* rework dsa test

* add initial ed25519 (not done)

* fix common.Certificate compile error

* add more functions to crypto.SigningPrivateKey interface, not everyone implements them yet

lib/common/certificate.go

@@ -38,15 +38,19 @@ func (c Certificate) Type() byte {
 }
 
 // get the length of the data in this certificate
+// return -1 if the size of the certificate is invalid
 func (c Certificate) Len() int {
+	if len(c) <= 2 {
+		// invalid size
+		return -1
+	}
 	return int(binary.BigEndian.Uint16(c[1:3]))
 }
 
-// get the data for this certificate or null if non exists
+// get the data for this certificate or null if none exists
 func (c Certificate) Data() (d []byte) {
 	l := c.Len()
-	if l > 0 {
-		// TODO(psi): check bounds correctly?
+	if l > 0 && len(c) <= 3+l {
 		d = c[3 : 3+l]
 	}
 	return

lib/crypto/dsa.go

@@ -42,7 +42,7 @@ var param = dsa.Parameters{
 }
 
 // generate a dsa keypair
-func DSAGenerate(priv *dsa.PrivateKey, rand io.Reader) error {
+func generateDSA(priv *dsa.PrivateKey, rand io.Reader) error {
 	// put our paramters in
 	priv.P = param.P
 	priv.Q = param.Q
@@ -60,16 +60,19 @@ func createDSAPublicKey(Y *big.Int) *dsa.PublicKey {
 }
 
 // createa i2p dsa private key given its public component
-func createDSAPrivkey(X *big.Int) *dsa.PrivateKey {
-	Y := new(big.Int)
-	Y.Exp(dsag, X, dsap)
-	return &dsa.PrivateKey{
-		PublicKey: dsa.PublicKey{
-			Parameters: param,
-			Y:          Y,
-		},
-		X: X,
+func createDSAPrivkey(X *big.Int) (k *dsa.PrivateKey) {
+	if X.Cmp(dsap) == -1 {
+		Y := new(big.Int)
+		Y.Exp(dsag, X, dsap)
+		k = &dsa.PrivateKey{
+			PublicKey: dsa.PublicKey{
+				Parameters: param,
+				Y:          Y,
+			},
+			X: X,
+		}
 	}
+	return
 }
 
 type DSAVerifier struct {
@@ -128,6 +131,26 @@ func (k DSAPrivateKey) NewSigner() (s Signer, err error) {
 	return
 }
 
+func (k DSAPrivateKey) Public() (pk DSAPublicKey, err error) {
+	p := createDSAPrivkey(new(big.Int).SetBytes(k[:]))
+	if p == nil {
+		err = ErrInvalidKeyFormat
+	} else {
+		copy(pk[:], p.Y.Bytes())
+	}
+	return
+}
+
+func (k DSAPrivateKey) Generate() (s DSAPrivateKey, err error) {
+	dk := new(dsa.PrivateKey)
+	err = generateDSA(dk, rand.Reader)
+	if err == nil {
+		copy(k[:], dk.X.Bytes())
+		s = k
+	}
+	return
+}
+
 func (ds *DSASigner) Sign(data []byte) (sig []byte, err error) {
 	h := sha1.Sum(data)
 	sig, err = ds.SignHash(h[:])

lib/crypto/dsa_test.go

@@ -1,27 +1,46 @@
 package crypto
 
 import (
-	"crypto/dsa"
-	"crypto/rand"
 	"testing"
 )
 
 func TestDSA(t *testing.T) {
-	rng := rand.Reader
-	kp := new(dsa.PrivateKey)
-	err := DSAGenerate(kp, rng)
+	var sk DSAPrivateKey
+	var pk DSAPublicKey
+	var err error
+	sk, err = sk.Generate()
 	if err == nil {
-		t.Logf("DSA Key Pair generated")
-	} else {
-		t.Logf("error while generating key: %s", err)
-		t.Fail()
+		zeros := 0 
+		for b, _ := range sk {
+			if b == 0 {
+				zeros ++
+			}
+		}
+		if zeros == len(sk) {
+			t.Logf("key generation yielded all zeros")
+			t.Fail()
+		}
+		pk, err = sk.Public()
+		if err == nil {
+			data := make([]byte, 512)
+			var sig []byte
+			var signer Signer
+			signer, err = sk.NewSigner()
+			if err == nil {
+				sig, err = signer.Sign(data)
+				if err == nil {
+					t.Logf("sig=%q", sig)
+					var verify Verifier
+					verify, err = pk.NewVerifier()
+					if err == nil {
+						err = verify.Verify(data, sig)
+					}
+				}
+			}
+		}
 	}
-	h := make([]byte, 20)
-	_, _, err = dsa.Sign(rng, kp, h)
-	if err == nil {
-		t.Log("signed")
-	} else {
-		t.Logf("error signing: %s", err)
+	if err != nil {
+		t.Logf("failed: %s", err.Error())
 		t.Fail()
 	}
 }

