Merge pull request #53 from microsoft/fips

Prioritize FIPS-enabled versions when automatically selecting a version

.github/workflows/test.yml

@@ -38,6 +38,8 @@ jobs:
       run: go test -gcflags=all=-d=checkptr -count 10 -v ./...
       env:
         GO_OPENSSL_VERSION_OVERRIDE: ${{ matrix.openssl-version-build }}
+    - name: Run Test - Build - No version override
+      run: go test -gcflags=all=-d=checkptr -v ./...
     - name: Run Test - Misc
       run: go test -gcflags=all=-d=checkptr -v .
       working-directory: ./misc

openssl/goopenssl.c

@@ -9,6 +9,27 @@
 #include <dlfcn.h>
 #include <stdio.h>
 
+int
+go_openssl_fips_enabled(void* handle)
+{
+    // For OpenSSL 1.x.
+    int (*FIPS_mode)(void);
+    FIPS_mode = (int (*)(void))dlsym(handle, "FIPS_mode");
+    if (FIPS_mode != NULL)
+        return FIPS_mode();
+
+    // For OpenSSL 3.x.
+    int (*EVP_default_properties_is_fips_enabled)(void*);
+    int (*OSSL_PROVIDER_available)(void*, const char*);
+    EVP_default_properties_is_fips_enabled = (int (*)(void*))dlsym(handle, "EVP_default_properties_is_fips_enabled"); 
+    OSSL_PROVIDER_available = (int (*)(void*, const char*))dlsym(handle, "OSSL_PROVIDER_available"); 
+    if (EVP_default_properties_is_fips_enabled != NULL && OSSL_PROVIDER_available != NULL &&
+        EVP_default_properties_is_fips_enabled(NULL) == 1 && OSSL_PROVIDER_available(NULL, "fips") == 1)
+            return 1;
+
+    return 0;
+}
+
 static unsigned long
 version_num(void* handle)
 {

openssl/goopenssl.h

@@ -7,6 +7,7 @@
 
 #include "openssl_funcs.h"
 
+int go_openssl_fips_enabled(void* handle);
 int go_openssl_version_major(void* handle);
 int go_openssl_version_minor(void* handle);
 int go_openssl_thread_setup(void);

openssl/openssl.go

@@ -24,9 +24,6 @@ import (
 var (
 	providerNameFips    = C.CString("fips")
 	providerNameDefault = C.CString("default")
-	propFipsYes         = C.CString("fips=yes")
-	propFipsNo          = C.CString("fips=no")
-	algProve            = C.CString("SHA2-256")
 )
 
 var (
@@ -126,26 +123,33 @@ func loadLibrary(version string) (unsafe.Pointer, error) {
 		}
 		return handle, nil
 	}
+	var fallbackHandle unsafe.Pointer
 	for _, v := range knownVersions {
 		handle := dlopen(v)
-		if handle != nil {
+		if handle == nil {
+			continue
+		}
+		if C.go_openssl_fips_enabled(handle) == 1 {
+			// Found a FIPS enabled version, use it.
+			if fallbackHandle != nil {
+				// If we found a FIPS enabled version but we already have a fallback
+				// version, close the fallback version.
+				C.dlclose(fallbackHandle)
+			}
 			return handle, nil
 		}
+		if fallbackHandle == nil {
+			// Remember the first version that exists but is not FIPS enabled
+			// in case we don't find any FIPS enabled version.
+			fallbackHandle = handle
+		} else {
+			C.dlclose(handle)
+		}
 	}
-	return nil, errors.New("openssl: can't load libcrypto.so using any known version suffix")
-}
-
-// providerAvailable looks through provider's digests
-// checking if there is any that matches the props query.
-func providerAvailable(props *C.char) bool {
-	C.go_openssl_ERR_set_mark()
-	md := C.go_openssl_EVP_MD_fetch(nil, algProve, props)
-	C.go_openssl_ERR_pop_to_mark()
-	if md == nil {
-		return false
+	if fallbackHandle != nil {
+		return fallbackHandle, nil
 	}
-	C.go_openssl_EVP_MD_free(md)
-	return true
+	return nil, errors.New("openssl: can't load libcrypto.so using any known version suffix")
 }
 
 // FIPS returns true if OpenSSL is running in FIPS mode, else returns false.
@@ -159,53 +163,49 @@ func FIPS() bool {
 		}
 		// EVP_default_properties_is_fips_enabled can return true even if the FIPS provider isn't loaded,
 		// it is only based on the default properties.
-		return providerAvailable(propFipsYes)
+		return C.go_openssl_OSSL_PROVIDER_available(nil, providerNameFips) == 1
 	default:
 		panic(errUnsuportedVersion())
 	}
 }
 
