Generate PKEYs using EVP_PKEY_Q_keygen (#229)

* generate PKEYs using EVP_PKEY_Q_keygen

* Update shims.h

Co-authored-by: Davis Goodin <dagood@users.noreply.github.com>

* Update comment on variadic functions

* Fix indentation in generateEVPPKey function

* Refactor curveID handling in generateEVPPKey

---------

Co-authored-by: Davis Goodin <dagood@users.noreply.github.com>

cmd/checkheader/main.go

@@ -227,6 +227,11 @@ func tryConvertDefineFunc(w io.Writer, l string, i int) bool {
 	if !strings.HasPrefix(l, "DEFINEFUNC") {
 		return false
 	}
+	if strings.HasPrefix(l, "DEFINEFUNC_VARIADIC") {
+		// Variadic functions are not supported. There is not enough
+		// information in the macro to create use it in writeDefineFunc.
+		return false
+	}
 	i1 := strings.IndexByte(l, '(')
 	// The first ")," match is always the end of the argument list parameter.
 	// We are not interested in the last parameter and parsing them would complicate the algorithm.

ed25519.go

@@ -9,7 +9,6 @@ import (
 	"runtime"
 	"strconv"
 	"sync"
-	"unsafe"
 )
 
 const (
@@ -37,9 +36,7 @@ var supportsEd25519 = sync.OnceValue(func() bool {
 			}
 		}
 	case 3:
-		name := C.CString("ED25519")
-		defer C.free(unsafe.Pointer(name))
-		sig := C.go_openssl_EVP_SIGNATURE_fetch(nil, name, nil)
+		sig := C.go_openssl_EVP_SIGNATURE_fetch(nil, keyTypeED25519, nil)
 		if sig != nil {
 			C.go_openssl_EVP_SIGNATURE_free(sig)
 			return true

evp.go

@@ -13,6 +13,12 @@ import (
 	"unsafe"
 )
 
+var (
+	keyTypeRSA     = C.CString("RSA")
+	keyTypeEC      = C.CString("EC")
+	keyTypeED25519 = C.CString("ED25519")
+)
+
 // cacheMD is a cache of crypto.Hash to GO_EVP_MD_PTR.
 var cacheMD sync.Map
 
@@ -157,33 +163,53 @@ func cryptoHashToMD(ch crypto.Hash) (md C.GO_EVP_MD_PTR) {
 	return nil
 }
 
+// generateEVPPKey generates a new EVP_PKEY with the given id and properties.
 func generateEVPPKey(id C.int, bits int, curve string) (C.GO_EVP_PKEY_PTR, error) {
 	if bits != 0 && curve != "" {
 		return nil, fail("incorrect generateEVPPKey parameters")
 	}
-	ctx := C.go_openssl_EVP_PKEY_CTX_new_id(id, nil)
-	if ctx == nil {
-		return nil, newOpenSSLError("EVP_PKEY_CTX_new_id failed")
-	}
-	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 failed")
-	}
-	if bits != 0 {
-		if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, id, -1, C.GO_EVP_PKEY_CTRL_RSA_KEYGEN_BITS, C.int(bits), nil) != 1 {
-			return nil, newOpenSSLError("EVP_PKEY_CTX_ctrl failed")
+	var pkey C.GO_EVP_PKEY_PTR
+	switch vMajor {
+	case 1:
+		ctx := C.go_openssl_EVP_PKEY_CTX_new_id(id, nil)
+		if ctx == nil {
+			return nil, newOpenSSLError("EVP_PKEY_CTX_new_id")
+		}
+		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")
+		}
+		if bits != 0 {
+			if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, id, -1, C.GO_EVP_PKEY_CTRL_RSA_KEYGEN_BITS, C.int(bits), nil) != 1 {
+				return nil, newOpenSSLError("EVP_PKEY_CTX_ctrl")
+			}
 		}
-	}
-	if curve != "" {
-		nid := curveNID(curve)
-		if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, id, -1, C.GO_EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID, nid, nil) != 1 {
-			return nil, newOpenSSLError("EVP_PKEY_CTX_ctrl failed")
+		if curve != "" {
+			if C.go_openssl_EVP_PKEY_CTX_ctrl(ctx, id, -1, C.GO_EVP_PKEY_CTRL_EC_PARAMGEN_CURVE_NID, curveNID(curve), nil) != 1 {
+				return nil, newOpenSSLError("EVP_PKEY_CTX_ctrl")
+			}
 		}
+		if C.go_openssl_EVP_PKEY_keygen(ctx, &pkey) != 1 {
+			return nil, newOpenSSLError("EVP_PKEY_keygen")
+		}
+	case 3:
+		switch id {
+		case C.GO_EVP_PKEY_RSA:
+			pkey = C.go_openssl_EVP_PKEY_Q_keygen_RSA(nil, nil, keyTypeRSA, C.size_t(bits))
+		case C.GO_EVP_PKEY_EC:
+			pkey = C.go_openssl_EVP_PKEY_Q_keygen_EC(nil, nil, keyTypeEC, C.go_openssl_OBJ_nid2sn(curveNID(curve)))
+		case C.GO_EVP_PKEY_ED25519:
+			pkey = C.go_openssl_EVP_PKEY_Q_keygen(nil, nil, keyTypeED25519)
+		default:
+			panic("unsupported key type '" + strconv.Itoa(int(id)) + "'")
+		}
+		if pkey == nil {
+			return nil, newOpenSSLError("EVP_PKEY_Q_keygen")
+		}
+	default:
+		panic(errUnsupportedVersion())
 	}
-	var pkey C.GO_EVP_PKEY_PTR
-	if C.go_openssl_EVP_PKEY_keygen(ctx, &pkey) != 1 {
-		return nil, newOpenSSLError("EVP_PKEY_keygen failed")
-	}
+
 	return pkey, nil
 }
 

