Merge #19514: [net/net processing] check banman pointer before dereferencing

ca3585a483ca5f6fc4cc54fd1530f89d13e5b7b0 [net/net processing] check banman pointer before dereferencing (John Newbery)

Pull request description:

  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.

ACKs for top commit:
  jonatack:
    ACK ca3585a
  theStack:
    ACK https://github.com/bitcoin/bitcoin/commit/ca3585a483ca5f6fc4cc54fd1530f89d13e5b7b0

Tree-SHA512: 726401c8921b9a502029ead34ae797473a1bc359d6e4e58dcbe3e25b70dde40bb100723be467fd3e2bf418892c493911998226de19c9d529d72034e3be26be48

1 files changed, 1 insertions, 0 deletions

diff --git a/src/net_processing.h b/src/net_processing.h
index 3479ef6865..fa1555fbe6 100644
--- a/src/net_processing.h
+++ b/src/net_processing.h
@@ -29,6 +29,7 @@ static const int DISCOURAGEMENT_THRESHOLD{100};
 class PeerLogicValidation final : public CValidationInterface, public NetEventsInterface {
 private:
     CConnman* const connman;
+    /** Pointer to this node's banman. May be nullptr - check existence before dereferencing. */
     BanMan* const m_banman;
     ChainstateManager& m_chainman;
     CTxMemPool& m_mempool;