Add ECDH_compute_key_fips inside the module.
This change adds a function so that an ECDH and the hashing of the
resulting 'x' coordinate can occur inside the FIPS boundary.
Change-Id: If93c20a70dc9dcbca49056f10915d3ce064f641f
Reviewed-on: https://boringssl-review.googlesource.com/30104
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/fipsmodule/ecdh/ecdh.c b/crypto/fipsmodule/ecdh/ecdh.c
new file mode 100644
index 0000000..cd9d7ea
--- /dev/null
+++ b/crypto/fipsmodule/ecdh/ecdh.c
@@ -0,0 +1,161 @@
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ *
+ * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
+ * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
+ * to the OpenSSL project.
+ *
+ * The ECC Code is licensed pursuant to the OpenSSL open source
+ * license provided below.
+ *
+ * The ECDH software is originally written by Douglas Stebila of
+ * Sun Microsystems Laboratories.
+ *
+ */
+/* ====================================================================
+ * Copyright (c) 2000-2002 The OpenSSL Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ * software must display the following acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ * endorse or promote products derived from this software without
+ * prior written permission. For written permission, please contact
+ * licensing@OpenSSL.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ * nor may "OpenSSL" appear in their names without prior written
+ * permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ * acknowledgment:
+ * "This product includes software developed by the OpenSSL Project
+ * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com). This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com). */
+
+#include <openssl/ecdh.h>
+
+#include <limits.h>
+#include <string.h>
+
+#include <openssl/bn.h>
+#include <openssl/ec.h>
+#include <openssl/ec_key.h>
+#include <openssl/err.h>
+#include <openssl/mem.h>
+#include <openssl/sha.h>
+
+#include "../ec/internal.h"
+
+
+int ECDH_compute_key_fips(uint8_t *out, size_t out_len, const EC_POINT *pub_key,
+ const EC_KEY *priv_key) {
+ if (priv_key->priv_key == NULL) {
+ OPENSSL_PUT_ERROR(ECDH, ECDH_R_NO_PRIVATE_VALUE);
+ return 0;
+ }
+ const EC_SCALAR *const priv = &priv_key->priv_key->scalar;
+
+ BN_CTX *ctx = BN_CTX_new();
+ if (ctx == NULL) {
+ return 0;
+ }
+ BN_CTX_start(ctx);
+
+ int ret = 0;
+ size_t buflen = 0;
+ uint8_t *buf = NULL;
+
+ const EC_GROUP *const group = EC_KEY_get0_group(priv_key);
+ EC_POINT *shared_point = EC_POINT_new(group);
+ if (shared_point == NULL) {
+ OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ if (!ec_point_mul_scalar(group, shared_point, NULL, pub_key, priv, ctx)) {
+ OPENSSL_PUT_ERROR(ECDH, ECDH_R_POINT_ARITHMETIC_FAILURE);
+ goto err;
+ }
+
+ BIGNUM *x = BN_CTX_get(ctx);
+ if (!x) {
+ OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ if (!EC_POINT_get_affine_coordinates_GFp(group, shared_point, x, NULL, ctx)) {
+ OPENSSL_PUT_ERROR(ECDH, ECDH_R_POINT_ARITHMETIC_FAILURE);
+ goto err;
+ }
+
+ buflen = (EC_GROUP_get_degree(group) + 7) / 8;
+ buf = OPENSSL_malloc(buflen);
+ if (buf == NULL) {
+ OPENSSL_PUT_ERROR(ECDH, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+
+ if (!BN_bn2bin_padded(buf, buflen, x)) {
+ OPENSSL_PUT_ERROR(ECDH, ERR_R_INTERNAL_ERROR);
+ goto err;
+ }
+
+ switch (out_len) {
+ case SHA224_DIGEST_LENGTH:
+ SHA224(buf, buflen, out);
+ break;
+ case SHA256_DIGEST_LENGTH:
+ SHA256(buf, buflen, out);
+ break;
+ case SHA384_DIGEST_LENGTH:
+ SHA384(buf, buflen, out);
+ break;
+ case SHA512_DIGEST_LENGTH:
+ SHA512(buf, buflen, out);
+ break;
+ default:
+ OPENSSL_PUT_ERROR(ECDH, ECDH_R_UNKNOWN_DIGEST_LENGTH);
+ goto err;
+ }
+
+ ret = 1;
+
+err:
+ OPENSSL_free(buf);
+ EC_POINT_free(shared_point);
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ return ret;
+}