goopenssl.c

@@ -22,6 +22,7 @@
 #define DEFINEFUNC_3_0(ret, func, args, argscall)              DEFINEFUNC(ret, func, args, argscall)
 #define DEFINEFUNC_RENAMED_1_1(ret, func, oldfunc, args, argscall) DEFINEFUNC(ret, func, args, argscall)
 #define DEFINEFUNC_RENAMED_3_0(ret, func, oldfunc, args, argscall) DEFINEFUNC(ret, func, args, argscall)
+#define DEFINEFUNC_VARIADIC_3_0(ret, func, newname, args, argscall)  DEFINEFUNC(ret, newname, args, argscall)
 
 FOR_ALL_OPENSSL_FUNCTIONS
 
@@ -34,6 +35,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #undef DEFINEFUNC_3_0
 #undef DEFINEFUNC_RENAMED_1_1
 #undef DEFINEFUNC_RENAMED_3_0
+#undef DEFINEFUNC_VARIADIC_3_0
 
 // go_openssl_fips_enabled returns 1 if FIPS mode is enabled, 0 otherwise.
 // As a special case, it returns -1 if it cannot determine if FIPS mode is enabled.
@@ -140,6 +142,11 @@ go_openssl_load_functions(void* handle, unsigned int major, unsigned int minor,
     {                                                               \
         DEFINEFUNC_INTERNAL(func, #func)                            \
     }
+#define DEFINEFUNC_VARIADIC_3_0(ret, func, newname, args, argscall)   \
+    if (major == 3)                                                 \
+    {                                                               \
+        DEFINEFUNC_INTERNAL(newname, #func)                         \
+    }
 
 FOR_ALL_OPENSSL_FUNCTIONS
 
@@ -152,6 +159,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #undef DEFINEFUNC_3_0
 #undef DEFINEFUNC_RENAMED_1_1
 #undef DEFINEFUNC_RENAMED_3_0
+#undef DEFINEFUNC_VARIADIC_3_0
 }
 
 static unsigned long

goopenssl.h

@@ -59,6 +59,8 @@ int go_openssl_DSA_set0_key_backport(GO_DSA_PTR d, GO_BIGNUM_PTR pub_key, GO_BIG
     DEFINEFUNC(ret, func, args, argscall)
 #define DEFINEFUNC_RENAMED_3_0(ret, func, oldfunc, args, argscall)     \
     DEFINEFUNC(ret, func, args, argscall)
+#define DEFINEFUNC_VARIADIC_3_0(ret, func, newname, args, argscall)     \
+    DEFINEFUNC(ret, newname, args, argscall)
 
