Re: Bogus locator in getheaders

Thanks for reply. I admit that my C++ is not very good, so I could be missing something or misreading something. However, I can't see what you say in the code.

In primitives\block.h we have

Code:

struct CBlockLocator
{
   std::vector vHave;

   CBlockLocator() {}

   explicit CBlockLocator(const std::vector& vHaveIn) : vHave(vHaveIn) {}

   ADD_SERIALIZE_METHODS;

   template
   inline void SerializationOp(Stream& s, Operation ser_action) {
   int nVersion = s.GetVersion();
   if (!(s.GetType() & SER_GETHASH))
   READWRITE(nVersion);
   READWRITE(vHave);
   }

So it seems there is no filtering on serialization - i.e. it looks like "what comes from network is going directly to the object instance". So if I read it correctly - if I send 100k hashes in locator, this object will be initialized with all of them.

Then in validation.cpp we have

Code:

CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
{
   AssertLockHeld(cs_main);

   // Find the latest block common to locator and chain - we expect that
   // locator.vHave is sorted descending by height.
   for (const uint256& hash : locator.vHave) {
   CBlockIndex* pindex = LookupBlockIndex(hash);
   if (pindex) {
   if (chain.Contains(pindex))
   return pindex;
   if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
   return chain.Tip();
   }
   }
   }
   return chain.Genesis();
}

so that looks to me like we go through all of them and we do lookups and we only have further processing when it is found.

What I don't see then is where this is implemented:

Quote

because the client software doesn't check all the hashes exhaustively