This makes sure that retransmits by a whitelisted peer also actually
result in a retransmit.
Further, this changes the logic to never relay in case we would assign
a DoS score, as we expect to get DoS banned ourselves as a result.
Adds 127.0.0.1:9050 for the .onion proxy if we can succesfully connect
to the control port.
Natural followup to creating hidden services automatically.
Previously all of these functions could return negative values (for different
readons). Large portions of the codebase currently assume that these
functions return positive values.
Previously peers which implement a protocol version less than NO_BLOOM_VERSION
would not be disconnected for sending a filter command, regardless of the
peerbloomfilter option.
Many node operators do not wish to provide expensive bloom filtering for SPV
clients, previously they had to cherry pick the commit which enabled the
disconnect logic.
The default should remain false until a sufficient percent of SPV clients
have updated.
1) Chainparams: Explicit CChainParams arg for main:
-AcceptBlock
-AcceptBlockHeader
-ActivateBestChain
-ConnectTip
-InitBlockIndex
-LoadExternalBlockFile
-VerifyDB parametric constructor
2) Also pickup more Params()\. in main.cpp
3) Pass nPruneAfterHeight explicitly to new FindFilesToPrune() in main.cpp
The setAskFor duplicate elimination was too eager and removed entries
when we still had no getdata response, allowing the peer to keep
INVing and not responding.
mapAlreadyAskedFor does not keep track of which peer has a request queued for a
particular tx. As a result, a peer can blind a node to a tx indefinitely by
sending many invs for the same tx, and then never replying to getdatas for it.
Each inv received will be placed 2 minutes farther back in mapAlreadyAskedFor,
so a short message containing 10 invs would render that tx unavailable for 20
minutes.
This is fixed by disallowing a peer from having more than one entry for a
particular inv in mapAlreadyAskedFor at a time.
80ae230 Improve log messages for blocks only violations. (Patick Strateman)
08843ed Add relaytxes status to getpeerinfo (Peter Todd)
d8aaa51 Bail early in processing transactions in blocks only mode. (Patick Strateman)
3587f6a Fix relay mechanism for whitelisted peers under blocks only mode. (Patick Strateman)
6531f17 Add mediantime field to getblock and getblockheader (Peter Todd)
7259769 Document new mediantime field in getblockchaininfo (Peter Todd)
c277a63 Clarify nLockTime-by-time comment in CheckFinalTx() (Peter Todd)
748321e Add mediantime field to getblockchaininfo RPC call (Peter Todd)
Previously in blocks only mode all inv messages where type!=MSG_BLOCK would be
rejected without regard for whitelisting or whitelistalwaysrelay.
As such whitelisted peers would never send the transaction (which would be
processed).
Compute the value of inputs that already are in the chain at time of mempool entry and only increase priority due to aging for those inputs. This effectively changes the CTxMemPoolEntry's GetPriority calculation from an upper bound to a lower bound.
It's possible coins with the same hash exist when you create a duplicate coinbase, so previously we were reading from the database to make sure we had the old coins cached so if we were to spend the new ones, the old ones would also be spent. This pull instead just marks the new coins as not fresh if they are from a coinbase, so if they are spent they will be written all the way down to the database anyway overwriting any duplicates.
Previously it would break if you flushed a parent cache while there was a child cache referring to it. This change will allow the flushing of parent caches.
1cf3dd8 Add unit test for UpdateCoins (Alex Morcos)
03c8282 Make CCoinsViewTest behave like CCoinsViewDB (Alex Morcos)
14470f9 ModifyNewCoins saves database lookups (Alex Morcos)
This provides more conservative estimates and reacts more quickly to a backlog.
Unfortunately the unit test for fee estimation depends on the success threshold (and the decay) chosen; also modify the unit test for the new default success thresholds.
