Add public key method enumeration function.

Add functions to enumerate public key methods. Add test to ensure table
is in the correct order.
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4015)

crypto/evp/pmeth_lib.c

@@ -290,6 +290,27 @@ int EVP_PKEY_meth_add0(const EVP_PKEY_METHOD *pmeth)
     return 1;
 }
 
+size_t EVP_PKEY_meth_get_count(void)
+{
+    size_t rv = OSSL_NELEM(standard_methods);
+
+    if (app_pkey_methods)
+        rv += sk_EVP_PKEY_METHOD_num(app_pkey_methods);
+    return rv;
+}
+
+const EVP_PKEY_METHOD *EVP_PKEY_meth_get0(size_t idx)
+{
+    if (idx < OSSL_NELEM(standard_methods))
+        return standard_methods[idx];
+    if (app_pkey_methods == NULL)
+        return NULL;
+    idx -= OSSL_NELEM(standard_methods);
+    if (idx >= (size_t)sk_EVP_PKEY_METHOD_num(app_pkey_methods))
+        return NULL;
+    return sk_EVP_PKEY_METHOD_value(app_pkey_methods, idx);
+}
+
 void EVP_PKEY_CTX_free(EVP_PKEY_CTX *ctx)
 {
     if (ctx == NULL)

doc/man3/EVP_PKEY_meth_get_count.pod

+=pod
+
+=head1 NAME
+
+EVP_PKEY_meth_get_count, EVP_PKEY_meth_get0, EVP_PKEY_meth_get0_info - enumeratepublic key methods
+
+=head1 SYNOPSIS
+
+ #include <openssl/evp.h>
+
+ size_t EVP_PKEY_meth_get_count(void);
+ const EVP_PKEY_METHOD *EVP_PKEY_meth_get0(size_t idx);
+ void EVP_PKEY_meth_get0_info(int *ppkey_id, int *pflags,
+                              const EVP_PKEY_METHOD *meth);
+
+=head1 DESCRIPTION
+
+EVP_PKEY_meth_count() returns a count of the number of public key methods
+available: it includes standard methods and any methods added by the
+application.
+
+EVP_PKEY_meth_get0() returns the public key method B<idx>. The value of B<idx>
+must be between zero and EVP_PKEY_meth_get_count() - 1.
+
+EVP_PKEY_meth_get0_info() returns the public key ID (a NID) and any flags
+associated with the public key method B<*meth>.
+
+=head1 RETURN VALUES
+
+EVP_PKEY_meth_count() returns the number of available public key methods.
+
+EVP_PKEY_meth_get0() return a public key method or B<NULL> if B<idx> is
+out of range.
+
+EVP_PKEY_meth_get0_info() does not return a value.
+
+=head1 SEE ALSO
+
+L<EVP_PKEY_new(3)>
+
+=head1 COPYRIGHT
+
+Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (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
+L<https://www.openssl.org/source/license.html>.
+
+=cut

include/openssl/evp.h

@@ -1263,6 +1263,8 @@ void EVP_PKEY_meth_get0_info(int *ppkey_id, int *pflags,
 void EVP_PKEY_meth_copy(EVP_PKEY_METHOD *dst, const EVP_PKEY_METHOD *src);
 void EVP_PKEY_meth_free(EVP_PKEY_METHOD *pmeth);
 int EVP_PKEY_meth_add0(const EVP_PKEY_METHOD *pmeth);
+size_t EVP_PKEY_meth_get_count(void);
+const EVP_PKEY_METHOD *EVP_PKEY_meth_get0(size_t idx);
 
 EVP_PKEY_CTX *EVP_PKEY_CTX_new(EVP_PKEY *pkey, ENGINE *e);
 EVP_PKEY_CTX *EVP_PKEY_CTX_new_id(int id, ENGINE *e);

test/pkey_meth_test.c

@@ -15,13 +15,8 @@
 #include <openssl/evp.h>
 #include "testutil.h"
 
-/**********************************************************************
- *
- * Test of EVP_PKEY_ASN1 method ordering
- *
- ***/
-
-static int test_asn1_meths()
+/* Test of EVP_PKEY_ASN1_METHOD ordering */
+static int test_asn1_meths(void)
 {
     int i;
     int prev = -1;
@@ -52,8 +47,37 @@ static int test_asn1_meths()
     return good;
 }
 
+/* Test of EVP_PKEY_METHOD ordering */
+static int test_pkey_meths()
+{
+    size_t i;
+    int prev = -1;
+    int good = 1;
+    int pkey_id;
+    const EVP_PKEY_METHOD *pmeth;
+
+    for (i = 0; i < EVP_PKEY_meth_get_count(); i++) {
+        pmeth = EVP_PKEY_meth_get0(i);
+        EVP_PKEY_meth_get0_info(&pkey_id, NULL, pmeth);
+        if (pkey_id < prev)
+            good = 0;
+        prev = pkey_id;
+
+    }
+    if (!good) {
+        TEST_error("EVP_PKEY_METHOD table out of order");
+        for (i = 0; i < EVP_PKEY_meth_get_count(); i++) {
+            pmeth = EVP_PKEY_meth_get0(i);
+            EVP_PKEY_meth_get0_info(&pkey_id, NULL, pmeth);
+            TEST_note("%d : %s", pkey_id, OBJ_nid2ln(pkey_id));
+        }
+    }
+    return good;
+}
+
 int setup_tests()
 {
     ADD_TEST(test_asn1_meths);
+    ADD_TEST(test_pkey_meths);
     return 1;
 }