Merge bitcoin/bitcoin#33007: test: fix ReadTopologicalSet unsigned integer overflow

31c4e77 test: fix ReadTopologicalSet unsigned integer overflow (ismaelsadeeq)

Pull request description:

  This PR is a simple fix for a potential unsigned integer overflow in ReadTopologicalSet.
  We obtain the value of `mask` from fuzz input, which can be the maximum representable value.
  Adding 1 to it would then cause an overflow.

  The fix skips the addition when the read value is already the maximum.

  See bitcoin/bitcoin#30605 (comment) for more context

ACKs for top commit:
  maflcko:
    lgtm ACK 31c4e77

Tree-SHA512: f58d7907f66a0de0ed8d4b1cad6a4971f65925a99f3c030537c21c4d84126b643257c65865242caf7d445b9cbb7a71a1816a9f870ab7520625c4c16cd41979cb

Author: fanquake

src/test/fuzz/cluster_linearize.cpp

@@ -304,7 +304,7 @@ SetType ReadTopologicalSet(const DepGraph<SetType>& depgraph, const SetType& tod
     try {
         reader >> VARINT(mask);
     } catch(const std::ios_base::failure&) {}
-    mask += non_empty;
+    if (mask != uint64_t(-1)) mask += non_empty;
 
     SetType ret;
     for (auto i : todo) {