From 6f04264bbba18dd82157e2f5b8384e2f2b0969f2 Mon Sep 17 00:00:00 2001
From: Kaz Wesley <kaz@lambdaverse.org>
Date: Wed, 14 Nov 2018 11:53:27 -0800
Subject: [PATCH] fix uninitialized read when stringifying an addrLocal

Reachable from either place where SetIP is used when our best-guess
addrLocal for a peer is IPv4, but the peer tells us it's reaching us at
an IPv6 address.

In that case, SetIP turns an IPv4 address into an IPv6 address without
setting the scopeId, which is subsequently read in GetSockAddr during
CNetAddr::ToStringIP and passed to getnameinfo. Fix by ensuring every
constructor initializes the scopeId field with something.

Github-Pull: #14728
Rebased-From: b7b36decaf878a8c1dcfdb4a27196c730043474b
---
 src/netaddress.cpp | 1 -
 src/netaddress.h   | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/netaddress.cpp b/src/netaddress.cpp
index 778c2700f95..9c6daefef68 100644
--- a/src/netaddress.cpp
+++ b/src/netaddress.cpp
@@ -17,7 +17,6 @@ static const unsigned char g_internal_prefix[] = { 0xFD, 0x6B, 0x88, 0xC0, 0x87,
 CNetAddr::CNetAddr()
 {
     memset(ip, 0, sizeof(ip));
-    scopeId = 0;
 }
 
 void CNetAddr::SetIP(const CNetAddr& ipIn)
diff --git a/src/netaddress.h b/src/netaddress.h
index cc0e4d4f122..dc55d8b1a8c 100644
--- a/src/netaddress.h
+++ b/src/netaddress.h
@@ -33,7 +33,7 @@ class CNetAddr
 {
     protected:
         unsigned char ip[16]; // in network byte order
-        uint32_t scopeId; // for scoped/link-local ipv6 addresses
+        uint32_t scopeId{0}; // for scoped/link-local ipv6 addresses
 
     public:
         CNetAddr();