These are more useful fee and priority estimation functions. If there is no fee/pri high enough for the target you are aiming for, it will give you the estimate for the lowest target that you can reliably obtain. This is better than defaulting to the minimum. It will also pass back the target for which it returned an answer.
bbf49da Fix comment for blocksonly parameter interactions (Patick Strateman)
6a4982f Fix fRelayTxs comment (Patick Strateman)
59441a0 Display DEFAULT_WHITELISTALWAYSRELAY in help text (Patick Strateman)
71a2683 Use DEFAULT_BLOCKSONLY and DEFAULT_WHITELISTALWAYSRELAY constants (Patick Strateman)
762b13b Add help text for blocksonly and whitelistalwaysrelay (Patick Strateman)
3a96497 Add whitelistalwaysrelay option (Patick Strateman)
420fa81 Do not process tx inv's in blocksonly mode (Patick Strateman)
4044f07 Add blocksonly mode (Patick Strateman)
Useful now that BIP113 is enforced for transactions entering the
mempool. Was previously only (indirectly) available by calling
getblocktemplate, a relatively expensive RPC call.
This continues/fixes #6719.
`event_base_loopbreak` was not doing what I expected it to, at least in
libevent 2.0.21.
What I expected was that it sets a timeout, given that no other pending
events it would exit in N seconds. However, what it does was delay the
event loop exit with 10 seconds, even if nothing is pending.
Solve it in a different way: give the event loop thread time to exit
out of itself, and if it doesn't, send loopbreak.
This speeds up the RPC tests a lot, each exit incurred a 10 second
overhead, with this change there should be no shutdown overhead in the
common case and up to two seconds if the event loop is blocking.
As a bonus this breaks dependency on boost::thread_group, as the HTTP
server minds its own offspring.
2bfb82b Merge pull request #351
06aeea5 Turn secp256k1_ec_pubkey_serialize outlen to in/out
970164d Merge pull request #348
6466625 Improvements for coordinate decompression
e2100ad Merge pull request #347
8e48787 Change secp256k1_ec_pubkey_combine's count argument to size_t.
c69dea0 Clear output in more cases for pubkey_combine, adds tests.
269d422 Comment copyediting.
b4d17da Merge pull request #344
4709265 Merge pull request #345
26abce7 Adds 32 static test vectors for scalar mul, sqr, inv.
5b71a3f Better error case handling for pubkey_create & pubkey_serialize, more tests.
3b7bc69 Merge pull request #343
eed87af Change contrib/laxder from headers-only to files compilable as standalone C
d7eb1ae Merge pull request #342
7914a6e Make lax_der_privatekey_parsing.h not depend on internal code
73f64ff Merge pull request #339
9234391 Overhaul flags handling
1a36898 Make flags more explicit, add runtime checks.
1a3e03a Merge pull request #340
96be204 Add additional tests for eckey and arg-checks.
bb5aa4d Make the tweak function zeroize-output-on-fail behavior consistent.
4a243da Move secp256k1_ec_privkey_import/export to contrib.
1b3efc1 Move secp256k1_ecdsa_sig_recover into the recovery module.
e3cd679 Eliminate all side-effects from VERIFY_CHECK() usage.
b30fc85 Avoid nonce_function_rfc6979 algo16 argument emulation.
70d4640 Make secp256k1_ec_pubkey_create skip processing invalid secret keys.
6c476a8 Minor comment improvements.
131afe5 Merge pull request #334
0c6ab2f Introduce explicit lower-S normalization
fea19e7 Add contrib/lax_der_parsing.h
3bb9c44 Rewrite ECDSA signature parsing code
fa57f1b Use secp256k1_rand_int and secp256k1_rand_bits more
49b3749 Add new tests for the extra testrand functions
f684d7d Faster secp256k1_rand_int implementation
251b1a6 Improve testrand: add extra random functions
31994c8 Merge pull request #338
f79aa88 Bugfix: swap arguments to noncefp
c98df26 Merge pull request #319
67f7da4 Extensive interface and operations tests for secp256k1_ec_pubkey_parse.
ee2cb40 Add ARG_CHECKs to secp256k1_ec_pubkey_parse/secp256k1_ec_pubkey_serialize
7450ef1 Merge pull request #328
68a3c76 Merge pull request #329
98135ee Merge pull request #332
37100d7 improve ECDH header-doc
b13d749 Fix couple of typos in API comments
7c823e3 travis: fixup module configs
cc3141a Merge pull request #325
ee58fae Merge pull request #326
213aa67 Do not force benchmarks to be statically linked.
