Support for type hints was introduced in Python 3.5. Type hints make it easier to read and review code in my opinion. Also an IDE may discover a potential bug sooner. Yet, as PEP 484 says: "It should also be emphasized that Python will remain a dynamically typed language, and the authors have no desire to ever make type hints mandatory, even by convention."
Mypy is used in lint-python.sh to do the type checking. The package is standard so there is little chance that it will be abandoned. Mypy checks that type hints in source code are correct when they are not, it fails with an error.
Useful resources:
* https://docs.python.org/3.5/library/typing.html
* https://www.python.org/dev/peps/pep-0484/
c4b0c08f7c Update tx-size-small comment with relevant CVE disclosure (Gregory Sanders)
Pull request description:
Code first introduced under https://github.com/bitcoin/bitcoin/pull/11423 with essentially no description and no discussion.
ACKs for top commit:
MarcoFalke:
ACK c4b0c08f7c
fanquake:
ACK c4b0c08f7c
Tree-SHA512: 95d5c92998b8b1e944c477dbaee265b62612b6e815099ab31d9ff580b4dff777abaf7f326a284644709f918aa1510412d62310689b1250ef6e64de7b19ca9f71
CVE-2018-17144 and CVE-2012-2459 are only partially tested for regression.
- CVE-2018-17144 is not tested for the inflation bug.
- CVE-2012-2459 is only tested for the mutated block being rejected, not
for the original block being accepted afterwards.
This commit fixes that limitation.
Also added functional test for CVE-2010-5137.
0ff1c2a838 Separate reason for premature spends (coinbase/locktime) (Suhas Daftuar)
54470e767b Assert validation reasons are contextually correct (Suhas Daftuar)
2120c31521 [refactor] Update some comments in validation.cpp as we arent doing DoS there (Matt Corallo)
12dbdd7a41 [refactor] Drop unused state.DoS(), state.GetDoS(), state.CorruptionPossible() (Matt Corallo)
aa502b88d1 scripted-diff: Remove DoS calls to CValidationState (Matt Corallo)
7721ad64f4 [refactor] Prep for scripted-diff by removing some \ns which annoy sed. (Matt Corallo)
5e78c5734b Allow use of state.Invalid() for all reasons (Matt Corallo)
6b34bc6b6f Fix handling of invalid headers (Suhas Daftuar)
ef54b486d5 [refactor] Use Reasons directly instead of DoS codes (Matt Corallo)
9ab2a0412e CorruptionPossible -> BLOCK_MUTATED (Matt Corallo)
6e55b292b0 CorruptionPossible -> TX_WITNESS_MUTATED (Matt Corallo)
7df16e70e6 LookupBlockIndex -> CACHED_INVALID (Matt Corallo)
c8b0d22698 [refactor] Drop redundant nDoS, corruptionPossible, SetCorruptionPossible (Matt Corallo)
34477ccd39 [refactor] Add useful-for-dos "reason" field to CValidationState (Matt Corallo)
6a7f8777a0 Ban all peers for all block script failures (Suhas Daftuar)
7b999103e2 Clean up banning levels (Matt Corallo)
b8b4c80146 [refactor] drop IsInvalid(nDoSOut) (Matt Corallo)
8818729013 [refactor] Refactor misbehavior ban decisions to MaybePunishNode() (Matt Corallo)
00e11e61c0 [refactor] rename stateDummy -> orphan_state (Matt Corallo)
f34fa719cf Drop obsolete sigops comment (Matt Corallo)
Pull request description:
This is a rebase of #11639 with some fixes for the last few comments which were not yet addressed.
The original PR text, with some strikethroughs of text that is no longer correct:
> This cleans up an old main-carryover - it made sense that main could decide what DoS scores to assign things because the DoS scores were handled in a different part of main, but now validation is telling net_processing what DoS scores to assign to different things, which is utter nonsense. Instead, we replace CValidationState's nDoS and CorruptionPossible with a general ValidationInvalidReason, which net_processing can handle as it sees fit. I keep the behavior changes here to a minimum, but in the future we can utilize these changes for other smarter behavior, such as disconnecting/preferring to rotate outbound peers based on them providing things which are invalid due to SOFT_FORK because we shouldn't ban for such cases.
>
> This is somewhat complementary with, though obviously conflicts heavily with #11523, which added enums in place of DoS scores, as well as a few other cleanups (which are still relevant).
>
> Compared with previous bans, the following changes are made:
>
> Txn with empty vin/vout or null prevouts move from 10 DoS
> points to 100.
> Loose transactions with a dependency loop now result in a ban
> instead of 10 DoS points.
> ~~BIP68-violation no longer results in a ban as it is SOFT_FORK.~~
> ~~Non-SegWit SigOp violation no longer results in a ban as it
> considers P2SH sigops and is thus SOFT_FORK.~~
> ~~Any script violation in a block no longer results in a ban as
> it may be the result of a SOFT_FORK. This should likely be
> fixed in the future by differentiating between them.~~
> Proof of work failure moves from 50 DoS points to a ban.
> Blocks with timestamps under MTP now result in a ban, blocks
> too far in the future continue to not result in a ban.
> Inclusion of non-final transactions in a block now results in a
> ban instead of 10 DoS points.
Note: The change to ban all peers for consensus violations is actually NOT the change I'd like to make -- I'd prefer to only ban outbound peers in those situations. The current behavior is a bit of a mess, however, and so in the interests of advancing this PR I tried to keep the changes to a minimum. I plan to revisit the behavior in a followup PR.
EDIT: One reviewer suggested I add some additional context for this PR:
> The goal of this work was to make net_processing aware of the actual reasons for validation failures, rather than just deal with opaque numbers instructing it to do something.
>
> In the future, I'd like to make it so that we use more context to decide how to punish a peer. One example is to differentiate inbound and outbound peer misbehaviors. Another potential example is if we'd treat RECENT_CONSENSUS_CHANGE failures differently (ie after the next consensus change is implemented), and perhaps again we'd want to treat some peers differently than others.
ACKs for commit 0ff1c2:
jnewbery:
utACK 0ff1c2a838
ryanofsky:
utACK 0ff1c2a838. Only change is dropping the first commit (f3883a321bf4ab289edcd9754b12cae3a648b175), and dropping the temporary `assert(level == GetDoS())` that was in 35ee77f2832eaffce30042e00785c310c5540cdc (now c8b0d22698)
Tree-SHA512: e915a411100876398af5463d0a885920e44d473467bb6af991ef2e8f2681db6c1209bb60f848bd154be72d460f039b5653df20a6840352c5f7ea5486d9f777a3
Compared with previous bans, the following changes are made:
* Txn with empty vin/vout or null prevouts move from 10 DoS
points to 100.
* Loose transactions with a dependency loop now result in a ban
instead of 10 DoS points.
* Many pre-segwit soft-fork errors now result in a ban.
Note: Transactions that violate soft-fork script flags since P2SH do not generally
result in a ban. Also, banning behavior for invalid blocks is dependent on
whether the node is validating with multiple script check threads, due to a long-
standing bug. That inconsistency is still present after this commit.
* Proof of work failure moves from 50 DoS points to a ban.
* Blocks with timestamps under MTP now result in a ban, blocks
too far in the future continue to *not* result in a ban.
* Inclusion of non-final transactions in a block now results in a
ban instead of 10 DoS points.
Co-authored-by: Anthony Towns <aj@erisian.com.au>
