From: Nikita Popov <nikita.ppv@gmail.com>
Date: Wed, 19 Jun 2019 12:04:54 +0000 (+0200)
Subject: Avoid memcpy UB in streams
X-Git-Tag: php-7.4.0alpha2~51^2~14
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f26e77b05fe14e580e982c75887314b7fae7b777;p=php

Avoid memcpy UB in streams
---

diff --git a/main/streams/streams.c b/main/streams/streams.c
index f1ff923dee..08b8e62014 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -586,7 +586,9 @@ PHPAPI void _php_stream_fill_read_buffer(php_stream *stream, size_t size)
 							stream->readbuf = perealloc(stream->readbuf, stream->readbuflen,
 									stream->is_persistent);
 						}
-						memcpy(stream->readbuf + stream->writepos, bucket->buf, bucket->buflen);
+						if (bucket->buflen) {
+							memcpy(stream->readbuf + stream->writepos, bucket->buf, bucket->buflen);
+						}
 						stream->writepos += bucket->buflen;
 
 						php_stream_bucket_unlink(bucket);