From ea9c030249cb3db7a923c8e546df9897e0a39384 Mon Sep 17 00:00:00 2001
From: Saagar Jha <saagar@saagarjha.com>
Date: Mon, 10 Apr 2023 01:34:48 -0700
Subject: [PATCH] Fix heap overflow from curl-originating buffers

Most of xs.h seems to expect that buffers are rounded up to block size,
so we should preserve that invariant here. (In particular, xs_expand
will avoid calling xs_realloc if the new size fits in the same block,
which means that if we don't pad out the data it will expand out of the
memory we're allocated.)
---
 xs_curl.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xs_curl.h b/xs_curl.h
index e880a0d..ca90f92 100644
--- a/xs_curl.h
+++ b/xs_curl.h
@@ -55,7 +55,7 @@ static int _data_callback(void *buffer, size_t size,
 
     /* open space */
     pd->size += sz;
-    pd->data = xs_realloc(pd->data, pd->size + 1);
+    pd->data = xs_realloc(pd->data, _xs_blk_size(pd->size + 1));
 
     /* copy data */
     memcpy(pd->data + pd->offset, buffer, sz);