// Extract the RSA public key from the Key record
func (k *RR_DNSKEY) pubKeyRSA() *rsa.PublicKey {
keybuf, err := packBase64([]byte(k.PublicKey))
if err != nil {
return nil
}
// RFC 2537/3110, section 2. RSA Public KEY Resource Records
// Length is in the 0th byte, unless its zero, then it
// it in bytes 1 and 2 and its a 16 bit number
explen := uint16(keybuf[0])
keyoff := 1
if explen == 0 {
explen = uint16(keybuf[1])<<8 | uint16(keybuf[2])
keyoff = 3
}
pubkey := new(rsa.PublicKey)
pubkey.N = big.NewInt(0)
shift := (explen - 1) * 8
for i := int(explen - 1); i >= 0; i-- {
pubkey.E += int(keybuf[keyoff+i]) << shift
shift -= 8
}
pubkey.N.SetBytes(keybuf[keyoff+int(explen):])
return pubkey
}
// msg -> rsa
func UnpackKey(k *msgs.PublicKey) *rsa.PublicKey {
var key rsa.PublicKey
key.N = new(big.Int)
key.N.SetBytes(k.N)
key.E = int(*k.E)
return &key
}
// Call with tpm 2.0 and the quote handle, get the key back for serialization in AttestCertRequest.
func GetRsaKeyFromHandle(rw io.ReadWriter, handle Handle) (*rsa.PublicKey, error) {
publicBlob, _, _, err := ReadPublic(rw, handle)
if err != nil {
return nil, errors.New("Can't get public key blob")
}
rsaParams, err := DecodeRsaBuf(publicBlob)
publicKey := new(rsa.PublicKey)
// TODO(jlm): read exponent from blob
publicKey.E = 0x00010001
M := new(big.Int)
M.SetBytes(rsaParams.Modulus)
publicKey.N = M
return publicKey, nil
}
func (sess *Session) encryptPassword(password string, spk *steamPublicKey) (string, error) {
pk := new(rsa.PublicKey)
exp, err := spk.exponent()
if err != nil {
return "", fmt.Errorf(errorGettingKey, err.Error())
}
pk.E = int(exp)
if pk.N, err = spk.modulus(); err != nil {
return "", fmt.Errorf(errorGettingKey, err.Error())
}
out, err := rsa.EncryptPKCS1v15(rand.Reader, pk, []byte(password))
if err != nil {
return "", err
}
return base64.StdEncoding.EncodeToString(out), nil
}
// Convert string to an RSA public key
func Base64ToPub(s string) (*rsa.PublicKey, os.Error) {
if len(s) == 0 {
return nil, nil
}
if !verifyCRC(s) {
return nil, nil
}
s = s[0 : len(s)-1]
enc := base64.StdEncoding
pk := rsa.PublicKey{}
buf := make([]byte, 4096) // shoud be big enough
src := []byte(s)
k := -1
// N
if k = firstComma(src); k < 0 {
return nil, os.ErrorString("missing delimiter")
}
n, err := enc.Decode(buf, src[0:k])
if err != nil {
return nil, err
}
pk.N = &big.Int{}
pk.N.SetBytes(buf[0:n])
src = src[k+1:]
// E
n, err = enc.Decode(buf, src)
if err != nil {
return nil, err
}
pke64, err := bytesToInt64(buf[0:n])
if err != nil {
return nil, err
}
pk.E = int(pke64)
return &pk, nil
}
// parseRSA parses an RSA key according to RFC 4253, section 6.6.
func parseRSA(in []byte) (out *rsa.PublicKey, rest []byte, ok bool) {
key := new(rsa.PublicKey)
bigE, in, ok := parseInt(in)
if !ok || bigE.BitLen() > 24 {
return
}
e := bigE.Int64()
if e < 3 || e&1 == 0 {
ok = false
return
}
key.E = int(e)
if key.N, in, ok = parseInt(in); !ok {
return
}
ok = true
return key, in, ok
}
// parseRSA parses an RSA key according to RFC 4253, section 6.6.
func parseRSA(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
E *big.Int
N *big.Int
Rest []byte `ssh:"rest"`
}
if err := Unmarshal(in, &w); err != nil {
return nil, nil, err
}
if w.E.BitLen() > 24 {
return nil, nil, errors.New("ssh: exponent too large")
}
e := w.E.Int64()
if e < 3 || e&1 == 0 {
return nil, nil, errors.New("ssh: incorrect exponent")
}
var key rsa.PublicKey
key.E = int(e)
key.N = w.N
return (*rsaPublicKey)(&key), w.Rest, nil
}
// publicKeyRSA returns the RSA public key from a DNSKEY record.
