add DH_up_ref() and unit test

src/ssl.c

@@ -33996,6 +33996,17 @@ WOLFSSL_DH* wolfSSL_DH_new(void)
     }
 
     InitwolfSSL_DH(external);
+
+    external->refCount = 1;
+#ifndef SINGLE_THREADED
+    if (wc_InitMutex(&external->refMutex) != 0) {
+        WOLFSSL_MSG("wc_InitMutex WOLFSSL_DH failure");
+        XFREE(key, NULL, DYNAMIC_TYPE_DH);
+        XFREE(external, NULL, DYNAMIC_TYPE_DH);
+        return NULL;
+    }
+#endif
+
     if (wc_InitDhKey(key) != 0) {
         WOLFSSL_MSG("wolfSSL_DH_new InitDhKey failure");
         XFREE(key, NULL, DYNAMIC_TYPE_DH);
@@ -34011,9 +34022,30 @@ WOLFSSL_DH* wolfSSL_DH_new(void)
 
 void wolfSSL_DH_free(WOLFSSL_DH* dh)
 {
+    int doFree = 0;
+
     WOLFSSL_ENTER("wolfSSL_DH_free");
 
     if (dh) {
+
+    #ifndef SINGLE_THREADED
+        if (wc_LockMutex(&dh->refMutex) != 0) {
+            WOLFSSL_MSG("Could not lock DH mutex");
+        }
+    #endif
+        /* only free if all references to it are done */
+        dh->refCount--;
+        if (dh->refCount == 0) {
+            doFree = 1;
+        }
+    #ifndef SINGLE_THREADED
+        wc_UnLockMutex(&dh->refMutex);
+    #endif
+
+        if (doFree == 0) {
+            return;
+        }
+
         if (dh->internal) {
             wc_FreeDhKey((DhKey*)dh->internal);
             XFREE(dh->internal, NULL, DYNAMIC_TYPE_DH);
@@ -34030,6 +34062,26 @@ void wolfSSL_DH_free(WOLFSSL_DH* dh)
     }
 }
 
+int wolfSSL_DH_up_ref(WOLFSSL_DH* dh)
+{
+    WOLFSSL_ENTER("wolfSSL_DH_up_ref");
+
+    if (dh) {
+    #ifndef SINGLE_THREADED
+        if (wc_LockMutex(&dh->refMutex) != 0) {
+            WOLFSSL_MSG("Failed to lock DH mutex");
+        }
+    #endif
+        dh->refCount++;
+    #ifndef SINGLE_THREADED
+        wc_UnLockMutex(&dh->refMutex);
+    #endif
+        return WOLFSSL_SUCCESS;
+    }
+
+    return WOLFSSL_FAILURE;
+}
+
 int SetDhInternal(WOLFSSL_DH* dh)
 {
     int            ret = WOLFSSL_FATAL_ERROR;

tests/api.c

@@ -51442,6 +51442,15 @@ static void test_wolfSSL_DH(void)
     AssertPtrEq(q, NULL);
     AssertPtrEq(g, NULL);
     DH_free(dh);
+
+    /* Test DH_up_ref() */
+    dh = wolfSSL_DH_new();
+    AssertNotNull(dh);
+    AssertIntEQ(wolfSSL_DH_up_ref(NULL), WOLFSSL_FAILURE);
+    AssertIntEQ(wolfSSL_DH_up_ref(dh), WOLFSSL_SUCCESS);
+    DH_free(dh); /* decrease ref count */
+    DH_free(dh); /* free WOLFSSL_DH */
+
     printf(resultFmt, passed);
 #endif /* OPENSSL_EXTRA && !NO_DH */
 }

wolfssl/openssl/dh.h

@@ -41,15 +41,19 @@ struct WOLFSSL_DH {
     WOLFSSL_BIGNUM* p;
     WOLFSSL_BIGNUM* g;
     WOLFSSL_BIGNUM* q;
-    WOLFSSL_BIGNUM* pub_key;      /* openssh deference g^x */
-    WOLFSSL_BIGNUM* priv_key;     /* openssh deference x   */
+    WOLFSSL_BIGNUM* pub_key;     /* openssh deference g^x */
+    WOLFSSL_BIGNUM* priv_key;    /* openssh deference x   */
     void*          internal;     /* our DH */
     char           inSet;        /* internal set from external ? */
     char           exSet;        /* external set from internal ? */
     /*added for lighttpd openssl compatibility, go back and add a getter in
      * lighttpd src code.
      */
-     int length;
+    int length;
+#ifndef SINGLE_THREADED
+    wolfSSL_Mutex refMutex;      /* ref count mutex */
+#endif
+    int refCount;                /* reference count */
 };
 
 WOLFSSL_API WOLFSSL_DH *wolfSSL_d2i_DHparams(WOLFSSL_DH **dh,
@@ -58,6 +62,7 @@ WOLFSSL_API int wolfSSL_i2d_DHparams(const WOLFSSL_DH *dh, unsigned char **out);
 WOLFSSL_API WOLFSSL_DH* wolfSSL_DH_new(void);
 WOLFSSL_API void        wolfSSL_DH_free(WOLFSSL_DH* dh);
 WOLFSSL_API WOLFSSL_DH* wolfSSL_DH_dup(WOLFSSL_DH* dh);
+WOLFSSL_API int         wolfSSL_DH_up_ref(WOLFSSL_DH* dh);
 
 WOLFSSL_API int wolfSSL_DH_check(const WOLFSSL_DH *dh, int *codes);
 WOLFSSL_API int wolfSSL_DH_size(WOLFSSL_DH* dh);
@@ -72,13 +77,13 @@ WOLFSSL_API int wolfSSL_DH_set0_pqg(WOLFSSL_DH *dh, WOLFSSL_BIGNUM *p,
 
 WOLFSSL_API WOLFSSL_DH* wolfSSL_DH_get_2048_256(void);
 
-
 #if defined(OPENSSL_EXTRA) || defined(OPENSSL_EXTRA_X509_SMALL)
 
 typedef WOLFSSL_DH                   DH;
 
-#define DH_new  wolfSSL_DH_new
-#define DH_free wolfSSL_DH_free
+#define DH_new    wolfSSL_DH_new
+#define DH_free   wolfSSL_DH_free
+#define DH_up_ref wolfSSL_DH_up_ref
 
 #define d2i_DHparams    wolfSSL_d2i_DHparams
 #define i2d_DHparams    wolfSSL_i2d_DHparams