From: Alexander Couzens <lynxis@fe80.eu>
Date: Sun, 11 Jun 2017 11:01:06 +0000 (+0200)
Subject: uclient-fetch: read_data_cb: fix a potential buffer overflow
X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fuclient.git;a=commitdiff_plain;h=83ce236dab867842cdba88a57db50aae0fd9a4ce

uclient-fetch: read_data_cb: fix a potential buffer overflow

When a backend->read() is not implement or returns -1,
This -1 is interpreted as unsigned int resulting
in an access far behind the buffer.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
---

diff --git a/uclient-fetch.c b/uclient-fetch.c
index d9582f5..dff144b 100644
--- a/uclient-fetch.c
+++ b/uclient-fetch.c
@@ -262,7 +262,7 @@ static void read_data_cb(struct uclient *cl)
 
 	while (1) {
 		len = uclient_read(cl, buf, sizeof(buf));
-		if (!len)
+		if (len <= 0)
 			return;
 
 		out_bytes += len;