EVP & TLS: Add necessary EC_KEY data extraction functions, and use them

libssl code uses EVP_PKEY_get0_EC_KEY() to extract certain basic data
from the EC_KEY.  We replace that with internal EVP_PKEY functions.

This may or may not be refactored later on.
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11358)

Configurations/unix-Makefile.tmpl

@@ -1025,6 +1025,7 @@ errors:
        qw( include/internal/dso.h
            include/internal/o_dir.h
            include/internal/err.h
+           include/internal/evp.h
            include/internal/sslconf.h );
    our @cryptoskipheaders = ( @sslheaders,
        qw( include/openssl/conf_api.h

crypto/evp/p_lib.c

@@ -33,6 +33,7 @@
 
 #include "crypto/asn1.h"
 #include "crypto/evp.h"
+#include "internal/evp.h"
 #include "internal/provider.h"
 #include "evp_local.h"
 
@@ -810,6 +811,48 @@ int EVP_PKEY_can_sign(const EVP_PKEY *pkey)
     return 0;
 }
 
+#ifndef OPENSSL_NO_EC
+/*
+ * TODO rewrite when we have proper data extraction functions
+ * Note: an octet pointer would be desirable!
+ */
+static OSSL_CALLBACK get_ec_curve_name_cb;
+static int get_ec_curve_name_cb(const OSSL_PARAM params[], void *arg)
+{
+    const OSSL_PARAM *p = NULL;
+
+    if ((p = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_EC_NAME)) != NULL)
+        return OSSL_PARAM_get_utf8_string(p, arg, 0);
+
+    /* If there is no curve name, this is not an EC key */
+    return 0;
+}
+
+int evp_pkey_get_EC_KEY_curve_nid(const EVP_PKEY *pkey)
+{
+    int ret = NID_undef;
+
+    if (pkey->keymgmt == NULL) {
+        if (EVP_PKEY_base_id(pkey) == EVP_PKEY_EC) {
+            EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
+
+            ret = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
+        }
+    } else if (EVP_PKEY_is_a(pkey, "EC") || EVP_PKEY_is_a(pkey, "SM2")) {
+        char *curve_name = NULL;
+
+        ret = evp_keymgmt_export(pkey->keymgmt, pkey->keydata,
+                                 OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
+                                 get_ec_curve_name_cb, &curve_name);
+        if (ret)
+            ret = ec_curve_name2nid(curve_name);
+        OPENSSL_free(curve_name);
+    }
+
+    return ret;
+}
+#endif
+
 static int print_reset_indent(BIO **out, int pop_f_prefix, long saved_indent)
 {
     BIO_set_indent(*out, saved_indent);

include/internal/evp.h

+/*
+ * 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
+ */
+
+#ifndef OSSL_INTERNAL_EVP_H
+# define OSSL_INTERNAL_EVP_H
+
+# include <openssl/evp.h>
+
+# ifndef OPENSSL_NO_EC
+/*
+ * TODO(3.0) While waiting for more generic getters, we have these functions
+ * as an interim solution.  This should be removed when the generic getters
+ * appear.
+ */
+int evp_pkey_get_EC_KEY_curve_nid(const EVP_PKEY *pkey);
+# endif
+#endif

include/openssl/evp.h

@@ -1111,6 +1111,7 @@ int EVP_PKEY_base_id(const EVP_PKEY *pkey);
 int EVP_PKEY_bits(const EVP_PKEY *pkey);
 int EVP_PKEY_security_bits(const EVP_PKEY *pkey);
 int EVP_PKEY_size(const EVP_PKEY *pkey);
+int EVP_PKEY_can_sign(const EVP_PKEY *pkey);
 int EVP_PKEY_set_type(EVP_PKEY *pkey, int type);
 int EVP_PKEY_set_type_str(EVP_PKEY *pkey, const char *str, int len);
 int EVP_PKEY_set_type_by_keymgmt(EVP_PKEY *pkey, EVP_KEYMGMT *keymgmt);

