Add support for crypto/dsa

dsa.go

@@ -0,0 +1,331 @@
+//go:build !cmd_go_bootstrap
+
+package openssl
+
+// #include "goopenssl.h"
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+var (
+	paramPbits = C.CString("pbits")
+	paramQbits = C.CString("qbits")
+	paramP     = C.CString("p")
+	paramQ     = C.CString("q")
+	paramG     = C.CString("g")
+)
+
+// DSAParameters contains the DSA parameters.
+type DSAParameters struct {
+	P, Q, G BigInt
+}
+
+// PrivateKeyDSA represents a DSA private key.
+type PrivateKeyDSA struct {
+	DSAParameters
+	X, Y BigInt
+
+	_pkey C.GO_EVP_PKEY_PTR
+}
+
+func (k *PrivateKeyDSA) finalize() {
+	C.go_openssl_EVP_PKEY_free(k._pkey)
+}
+
+func (k *PrivateKeyDSA) withKey(f func(C.GO_EVP_PKEY_PTR) C.int) C.int {
+	defer runtime.KeepAlive(k)
+	return f(k._pkey)
+}
+
+// PublicKeyDSA represents a DSA public key.
+type PublicKeyDSA struct {
+	DSAParameters
+	Y BigInt
+
+	_pkey C.GO_EVP_PKEY_PTR
+}
+
+func (k *PublicKeyDSA) finalize() {
+	C.go_openssl_EVP_PKEY_free(k._pkey)
+}
+
+func (k *PublicKeyDSA) withKey(f func(C.GO_EVP_PKEY_PTR) C.int) C.int {
+	defer runtime.KeepAlive(k)
+	return f(k._pkey)
+}
+
+// GenerateDSAParameters generates a set of DSA parameters.
+func GenerateDSAParameters(l, n int) (DSAParameters, error) {
+	// The DSA parameters are generated by creating a new DSA key and
+	// extracting the domain parameters from it.
+
+	// Generate a new DSA key context and set the known parameters.
+	ctx := C.go_openssl_EVP_PKEY_CTX_new_id(C.GO_EVP_PKEY_DSA, nil)
+	if ctx == nil {
+		return DSAParameters{}, newOpenSSLError("EVP_PKEY_CTX_new_id failed")
+	}
+	defer C.go_openssl_EVP_PKEY_CTX_free(ctx)
+	if C.go_openssl_EVP_PKEY_paramgen_init(ctx) != 1 {
+		return DSAParameters{}, newOpenSSLError("EVP_PKEY_paramgen_init failed")
+	}
+	if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, C.GO_EVP_PKEY_DSA, -1, C.GO_EVP_PKEY_CTRL_DSA_PARAMGEN_BITS, C.int(l), nil) != 1 {
+		return DSAParameters{}, newOpenSSLError("EVP_PKEY_CTX_ctrl failed")
+	}
+	if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, C.GO_EVP_PKEY_DSA, -1, C.GO_EVP_PKEY_CTRL_DSA_PARAMGEN_Q_BITS, C.int(n), nil) != 1 {
+		return DSAParameters{}, newOpenSSLError("EVP_PKEY_CTX_ctrl failed")
+	}
+	var pkey C.GO_EVP_PKEY_PTR
+	if C.go_openssl_EVP_PKEY_paramgen(ctx, &pkey) != 1 {
+		return DSAParameters{}, newOpenSSLError("EVP_PKEY_paramgen failed")
+	}
+	defer C.go_openssl_EVP_PKEY_free(pkey)
+
+	// Extract the domain parameters from the generated key.
+	var p, q, g C.GO_BIGNUM_PTR
+	switch vMajor {
+	case 1:
+		dsa := getDSA(pkey)
+		if vMinor == 0 {
+			C.go_openssl_DSA_get0_pqg_backport(dsa, &p, &q, &g)
+		} else {
+			C.go_openssl_DSA_get0_pqg(dsa, &p, &q, &g)
+		}
+	case 3:
+		defer func() {
+			C.go_openssl_BN_free(p)
+			C.go_openssl_BN_free(q)
+			C.go_openssl_BN_free(g)
+		}()
+		if C.go_openssl_EVP_PKEY_get_bn_param(pkey, paramP, &p) != 1 ||
+			C.go_openssl_EVP_PKEY_get_bn_param(pkey, paramQ, &q) != 1 ||
+			C.go_openssl_EVP_PKEY_get_bn_param(pkey, paramG, &g) != 1 {
+			return DSAParameters{}, newOpenSSLError("EVP_PKEY_get_bn_param")
+		}
+	default:
+		panic(errUnsupportedVersion())
+	}
+
+	return DSAParameters{
+		P: bnToBig(p),
+		Q: bnToBig(q),
+		G: bnToBig(g),
+	}, nil
+}
+
+// NewPrivateKeyDSA creates a new DSA private key from the given parameters.
