1 files changed, 100 insertions, 0 deletions
diff --git a/src/rs1.c b/src/rs1.c
new file mode 100644
index 0000000..03636b5
--- /dev/null
+++ b/src/rs1.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2021 Yubico AB. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <openssl/rsa.h>
+#include <openssl/obj_mac.h>
+
+#include "fido.h"
+
+#if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x3050200fL
+static EVP_MD *
+rs1_get_EVP_MD(void)
+{
+	const EVP_MD *from;
+	EVP_MD *to = NULL;
+
+	if ((from = EVP_sha1()) != NULL && (to = malloc(sizeof(*to))) != NULL)
+		memcpy(to, from, sizeof(*to));
+
+	return (to);
+}
+
+static void
+rs1_free_EVP_MD(EVP_MD *md)
+{
+	freezero(md, sizeof(*md));
+}
+#elif OPENSSL_VERSION_NUMBER >= 0x30000000
+static EVP_MD *
+rs1_get_EVP_MD(void)
+{
+	return (EVP_MD_fetch(NULL, "SHA-1", NULL));
+}
+
+static void
+rs1_free_EVP_MD(EVP_MD *md)
+{
+	EVP_MD_free(md);
+}
+#else
+static EVP_MD *
+rs1_get_EVP_MD(void)
+{
+	const EVP_MD *md;
+
+	if ((md = EVP_sha1()) == NULL)
+		return (NULL);
+
+	return (EVP_MD_meth_dup(md));
+}
+
+static void
+rs1_free_EVP_MD(EVP_MD *md)
+{
+	EVP_MD_meth_free(md);
+}
+#endif /* LIBRESSL_VERSION_NUMBER */
+
+int
+rs1_verify_sig(const fido_blob_t *dgst, EVP_PKEY *pkey,
+    const fido_blob_t *sig)
+{
+	EVP_PKEY_CTX	*pctx = NULL;
+	EVP_MD		*md = NULL;
+	int		 ok = -1;
+
+	if (EVP_PKEY_base_id(pkey) != EVP_PKEY_RSA) {
+		fido_log_debug("%s: EVP_PKEY_base_id", __func__);
+		goto fail;
+	}
+
+	if ((md = rs1_get_EVP_MD()) == NULL) {
+		fido_log_debug("%s: rs1_get_EVP_MD", __func__);
+		goto fail;
+	}
+
+	if ((pctx = EVP_PKEY_CTX_new(pkey, NULL)) == NULL ||
+	    EVP_PKEY_verify_init(pctx) != 1 ||
+	    EVP_PKEY_CTX_set_rsa_padding(pctx, RSA_PKCS1_PADDING) != 1 ||
+	    EVP_PKEY_CTX_set_signature_md(pctx, md) != 1) {
+		fido_log_debug("%s: EVP_PKEY_CTX", __func__);
+		goto fail;
+	}
+
+	if (EVP_PKEY_verify(pctx, sig->ptr, sig->len, dgst->ptr,
+	    dgst->len) != 1) {
+		fido_log_debug("%s: EVP_PKEY_verify", __func__);
+		goto fail;
+	}
+
+	ok = 0;
+fail:
+	EVP_PKEY_CTX_free(pctx);
+	rs1_free_EVP_MD(md);
+
+	return (ok);
+}