a cipher.Block given a key.
create(key []byte) (cipher.Block, error)
// deriveKey returns a key derived from the given password and salt.
deriveKey(salt, password []byte, iterations int) []byte
// deriveKey returns an IV derived from the given password and salt.
deriveIV(salt, password []byte, iterations int) []byte
}
type shaWithTripleDESCBC struct{}
func (shaWithTripleDESCBC) create(key []byte) (cipher.Block, error) {
return des.NewTripleDESCipher(key)
}
func (shaWithTripleDESCBC) deriveKey(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 1, 24)
}
func (shaWithTripleDESCBC) deriveIV(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 2, 8)
}
type shaWith128BitRC2CBC struct{}
func (shaWith128BitRC2CBC) create(key []byte) (cipher.Block, error) {
return rc2.New(key, len(key)*8)
}
func (shaWith128BitRC2CBC) deriveKey(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 1, 16)
}
func (shaWith128BitRC2CBC) deriveIV(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 2, 8)
}
type shaWith40BitRC2CBC struct{}
func (shaWith40BitRC2CBC) create(key []byte) (cipher.Block, error) {
return rc2.New(key, len(key)*8)
}
func (shaWith40BitRC2CBC) deriveKey(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 1, 5)
}
func (shaWith40BitRC2CBC) deriveIV(salt, password []byte, iterations int) []byte {
return pbkdf(sha1Sum, 20, 64, salt, password, iterations, 2, 8)
}
type pbeParams struct {
Salt []byte
Iterations int
}
func pbeCipherFor(algorithm pkix.AlgorithmIdentifier, password []byte) (cipher.Block, []byte, error) {
var cipherType pbeCipher
switch {
case algorithm.Algorithm.Equal(oidPBEWithSHAAnd3KeyTripleDESCBC):
cipherType = shaWithTripleDESCBC{}
case algorithm.Algorithm.Equal(oidPBEWithSHAAnd128BitRC2CBC):
cipherType = shaWith128BitRC2CBC{}
case algorithm.Algorithm.Equal(oidPBEWithSHAAnd40BitRC2CBC):
cipherType = shaWith40BitRC2CBC{}
case algorithm.Algorithm.Equal(oidPBES2):
// rfc7292#appendix-B.1 (the original PKCS#12 PBE) requires passwords formatted as BMPStrings.
// However, rfc8018#section-3 recommends that the password for PBES2 follow ASCII or UTF-8.
// This is also what Windows expects.
// Therefore, we convert the password to UTF-8.
originalPassword, err := decodeBMPString(password)
if err != nil {
return nil, nil, err
}
utf8Password := []byte(originalPassword)
return pbes2CipherFor(algorithm, utf8Password)
default:
return nil, nil, NotImplementedError("pbe algorithm " + algorithm.Algorithm.String() + " is not supported")
}
var params pbeParams
if err := unmarshal(algorithm.Parameters.FullBytes, ¶ms); err != nil {
return nil, nil, err
}
key := cipherType.deriveKey(params.Salt, password, params.Iterations)
iv := cipherType.deriveIV(params.Salt, password, params.Iterations)
block, err := cipherType.create(key)
if err != nil {
return nil, nil, err
}
return block, iv, nil
}
func pbDecrypterFor(algorithm pkix.AlgorithmIdentifier, password []byte) (cipher.BlockMode, int, error) {
block, iv, err := pbeCipherFor(algorithm, password)
if err != nil {
return nil, 0, err
}
return cipher.NewCBCDecrypter(block, iv), block.BlockSize(), nil
}
func pbDecrypt(info decryptable, password []byte) (decrypted []byte, err error) {
cbc, blockSize, err := pbDecrypterFor(info.Algorithm(), password)
if err != nil {
return nil, err
}
encrypted := info.Data()
if len(encrypted) == 0 {
return nil, errors.New("pkcs12: empty encrypted data")
}
if len(encrypted)%blockSize != 0 {
return nil, errors.New("pkcs12: input is not a multiple of the block size")
}
decrypted = make([]byte, len(encrypted))
cbc.CryptBlocks(decrypted, encrypted)
psLen := int(decrypted[len(decrypted)-1])
if psLen == 0 || psLen > blockSize {
return nil, ErrDecryption
}
if len(decrypted) < psLen {
return nil, ErrDecryption
}
ps := decrypted[len(decrypted)-psLen:]
decrypted = decrypted[:len(decrypted)-psLen]
if bytes.Compare(ps, bytes.Repeat([]byte{byte(psLen)}, psLen)) != 0 {
return nil, ErrDecryption
}
return
}
// PBES2-params ::= SEQUENCE {
// keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
// encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
