[net/net processing] check banman pointer before dereferencing

Although we currently don't do this, it should be possible to create a
CConnman or PeerLogicValidation without a Banman instance. Therefore
always check that banman exists before dereferencing the pointer.

Also add comments to the m_banman members of CConnman and
PeerLogicValidation to document that these may be nullptr.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/net.h b/src/net.h
index 6673e02d68..b240e52a18 100644
--- a/src/net.h
+++ b/src/net.h
@@ -447,6 +447,7 @@ private:
     std::atomic<int> nBestHeight;
     CClientUIInterface* clientInterface;
     NetEventsInterface* m_msgproc;
+    /** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */
     BanMan* m_banman;
 
     /** SipHasher seeds for deterministic randomness */