func (k *RR_DNSKEY) publicKeyRSA() *rsa.PublicKey {
keybuf, err := packBase64([]byte(k.PublicKey))
if err != nil {
return nil
}
// RFC 2537/3110, section 2. RSA Public KEY Resource Records
// Length is in the 0th byte, unless its zero, then it
// it in bytes 1 and 2 and its a 16 bit number
explen := uint16(keybuf[0])
keyoff := 1
if explen == 0 {
explen = uint16(keybuf[1])<<8 | uint16(keybuf[2])
keyoff = 3
}
pubkey := new(rsa.PublicKey)
pubkey.N = big.NewInt(0)
shift := uint64((explen - 1) * 8)
expo := uint64(0)
for i := int(explen - 1); i > 0; i-- {
expo += uint64(keybuf[keyoff+i]) << shift
shift -= 8
}
// Remainder
expo += uint64(keybuf[keyoff])
if expo > 2<<31 {
// Larger expo than supported.
// println("dns: F5 primes (or larger) are not supported")
return nil
}
pubkey.E = int(expo)
pubkey.N.SetBytes(keybuf[keyoff+int(explen):])
return pubkey
}
func BuildAttestCertRequest(tpmDevice io.ReadWriter, quoteHandle Handle, endorsementHandle Handle, endorsementCert []byte,
taoName string, ownerPw string) (*AttestCertRequest, error) {
// Get Quote key.
tpm2QuoteKeyBlob, tpm2QuoteKeyName, _, err := ReadPublic(tpmDevice, quoteHandle)
if err != nil {
return nil, err
}
rsaQuoteParams, err := DecodeRsaBuf(tpm2QuoteKeyBlob)
if err != nil {
return nil, err
}
quoteKey := new(rsa.PublicKey)
quoteKey.N = new(big.Int)
quoteKey.N.SetBytes(rsaQuoteParams.Modulus)
quoteKey.E = int(rsaQuoteParams.Exp)
request := new(AttestCertRequest)
// DER encoded subject key
derSubjectKey, err := x509.MarshalPKIXPublicKey(quoteKey)
if err != nil {
return nil, err
}
var hashedQuoteKey []byte
if rsaQuoteParams.Hash_alg == AlgTPM_ALG_SHA1 {
sha1Str := "sha1"
request.HashType = &sha1Str
sha1Hash := sha1.New()
sha1Hash.Write([]byte(derSubjectKey))
hashedQuoteKey = sha1Hash.Sum(nil)
} else if rsaQuoteParams.Hash_alg == AlgTPM_ALG_SHA256 {
sha256Str := "sha256"
request.HashType = &sha256Str
sha256Hash := sha256.New()
sha256Hash.Write([]byte(derSubjectKey))
hashedQuoteKey = sha256Hash.Sum(nil)
} else {
return nil, errors.New("RequestDomainQuoteCert: Quote key has unknown cert type")
}
sigAlg := uint16(AlgTPM_ALG_NULL)
tpm2AttestBlob, tpm2SigBlob, err := Quote(tpmDevice, quoteHandle, ownerPw, ownerPw,
hashedQuoteKey, []int{17, 18}, sigAlg)
if err != nil {
return nil, err
}
request.AttestBlob = tpm2AttestBlob
request.SigBlob = tpm2SigBlob
request.KeyName = &taoName
request.SubjectPublicKey = derSubjectKey
request.DerEndorsementCert = endorsementCert
if rsaQuoteParams.Enc_alg == AlgTPM_ALG_RSA {
rsaStr := "rsa"
request.KeyType = &rsaStr
} else {
return nil, errors.New("RequestDomainQuoteCert: Bad quote key type")
}
request.Tpm2KeyName = tpm2QuoteKeyName
// TODO: request.CertChain
return request, nil
}
func sshToPubkey(key string) (pubkey SSHKey) {
verbose("Converting SSH input into a public key...", 3)
/* An RSA SSH key can have leading key options (including quoted
* whitespace) and trailing comments (including whitespace). We
* take a short cut here and assume that if it contains the known
* RSA pattern, then that field must be the actual key. This
* would be a false assumption if one of the comments or options
* contained that same pattern, but anybody who creates such a key
* can fo screw themselves. */
i := strings.Index(key, OPENSSH_RSA_KEY_SUBSTRING)
if i < 0 {
fmt.Fprintf(os.Stderr, "Not an ssh RSA public key: '%v'\n", key)
return
}
fields := strings.Split(key[i:], " ")
decoded := decode(fields[1])
if len(decoded) < 1 {
fmt.Fprintf(os.Stderr, "Unable to decode key.\n")
return
}
/* Based on:
* http://cpansearch.perl.org/src/MALLEN/Convert-SSH2-0.01/lib/Convert/SSH2.pm
* https://gist.github.com/mahmoudimus/1654254,
* http://golang.org/src/pkg/crypto/x509/x509.go
*
* See also: http://www.netmeister.org/blog/ssh2pkcs8.html
*
* The key format is base64 encoded tuples of:
