From afbdc96638a769d9bee8579d8b70f54537f5e891 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Fri, 22 Sep 2017 14:24:39 +0200
Subject: file_range: avoid integer overflow when figuring out byte range

When trying to bump the value with one and the value is already at max,
it causes an integer overflow.

Closes #1908
Detected by oss-fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3465

Assisted-by: Max Dymond
---
 lib/file.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'lib')

diff --git a/lib/file.c b/lib/file.c
index 82c576f38..7cfdab19f 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -165,6 +165,9 @@ static CURLcode file_range(struct connectdata *conn)
     else {
       /* X-Y */
       totalsize = to-from;
+      if(totalsize == CURL_OFF_T_MAX)
+        /* this is too big to increase, so bail out */
+        return CURLE_RANGE_ERROR;
       data->req.maxdownload = totalsize + 1; /* include last byte */
       data->state.resume_from = from;
       DEBUGF(infof(data, "RANGE from %" CURL_FORMAT_CURL_OFF_T
-- 
cgit v1.2.3