Add EVP_PKEY_gettable_params support for accessing EVP_PKEY key data fields

Currently only RSA, EC and ECX are supported (DH and DSA need to be added to the keygen
PR's seperately because the fields supported have changed significantly).

The API's require the keys to be provider based.

Made the keymanagement export and get_params functions share the same code by supplying
support functions that work for both a OSSL_PARAM_BLD as well as a OSSL_PARAM[].
This approach means that complex code is not required to build an
empty OSSL_PARAM[] with the correct sized fields before then doing a second
pass to populate the array.

The RSA factor arrays have been changed to use unique key names to simplify the interface
needed by the user.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11365)

1 files changed, 111 insertions, 0 deletions

diff --git a/crypto/param_build_set.c b/crypto/param_build_set.c
new file mode 100644
index 0000000000..b74b0d59ee
--- /dev/null
+++ b/crypto/param_build_set.c
@@ -0,0 +1,111 @@
+/*
+ * 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
+ */
+
+/*
+ * Key Management utility functions to share functionality between the export()
+ * and get_params() methods.
+ * export() uses OSSL_PARAM_BLD, and get_params() used the OSSL_PARAM[] to
+ * fill in parameter data for the same key and data fields.
+ */
+
+#include <openssl/core_names.h>
+#include "internal/param_build_set.h"
+
+DEFINE_SPECIAL_STACK_OF_CONST(BIGNUM_const, BIGNUM)
+
+int ossl_param_build_set_int(OSSL_PARAM_BLD *bld, OSSL_PARAM *p,
+                             const char *key, int num)
+{
+    if (bld != NULL)
+        return OSSL_PARAM_BLD_push_int(bld, key, num);
+    p = OSSL_PARAM_locate(p, key);
+    if (p != NULL)
+        return OSSL_PARAM_set_int(p, num);
+    return 1;
+}
+
+int ossl_param_build_set_utf8_string(OSSL_PARAM_BLD *bld, OSSL_PARAM *p,
+                                     const char *key, const char *buf)
+{
+    if (bld != NULL)
+        return OSSL_PARAM_BLD_push_utf8_string(bld, key, buf, 0);
+    p = OSSL_PARAM_locate(p, key);
+    if (p != NULL)
+        return OSSL_PARAM_set_utf8_string(p, buf);
+    return 1;
+}
+
+int ossl_param_build_set_octet_string(OSSL_PARAM_BLD *bld, OSSL_PARAM *p,
+                                      const char *key,
+                                      const unsigned char *data,
+                                      size_t data_len)
+{
+    if (bld != NULL)
+        return OSSL_PARAM_BLD_push_octet_string(bld, key, data, data_len);
+
+    p = OSSL_PARAM_locate(p, key);
+    if (p != NULL)
+        return OSSL_PARAM_set_octet_string(p, data, data_len);
+    return 1;
+}
+
+int ossl_param_build_set_bn_pad(OSSL_PARAM_BLD *bld, OSSL_PARAM *p,
+                                const char *key, const BIGNUM *bn,  size_t sz)
+{
+    if (bld != NULL)
+        return OSSL_PARAM_BLD_push_BN_pad(bld, key, bn, sz);
+    p = OSSL_PARAM_locate(p, key);
+    if (p != NULL) {
+        if (sz > p->data_size)
+            return 0;
+        /* TODO(3.0) Change to use OSSL_PARAM_set_BN_pad */
+        p->data_size = sz;
+        return OSSL_PARAM_set_BN(p, bn);
+    }
+    return 1;
+}
+
+int ossl_param_build_set_bn(OSSL_PARAM_BLD *bld, OSSL_PARAM *p,
+                            const char *key, const BIGNUM *bn)
+{
+    if (bld != NULL)
+        return OSSL_PARAM_BLD_push_BN(bld, key, bn);
+
+    p = OSSL_PARAM_locate(p, key);
+    if (p != NULL)
+        return OSSL_PARAM_set_BN(p, bn) > 0;
+    return 1;
+}
+
+int ossl_param_build_set_multi_key_bn(OSSL_PARAM_BLD *bld, OSSL_PARAM *params,
+                                      const char *names[],
+                                      STACK_OF(BIGNUM_const) *stk)
+{
+    int i, sz = sk_BIGNUM_const_num(stk);
+    OSSL_PARAM *p;
+
+
+    if (bld != NULL) {
+        for (i = 0; i < sz && names[i] != NULL; ++i) {
+            if (!OSSL_PARAM_BLD_push_BN(bld, names[i],
+                                        sk_BIGNUM_const_value(stk, i)))
+                return 0;
+        }
+        return 1;
+    }
+
+    for (i = 0; i < sz && names[i] != NULL; ++i) {
+        p = OSSL_PARAM_locate(params, names[i]);
+        if (p != NULL) {
+            if (!OSSL_PARAM_set_BN(p, sk_BIGNUM_const_value(stk, i)))
+                return 0;
+        }
+    }
+    return 1;
+}