Make DH opaque

Move the dh_st structure into an internal header file and provide
relevant accessors for the internal fields.

Reviewed-by: Richard Levitte <levitte@openssl.org>

3 files changed, 50 insertions, 22 deletions

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index fe1cde69e1..5b53b8605d 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -1527,6 +1527,7 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
         PACKET prime, generator, pub_key;
 
         DH *dh;
+        BIGNUM *p, *g, *bnpub_key;
 
         if (!PACKET_get_length_prefixed_2(pkt, &prime)
             || !PACKET_get_length_prefixed_2(pkt, &generator)
@@ -1550,22 +1551,41 @@ MSG_PROCESS_RETURN tls_process_key_exchange(SSL *s, PACKET *pkt)
             goto err;
         }
 
-        if ((dh->p = BN_bin2bn(PACKET_data(&prime),
-                               PACKET_remaining(&prime), NULL)) == NULL
-            || (dh->g = BN_bin2bn(PACKET_data(&generator),
-                                  PACKET_remaining(&generator), NULL)) == NULL
-            || (dh->pub_key =
-                BN_bin2bn(PACKET_data(&pub_key),
-                          PACKET_remaining(&pub_key), NULL)) == NULL) {
+        p = BN_bin2bn(PACKET_data(&prime), PACKET_remaining(&prime), NULL);
+        g = BN_bin2bn(PACKET_data(&generator), PACKET_remaining(&generator),
+                      NULL);
+        bnpub_key = BN_bin2bn(PACKET_data(&pub_key), PACKET_remaining(&pub_key),
+                              NULL);
+        if (p == NULL || g == NULL || bnpub_key == NULL) {
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+            BN_free(p);
+            BN_free(g);
+            BN_free(bnpub_key);
             goto err;
         }
 
-        if (BN_is_zero(dh->p) || BN_is_zero(dh->g) || BN_is_zero(dh->pub_key)) {
+        if (BN_is_zero(p) || BN_is_zero(g) || BN_is_zero(bnpub_key)) {
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_BAD_DH_VALUE);
+            BN_free(p);
+            BN_free(g);
+            BN_free(bnpub_key);
             goto f_err;
         }
 
+        if (!DH_set0_pqg(dh, p, NULL, g)) {
+            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+            BN_free(p);
+            BN_free(g);
+            BN_free(bnpub_key);
+            goto err;
+        }
+
+        if (!DH_set0_key(dh, bnpub_key, NULL)) {
+            SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, ERR_R_BN_LIB);
+            BN_free(bnpub_key);
+            goto err;
+        }
+
         if (!ssl_security(s, SSL_SECOP_TMP_DH, DH_security_bits(dh), 0, dh)) {
             al = SSL_AD_HANDSHAKE_FAILURE;
             SSLerr(SSL_F_TLS_PROCESS_KEY_EXCHANGE, SSL_R_DH_KEY_TOO_SMALL);
@@ -2254,6 +2274,7 @@ psk_err:
 #ifndef OPENSSL_NO_DH
     else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
         DH *dh_clnt = NULL;
+        BIGNUM *pub_key;
         skey = s->s3->peer_tmp;
         if (skey == NULL) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
@@ -2271,9 +2292,10 @@ psk_err:
 
 
         /* send off the data */
-        n = BN_num_bytes(dh_clnt->pub_key);
+        DH_get0_key(dh_clnt, &pub_key, NULL);
+        n = BN_num_bytes(pub_key);
         s2n(n, p);
-        BN_bn2bin(dh_clnt->pub_key, p);
+        BN_bn2bin(pub_key, p);
         n += 2;
         EVP_PKEY_free(ckey);
         ckey = NULL;
diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index 23e790356c..38fa9455ff 100644
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -1772,9 +1772,8 @@ int tls_construct_server_key_exchange(SSL *s)
         EVP_PKEY_free(pkdh);
         pkdh = NULL;
 
-        r[0] = dh->p;
-        r[1] = dh->g;
-        r[2] = dh->pub_key;
+        DH_get0_pqg(dh, &r[0], NULL, &r[1]);
+        DH_get0_key(dh, &r[2], NULL);
     } else
 #endif
 #ifndef OPENSSL_NO_EC
@@ -2301,6 +2300,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         EVP_PKEY *skey = NULL;
         DH *cdh;
         unsigned int i;
+        BIGNUM *pub_key;
 
         if (!PACKET_get_net_2(pkt, &i)) {
             if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
@@ -2343,9 +2343,12 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
             goto err;
         }
         cdh = EVP_PKEY_get0_DH(ckey);
-        cdh->pub_key = BN_bin2bn(data, i, NULL);
-        if (cdh->pub_key == NULL) {
-            SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, SSL_R_BN_LIB);
+        pub_key = BN_bin2bn(data, i, NULL);
+
+        if (pub_key == NULL || !DH_set0_key(cdh, pub_key, NULL)) {
+            SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+            if (pub_key != NULL)
+                BN_free(pub_key);
             goto err;
         }
 
diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 6e7b5edbc4..a4cd23ab39 100644
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -4091,17 +4091,20 @@ DH *ssl_get_auto_dh(SSL *s)
 
     if (dh_secbits >= 128) {
         DH *dhp = DH_new();
+        BIGNUM *p, *g;
         if (dhp == NULL)
             return NULL;
-        dhp->g = BN_new();
-        if (dhp->g != NULL)
-            BN_set_word(dhp->g, 2);
+        g = BN_new();
+        if (g != NULL)
+            BN_set_word(g, 2);
         if (dh_secbits >= 192)
-            dhp->p = get_rfc3526_prime_8192(NULL);
+            p = get_rfc3526_prime_8192(NULL);
         else
-            dhp->p = get_rfc3526_prime_3072(NULL);
-        if (dhp->p == NULL || dhp->g == NULL) {
+            p = get_rfc3526_prime_3072(NULL);
+        if (p == NULL || g == NULL || !DH_set0_pqg(dhp, p, NULL, g)) {
             DH_free(dhp);
+            BN_free(p);
+            BN_free(g);
             return NULL;
         }
         return dhp;