ssl/ssl_rsa.c

@@ -338,7 +338,7 @@ static int ssl_set_cert(CERT *c, X509 *x)
         return 0;
     }
 #ifndef OPENSSL_NO_EC
-    if (i == SSL_PKEY_ECC && !EC_KEY_can_sign(EVP_PKEY_get0_EC_KEY(pkey))) {
+    if (i == SSL_PKEY_ECC && !EVP_PKEY_can_sign(pkey)) {
         SSLerr(SSL_F_SSL_SET_CERT, SSL_R_ECC_CERT_NOT_FOR_SIGNING);
         return 0;
     }

ssl/statem/statem_lib.c

@@ -14,6 +14,7 @@
 #include "../ssl_local.h"
 #include "statem_local.h"
 #include "internal/cryptlib.h"
+#include "internal/evp.h"
 #include <openssl/buffer.h>
 #include <openssl/objects.h>
 #include <openssl/evp.h>
@@ -1531,7 +1532,6 @@ static int is_tls13_capable(const SSL *s)
     int i;
 #ifndef OPENSSL_NO_EC
     int curve;
-    EC_KEY *eckey;
 #endif
 
 #ifndef OPENSSL_NO_PSK
@@ -1563,10 +1563,8 @@ static int is_tls13_capable(const SSL *s)
          * more restrictive so check that our sig algs are consistent with this
          * EC cert. See section 4.2.3 of RFC8446.
          */
-        eckey = EVP_PKEY_get0_EC_KEY(s->cert->pkeys[SSL_PKEY_ECC].privatekey);
-        if (eckey == NULL)
-            continue;
-        curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(eckey));
+        curve = evp_pkey_get_EC_KEY_curve_nid(s->cert->pkeys[SSL_PKEY_ECC]
+                                              .privatekey);
         if (tls_check_sigalg_curve(s, curve))
             return 1;
 #else

ssl/t1_lib.c

@@ -22,6 +22,7 @@
 #include <openssl/dh.h>
 #include <openssl/bn.h>
 #include "internal/nelem.h"
+#include "internal/evp.h"
 #include "ssl_local.h"
 #include <openssl/ct.h>
 
@@ -583,7 +584,7 @@ static int tls1_check_pkey_comp(SSL *s, EVP_PKEY *pkey)
     size_t i;
 
     /* If not an EC key nothing to check */
-    if (EVP_PKEY_id(pkey) != EVP_PKEY_EC)
+    if (!EVP_PKEY_is_a(pkey, "EC"))
         return 1;
     ec = EVP_PKEY_get0_EC_KEY(pkey);
     grp = EC_KEY_get0_group(ec);
@@ -624,13 +625,11 @@ static int tls1_check_pkey_comp(SSL *s, EVP_PKEY *pkey)
 /* Return group id of a key */
 static uint16_t tls1_get_group_id(EVP_PKEY *pkey)
 {
-    EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
-    const EC_GROUP *grp;
+    int curve_nid = evp_pkey_get_EC_KEY_curve_nid(pkey);
 
-    if (ec == NULL)
+    if (curve_nid == NID_undef)
         return 0;
-    grp = EC_KEY_get0_group(ec);
-    return tls1_nid2group_id(EC_GROUP_get_curve_name(grp));
+    return tls1_nid2group_id(curve_nid);
 }
 
 /*
@@ -645,7 +644,7 @@ static int tls1_check_cert_param(SSL *s, X509 *x, int check_ee_md)
     if (pkey == NULL)
         return 0;
     /* If not EC nothing to do */
-    if (EVP_PKEY_id(pkey) != EVP_PKEY_EC)
+    if (!EVP_PKEY_is_a(pkey, "EC"))
         return 1;
     /* Check compression */
     if (!tls1_check_pkey_comp(s, pkey))
@@ -1111,10 +1110,22 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
     const EVP_MD *md = NULL;
     char sigalgstr[2];
     size_t sent_sigslen, i, cidx;
-    int pkeyid = EVP_PKEY_id(pkey);
+    int pkeyid = -1;
     const SIGALG_LOOKUP *lu;
     int secbits = 0;
 
+    /*
+     * TODO(3.0) Remove this when we adapted this function for provider
+     * side keys.  We know that EVP_PKEY_get0() downgrades an EVP_PKEY
+     * to contain a legacy key.
+     *
+     * THIS IS TEMPORARY
+     */
+    EVP_PKEY_get0(pkey);
+    if (EVP_PKEY_id(pkey) == EVP_PKEY_NONE)
+        return 0;
+
+    pkeyid = EVP_PKEY_id(pkey);
     /* Should never happen */
     if (pkeyid == -1)
         return -1;
@@ -1163,8 +1174,7 @@ int tls12_check_peer_sigalg(SSL *s, uint16_t sig, EVP_PKEY *pkey)
 