* - four bytes representing the length of the next data field
* - the data field
*
* In practice, for an RSA key, we get:
* - four bytes [0 0 0 7]
* - the string "ssh-rsa" (7 bytes)
* - four bytes
* - the exponent
* - four bytes
* - the modulus
*/
var k rsa.PublicKey
n := 0
for len(decoded) > 4 {
var dlen uint32
bbuf := bytes.NewReader(decoded[:4])
err := binary.Read(bbuf, binary.BigEndian, &dlen)
if err != nil {
fmt.Printf("%v\n", err)
continue
}
chunklen := int(dlen) + 4
if len(decoded) < chunklen {
fmt.Fprintf(os.Stderr, "Invalid data while trying to extract public key.\n")
fmt.Fprintf(os.Stderr, "Maybe a corrupted key?\n%v\n", key)
return
}
data := decoded[4:chunklen]
decoded = decoded[chunklen:]
switch n {
case 0:
if ktype := fmt.Sprintf("%s", data); ktype != "ssh-rsa" {
fmt.Fprintf(os.Stderr, "Unsupported key type (%v).\n", ktype)
return
}
case 1:
i := new(big.Int)
i.SetString(fmt.Sprintf("0x%v", hex.EncodeToString(data)), 0)
k.E = int(i.Int64())
case 2:
i := new(big.Int)
/* The value in this field is signed, so the first
* byte should be 0, so we strip it. */
i.SetString(fmt.Sprintf("0x%v", hex.EncodeToString(data[1:])), 0)
k.N = i
}
n++
}
pubkey.Key = k
pubkey.Fingerprint = getFingerPrint(k)
return
}
func main() {
if len(os.Args) > 1 {
log.Fatal("Unexpected arguments. This program can only read input from stdin.")
}
input, err := ioutil.ReadAll(os.Stdin)
if err != nil {
log.Fatal(err)
}
key := string(input)
/* An RSA SSH key can have leading key options (including quoted
* whitespace) and trailing comments (including whitespace). We
* take a short cut here and assume that if it contains the known
* RSA pattern, then that field must be the actual key. This
* would be a false assumption if one of the comments or options
* contained that same pattern, but anybody who creates such a key
* can fo screw themselves. */
i := strings.Index(key, "ssh-rsa AAAAB3NzaC1")
if i < 0 {
log.Fatal("Input does not look like a valid SSH RSA key.")
}
fields := strings.Split(key[i:], " ")
decoded, err := base64.StdEncoding.DecodeString(fields[1])
if err != nil {
log.Fatal("Unable to decode key: %v", err)
}
/* Based on:
* http://cpansearch.perl.org/src/MALLEN/Convert-SSH2-0.01/lib/Convert/SSH2.pm
* https://gist.github.com/mahmoudimus/1654254,
* http://golang.org/src/pkg/crypto/x509/x509.go
*
* The key format is base64 encoded tuples of:
* - four bytes representing the length of the next data field
* - the data field
*
* In practice, for an RSA key, we get:
* - four bytes [0 0 0 7]
* - the string "ssh-rsa" (7 bytes)
* - four bytes
* - the exponent
* - four bytes
* - the modulus
*/
n := 0
var pubkey rsa.PublicKey
for len(decoded) > 0 {
var dlen uint32
bbuf := bytes.NewReader(decoded[:4])
err := binary.Read(bbuf, binary.BigEndian, &dlen)
if err != nil {
log.Fatal(err)
}
data := decoded[4 : int(dlen)+4]
decoded = decoded[4+int(dlen):]
if n == 0 {
if ktype := fmt.Sprintf("%s", data); ktype != "ssh-rsa" {
log.Fatal("Unsupported key type (%v).", ktype)
}
} else if n == 1 {
i := new(big.Int)
i.SetString(fmt.Sprintf("0x%v", hex.EncodeToString(data)), 0)
pubkey.E = int(i.Int64())
} else if n == 2 {
i := new(big.Int)
/* The value in this field is signed, so the first
* byte should be 0, so we strip it. */
i.SetString(fmt.Sprintf("0x%v", hex.EncodeToString(data[1:])), 0)
pubkey.N = i
break
}
n += 1
}
enc, err := asn1.Marshal(pubkey)
if err != nil {
log.Fatal("Unable to marshal pubkey (%v): %v", pubkey, err)
}
bitstring := asn1.BitString{enc, len(enc) * 8}
type AlgorithmIdentifier struct {
Algorithm asn1.ObjectIdentifier
Parameters asn1.RawValue
}
var null = asn1.RawValue{Tag: 5}
var pkid = AlgorithmIdentifier{asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}, null}
type keyseq struct {
Algorithm AlgorithmIdentifier
