Merge bitcoin/bitcoin#24804: Sanity assert GetAncestor() != nullptr where appropriate

308dd2e93e Sanity assert GetAncestor() != nullptr where appropriate (Adam Jonas)

Pull request description:

  Re-opening #17232. I have rebased the PR and addressed jonatack's nit suggestions.

  Add sanity asserts for return value of `CBlockIndex::GetAncestor()` where appropriate.

  In validation.cpp `CheckSequenceLocks`, check the return value of `tip->GetAncestor(maxInputHeight)` stored into `lp->maxInputBlock`. If it ever returns `nullptr` because the ancestor isn't found, it's going to be a bad bug to keep going, since a `LockPoints` object with the `maxInputBlock` member set to `nullptr` signifies no relative lock time.

  In the other places, the added asserts would prevent accidental dereferencing of a null pointer which is undefined behavior.

  Co-Authored-By: Adam Jonas <jonas@chaincode.com>
  Co-Authored-By: danra <danra@users.noreply.github.com>

ACKs for top commit:
  jonatack:
    ACK 308dd2e93e

Tree-SHA512: 5bfdaab1499607ae2c3cd3e2e9e8c37850bfd0e327e680f4e36c81f9c6d98a543af78ecfac1ab0e06325d264412615a04d52005875780c7db2a4d81bd2d2259a
This commit is contained in:
MacroFake
2022-05-06 11:46:10 +02:00
5 changed files with 39 additions and 28 deletions

View File

@@ -250,7 +250,12 @@ bool CheckSequenceLocksAtTip(CBlockIndex* tip,
maxInputHeight = std::max(maxInputHeight, height);
}
}
lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
// tip->GetAncestor(maxInputHeight) should never return a nullptr
// because maxInputHeight is always less than the tip height.
// It would, however, be a bad bug to continue execution, since a
// LockPoints object with the maxInputBlock member set to nullptr
// signifies no relative lock time.
lp->maxInputBlock = Assert(tip->GetAncestor(maxInputHeight));
}
}
return EvaluateSequenceLocks(index, lockPair);
@@ -4108,10 +4113,11 @@ bool CChainState::ReplayBlocks()
// Roll forward from the forking point to the new tip.
int nForkHeight = pindexFork ? pindexFork->nHeight : 0;
for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight; ++nHeight) {
const CBlockIndex* pindex = pindexNew->GetAncestor(nHeight);
LogPrintf("Rolling forward %s (%i)\n", pindex->GetBlockHash().ToString(), nHeight);
const CBlockIndex& pindex{*Assert(pindexNew->GetAncestor(nHeight))};
LogPrintf("Rolling forward %s (%i)\n", pindex.GetBlockHash().ToString(), nHeight);
uiInterface.ShowProgress(_("Replaying blocks…").translated, (int) ((nHeight - nForkHeight) * 100.0 / (pindexNew->nHeight - nForkHeight)) , false);
if (!RollforwardBlock(pindex, cache)) return false;
if (!RollforwardBlock(&pindex, cache)) return false;
}
cache.SetBestBlock(pindexNew->GetBlockHash());