From f58b6152f37bdfe4829a55b581d693479814eb29 Mon Sep 17 00:00:00 2001
From: Piotr Sarna <sarna@skytechnology.pl>
Date: Fri, 25 Aug 2017 16:33:06 +0200
Subject: [PATCH] Fixed potential stack corruption with sprintf

string representation of _nwid itself could take up 16 bytes,
so 17 is definitely not enough for this format string.
snprintf is used as a panic check for future changes,
so we could get a truncated string instead of stack corruption.
---
 src/VirtualTap.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/VirtualTap.cpp b/src/VirtualTap.cpp
index e38f277..af84bac 100644
--- a/src/VirtualTap.cpp
+++ b/src/VirtualTap.cpp
@@ -97,9 +97,9 @@ namespace ZeroTier {
 	{
 		vtaps.push_back((void*)this);
 		// set interface name
-		char tmp3[17];
+		char tmp3[64];
 		ifindex = devno;
-		sprintf(tmp3, "libzt%d-%lx", devno++, _nwid);
+		snprintf(tmp3, 64, "libzt%d-%lx", devno++, _nwid);
 		_dev = tmp3;
 		DEBUG_INFO("set VirtualTap interface name to: %s", _dev.c_str());
 		_thread = Thread::start(this);