338fc8b Add API exports to secp256k1_nonce_function_default and secp256k1_nonce_function_rfc6979.
52fd03f Merge pull request #320
9f6993f Remove some dead code.
357f8cd Merge pull request #314
118cd82 Use explicit symbol visibility.
4e64608 Include public module headers when compiling modules.
1f41437 Merge pull request #316
fe0d463 Merge pull request #317
cfe0ed9 Fix miscellaneous style nits that irritate overactive static analysis.
2b199de Use the explicit NULL macro for pointer comparisons.
9e90516 Merge pull request #294
dd891e0 Get rid of _t as it is POSIX reserved
201819b Merge pull request #313
912f203 Eliminate a few unbraced statements that crept into the code.
eeab823 Merge pull request #299
486b9bb Use a flags bitfield for compressed option to secp256k1_ec_pubkey_serialize and secp256k1_ec_privkey_export
05732c5 Callback data: Accept pointers to either const or non-const data
1973c73 Bugfix: Reinitialise buffer lengths that have been used as outputs
788038d Use size_t for lengths (at least in external API)
c9d7c2a secp256k1_context_set_{error,illegal}_callback: Restore default handler by passing NULL as function argument
9aac008 secp256k1_context_destroy: Allow NULL argument as a no-op
64b730b secp256k1_context_create: Use unsigned type for flags bitfield
cb04ab5 Merge pull request #309
a551669 Merge pull request #295
81e45ff Update group_impl.h
85e3a2c Merge pull request #112
b2eb63b Merge pull request #293
dc0ce9f [API BREAK] Change argument order to out/outin/in
6d947ca Merge pull request #298
c822693 Merge pull request #301
6d04350 Merge pull request #303
7ab311c Merge pull request #304
5fb3229 Fixes a bug where bench_sign would fail due to passing in too small a buffer.
263dcbc remove unused assignment
b183b41 bugfix: "ARG_CHECK(ctx != NULL)" makes no sense
6da1446 build: fix parallel build
5eb4356 Merge pull request #291
c996d53 Print success
9f443be Move pubkey recovery code to separate module
d49abbd Separate ECDSA recovery tests
439d34a Separate recoverable and normal signatures
a7b046e Merge pull request #289
f66907f Improve/reformat API documentation secp256k1.h
2f77487 Add context building benchmarks
cc623d5 Merge pull request #287
de7e398 small typo fix
9d96e36 Merge pull request #280
432e1ce Merge pull request #283
14727fd Use correct name in gitignore
356b0e9 Actually test static precomputation in Travis
ff3a5df Merge pull request #284
2587208 Merge pull request #212
a5a66c7 Add support for custom EC-Schnorr-SHA256 signatures
d84a378 Merge pull request #252
72ae443 Improve perf. of cmov-based table lookup
92e53fc Implement endomorphism optimization for secp256k1_ecmult_const
ed35d43 Make `secp256k1_scalar_add_bit` conditional; make `secp256k1_scalar_split_lambda_var` constant time
91c0ce9 Add benchmarks for ECDH and const-time multiplication
0739bbb Add ECDH module which works by hashing the output of ecmult_const
4401500 Add constant-time multiply `secp256k1_ecmult_const` for ECDH
e4ce393 build: fix hard-coded usage of "gen_context"
b8e39ac build: don't use BUILT_SOURCES for the static context header
baa75da tests: add a couple tests
ae4f0c6 Merge pull request #278
995c548 Introduce callback functions for dealing with errors.
c333074 Merge pull request #282
18c329c Remove the internal secp256k1_ecdsa_sig_t type
74a2acd Add a secp256k1_ecdsa_signature_t type
23cfa91 Introduce secp256k1_pubkey_t type
4c63780 Merge pull request #269
3e6f1e2 Change rfc6979 implementation to be a generic PRNG
ed5334a Update configure.ac to make it build on OpenBSD
1b68366 Merge pull request #274
a83bb48 Make ecmult static precomputation default
166b32f Merge pull request #276
c37812f Add gen_context src/ecmult_static_context.h to CLEANFILES to fix distclean.
125c15d Merge pull request #275
76f6769 Fix build with static ecmult altroot and make dist.