 // SetFIPS enables or disables FIPS mode.
 //
-// It implements the following provider fallback logic for OpenSSL 3:
-//    - The "fips" provider is loaded if enabled=true and no loaded provider matches "fips=yes".
-//    - The "default" provider is loaded if enabled=false and no loaded provider matches "fips=no".
-// This logic allows advanced users to define their own providers that match "fips=yes" and "fips=no" using the OpenSSL config file.
+// On OpenSSL 3, the `fips` provider is loaded if enabled is true,
+// else the `default` provider is loaded.
 func SetFIPS(enabled bool) error {
+	var mode C.int
+	if enabled {
+		mode = C.int(1)
+	} else {
+		mode = C.int(0)
+	}
 	switch vMajor {
 	case 1:
-		var mode C.int
-		if enabled {
-			mode = C.int(1)
-		} else {
-			mode = C.int(0)
-		}
 		if C.go_openssl_FIPS_mode_set(mode) != 1 {
 			return newOpenSSLError("openssl: FIPS_mode_set")
 		}
 		return nil
 	case 3:
-		var props, provName *C.char
+		var provName *C.char
 		if enabled {
-			props = propFipsYes
 			provName = providerNameFips
 		} else {
-			props = propFipsNo
 			provName = providerNameDefault
 		}
-		// Check if there is any provider that matches props.
-		if !providerAvailable(props) {
+		// Check if provName is not loaded.
+		if C.go_openssl_OSSL_PROVIDER_available(nil, provName) == 0 {
 			// If not, fallback to provName provider.
 			if C.go_openssl_OSSL_PROVIDER_load(nil, provName) == nil {
-				return newOpenSSLError("openssl: OSSL_PROVIDER_try_load")
+				return newOpenSSLError("openssl: OSSL_PROVIDER_load")
 			}
 			// Make sure we now have a provider available.
-			if !providerAvailable(props) {
+			if C.go_openssl_OSSL_PROVIDER_available(nil, provName) == 0 {
 				return fail("SetFIPS(" + strconv.FormatBool(enabled) + ") not supported")
 			}
 		}
-		if C.go_openssl_EVP_set_default_properties(nil, props) != 1 {
-			return newOpenSSLError("openssl: EVP_set_default_properties")
+		if C.go_openssl_EVP_default_properties_enable_fips(nil, mode) != 1 {
+			return newOpenSSLError("openssl: EVP_default_properties_enable_fips")
 		}
 		return nil
 	default:
@@ -281,6 +281,7 @@ func bnToBig(bn C.GO_BIGNUM_PTR) BigInt {
 // output depends on the input. noescape is inlined and currently
 // compiles down to zero instructions.
 // USE CAREFULLY!
+//
 //go:nosplit
 func noescape(p unsafe.Pointer) unsafe.Pointer {
 	x := uintptr(p)

openssl/openssl_funcs.h

@@ -150,8 +150,6 @@ typedef struct {
 // #include <openssl/provider.h>
 // #endif
 #define FOR_ALL_OPENSSL_FUNCTIONS \
-DEFINEFUNC(int, ERR_set_mark, (void), ()) \
-DEFINEFUNC(int, ERR_pop_to_mark, (void), ()) \
 DEFINEFUNC(unsigned long, ERR_get_error, (void), ()) \
 DEFINEFUNC(void, ERR_error_string_n, (unsigned long e, char *buf, size_t len), (e, buf, len)) \
 DEFINEFUNC_RENAMED_1_1(const char *, OpenSSL_version, SSLeay_version, (int type), (type)) \
@@ -165,8 +163,9 @@ DEFINEFUNC_1_1(int, OPENSSL_init_crypto, (uint64_t ops, const GO_OPENSSL_INIT_SE
 DEFINEFUNC_LEGACY_1(int, FIPS_mode, (void), ()) \
 DEFINEFUNC_LEGACY_1(int, FIPS_mode_set, (int r), (r)) \
 DEFINEFUNC_3_0(int, EVP_default_properties_is_fips_enabled, (GO_OSSL_LIB_CTX_PTR libctx), (libctx)) \
-DEFINEFUNC_3_0(int, EVP_set_default_properties, (GO_OSSL_LIB_CTX_PTR libctx, const char *propq), (libctx, propq)) \
+DEFINEFUNC_3_0(int, EVP_default_properties_enable_fips, (GO_OSSL_LIB_CTX_PTR libctx, int enable), (libctx, enable)) \
 DEFINEFUNC_3_0(GO_OSSL_PROVIDER_PTR, OSSL_PROVIDER_load, (GO_OSSL_LIB_CTX_PTR libctx, const char *name), (libctx, name)) \
+DEFINEFUNC_3_0(int, OSSL_PROVIDER_available, (GO_OSSL_LIB_CTX_PTR libctx, const char *name), (libctx, name)) \
 DEFINEFUNC(int, RAND_bytes, (unsigned char* arg0, int arg1), (arg0, arg1)) \
 DEFINEFUNC(int, EVP_DigestInit, (GO_EVP_MD_CTX_PTR ctx, const GO_EVP_MD_PTR type), (ctx, type)) \
 DEFINEFUNC(int, EVP_DigestInit_ex, (GO_EVP_MD_CTX_PTR ctx, const GO_EVP_MD_PTR type, GO_ENGINE_PTR impl), (ctx, type, impl)) \
@@ -186,8 +185,6 @@ DEFINEFUNC(const GO_EVP_MD_PTR, EVP_sha256, (void), ()) \
 DEFINEFUNC(const GO_EVP_MD_PTR, EVP_sha384, (void), ()) \
 DEFINEFUNC(const GO_EVP_MD_PTR, EVP_sha512, (void), ()) \
 DEFINEFUNC_1_1(const GO_EVP_MD_PTR, EVP_md5_sha1, (void), ()) \
-DEFINEFUNC_3_0(GO_EVP_MD_PTR, EVP_MD_fetch, (GO_OSSL_LIB_CTX_PTR ctx, const char *algorithm, const char *properties), (ctx, algorithm, properties)) \
-DEFINEFUNC_3_0(void, EVP_MD_free, (GO_EVP_MD_PTR md), (md)) \
 DEFINEFUNC_RENAMED_3_0(int, EVP_MD_get_size, EVP_MD_size, (const GO_EVP_MD_PTR arg0), (arg0)) \
 DEFINEFUNC_LEGACY_1_0(void, HMAC_CTX_init, (GO_HMAC_CTX_PTR arg0), (arg0)) \
 DEFINEFUNC_LEGACY_1_0(void, HMAC_CTX_cleanup, (GO_HMAC_CTX_PTR arg0), (arg0)) \