+func NewPrivateKeyDSA(params DSAParameters, x, y BigInt) (*PrivateKeyDSA, error) {
+	if x == nil || y == nil {
+		panic("x and y must not be nil")
+	}
+	pkey, err := newDSA(params, x, y)
+	if err != nil {
+		return nil, err
+	}
+	k := &PrivateKeyDSA{params, x, y, pkey}
+	runtime.SetFinalizer(k, (*PrivateKeyDSA).finalize)
+	return k, nil
+}
+
+// NewPublicKeyDSA creates a new DSA public key from the given parameters.
+func NewPublicKeyDSA(params DSAParameters, y BigInt) (*PublicKeyDSA, error) {
+	if y == nil {
+		panic("y must not be nil")
+	}
+	pkey, err := newDSA(params, nil, y)
+	if err != nil {
+		return nil, err
+	}
+	k := &PublicKeyDSA{params, y, pkey}
+	runtime.SetFinalizer(k, (*PublicKeyDSA).finalize)
+	return k, nil
+}
+
+// GenerateKeyDSA generates a new private DSA key using the given parameters.
+func GenerateKeyDSA(params DSAParameters) (*PrivateKeyDSA, error) {
+	pkey, err := newDSA(params, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	var x, y C.GO_BIGNUM_PTR
+	switch vMajor {
+	case 1:
+		dsa := getDSA(pkey)
+		if vMinor == 0 {
+			C.go_openssl_DSA_get0_key_backport(dsa, &y, &x)
+		} else {
+			C.go_openssl_DSA_get0_key(dsa, &y, &x)
+		}
+	case 3:
+		defer func() {
+			C.go_openssl_BN_clear_free(x)
+			C.go_openssl_BN_free(y)
+		}()
+		if C.go_openssl_EVP_PKEY_get_bn_param(pkey, paramPubKey, &y) != 1 ||
+			C.go_openssl_EVP_PKEY_get_bn_param(pkey, paramPrivKey, &x) != 1 {
+			return nil, newOpenSSLError("EVP_PKEY_get_bn_param")
+		}
+	default:
+		panic(errUnsupportedVersion())
+	}
+	k := &PrivateKeyDSA{params, bnToBig(x), bnToBig(y), pkey}
+	runtime.SetFinalizer(k, (*PrivateKeyDSA).finalize)
+	return k, nil
+}
+
+// SignDSA signs a hash (which should be the result of hashing a larger message).
+func SignDSA(priv *PrivateKeyDSA, hash []byte) ([]byte, error) {
+	return evpSign(priv.withKey, 0, 0, 0, hash)
+}
+
+// VerifyDSA verifiessig using the public key, pub.
+func VerifyDSA(pub *PublicKeyDSA, hash []byte, sig []byte) bool {
+	return evpVerify(pub.withKey, 0, 0, 0, sig, hash) == nil
+}
+
+func newDSA(params DSAParameters, x, y BigInt) (C.GO_EVP_PKEY_PTR, error) {
+	switch vMajor {
+	case 1:
+		return newDSA1(params, x, y)
+	case 3:
+		return newDSA3(params, x, y)
+	default:
+		panic(errUnsupportedVersion())
+	}
+}
+
+func newDSA1(params DSAParameters, x, y BigInt) (C.GO_EVP_PKEY_PTR, error) {
+	checkMajorVersion(1)
+
+	dsa := C.go_openssl_DSA_new()
+	p, q, g := bigToBN(params.P), bigToBN(params.Q), bigToBN(params.G)
+	var ret C.int
+	if vMinor == 0 {
+		ret = C.go_openssl_DSA_set0_pqg_backport(dsa, p, q, g)
+	} else {
+		ret = C.go_openssl_DSA_set0_pqg(dsa, p, q, g)
+	}
+	if ret != 1 {
+		C.go_openssl_BN_free(p)
+		C.go_openssl_BN_free(q)
+		C.go_openssl_BN_free(g)
+		C.go_openssl_DSA_free(dsa)
+		return nil, newOpenSSLError("DSA_set0_pqg failed")
+	}
+	if y != nil {
+		pub, priv := bigToBN(y), bigToBN(x)
+		if vMinor == 0 {
+			ret = C.go_openssl_DSA_set0_key_backport(dsa, pub, priv)
+		} else {
+			ret = C.go_openssl_DSA_set0_key(dsa, pub, priv)
+		}
+		if ret != 1 {
+			C.go_openssl_BN_free(pub)
+			C.go_openssl_BN_clear_free(priv)
+			C.go_openssl_DSA_free(dsa)
+			return nil, newOpenSSLError("DSA_set0_key failed")
+		}
+	} else {
