1 files changed, 167 insertions, 0 deletions
diff --git a/lib/isc/hmac.c b/lib/isc/hmac.c
new file mode 100644
index 0000000..bc35bef
--- /dev/null
+++ b/lib/isc/hmac.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <openssl/err.h>
+#include <openssl/evp.h>
+#include <openssl/opensslv.h>
+
+#include <isc/assertions.h>
+#include <isc/hmac.h>
+#include <isc/md.h>
+#include <isc/safe.h>
+#include <isc/string.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+#include "openssl_shim.h"
+
+isc_hmac_t *
+isc_hmac_new(void) {
+	EVP_MD_CTX *hmac = EVP_MD_CTX_new();
+	RUNTIME_CHECK(hmac != NULL);
+	return ((isc_hmac_t *)hmac);
+}
+
+void
+isc_hmac_free(isc_hmac_t *hmac) {
+	if (hmac == NULL) {
+		return;
+	}
+
+	EVP_MD_CTX_free((EVP_MD_CTX *)hmac);
+}
+
+isc_result_t
+isc_hmac_init(isc_hmac_t *hmac, const void *key, const size_t keylen,
+	      const isc_md_type_t *md_type) {
+	EVP_PKEY *pkey;
+
+	REQUIRE(hmac != NULL);
+	REQUIRE(key != NULL);
+	REQUIRE(keylen <= INT_MAX);
+
+	if (md_type == NULL) {
+		return (ISC_R_NOTIMPLEMENTED);
+	}
+
+	pkey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, key, keylen);
+	if (pkey == NULL) {
+		ERR_clear_error();
+		return (ISC_R_CRYPTOFAILURE);
+	}
+
+	if (EVP_DigestSignInit(hmac, NULL, md_type, NULL, pkey) != 1) {
+		EVP_PKEY_free(pkey);
+		ERR_clear_error();
+		return (ISC_R_CRYPTOFAILURE);
+	}
+
+	EVP_PKEY_free(pkey);
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_hmac_reset(isc_hmac_t *hmac) {
+	REQUIRE(hmac != NULL);
+
+	if (EVP_MD_CTX_reset(hmac) != 1) {
+		ERR_clear_error();
+		return (ISC_R_CRYPTOFAILURE);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_hmac_update(isc_hmac_t *hmac, const unsigned char *buf, const size_t len) {
+	REQUIRE(hmac != NULL);
+
+	if (buf == NULL || len == 0) {
+		return (ISC_R_SUCCESS);
+	}
+
+	if (EVP_DigestSignUpdate(hmac, buf, len) != 1) {
+		ERR_clear_error();
+		return (ISC_R_CRYPTOFAILURE);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_hmac_final(isc_hmac_t *hmac, unsigned char *digest,
+	       unsigned int *digestlen) {
+	REQUIRE(hmac != NULL);
+	REQUIRE(digest != NULL);
+	REQUIRE(digestlen != NULL);
+
+	size_t len = *digestlen;
+
+	if (EVP_DigestSignFinal(hmac, digest, &len) != 1) {
+		ERR_clear_error();
+		return (ISC_R_CRYPTOFAILURE);
+	}
+
+	*digestlen = (unsigned int)len;
+
+	return (ISC_R_SUCCESS);
+}
+
+const isc_md_type_t *
+isc_hmac_get_md_type(isc_hmac_t *hmac) {
+	REQUIRE(hmac != NULL);
+
+	return (EVP_MD_CTX_get0_md(hmac));
+}
+
+size_t
+isc_hmac_get_size(isc_hmac_t *hmac) {
+	REQUIRE(hmac != NULL);
+
+	return ((size_t)EVP_MD_CTX_size(hmac));
+}
+
+int
+isc_hmac_get_block_size(isc_hmac_t *hmac) {
+	REQUIRE(hmac != NULL);
+
+	return (EVP_MD_CTX_block_size(hmac));
+}
+
+isc_result_t
+isc_hmac(const isc_md_type_t *type, const void *key, const size_t keylen,
+	 const unsigned char *buf, const size_t len, unsigned char *digest,
+	 unsigned int *digestlen) {
+	isc_result_t res;
+	isc_hmac_t *hmac = isc_hmac_new();
+
+	res = isc_hmac_init(hmac, key, keylen, type);
+	if (res != ISC_R_SUCCESS) {
+		goto end;
+	}
+
+	res = isc_hmac_update(hmac, buf, len);
+	if (res != ISC_R_SUCCESS) {
+		goto end;
+	}
+
+	res = isc_hmac_final(hmac, digest, digestlen);
+	if (res != ISC_R_SUCCESS) {
+		goto end;
+	}
+end:
+	isc_hmac_free(hmac);
+
+	return (res);
+}