5133f78 Merge pull request #254
b0a60e6 Merge pull request #258
733c1e6 Add travis build to test the static context.
fbecc38 Add ability to use a statically generated ecmult context.
4fb174d Merge pull request #263
4ab8990 Merge pull request #270
bdf0e0c Merge pull request #271
31d0c1f Merge pull request #273
eb2c8ff Add missing casts to SECP256K1_FE_CONST_INNER
55399c2 Further performance improvements to _ecmult_wnaf
99fd963 Add secp256k1_ec_pubkey_compress(), with test similar to the related decompress() function.
145cc6e Improve performance of _ecmult_wnaf
36b305a Verify the result of GMP modular inverse using non-GMP code
0cbc860 Merge pull request #266
06ff7fe Merge pull request #267
5a43124 Save 1 _fe_negate since s1 == -s2
a5d796e Update code comments
3f3964e Add specific VERIFY tests for _fe_cmov
7d054cd Refactor to save a _fe_negate
b28d02a Refactor to remove a local var
55e7fc3 Perf. improvement in _gej_add_ge
a0601cd Fix VERIFY calculations in _fe_cmov methods
17f7148 Merge pull request #261
7657420 Add tests for adding P+Q with P.x!=Q.x and P.y=-Q.y
8c5d5f7 tests: Add failing unit test for #257 (bad addition formula)
5de4c5d gej_add_ge: fix degenerate case when computing P + (-lambda)P
bcf2fcf gej_add_ge: rearrange algebra
e2a07c7 Fix compilation with C++
873a453 Merge pull request #250
91eb0da Merge pull request #247
210ffed Use separate in and out pointers in `secp256k1_ec_pubkey_decompress`
a1d5ae1 Tiny optimization
729badf Merge pull request #210
2d5a186 Apply effective-affine trick to precomp
4f9791a Effective affine addition in EC multiplication
2b4cf41 Use pkg-config always when possible, with failover to manual checks for libcrypto
git-subtree-dir: src/secp256k1
git-subtree-split: 2bfb82b10edf0f0b0e366a12f94c8b21a914159d
58ef0ff doc: update docs for Tor listening (Wladimir J. van der Laan)
68ccdc4 doc: Mention Tor listening in release notes (Wladimir J. van der Laan)
09c1ae1 torcontrol improvements and fixes (Wladimir J. van der Laan)
2f796e5 Better error message if Tor version too old (Peter Todd)
8f4e67f net: Automatically create hidden service, listen on Tor (Wladimir J. van der Laan)
- Force AUTHCOOKIE size to be 32 bytes: This provides protection against
an attack where a process pretends to be Tor and uses the cookie
authentication method to nab arbitrary files such as the
wallet
- torcontrol logging
- fix cookie auth
- add HASHEDPASSWORD auth, fix fd leak when fwrite() fails
- better error reporting when cookie file is not ok
- better init/shutdown flow
- stop advertizing service when disconnected from tor control port
- COOKIE->SAFECOOKIE auth
69d373f Don't wipe the sigcache in TestBlockValidity (Pieter Wuille)
0b9e9dc Evict sigcache entries that are seen in a block (Pieter Wuille)
830e3f3 Make sigcache faster and more efficient (Pieter Wuille)
Previous text could be interpreted as the the _additional_ fee paid by
the result on top of the fee the original version paid, rather than the
correct interpretation: the absolute fee the resulting tx pays.
Previously all conflicting transactions were evaluated as a whole to
determine if the feerate was being increased. This meant that low
feerate children pulled the feerate down, potentially allowing a high
transaction with a high feerate to be replaced by one with a lower
feerate.
Replaces transactions already in the mempool if a new transaction seen
with a higher fee, specifically both a higher fee per KB and a higher
absolute fee. Children are evaluateed for replacement as well, using the
mempool package tracking to calculate replaced fees/size. Transactions
can opt-out of transaction replacement by setting nSequence >= maxint-1
on all inputs. (which all wallets do already)
Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket
API, to create and destroy 'ephemeral' hidden services programmatically.
https://stem.torproject.org/api/control.html#stem.control.Controller.create_ephemeral_hidden_service
This means that if Tor is running (and proper authorization is available),
bitcoin automatically creates a hidden service to listen on, without user
manual configuration. This will positively affect the number of available
.onion nodes.
