The length of vectors, maps, sets, etc are serialized using
Write/ReadCompactSize -- which, unfortunately, do not use a
unique encoding.
So deserializing and then re-serializing a transaction (for example)
can give you different bits than you started with. That doesn't
cause any problems that we are aware of, but it is exactly the type
of subtle mismatch that can lead to exploits.
With this pull, reading a non-canonical CompactSize throws an
exception, which means nodes will ignore 'tx' or 'block' or
other messages that are not properly encoded.
Please check my logic... but this change is safe with respect to
causing a network split. Old clients that receive
non-canonically-encoded transactions or blocks deserialize
them into CTransaction/CBlock structures in memory, and then
re-serialize them before relaying them to peers.
And please check my logic with respect to causing a blockchain
split: there are no CompactSize fields in the block header, so
the block hash is always canonical. The merkle root in the block
header is computed on a vector<CTransaction>, so
any non-canonical encoding of the transactions in 'tx' or 'block'
messages is erased as they are read into memory by old clients,
and does not affect the block hash. And, as noted above, old
clients re-serialize (with canonical encoding) 'tx' and 'block'
messages before relaying to peers.
Orphan transactions were stored as a CDataStream pointer;
this changes the mapOrphanTransactions data structures to
store orphans as a CTransaction.
This also fixes CVE-2013-4627 by always re-serializing
transactions before relaying them.
The new class is accessed via the Params() method and holds
most things that vary between main, test and regtest networks.
The regtest mode has two purposes, one is to run the
bitcoind/bitcoinj comparison tool which compares two separate
implementations of the Bitcoin protocol looking for divergence.
The other is that when run, you get a local node which can mine
a single block instantly, which is highly convenient for testing
apps during development as there's no need to wait 10 minutes for
a block on the testnet.
This (nearly) doesn't change fee rules at all:
* To make it into the fee transaction area, the dPriority comparison
changed from < to <=
* We now just ignore transactions > MAX_BLOCK_SIZE/4 instead of
doing some calculations to require increasingly large fees as
size increases.
Removed AreInputsStandard from CTransaction, made it a regular function in main.
Moved CTransaction::GetOutputFor to CCoinsViewCache.
Moved GetLegacySigOpCount and GetP2SHSigOpCount out of CTransaction into regular functions in main.
Moved GetValueIn and HaveInputs from CTransaction into CCoinsViewCache.
Moved AllowFree, ClientCheckInputs, CheckInputs, UpdateCoins, and CheckTransaction out of CTransaction and into main.
Moved IsStandard and IsFinal out of CTransaction and put them in main as IsStandardTx and IsFinalTx. Moved GetValueOut out of CTransaction into main. Moved CTxIn, CTxOut, and CTransaction into core.
Added minimum fee parameter to CTxOut::IsDust() temporarily until CTransaction is moved to core.h so that CTxOut needn't know about CTransaction.
- explicitly set the default of all GetBoolArg() calls
- rework getarg_test.cpp and util_tests.cpp to cover this change
- some indentation fixes
- move macdockiconhandler.h include in bitcoin.cpp to the "our headers"
section
Write bestblock records in wallets:
* Every 20160 blocks synced, no matter what (before: none during IBD)
* Every 144 blocks after IBD (before: for every block, slow)
* When creating a new wallet
* At shutdown
This should result in far fewer spurious rescans.
Remove the pnext pointer in CBlockIndex, and replace it with a
vBlockIndexByHeight vector (no effect on memory usage). pnext can
now be replaced by vBlockIndexByHeight[nHeight+1], but
FindBlockByHeight becomes constant-time.
This also means the entire mapBlockIndex structure and the block
index entries in it become purely blocktree-related data, and
independent from the currently active chain, potentially allowing
them to be protected by separate mutexes in the future.
Every block index entry currently requires a separately-allocated
CBigNum. By replacing them with uint256, it's just 32 bytes extra
in CBlockIndex itself.
This should save us a few megabytes in RAM, and less allocation
overhead.
This introduces the concept of the 'sync node', which is the one we
asked for missing blocks. In case the sync node goes away, a new one
will be selected.
For now, the heuristic is very simple, but it can easily be extended
later to add better policies.
Cozz Lovan