From 0abae1636d7054266dd20724c0d5e06617d9f679 Mon Sep 17 00:00:00 2001
From: Richard Levitte <levitte@openssl.org>
Date: Mon, 23 Mar 2020 05:40:47 +0100
Subject: EVP: Implement support for key downgrading in backends

Downgrading EVP_PKEYs from containing provider side internal keys to
containing legacy keys demands support in the EVP_PKEY_ASN1_METHOD.

This became a bit elaborate because the code would be almost exactly
the same as the import functions int EVP_KEYMGMT.  Therefore, we end
up moving most of the code to common backend support files that can be
used both by legacy backend code and by our providers.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11375)
---
 crypto/ffc/build.info    |  2 +-
 crypto/ffc/ffc_backend.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 crypto/ffc/ffc_backend.c

(limited to 'crypto/ffc')

diff --git a/crypto/ffc/build.info b/crypto/ffc/build.info
index c8bc7e9018..a04430d1d1 100644
--- a/crypto/ffc/build.info
+++ b/crypto/ffc/build.info
@@ -1,7 +1,7 @@
 LIBS=../../libcrypto
 
 $COMMON=ffc_params.c ffc_params_generate.c ffc_key_generate.c\
-        ffc_params_validate.c ffc_key_validate.c
+        ffc_params_validate.c ffc_key_validate.c ffc_backend.c
 
 SOURCE[../../libcrypto]=$COMMON
 SOURCE[../../providers/libfips.a]=$COMMON
diff --git a/crypto/ffc/ffc_backend.c b/crypto/ffc/ffc_backend.c
new file mode 100644
index 0000000000..cde9e43da3
--- /dev/null
+++ b/crypto/ffc/ffc_backend.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/core_names.h>
+#include "internal/ffc.h"
+
+/*
+ * The intention with the "backend" source file is to offer backend support
+ * for legacy backends (EVP_PKEY_ASN1_METHOD and EVP_PKEY_METHOD) and provider
+ * implementations alike.
+ */
+
+int ffc_fromdata(FFC_PARAMS *ffc, const OSSL_PARAM params[])
+{
+    const OSSL_PARAM *param_p, *param_q, *param_g;
+    BIGNUM *p = NULL, *q = NULL, *g = NULL;
+
+    if (ffc == NULL)
+        return 0;
+
+    param_p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_FFC_P);
+    param_q = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_FFC_Q);
+    param_g = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_FFC_G);
+
+    if ((param_p != NULL && !OSSL_PARAM_get_BN(param_p, &p))
+        || (param_q != NULL && !OSSL_PARAM_get_BN(param_q, &q))
+        || (param_g != NULL && !OSSL_PARAM_get_BN(param_g, &g)))
+        goto err;
+
+    ffc_params_set0_pqg(ffc, p, q, g);
+    return 1;
+
+ err:
+    BN_free(p);
+    BN_free(q);
+    BN_free(g);
+    return 0;
+}
-- 
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