Transactions are not allowed in the memory pool or selected for inclusion in a block until their lock times exceed chainActive.Tip()->GetMedianTimePast(). However blocks including transactions which are only mature under the old rules are still accepted; this is *not* the soft-fork required to actually rely on the new constraint in production.
The lock-time code currently uses CBlock::nTime as the cutoff point for time based locked transactions. This has the unfortunate outcome of creating a perverse incentive for miners to lie about the time of a block in order to collect more fees by including transactions that by wall clock determination have not yet matured. By using CBlockIndex::GetMedianTimePast from the prior block instead, the self-interested miner no longer gains from generating blocks with fraudulent timestamps. Users can compensate for this change by simply adding an hour (3600 seconds) to their time-based lock times.
If enforced, this would be a soft-fork change. This commit only adds the functionality on an unexecuted code path, without changing the behaviour of Bitcoin Core.
6af25b0 Add BIP65 to getblockchaininfo softforks list (Peter Todd)
ba1da90 Show softfork status in getblockchaininfo (Wladimir J. van der Laan)
70a427b CLTV: Add more tests to improve coverage (Esteban Ordano)
c5a27f4 Add RPC tests for the CHECKLOCKTIMEVERIFY (BIP65) soft-fork (Peter Todd)
5e82e1c Add CHECKLOCKTIMEVERIFY (BIP65) soft-fork logic (Peter Todd)
6ea5ca4 Enable CHECKLOCKTIMEVERIFY as a standard script verify flag (Peter Todd)
4fa7a04 Replace NOP2 with CHECKLOCKTIMEVERIFY (BIP65) (Peter Todd)
6ec08db Move LOCKTIME_THRESHOLD to src/script/script.h (Peter Todd)
684636b Make CScriptNum() take nMaxNumSize as an argument (Peter Todd)
Nagle appears to be a significant contributor to latency now that the static
sleeps are gone. Most of our messages are relatively large compared to
IP + TCP so I do not expect this to create enormous overhead.
This may also reduce traffic burstyness somewhat.
Conflicts:
src/net.cpp
Rebased-From: a4e28b3d1e5c95eb0c87f144851cd65048c3e0bc
Github-Pull: #6867
This passes `-Wa,--noexecstack` to the assembler when building
platform-specific assembly files, to signal that a non-executable stack
can be used. This is the same approach as used by Debian
(see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=430583)
Rebased-From: bfcdc21a5da25ec1aa4aecc4cd8960dfa1c11781
Github-Pull: #6852
Prevent these warnings in clang 3.6:
./serialize.h:96:9: warning: explicitly assigning value of variable of type 'uint64_t' (aka 'unsigned long') to itself [-Wself-assign]
obj = (obj);
~~~ ^ ~~~
* Raise the debug window when hidden behind other windows
* Switch to the debug window when on another virtual desktop
* Show the debug window when minimized
This change is a conceptual copy of 5ffaaba and 382e9e2
GetTransaction needs to lock cs_main until ReadBlockFromDisk completes, the data inside CBlockIndex's can change since pruning. This lock was held by all calls to GetTransaction except rest_tx.
To bridge the time until a dynamic method for determining this fee is
merged.
This is especially aimed at the stable releases (0.10, 0.11) because
full mempool limiting, as will be in 0.12, is too invasive and risky to
backport.
Github-Pull: #6793
Rebased-From: 28e3249e53b8ef7516636df0f1406466a513095d 4e2efb3c5fde4b1e332cc032e3dc4082ec4e3cac
Common sentiment is that the miniupnpc codebase likely contains further
vulnerabilities.
I'd prefer to get rid of the dependency completely, but a compromise for
now is to at least disable it by default.
Github-Pull: #6795
Rebased-From: 21d27ebad5721bc61c62bc72dc3ab3197f9da268
This version of miniupnpc fixes a buffer overflow in the XML (ugh)
parser during initial network discovery.
http://talosintel.com/reports/TALOS-2015-0035/
The commit fixing the vulnerability is:
79cca974a4
Reported by timothy on IRC.
Github-Pull: 6789
Rebased-From: 0cca0248f030ea32bd8de778b5a2782e0d191978
The main effect is to exit processing for recently-rejected hashes,
in case they are pushed to us without prior advertisement. This
behavior was seen in the wild.
An additional effect is to do early checks for mempool or mapOrphan
existence. No logging or nDoS tracking is needed for failures of
these checks.