         /* For TLS 1.3 or Suite B check curve matches signature algorithm */
         if (SSL_IS_TLS13(s) || tls1_suiteb(s)) {
-            EC_KEY *ec = EVP_PKEY_get0_EC_KEY(pkey);
-            int curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
+            int curve = evp_pkey_get_EC_KEY_curve_nid(pkey);
 
             if (lu->curve != NID_undef && curve != lu->curve) {
                 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER,
@@ -2449,17 +2459,14 @@ int tls1_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain,
     if (!s->server && strict_mode) {
         STACK_OF(X509_NAME) *ca_dn;
         int check_type = 0;
-        switch (EVP_PKEY_id(pk)) {
-        case EVP_PKEY_RSA:
+
+        if (EVP_PKEY_is_a(pk, "RSA"))
             check_type = TLS_CT_RSA_SIGN;
-            break;
-        case EVP_PKEY_DSA:
+        else if (EVP_PKEY_is_a(pk, "DSA"))
             check_type = TLS_CT_DSS_SIGN;
-            break;
-        case EVP_PKEY_EC:
+        else if (EVP_PKEY_is_a(pk, "EC"))
             check_type = TLS_CT_ECDSA_SIGN;
-            break;
-        }
+
         if (check_type) {
             const uint8_t *ctypes = s->s3.tmp.ctype;
             size_t j;
@@ -2820,10 +2827,8 @@ static const SIGALG_LOOKUP *find_sig_alg(SSL *s, X509 *x, EVP_PKEY *pkey)
 
         if (lu->sig == EVP_PKEY_EC) {
 #ifndef OPENSSL_NO_EC
-            if (curve == -1) {
-                EC_KEY *ec = EVP_PKEY_get0_EC_KEY(tmppkey);
-                curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
-            }
+            if (curve == -1)
+                curve = evp_pkey_get_EC_KEY_curve_nid(tmppkey);
             if (lu->curve != NID_undef && curve != lu->curve)
                 continue;
 #else
@@ -2882,15 +2887,13 @@ int tls_choose_sigalg(SSL *s, int fatalerrs)
             size_t i;
             if (s->s3.tmp.peer_sigalgs != NULL) {
 #ifndef OPENSSL_NO_EC
-                int curve;
+                int curve = -1;
 
                 /* For Suite B need to match signature algorithm to curve */
-                if (tls1_suiteb(s)) {
-                    EC_KEY *ec = EVP_PKEY_get0_EC_KEY(s->cert->pkeys[SSL_PKEY_ECC].privatekey);
-                    curve = EC_GROUP_get_curve_name(EC_KEY_get0_group(ec));
-                } else {
-                    curve = -1;
-                }
+                if (tls1_suiteb(s))
+                    curve =
+                        evp_pkey_get_EC_KEY_curve_nid(s->cert->pkeys[SSL_PKEY_ECC]
+                                                      .privatekey);
 #endif
 
                 /*

util/libcrypto.num

@@ -5039,3 +5039,4 @@ EVP_PKEY_get_utf8_string_param          ?	3_0_0	EXIST::FUNCTION:
 EVP_PKEY_get_octet_string_param         ?	3_0_0	EXIST::FUNCTION:
 EVP_PKEY_is_a                           ?	3_0_0	EXIST::FUNCTION:
 EVP_PKEY_can_sign                       ?	3_0_0	EXIST::FUNCTION:
+evp_pkey_get_EC_KEY_curve_nid           ?	3_0_0	EXIST::FUNCTION:EC

util/missingcrypto.txt

@@ -1558,6 +1558,8 @@ conf_ssl_name_find(3)
 d2i_X509_bio(3)
 d2i_X509_fp(3)
 err_free_strings_int(3)
+# The following is internal but exported by libcrypto
+evp_pkey_get_EC_KEY_curve_nid(3)
 i2a_ACCESS_DESCRIPTION(3)
 i2a_ASN1_ENUMERATED(3)
 i2a_ASN1_INTEGER(3)