+		if C.go_openssl_DSA_generate_key(dsa) != 1 {
+			C.go_openssl_DSA_free(dsa)
+			return nil, newOpenSSLError("DSA_generate_key failed")
+		}
+	}
+	pkey := C.go_openssl_EVP_PKEY_new()
+	if pkey == nil {
+		C.go_openssl_DSA_free(dsa)
+		return nil, newOpenSSLError("EVP_PKEY_new failed")
+	}
+	if C.go_openssl_EVP_PKEY_assign(pkey, C.GO_EVP_PKEY_DSA, unsafe.Pointer(dsa)) != 1 {
+		C.go_openssl_DSA_free(dsa)
+		C.go_openssl_EVP_PKEY_free(pkey)
+		return nil, newOpenSSLError("EVP_PKEY_assign failed")
+	}
+	return pkey, nil
+}
+
+func newDSA3(params DSAParameters, x, y BigInt) (C.GO_EVP_PKEY_PTR, error) {
+	checkMajorVersion(3)
+
+	bld := C.go_openssl_OSSL_PARAM_BLD_new()
+	if bld == nil {
+		return nil, newOpenSSLError("OSSL_PARAM_BLD_new")
+	}
+	defer C.go_openssl_OSSL_PARAM_BLD_free(bld)
+	p, q, g := bigToBN(params.P), bigToBN(params.Q), bigToBN(params.G)
+	defer func() {
+		C.go_openssl_BN_free(p)
+		C.go_openssl_BN_free(q)
+		C.go_openssl_BN_free(g)
+	}()
+	if C.go_openssl_OSSL_PARAM_BLD_push_BN(bld, paramP, p) != 1 ||
+		C.go_openssl_OSSL_PARAM_BLD_push_BN(bld, paramQ, q) != 1 ||
+		C.go_openssl_OSSL_PARAM_BLD_push_BN(bld, paramG, g) != 1 {
+		return nil, newOpenSSLError("OSSL_PARAM_BLD_push_BN")
+	}
+	selection := C.int(C.GO_EVP_PKEY_KEYPAIR)
+	if y != nil {
+		pub := bigToBN(y)
+		defer C.go_openssl_BN_free(pub)
+		if C.go_openssl_OSSL_PARAM_BLD_push_BN(bld, paramPubKey, pub) != 1 {
+			return nil, newOpenSSLError("OSSL_PARAM_BLD_push_BN")
+		}
+		if x == nil {
+			selection = C.int(C.GO_EVP_PKEY_PUBLIC_KEY)
+		}
+	}
+	if x != nil {
+		priv := bigToBN(x)
+		defer C.go_openssl_BN_clear_free(priv)
+		if C.go_openssl_OSSL_PARAM_BLD_push_BN(bld, paramPrivKey, priv) != 1 {
+			return nil, newOpenSSLError("OSSL_PARAM_BLD_push_BN")
+		}
+	}
+	bldparams := C.go_openssl_OSSL_PARAM_BLD_to_param(bld)
+	if bldparams == nil {
+		return nil, newOpenSSLError("OSSL_PARAM_BLD_to_param")
+	}
+	defer C.go_openssl_OSSL_PARAM_free(bldparams)
+	pkey, err := newEvpFromParams(C.GO_EVP_PKEY_DSA, selection, bldparams)
+	if err != nil {
+		return nil, err
+	}
+	if y != nil {
+		return pkey, nil
+	}
+	// pkey doesn't contain the public component, but the crypto/dsa expects
+	// it to be always there. Generate a new key using pkey as domain parameters
+	// placeholder.
+	defer C.go_openssl_EVP_PKEY_free(pkey)
+	ctx := C.go_openssl_EVP_PKEY_CTX_new_from_pkey(nil, pkey, nil)
+	if ctx == nil {
+		return nil, newOpenSSLError("EVP_PKEY_CTX_new_from_pkey")
+	}
+	defer C.go_openssl_EVP_PKEY_CTX_free(ctx)
+	if C.go_openssl_EVP_PKEY_keygen_init(ctx) != 1 {
+		return nil, newOpenSSLError("EVP_PKEY_keygen_init")
+	}
+	var gkey C.GO_EVP_PKEY_PTR
+	if C.go_openssl_EVP_PKEY_keygen(ctx, &gkey) != 1 {
+		return nil, newOpenSSLError("EVP_PKEY_keygen")
+	}
+	return gkey, nil
+}
+
+// getDSA returns the DSA from pkey.
+// If pkey does not contain an DSA it panics.
+// The returned key should not be freed.
+func getDSA(pkey C.GO_EVP_PKEY_PTR) (key C.GO_DSA_PTR) {
+	if vMajor == 1 && vMinor == 0 {
+		if key0 := C.go_openssl_EVP_PKEY_get0(pkey); key0 != nil {
+			key = C.GO_DSA_PTR(key0)
+		}
+	} else {
+		key = C.go_openssl_EVP_PKEY_get0_DSA(pkey)
+	}
+	if key == nil {
+		panic("pkey does not contain an DSA")
+	}
+	return key
+}