lib/crypto/ed25519.go

@@ -1,4 +1,93 @@
 package crypto
 
+/*
+#cgo pkg-config: libsodium
+#include <sodium.h>
+#include <stdint.h>
+*/
+import "C"
+
+import (
+	"crypto/sha512"
+	"errors"
+	"fmt"
+)
+
 type Ed25519PublicKey [32]byte
+
+type Ed25519Verifier struct {
+	k [32]C.uchar
+}
+
+func (k Ed25519PublicKey) NewVerifier() (v Verifier, err error) {
+	ev := new(Ed25519Verifier)
+	for i, b := range k {
+		ev.k[i] = C.uchar(b)
+	}
+	v = ev
+	return
+}
+
+func (v *Ed25519Verifier) VerifyHash(h, sig []byte) (err error) {
+	if len(sig) == C.crypto_sign_BYTES {
+		// valid size of sig
+		// copy signature and hash
+		var csig, ch [32]C.uchar
+		for i, b := range h {
+			ch[i] = C.uchar(b)
+		}
+		for i, b := range sig {
+			csig[i] = C.uchar(b)
+		}
+		// verify
+		if C.crypto_sign_verify_detached(&csig[0], &ch[0], C.ulonglong(32), &v.k[0]) == 0 {
+			// valid signature
+		} else {
+			// bad signature
+			err = ErrInvalidSignature
+		}
+	} else {
+		// bad size of sig
+		err = ErrBadSignatureSize
+	}
+	return
+}
+
+func (v *Ed25519Verifier) Verify(data, sig []byte) (err error) {
+	h := sha512.Sum512(data)
+	err = v.VerifyHash(h[:], sig)
+	return
+}
+
 type Ed25519PrivateKey [32]byte
+
+type Ed25519Signer struct {
+	k [32]C.uchar
+}
+
+func (s *Ed25519Signer) Sign(data []byte) (sig []byte, err error) {
+	h := sha512.Sum512(data)
+	sig, err = s.SignHash(h[:])
+	return
+}
+
+func (s *Ed25519Signer) SignHash(h []byte) (sig []byte, err error) {
+	var ch [32]C.uchar
+	for i, b := range h {
+		ch[i] = C.uchar(b)
+	}
+	var csig [32]C.uchar
+	var smlen_p C.ulonglong
+	res := C.crypto_sign_detached(&csig[0], &smlen_p, &ch[0], C.ulonglong(32), &s.k[0])
+	if res == 0 {
+		// success signing
+		sig = make([]byte, 32)
+		for i, b := range csig {
+			sig[i] = byte(b)
+		}
+	} else {
+		// failed signing
+		err = errors.New(fmt.Sprintf("failed to sign: crypto_sign_detached exit code %d", int(res)))
+	}
+	return
+}

lib/crypto/ed25519_test.go

@@ -0,0 +1,9 @@
+package crypto
+
+import (
+	"testing"
+)
+
+func TestEd25519(t *testing.T) {
+	
+}

lib/crypto/elg_test.go

@@ -22,7 +22,9 @@ func TestElg(t *testing.T) {
 				if err == nil {
 					dec, err := elgamalDecrypt(k, emsg, true)
 					if err == nil {
-						if !bytes.Equal(dec, msg) {
+						if bytes.Equal(dec, msg) {
+							t.Logf("%q == %q", dec, msg)
+						} else {
 							t.Logf("%q != %q", dec, msg)
 							t.Fail()
 						}

lib/crypto/sign.go

@@ -12,7 +12,7 @@ var ErrInvalidSignature = errors.New("invalid signature")
 type Verifier interface {
 	// verify hashed data with this signing key
 	// return nil on valid signature otherwise error
-	VerifyHash(data, sig []byte) error
+	VerifyHash(h, sig []byte) error
 	// verify an unhashed piece of data by hashing it and calling VerifyHash
 	Verify(data, sig []byte) error
 }
@@ -42,6 +42,11 @@ type SigningPrivateKey interface {
 	// create a new signer to sign data
 	// return signer or nil and error if key format is invalid
 	NewSigner() (Signer, error)
-
+	// length of this private key
 	Len() int
+	// get public key or return nil and error if invalid key data in private key
+	Public() (SigningPublicKey, error)
+	// generate a new private key, put it into itself
+	// returns itself or nil and error if an error occurs
+	Generate() (SigningPrivateKey, error)
 }