- When the node is started, connect to Tor through control socket
- Send `ADD_ONION` command
- First time:
- Make it create a hidden service key
- Save the key in the data directory for later usage
- Make it redirect port 8333 to the local port 8333 (or whatever port we're listening on).
- Keep control socket connection open for as long node is running. The hidden service will
(by default) automatically go away when the connection is closed.
Process `getheaders` messages from whitelisted peers even if we are in
initial block download. Whitelisted peers can always use a node as a
block source.
Also log a debug message when the request is ignored, for
troubleshooting.
Fixes#6971.
d1c3762 Revert "Revert "Enable policy enforcing GetMedianTimePast as the end point of lock-time constraints"" (Gregory Maxwell)
e4e5334 Restore MedianTimePast for locktime. (Gregory Maxwell)
Previously, the undo weren't being flushed during a reindex because
fKnown was set to true in FindBlockPos. That is the correct behaviour
for block files as they aren't being touched, but undo files are
touched.
This changes the behaviour to always flush when switching to a new file
(even for block files, though that isn't really necessary).
The docs talk about bits 2 and 4 instead of 2 and 3, and bits are being
indexed from both 1 (describing nCode) and 0 (in second example).
Changed to use zero-indexing for all.
6342a48 Init: Use DEFAULT_TRANSACTION_MINFEE in help message (MarcoFalke)
a9c73a1 [wallet] Add comments for doxygen (MarcoFalke)
6b0e622 [wallet] Refactor to use new MIN_CHANGE (MarcoFalke)
a6efc01 Bugfix: Omit wallet-related options from -help when wallet is disabled (Luke Dashjr)
5f9260f Bugfix: If genproclimit is omitted to RPC setgenerate, don't change it; also show correct default in getmininginfo (Luke Dashjr)
420a82f Bugfix: Describe dblogsize option correctly (it refers to the wallet database, not memory pool) (Luke Dashjr)
caa3d42 Bugfix: RPC: blockchain: Display correct defaults in help for verifychain method (Luke Dashjr)
Moves the call Initialize() from init.cpp to CreateWithArguments() and handles the
return value. Moves the call Shutdown() from init.cpp to destructor.
Changes Initialize() and Shutdown() to protected members.
Revert "Revert "Add rules--presently disabled--for using GetMedianTimePast as endpoint for lock-time calculations""
This reverts commit 40cd32e835.
After careful analysis it was determined that the change was, in fact, safe and several people were suffering
momentary confusion about locktime semantics.
When processing a new transaction, in addition to spending the Coins of its txin's it creates a new Coins for its outputs. The existing ModifyCoins function will first make sure this Coins does not already exist. It can not exist due to BIP 30, but because of that the lookup can't be cached and always has to go to the database. Since we are creating the coins to match the new tx anyway, there is no point in checking if they exist first anyway. However this should not be used for coinbase tx's in order to preserve the historical behavior of overwriting the two existing duplicate tx pairs.
40cd32e Revert "Add rules--presently disabled--for using GetMedianTimePast as endpoint for lock-time calculations" (Gregory Maxwell)
8537ecd Revert "Enable policy enforcing GetMedianTimePast as the end point of lock-time constraints" (Gregory Maxwell)
This reverts commit 9d55050773.
As noted by Luke-Jr, under some conditions this will accept transactions which are invalid by the network
rules. This happens when the current block time is head of the median time past and a transaction's
locktime is in the middle.
This could be addressed by changing the rule to MAX(this_block_time, MTP+offset) but this solution and
the particular offset used deserve some consideration.
* Introduce new constant MIN_CHANGE and use it instead of the
hardcoded "CENT"
* Add test case for MIN_CHANGE
* Introduce new constant for -mintxfee default:
DEFAULT_TRANSACTION_MINFEE = 1000
Reduce the default limits on maximum number of transactions and the cumulative size of those transactions in both ancestor and descendant packages to 25 txs and 101kb total size.
Update the unittest that is meant to catch a transaction that is invalid
because it has a null input. The old test failed not because of that
but because it was considered a coinbase with too large script. This is
already checked with a different test, though.