// }
type pbes2Params struct {
Kdf pkix.AlgorithmIdentifier
EncryptionScheme pkix.AlgorithmIdentifier
}
// PBKDF2-params ::= SEQUENCE {
// salt CHOICE {
// specified OCTET STRING,
// otherSource AlgorithmIdentifier {{PBKDF2-SaltSources}}
// },
// iterationCount INTEGER (1..MAX),
// keyLength INTEGER (1..MAX) OPTIONAL,
// prf AlgorithmIdentifier {{PBKDF2-PRFs}} DEFAULT
// algid-hmacWithSHA1
// }
type pbkdf2Params struct {
Salt asn1.RawValue
Iterations int
KeyLength int `asn1:"optional"`
Prf pkix.AlgorithmIdentifier `asn1:"optional"`
}
func pbes2CipherFor(algorithm pkix.AlgorithmIdentifier, password []byte) (cipher.Block, []byte, error) {
var params pbes2Params
if err := unmarshal(algorithm.Parameters.FullBytes, ¶ms); err != nil {
return nil, nil, err
}
if !params.Kdf.Algorithm.Equal(oidPBKDF2) {
return nil, nil, NotImplementedError("pbes2 kdf algorithm " + params.Kdf.Algorithm.String() + " is not supported")
}
var kdfParams pbkdf2Params
if err := unmarshal(params.Kdf.Parameters.FullBytes, &kdfParams); err != nil {
return nil, nil, err
}
if kdfParams.Salt.Tag != asn1.TagOctetString {
return nil, nil, NotImplementedError("only octet string salts are supported for pbes2/pbkdf2")
}
var prf func() hash.Hash
switch {
case kdfParams.Prf.Algorithm.Equal(oidHmacWithSHA256):
prf = sha256.New
case kdfParams.Prf.Algorithm.Equal(oidHmacWithSHA512):
prf = sha512.New
case kdfParams.Prf.Algorithm.Equal(oidHmacWithSHA1):
prf = sha1.New
case kdfParams.Prf.Algorithm.Equal(asn1.ObjectIdentifier([]int{})):
prf = sha1.New
default:
return nil, nil, NotImplementedError("pbes2 prf " + kdfParams.Prf.Algorithm.String() + " is not supported")
}
var keyLen int
switch {
case params.EncryptionScheme.Algorithm.Equal(oidAES256CBC):
keyLen = 32
case params.EncryptionScheme.Algorithm.Equal(oidAES192CBC):
keyLen = 24
case params.EncryptionScheme.Algorithm.Equal(oidAES128CBC):
keyLen = 16
default:
return nil, nil, NotImplementedError("pbes2 algorithm " + params.EncryptionScheme.Algorithm.String() + " is not supported")
}
key := pbkdf2.Key(password, kdfParams.Salt.Bytes, kdfParams.Iterations, keyLen, prf)
iv := params.EncryptionScheme.Parameters.Bytes
block, err := aes.NewCipher(key)
if err != nil {
return nil, nil, err
}
return block, iv, nil
}
// decryptable abstracts an object that contains ciphertext.
type decryptable interface {
Algorithm() pkix.AlgorithmIdentifier
Data() []byte
}
func pbEncrypterFor(algorithm pkix.AlgorithmIdentifier, password []byte) (cipher.BlockMode, int, error) {
block, iv, err := pbeCipherFor(algorithm, password)
if err != nil {
return nil, 0, err
}
return cipher.NewCBCEncrypter(block, iv), block.BlockSize(), nil
}
func pbEncrypt(info encryptable, decrypted []byte, password []byte) error {
cbc, blockSize, err := pbEncrypterFor(info.Algorithm(), password)
if err != nil {
return err
}
psLen := blockSize - len(decrypted)%blockSize
encrypted := make([]byte, len(decrypted)+psLen)
copy(encrypted[:len(decrypted)], decrypted)
copy(encrypted[len(decrypted):], bytes.Repeat([]byte{byte(psLen)}, psLen))
cbc.CryptBlocks(encrypted, encrypted)
info.SetData(encrypted)
return nil
}
// encryptable abstracts a object that contains ciphertext.
type encryptable interface {
Algorithm() pkix.AlgorithmIdentifier
SetData([]byte)
}
func makePBES2Parameters(rand io.Reader, salt []byte, iterations int) ([]byte, error) {
var err error
randomIV := make([]byte, 16)
if _, err := rand.Read(randomIV); err != nil {
return nil, err
}
var kdfparams pbkdf2Params
if kdfparams.Salt.FullBytes, err = asn1.Marshal(salt); err != nil {
return nil, err
}
kdfparams.Iterations = iterations
kdfparams.Prf.Algorithm = oidHmacWithSHA256
var params pbes2Params
params.Kdf.Algorithm = oidPBKDF2
if params.Kdf.Parameters.FullBytes, err = asn1.Marshal(kdfparams); err != nil {
return nil, err
}
params.EncryptionScheme.Algorithm = oidAES256CBC
if params.EncryptionScheme.Parameters.FullBytes, err = asn1.Marshal(randomIV); err != nil {
return nil, err
}
return asn1.Marshal(params)
}
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