Merge #14696: qa: Add explicit references to related CVE's in p2p_invalid_block test.

0c62e3aa73 New regression testing for CVE-2018-17144, CVE-2012-2459, and CVE-2010-5137. (lucash-dev)
38bfca6bb2 Added comments referencing multiple CVEs in tests and production code. (lucash-dev)

Pull request description:

  This functional test includes two scenarios that test for regressions of vulnerabilities, but they are only briefly described. There are freely available documents explaining in detail the issues, but without explicit mentions, the developer trying to maintain the code needs an additional step of digging in commit history and PR conversations to figure it out.
  Added comments to explicitly mention  CVE-2018-17144 and CVE-2012-2459, for more complete documentation.
  This improves developer experience by making understanding the tests easier.

ACKs for top commit:
  laanwj:
    ACK 0c62e3aa73, checked the CVE numbers, thanks for adding documentation

Tree-SHA512: 3ee05351745193b8b959e4a25d50f25a693b2d24b0732ed53cf7d5882df40b5dd0f1877bd5c69cffb921d4a7acf9deb3cc1160b96dc730d9b5984151ad06b7c9

src/net_processing.cpp

@@ -2559,7 +2559,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
                 }
                 AddOrphanTx(ptx, pfrom->GetId());
 
-                // DoS prevention: do not allow mapOrphanTransactions to grow unbounded
+                // DoS prevention: do not allow mapOrphanTransactions to grow unbounded (see CVE-2012-3789)
                 unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, gArgs.GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
                 unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
                 if (nEvicted > 0) {