reftable/writer: fix memory leak if write fails

In reftable/writer.c:padded_write(), if w->writer failed, zeroed
allocated in `reftable_calloc` will leak. w->writer could be
`reftable_write_data` in reftable/stack.c, and could fail due to
some write error. Simply add reftable_free(zeroed) will solve this
problem.

In reftable/writer.c:writer_index_hash(), if `reftable_buf_add` failed,
key allocated by `reftable_malloc` will not be insert into `obj_index_tree`
thus leaks. Simple add reftable_free(key) will solve this problem.

Signed-off-by: Lidong Yan <[email protected]>

Author: brandb97

reftable/writer.c

@@ -57,8 +57,10 @@ static int padded_write(struct reftable_writer *w, uint8_t *data, size_t len,
 			return -1;
 
 		n = w->write(w->write_arg, zeroed, w->pending_padding);
-		if (n < 0)
+		if (n < 0) {
+			reftable_free(zeroed);
 			return n;
+		}
 
 		w->pending_padding = 0;
 		reftable_free(zeroed);
@@ -256,8 +258,10 @@ static int writer_index_hash(struct reftable_writer *w, struct reftable_buf *has
 
 		reftable_buf_reset(&key->hash);
 		err = reftable_buf_add(&key->hash, hash->buf, hash->len);
-		if (err < 0)
+		if (err < 0) {
+			reftable_free(key);
 			return err;
+		}
 		tree_insert(&w->obj_index_tree, key,
 			    &obj_index_tree_node_compare);
 	} else {