The new test is *not* a coinbase since it has two inputs, but one of
them is null. This really checks the corresponding code path in
CheckTransaction.
143d173 Use BOOST_CHECK_MESSAGE() rather than BOOST_CHECK() in alerts_tests.cpp and initialize strMiscWarning before calling PartitionCheck()." (Eric Lombrozo)
* -maxuploadtarget can be set in MiB
* if <limit> - ( time-left-in-24h-cycle / 600 * MAX_BLOCK_SIZE ) has reach, stop serve blocks older than one week and filtered blocks
* no action if limit has reached, no guarantee that the target will not be surpassed
* add outbound limit informations to rpc getnettotals
dea8d21 Enable policy enforcing GetMedianTimePast as the end point of lock-time constraints (Mark Friedenbach)
9d55050 Add rules--presently disabled--for using GetMedianTimePast as endpoint for lock-time calculations (Mark Friedenbach)
Until now there were quite a few leftovers, and only the coverage
related files in `src/` were cleaned, while the ones in the other dirs
remained. `qa/tmp/` is related to the BitcoinJ tests, and `cache/` is
related to RPC tests.
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.
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.
Add a comment that explains why the initial "getheader" requests are
made starting from the block preceding the currently best one.
Thanks to sdaftuar for the explanation!
There is no exact science to setting this parameter, but 5000
(just over 1 US cent at the time of writing) is higher than the
cost to relay a transaction around the network (the new benchmark
due to mempool limiting).
After each transaction which is added to mempool, we first call
Expire() to remove old transactions, then throwing away the
lowest-feerate transactions.
After throwing away transactions by feerate, we set the minimum
relay fee to the maximum fee transaction-and-dependant-set we
removed, plus the default minimum relay fee.
After the next block is received, the minimum relay fee is allowed
to decrease exponentially. Its halflife defaults to 12 hours, but
is decreased to 6 hours if the mempool is smaller than half its
maximum size, and 3 hours if the mempool is smaller than a quarter
its maximum size.
The minimum -maxmempool size is 40*-limitdescendantsize, as it is
easy for an attacker to play games with the cheapest
-limitdescendantsize transactions. -maxmempool defaults to 300MB.
This disables high-priority transaction relay when the min relay
fee adjustment is >0 (ie when the mempool is full). When the relay
fee adjustment drops below the default minimum relay fee / 2 it is
set to 0 (re-enabling priority-based free relay).
(note the 9x multiplier on (void*)'s for CTxMemPool::DynamicMemoryUsage
was accidentally introduced in 5add7a7 but should have waited for this
commit which adds the extra index)
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.
1534d9a Creates unittests for addrman, makes addrman testable. Adds several unittests for addrman to verify it works as expected. Makes small modifications to addrman to allow deterministic and targeted tests. (EthanHeilman)
Adds an `obfuscate` parameter to `CLevelDBWrapper` and makes use of it
for all new chainstate stores built via `CCoinsViewDB`. Also adds an
`Xor` method to `CDataStream`.
Thanks to @sipa @laanwj @pstratem @dexX7 @KyrosKrane @gmaxwell.
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 a81cd96805:
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
- to match the peers.dat handling also supply a debug.log entry for how
many entries were loaded from banlist.dat and how long it took
- add a GUI init message for loading the banlist (same as with peers.dat)
- move the same message for peers.dat upwards in the code, to be able to
reuse the timing variable nStart and also just log, if our read from
peers.dat didn't fail
- only start working on/with banlist data, if reading in the banlist from
disk didn't fail
- as CNode::setBannedIsDirty is false (default) when reading fails, we
don't need to explicitly set it to false to prevent writing
banlist.dat in that case either
Previously only one PUSHDATA was allowed, needlessly limiting
applications such as matching OP_RETURN contents with bloom filters that
operate on a per-PUSHDATA level. Now any combination that passes
IsPushOnly() is allowed, so long as the total size of the scriptPubKey
is less than 42 bytes. (unchanged modulo non-minimal PUSHDATA encodings)
Also, this fixes the odd bug where previously the PUSHDATA could be
replaced by any single opcode, even sigops consuming opcodes such as
CHECKMULTISIG. (20 sigops!)
