Fix wc_*_delete() functions (ZD 21415)

Save key->heap before calling wc_*_free(), which zeros the entire key
structure via ForceZero. The saved heap pointer is then passed to XFREE
instead of the now-zeroed key->heap.

Author: anhu

wolfcrypt/src/curve25519.c

@@ -1113,10 +1113,12 @@ curve25519_key* wc_curve25519_new(void* heap, int devId, int *result_code)
 }
 
 int wc_curve25519_delete(curve25519_key* key, curve25519_key** key_p) {
+    void* heap;
     if (key == NULL)
         return BAD_FUNC_ARG;
+    heap = key->heap;
     wc_curve25519_free(key);
-    XFREE(key, key->heap, DYNAMIC_TYPE_CURVE25519);
+    XFREE(key, heap, DYNAMIC_TYPE_CURVE25519);
     if (key_p != NULL)
         *key_p = NULL;
     return 0;

wolfcrypt/src/dilithium.c

@@ -10737,10 +10737,12 @@ dilithium_key* wc_dilithium_new(void* heap, int devId)
 
 int wc_dilithium_delete(dilithium_key* key, dilithium_key** key_p)
 {
+    void* heap;
     if (key == NULL)
         return BAD_FUNC_ARG;
+    heap = key->heap;
     wc_dilithium_free(key);
-    XFREE(key, key->heap, DYNAMIC_TYPE_DILITHIUM);
+    XFREE(key, heap, DYNAMIC_TYPE_DILITHIUM);
     if (key_p != NULL)
         *key_p = NULL;
 

wolfcrypt/src/ed25519.c

@@ -1047,10 +1047,12 @@ ed25519_key* wc_ed25519_new(void* heap, int devId, int *result_code)
 }
 
 int wc_ed25519_delete(ed25519_key* key, ed25519_key** key_p) {
+    void* heap;
     if (key == NULL)
         return BAD_FUNC_ARG;
+    heap = key->heap;
     wc_ed25519_free(key);
-    XFREE(key, key->heap, DYNAMIC_TYPE_ED25519);
+    XFREE(key, heap, DYNAMIC_TYPE_ED25519);
     if (key_p != NULL)
         *key_p = NULL;
     return 0;