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: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/11358)

3 files changed, 36 insertions, 35 deletions

diff --git a/ssl/ssl_rsa.c b/ssl/ssl_rsa.c
index 3a222e5571..ac9d01a766 100644
--- a/ssl/ssl_rsa.c
+++ b/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;
     }
diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c
index e9cfee027e..71a259e8f0 100644
--- a/ssl/statem/statem_lib.c
+++ b/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
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 624add64a8..beadf28f11 100644
--- a/ssl/t1_lib.c
+++ b/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
 
                 /*