 FOR_ALL_OPENSSL_FUNCTIONS
 
@@ -71,6 +73,7 @@ FOR_ALL_OPENSSL_FUNCTIONS
 #undef DEFINEFUNC_3_0
 #undef DEFINEFUNC_RENAMED_1_1
 #undef DEFINEFUNC_RENAMED_3_0
+#undef DEFINEFUNC_VARIADIC_3_0
 
 // go_hash_sum copies ctx into ctx2 and calls EVP_DigestFinal using ctx2.
 // This is necessary because Go hash.Hash mandates that Sum has no effect

shims.h

@@ -157,6 +157,15 @@ typedef void* GO_SHA_CTX_PTR;
 // DEFINEFUNC_RENAMED_3_0 acts like DEFINEFUNC but tries to load the function using the new name when using >= 3.x
 // and the old name when using 1.x. In both cases the function will have the new name.
 //
+// DEFINEFUNC_VARIADIC_3_0 acts like DEFINEFUNC but creates an alias with a more specific signature.
+// This is necessary to call variadic functions (functions that accept a variable number of arguments)
+// because variadic functions are not directly compatible with cgo. By defining a cgo-compatible alias
+// for each desired signature, the C compiler handles the variadic arguments rather than cgo.
+// Variadic functions are the only known incompatibility of this kind.
+// If you use this macro for a different reason, consider renaming it to something more general first.
+// See https://github.com/golang/go/issues/975.
+// The process is aborted if the function can't be loaded when using 3.0.0 or higher.
+//
 // #include <openssl/crypto.h>
 // #include <openssl/err.h>
 // #include <openssl/rsa.h>
@@ -298,6 +307,9 @@ DEFINEFUNC(int, EVP_PKEY_paramgen_init, (GO_EVP_PKEY_CTX_PTR ctx), (ctx)) \
 DEFINEFUNC(int, EVP_PKEY_paramgen, (GO_EVP_PKEY_CTX_PTR ctx, GO_EVP_PKEY_PTR *ppkey), (ctx, ppkey)) \
 DEFINEFUNC(int, EVP_PKEY_keygen_init, (GO_EVP_PKEY_CTX_PTR ctx), (ctx)) \
 DEFINEFUNC(int, EVP_PKEY_keygen, (GO_EVP_PKEY_CTX_PTR ctx, GO_EVP_PKEY_PTR *ppkey), (ctx, ppkey)) \
+DEFINEFUNC_VARIADIC_3_0(GO_EVP_PKEY_PTR, EVP_PKEY_Q_keygen, EVP_PKEY_Q_keygen, (GO_OSSL_LIB_CTX_PTR ctx, const char *propq, const char *type), (ctx, propq, type)) \
+DEFINEFUNC_VARIADIC_3_0(GO_EVP_PKEY_PTR, EVP_PKEY_Q_keygen, EVP_PKEY_Q_keygen_RSA, (GO_OSSL_LIB_CTX_PTR ctx, const char *propq, const char *type, size_t arg1), (ctx, propq, type, arg1)) \
+DEFINEFUNC_VARIADIC_3_0(GO_EVP_PKEY_PTR, EVP_PKEY_Q_keygen, EVP_PKEY_Q_keygen_EC, (GO_OSSL_LIB_CTX_PTR ctx, const char *propq, const char *type, const char *arg1), (ctx, propq, type, arg1)) \
 DEFINEFUNC(void, EVP_PKEY_CTX_free, (GO_EVP_PKEY_CTX_PTR arg0), (arg0)) \
 DEFINEFUNC(int, EVP_PKEY_CTX_ctrl, (GO_EVP_PKEY_CTX_PTR ctx, int keytype, int optype, int cmd, int p1, void *p2), (ctx, keytype, optype, cmd, p1, p2)) \
 DEFINEFUNC(int, EVP_PKEY_decrypt, (GO_EVP_PKEY_CTX_PTR arg0, unsigned char *arg1, size_t *arg2, const unsigned char *arg3, size_t arg4), (arg0, arg1, arg2, arg3, arg4)) \