Four cases included:
* The CLTV operand type mismatches the tx locktime. In the script it is
1 (interpreted as block height), but in the tx is 500000000
(interpreted as date)
* The stack is empty when executing OP_CLTV
* The tx is final by having only one input with MAX_INT sequence number
* The operand for CLTV is negative (after OP_0 OP_1 OP_SUB)
Rebased-From: cb54d17355864fa08826d6511a0d7692b21ef2c9
bip65-cltv.py is based on the earlier BIP66 soft-fork RPC test
implemented by Pieter Wuille's 819bcf9b99
bip65-cltv-p2p.py is based on the earlier BIP66 P2P test by Suhas
Daftuar's d76412b068
Rebased-From: 308257856099e82e91881ba97f741d840184727c
Transactions that fail CLTV verification will be rejected from the
mempool, making it easy to test the feature. However blocks containing
"invalid" CLTV-using transactions will still be accepted; this is *not*
the soft-fork required to actually enable CLTV for production use.
Rebased-From: ffd75adce01a78b3461b3ff05bcc2b530a9ce994
<nLockTime> CHECKLOCKTIMEVERIFY -> <nLockTime>
Fails if tx.nLockTime < nLockTime, allowing the funds in a txout to be
locked until some block height or block time in the future is reached.
Only the logic and unittests are implemented; this commit does not have
any actual soft-fork logic in it.
Thanks to Pieter Wuille for rebase.
Credit goes to Gregory Maxwell for the suggestion of comparing the
argument against the transaction nLockTime rather than the current
time/blockheight directly.
Rebased-From: bc60b2b4b401f0adff5b8b9678903ff8feb5867b
While the existing numeric opcodes are all limited to 4-byte bignum
arguments, new opcodes will need different limits.
Rebased-From: 99088d60d8a7747c6d1a7fd5d8cd388be1b3e138
This adds SCRIPT_VERIFY_LOW_S to STANDARD_SCRIPT_VERIFY_FLAGS which
will make the node require the canonical 'low-s' encoding for
ECDSA signatures when relaying or mining.
Consensus behavior is unchanged.
The rational is explained in a81cd96805ce6b65cca3a40ebbd3b2eb428abb7b:
Absent this kind of test ECDSA is not a strong signature as given
a valid signature {r, s} both that value and {r, -s mod n} are valid.
These two encodings have different hashes allowing third parties a
vector to change users txids. These attacks are avoided by picking
a particular form as canonical and rejecting the other form(s); in
the of the LOW_S rule, the smaller of the two possible S values is
used.
If widely deployed this change would eliminate the last remaining
known vector for nuisance malleability on boring SIGHASH_ALL
p2pkh transactions. On the down-side it will block most
transactions made by sufficiently out of date software.
Unlike the other avenues to change txids on boring transactions this
one was randomly violated by all deployed bitcoin software prior to
its discovery. So, while other malleability vectors where made
non-standard as soon as they were discovered, this one has remained
permitted. Even BIP62 did not propose applying this rule to
old version transactions, but conforming implementations have become
much more common since BIP62 was initially written.
Bitcoin Core has produced compatible signatures since a28fb70e in
September 2013, but this didn't make it into a release until 0.9
in March 2014; Bitcoinj has done so for a similar span of time.
Bitcoinjs and electrum have been more recently updated.
This does not replace the need for BIP62 or similar, as miners can
still cooperate to break transactions. Nor does it replace the
need for wallet software to handle malleability sanely[1]. This
only eliminates the cheap and irritating DOS attack.
[1] On the Malleability of Bitcoin Transactions
Marcin Andrychowicz, Stefan Dziembowski, Daniel Malinowski, Łukasz Mazurek
http://fc15.ifca.ai/preproceedings/bitcoin/paper_9.pdf
Rebased-From: b196b685c9089b74fd4ff3d9a28ea847ab36179b
Github-Pull: #6769
5094a81 Move recentRejects initialization to top of InitBlockIndex (Wladimir J. van der Laan)
ec9b6c3 Keep track of recently rejected transactions (Peter Todd)
6eed52e Only use randomly created nonces in CRollingBloomFilter. (Pieter Wuille)
83671ef Make CRollingBloomFilter set nTweak for you (Peter Todd)
25cf122 Reuse vector hashing code for uint256 (Pieter Wuille)
2983fe0 Add uint256 support to CRollingBloomFilter (Peter Todd)
Wladimir J. van der Laan
Pieter Wuille
Mark Friedenbach
Alex Morcos
Gregory Maxwell
Daniel Cousens
Matt Corallo
Mitchell Cash
Micha
Eric Lombrozo
Chris Kleeschulte
Luke Dashjr
MarcoFalke
Zak Wilcox
Diego Viola
Tom Harding
Peter Todd
Esteban Ordano