Convert TLS auto DH parameters to use EVP_PKEY

Previously a DH object was constructed and then assigned to an EVP_PKEY.
Instead we now construct the EVP_PKEY directly instead.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13368)

3 files changed, 34 insertions, 26 deletions

diff --git a/ssl/ssl_local.h b/ssl/ssl_local.h
index 5e47320d62..67bb0a8d52 100644
--- a/ssl/ssl_local.h
+++ b/ssl/ssl_local.h
@@ -2693,7 +2693,7 @@ __owur int ssl_validate_ct(SSL *s);
 #  endif
 
 #  ifndef OPENSSL_NO_DH
-__owur DH *ssl_get_auto_dh(SSL *s);
+__owur EVP_PKEY *ssl_get_auto_dh(SSL *s);
 #  endif
 
 __owur int ssl_security_cert(SSL *s, SSL_CTX *ctx, X509 *x, int vfy, int is_ee);
diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index 9d5e73f62c..d45afebf07 100644
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -2460,14 +2460,11 @@ int tls_construct_server_key_exchange(SSL *s, WPACKET *pkt)
         DH *dh;
 
         if (s->cert->dh_tmp_auto) {
-            DH *dhp = ssl_get_auto_dh(s);
-            pkdh = EVP_PKEY_new();
-            if (pkdh == NULL || dhp == NULL) {
-                DH_free(dhp);
+            pkdh = ssl_get_auto_dh(s);
+            if (pkdh == NULL) {
                 SSLfatal(s, SSL_AD_INTERNAL_ERROR, ERR_R_INTERNAL_ERROR);
                 goto err;
             }
-            EVP_PKEY_assign_DH(pkdh, dhp);
             pkdhp = pkdh;
         } else {
             pkdhp = cert->dh_tmp;
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index ff80b81167..9089cb8086 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -19,6 +19,7 @@
 #include <openssl/dh.h>
 #include <openssl/bn.h>
 #include <openssl/provider.h>
+#include <openssl/param_build.h>
 #include "internal/nelem.h"
 #include "internal/evp.h"
 #include "internal/tlsgroups.h"
@@ -2873,12 +2874,15 @@ int SSL_check_chain(SSL *s, X509 *x, EVP_PKEY *pk, STACK_OF(X509) *chain)
     return tls1_check_chain(s, x, pk, chain, -1);
 }
 
-#ifndef OPENSSL_NO_DH
-DH *ssl_get_auto_dh(SSL *s)
+EVP_PKEY *ssl_get_auto_dh(SSL *s)
 {
-    DH *dhp;
-    BIGNUM *p, *g;
+    EVP_PKEY *dhp = NULL;
+    BIGNUM *p;
     int dh_secbits = 80;
+    EVP_PKEY_CTX *pctx = NULL;
+    OSSL_PARAM_BLD *tmpl = NULL;
+    OSSL_PARAM *params = NULL;
+
     if (s->cert->dh_tmp_auto != 2) {
         if (s->s3.tmp.new_cipher->algorithm_auth & (SSL_aNULL | SSL_aPSK)) {
             if (s->s3.tmp.new_cipher->strength_bits == 256)
@@ -2892,15 +2896,6 @@ DH *ssl_get_auto_dh(SSL *s)
         }
     }
 
-    dhp = DH_new();
-    if (dhp == NULL)
-        return NULL;
-    g = BN_new();
-    if (g == NULL || !BN_set_word(g, 2)) {
-        DH_free(dhp);
-        BN_free(g);
-        return NULL;
-    }
     if (dh_secbits >= 192)
         p = BN_get_rfc3526_prime_8192(NULL);
     else if (dh_secbits >= 152)
@@ -2911,15 +2906,31 @@ DH *ssl_get_auto_dh(SSL *s)
         p = BN_get_rfc3526_prime_2048(NULL);
     else
         p = BN_get_rfc2409_prime_1024(NULL);
-    if (p == NULL || !DH_set0_pqg(dhp, p, NULL, g)) {
-        DH_free(dhp);
-        BN_free(p);
-        BN_free(g);
-        return NULL;
-    }
+    if (p == NULL)
+        goto err;
+
+    pctx = EVP_PKEY_CTX_new_from_name(s->ctx->libctx, "DH", s->ctx->propq);
+    if (pctx == NULL
+            || EVP_PKEY_key_fromdata_init(pctx) != 1)
+        goto err;
+
+    tmpl = OSSL_PARAM_BLD_new();
+    if (tmpl == NULL
+            || !OSSL_PARAM_BLD_push_BN(tmpl, OSSL_PKEY_PARAM_FFC_P, p)
+            || !OSSL_PARAM_BLD_push_uint(tmpl, OSSL_PKEY_PARAM_FFC_G, 2))
+        goto err;
+
+    params = OSSL_PARAM_BLD_to_param(tmpl);
+    if (params == NULL || EVP_PKEY_fromdata(pctx, &dhp, params) != 1)
+        goto err;
+
+err:
+    OSSL_PARAM_BLD_free_params(params);
+    OSSL_PARAM_BLD_free(tmpl);
+    EVP_PKEY_CTX_free(pctx);
+    BN_free(p);
     return dhp;
 }
-#endif
 
 static int ssl_security_cert_key(SSL *s, SSL_CTX *ctx, X509 *x, int op)
 {