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|
package dns
import (
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"crypto/rsa"
"io"
"math/big"
"strconv"
"strings"
)
// NewPrivateKey returns a PrivateKey by parsing the string s.
// s should be in the same form of the BIND private key files.
func (k *DNSKEY) NewPrivateKey(s string) (crypto.PrivateKey, error) {
if s == "" || s[len(s)-1] != '\n' { // We need a closing newline
return k.ReadPrivateKey(strings.NewReader(s+"\n"), "")
}
return k.ReadPrivateKey(strings.NewReader(s), "")
}
// ReadPrivateKey reads a private key from the io.Reader q. The string file is
// only used in error reporting.
// The public key must be known, because some cryptographic algorithms embed
// the public inside the privatekey.
func (k *DNSKEY) ReadPrivateKey(q io.Reader, file string) (crypto.PrivateKey, error) {
m, err := parseKey(q, file)
if m == nil {
return nil, err
}
if _, ok := m["private-key-format"]; !ok {
return nil, ErrPrivKey
}
if m["private-key-format"] != "v1.2" && m["private-key-format"] != "v1.3" {
return nil, ErrPrivKey
}
// TODO(mg): check if the pubkey matches the private key
algo, err := strconv.ParseUint(strings.SplitN(m["algorithm"], " ", 2)[0], 10, 8)
if err != nil {
return nil, ErrPrivKey
}
switch uint8(algo) {
case DSA:
priv, err := readPrivateKeyDSA(m)
if err != nil {
return nil, err
}
pub := k.publicKeyDSA()
if pub == nil {
return nil, ErrKey
}
priv.PublicKey = *pub
return priv, nil
case RSAMD5:
fallthrough
case RSASHA1:
fallthrough
case RSASHA1NSEC3SHA1:
fallthrough
case RSASHA256:
fallthrough
case RSASHA512:
priv, err := readPrivateKeyRSA(m)
if err != nil {
return nil, err
}
pub := k.publicKeyRSA()
if pub == nil {
return nil, ErrKey
}
priv.PublicKey = *pub
return priv, nil
case ECCGOST:
return nil, ErrPrivKey
case ECDSAP256SHA256:
fallthrough
case ECDSAP384SHA384:
priv, err := readPrivateKeyECDSA(m)
if err != nil {
return nil, err
}
pub := k.publicKeyECDSA()
if pub == nil {
return nil, ErrKey
}
priv.PublicKey = *pub
return priv, nil
default:
return nil, ErrPrivKey
}
}
// Read a private key (file) string and create a public key. Return the private key.
func readPrivateKeyRSA(m map[string]string) (*rsa.PrivateKey, error) {
p := new(rsa.PrivateKey)
p.Primes = []*big.Int{nil, nil}
for k, v := range m {
switch k {
case "modulus", "publicexponent", "privateexponent", "prime1", "prime2":
v1, err := fromBase64([]byte(v))
if err != nil {
return nil, err
}
switch k {
case "modulus":
p.PublicKey.N = big.NewInt(0)
p.PublicKey.N.SetBytes(v1)
case "publicexponent":
i := big.NewInt(0)
i.SetBytes(v1)
p.PublicKey.E = int(i.Int64()) // int64 should be large enough
case "privateexponent":
p.D = big.NewInt(0)
p.D.SetBytes(v1)
case "prime1":
p.Primes[0] = big.NewInt(0)
p.Primes[0].SetBytes(v1)
case "prime2":
p.Primes[1] = big.NewInt(0)
p.Primes[1].SetBytes(v1)
}
case "exponent1", "exponent2", "coefficient":
// not used in Go (yet)
case "created", "publish", "activate":
// not used in Go (yet)
}
}
return p, nil
}
func readPrivateKeyDSA(m map[string]string) (*dsa.PrivateKey, error) {
p := new(dsa.PrivateKey)
p.X = big.NewInt(0)
for k, v := range m {
switch k {
case "private_value(x)":
v1, err := fromBase64([]byte(v))
if err != nil {
return nil, err
}
p.X.SetBytes(v1)
case "created", "publish", "activate":
/* not used in Go (yet) */
}
}
return p, nil
}
func readPrivateKeyECDSA(m map[string]string) (*ecdsa.PrivateKey, error) {
p := new(ecdsa.PrivateKey)
p.D = big.NewInt(0)
// TODO: validate that the required flags are present
for k, v := range m {
switch k {
case "privatekey":
v1, err := fromBase64([]byte(v))
if err != nil {
return nil, err
}
p.D.SetBytes(v1)
case "created", "publish", "activate":
/* not used in Go (yet) */
}
}
return p, nil
}
// parseKey reads a private key from r. It returns a map[string]string,
// with the key-value pairs, or an error when the file is not correct.
func parseKey(r io.Reader, file string) (map[string]string, error) {
s := scanInit(r)
m := make(map[string]string)
c := make(chan lex)
k := ""
// Start the lexer
go klexer(s, c)
for l := range c {
// It should alternate
switch l.value {
case zKey:
k = l.token
case zValue:
if k == "" {
return nil, &ParseError{file, "no private key seen", l}
}
//println("Setting", strings.ToLower(k), "to", l.token, "b")
m[strings.ToLower(k)] = l.token
k = ""
}
}
return m, nil
}
// klexer scans the sourcefile and returns tokens on the channel c.
func klexer(s *scan, c chan lex) {
var l lex
str := "" // Hold the current read text
commt := false
key := true
x, err := s.tokenText()
defer close(c)
for err == nil {
l.column = s.position.Column
l.line = s.position.Line
switch x {
case ':':
if commt {
break
}
l.token = str
if key {
l.value = zKey
c <- l
// Next token is a space, eat it
s.tokenText()
key = false
str = ""
} else {
l.value = zValue
}
case ';':
commt = true
case '\n':
if commt {
// Reset a comment
commt = false
}
l.value = zValue
l.token = str
c <- l
str = ""
commt = false
key = true
default:
if commt {
break
}
str += string(x)
}
x, err = s.tokenText()
}
if len(str) > 0 {
// Send remainder
l.token = str
l.value = zValue
c <- l
}
}
|
