From f70a407611d11c7214b1f4a5b524148cc38c8a73 Mon Sep 17 00:00:00 2001
From: "Sergio R. Caprile" <scaprile@cesanta.com>
Date: Fri, 23 Sep 2022 19:34:36 -0300
Subject: [PATCH] issue #1734, avoid passing null ptr to memmove

---
 src/iobuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/iobuf.c b/src/iobuf.c
index c0084b09..2ffaa912 100644
--- a/src/iobuf.c
+++ b/src/iobuf.c
@@ -28,7 +28,7 @@ int mg_iobuf_resize(struct mg_iobuf *io, size_t new_size) {
     void *p = calloc(1, new_size);
     if (p != NULL) {
       size_t len = new_size < io->len ? new_size : io->len;
-      if (len > 0) memmove(p, io->buf, len);
+      if (len > 0 && io->buf != NULL) memmove(p, io->buf, len);
       zeromem(io->buf, io->size);
       free(io->buf);
       io->buf = (unsigned char *) p;