BitString asn1.BitString
}
ks := keyseq{pkid, bitstring}
enc, err = asn1.Marshal(ks)
if err != nil {
log.Fatal("Unable to marshal pubkey (%v): %v", pubkey, err)
}
fmt.Printf("-----BEGIN PUBLIC KEY-----\n")
out := base64.StdEncoding.EncodeToString(enc)
for len(out) > MAX_COLUMNS {
fmt.Printf("%v\n", out[:MAX_COLUMNS])
out = out[MAX_COLUMNS:]
}
fmt.Printf("%v\n", out)
fmt.Printf("-----END PUBLIC KEY-----\n")
}
// Combined Endorsement/Activate test
func TestCombinedEndorsementTest(t *testing.T) {
hash_alg_id := uint16(AlgTPM_ALG_SHA1)
// Open tpm
rw, err := OpenTPM("/dev/tpm0")
if err != nil {
fmt.Printf("OpenTPM failed %s\n", err)
return
}
// Flushall
err = Flushall(rw)
if err != nil {
t.Fatal("Flushall failed\n")
}
// CreatePrimary
var empty []byte
primaryparms := RsaParams{uint16(AlgTPM_ALG_RSA), uint16(AlgTPM_ALG_SHA1),
uint32(0x00030072), empty, uint16(AlgTPM_ALG_AES), uint16(128),
uint16(AlgTPM_ALG_CFB), uint16(AlgTPM_ALG_NULL), uint16(0),
uint16(2048), uint32(0x00010001), empty}
parent_handle, public_blob, err := CreatePrimary(rw,
uint32(OrdTPM_RH_OWNER), []int{0x7}, "", "", primaryparms)
if err != nil {
t.Fatal("CreatePrimary fails")
}
fmt.Printf("CreatePrimary succeeded\n")
endorseParams, err := DecodeRsaArea(public_blob)
if err != nil {
t.Fatal("DecodeRsaBuf fails", err)
}
// CreateKey
keyparms := RsaParams{uint16(AlgTPM_ALG_RSA), uint16(AlgTPM_ALG_SHA1),
uint32(0x00030072), empty, uint16(AlgTPM_ALG_AES), uint16(128),
uint16(AlgTPM_ALG_CFB), uint16(AlgTPM_ALG_NULL), uint16(0),
uint16(2048), uint32(0x00010001), empty}
private_blob, public_blob, err := CreateKey(rw, uint32(parent_handle),
[]int{7}, "", "01020304", keyparms)
if err != nil {
t.Fatal("CreateKey fails")
}
fmt.Printf("CreateKey succeeded\n")
// Load
key_handle, _, err := Load(rw, parent_handle, "", "",
public_blob, private_blob)
if err != nil {
t.Fatal("Load fails")
}
fmt.Printf("Load succeeded\n")
// ReadPublic
_, name, _, err := ReadPublic(rw, key_handle)
if err != nil {
t.Fatal("ReadPublic fails")
}
fmt.Printf("ReadPublic succeeded\n")
// Generate Credential
credential := []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf, 0x10}
fmt.Printf("Credential: %x\n", credential)
// Internal MakeCredential
credBlob, encrypted_secret0, err := InternalMakeCredential(rw, parent_handle, credential, name)
if err != nil {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Can't InternalMakeCredential\n")
}
// ActivateCredential
recovered_credential1, err := ActivateCredential(rw, key_handle, parent_handle,
"01020304", "", credBlob, encrypted_secret0)
if err != nil {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Can't ActivateCredential\n")
}
if bytes.Compare(credential, recovered_credential1) != 0 {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Credential and recovered credential differ\n")
}
fmt.Printf("InternalMake/Activate test succeeds\n\n")
protectorPublic := new(rsa.PublicKey)
protectorPublic.E = 0x00010001
M := new(big.Int)
M.SetBytes(endorseParams.Modulus)
protectorPublic.N = M
// MakeCredential
encrypted_secret, encIdentity, integrityHmac, err := MakeCredential(
protectorPublic, hash_alg_id, credential, name)
if err != nil {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Can't MakeCredential\n")
}
// ActivateCredential
recovered_credential2, err := ActivateCredential(rw,
key_handle, parent_handle, "01020304", "",
append(integrityHmac, encIdentity...), encrypted_secret)
if err != nil {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Can't ActivateCredential\n")
}
if bytes.Compare(credential, recovered_credential2) != 0 {
FlushContext(rw, key_handle)
FlushContext(rw, parent_handle)
t.Fatal("Credential and recovered credential differ\n")
}
fmt.Printf("Make/Activate test succeeds\n")
// Flush
FlushContext(rw, key_handle)
}