Truncate PKCS11 store when opening in write mode

+ Its unit test.

src/pkcs11_store.c

@@ -427,8 +427,11 @@ int wolfPKCS11_Store_Open(int type, CK_ULONG id1, CK_ULONG id2, int read,
     /* Set the 'readonly' flag in this handle if open with 'r' */
     if (read)
         handle->flags |= STORE_FLAGS_READONLY;
-    else
+    else {
         handle->flags &= ~STORE_FLAGS_READONLY;
+        /* Truncate the slot when opening in write mode */
+        update_store_size(handle->hdr, 2 * sizeof(uint32_t));
+    }
 
 
     /* Set start of the buffer after the tok/obj id fields */

tools/unit-tests/unit-pkcs11_store.c

@@ -84,6 +84,7 @@ START_TEST (test_store_and_load_objs) {
     void *store = NULL;
     const char secret1[] = "Everyone gets Friday off.";
     const char secret2[] = "This is just a test string.";
+    const char short_string[] = "Short string";
     char secret_rd[KEYVAULT_OBJ_SIZE];
 
     type = DYNAMIC_TYPE_ECC;
@@ -247,6 +248,26 @@ START_TEST (test_store_and_load_objs) {
     fail_if(ret != KEYVAULT_OBJ_SIZE - 8);
     fail_if(strncmp(dante_filler, secret_rd, KEYVAULT_OBJ_SIZE - 8) != 0);
     wolfPKCS11_Store_Close(store);
+
+    /* Reopen for writing, test truncate */
+    readonly = 0;
+    ret = wolfPKCS11_Store_Open(type, id_tok, id_obj, readonly, &store);
+    fail_unless(ret == 0, "Failed to create vault: %d", ret);
+    fail_if(store == NULL, "Did not receive a store address for vault");
+    fprintf(stderr, "open 3.33 successful\n");
+    ret = wolfPKCS11_Store_Write(store, short_string, strlen(short_string) + 1);
+    wolfPKCS11_Store_Close(store);
+
+    /* Reopen for reading */
+    readonly = 1;
+    ret = wolfPKCS11_Store_Open(type, id_tok, id_obj, readonly, &store);
+    fail_if(ret != 0, "Failed to reopen the vault in read-only mode: %d", ret);
+    /* Read out the content */
+    memset(secret_rd, 0, KEYVAULT_OBJ_SIZE);
+    ret = wolfPKCS11_Store_Read(store, secret_rd, KEYVAULT_OBJ_SIZE);
+    fail_if(ret != strlen(short_string) + 1);
+    fail_if(strcmp(short_string, secret_rd) != 0);
+    wolfPKCS11_Store_Close(store);
 }
 END_TEST