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net_processing: make any misbehavior trigger immediate discouragement #10

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So far, discouragement of peers triggers when their misbehavior score exceeds 100 points. Most types of misbehavior increment the score by 100, triggering immediate discouragement, but some types do not. This PR makes all increments equal to either 100 (meaning any misbehavior will immediately cause disconnection and discouragement) or 0 (making the behavior effectively unconditionally allowed), and then removes the logic for score accumulation.

This simplifies the code a bit, but also makes protocol expectations clearer: if a peer misbehaves, they get disconnected. There is no good reason why certain types of protocol violations should be permitted 4 times (howmuch=20) or 9 times (howmuch=10), while many others are never allowed. Furthermore, the distinction between these looks arbitrary.

To assess whether this does not unduly affect existing other software on the network, I've been running this with an additional patch (see https://github.com/sipa/bitcoin/commits/202403_nomisbehave_log) that adds logging whenever behavior is detected whose misbehavior increment is changed to 100 by this PR. Over the past day I have not seen any instances on my well-connected node (~150 incoming connections), but will continue to monitor.

The specific types of misbehavior that are changed to 100 are:

  • Sending us a block which does not connect to our header tree (which necessarily must have been unsollicited). [used to be score 10]
  • Sending us a headers with a non-continuous headers sequence. [used to be score 20]
  • Sending us more than 1000 addresses in a single addr or addrv2 message [used to be score 20]
  • Sending us more than 50000 invs in a single inv message [used to be score 20]
  • Sending us more than 2000 headers in a single headers message [used to be score 20]

The specific types of misbehavior that are changed to 0 are:

  • Sending us 10 (*) separate BIP130 headers announcements that do not connect to our block tree [used to be score 20]
  • Sending us more than 8 headers in a single headers message (which thus does not get treated as a BIP130 announcement) that does not connect to our block tree. [used to be score 10]

I believe that none of these behaviors are unavoidable, except for the one marked (*) which can in theory happen still due to interaction between BIP130 and variations in system clocks (the max 2 hour in the future rule). This one has been removed entirely. In order to remove the impact of the bug it was designed to deal with, without relying on misbehavior, a separate improvement is included that makes getheaders-tracking more accurate.

In another unrelated improvement, this also gets rid of the 8 header limit heuristic to determine whether an incoming non-connecting headers is a potential BIP130 announcement, as this rule is no longer needed to prevent spurious Misbehavior. Instead, any non-connecting headers is now treated as a potential announcement.

sipa added 5 commits March 12, 2024 14:46
Since bitcoin#25454 we keep track of the last
GETHEADERS request that was sent and wasn't responded to. So far, every incoming
HEADERS message is treated as a response to whatever GETHEADERS was last sent,
regardless of its contents.

This commit makes this tracking more accurate, by only treating HEADERS messages
which (1) are empty, (2) connect to our existing block header tree, or (3) are a
continuation of a low-work headers sync as responses that clear the "outstanding
GETHEADERS" state (m_last_getheaders_timestamp).

That means that HEADERS messages which do not satisfy any of the above criteria
will be ignored, not triggering a GETHEADERS, and potentially (for now, but see
later commit) increase misbehavior score.
This misbehavior was originally intended to prevent bandwidth wastage due to
actually observed very broken (but likely non-malicious) nodes that respond
to GETHEADERS with a response unrelated to the request, triggering a request
cycle.

This has however largely been addressed by the previous commit, which causes
non-connecting HEADERS that are received while a GETHEADERS has not been
responded to, to be ignored, as long as they do not time out (2 minutes).
With that, the specific misbehavior is largely irrelevant (for inbound peers,
it is now harmless; for outbound peers, the eviction logic will eventually
kick them out if they're not keeping up with headers at all).
With the Misbehavior score gone for non-connecting headers (see previous
commit), there is no need to only treat headers messages with up to 8
headers as potential BIP130 announcements. BIP130 does not specify such
a limit; it was purely a heuristic.
This removes the need to actually track misbehavior score (see further commit), because any
Misbehaving node will immediately hit the discouragement threshold.
@@ -129,8 +129,6 @@ static constexpr double BLOCK_DOWNLOAD_TIMEOUT_BASE = 1;
static constexpr double BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 0.5;
/** Maximum number of headers to announce when relaying blocks with headers message.*/
static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
/** Maximum number of unconnecting headers announcements before DoS score */
static const int MAX_NUM_UNCONNECTING_HEADERS_MSGS = 10;
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4 authors commented here with

return true;
}
break;
}
case BlockValidationResult::BLOCK_INVALID_HEADER:
case BlockValidationResult::BLOCK_CHECKPOINT:
case BlockValidationResult::BLOCK_INVALID_PREV:
if (peer) Misbehaving(*peer, 100, message);
if (peer) Misbehaving(*peer, message);
return true;
// Conflicting (but not necessarily invalid) data or different policy:
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2 authors commented here with

@@ -1876,7 +1852,7 @@ bool PeerManagerImpl::MaybePunishNodeForTx(NodeId nodeid, const TxValidationStat
break;
// The node is providing invalid data:
case TxValidationResult::TX_CONSENSUS:
if (peer) Misbehaving(*peer, 100, "");
if (peer) Misbehaving(*peer, "");
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2 authors commented here with

@@ -4551,7 +4515,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
ReadStatus status = partialBlock.InitData(cmpctblock, vExtraTxnForCompact);
if (status == READ_STATUS_INVALID) {
RemoveBlockRequest(pindex->GetBlockHash(), pfrom.GetId()); // Reset in-flight state in case Misbehaving does not result in a disconnect
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2 authors commented here with

adamjonas pushed a commit that referenced this pull request Mar 15, 2024
…BlockTx suppression

fa9dc92 test: Add missing CBlockPolicyEstimator::processBlockTx suppression (MarcoFalke)

Pull request description:

  Fixes bitcoin#28865 (comment)

  ```
  # FUZZ=policy_estimator UBSAN_OPTIONS="suppressions=/root/fuzz_dir/scratch/fuzz_gen/code/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1" ./src/test/fuzz/fuzz /tmp/crash-154b42214e70781a9c1ad72d3f2693913dcf8c06

  ...

  policy/fees.cpp:632:27: runtime error: implicit conversion from type 'unsigned int' of value 4294574080 (32-bit, unsigned) to type 'int' changed the value to -393216 (32-bit, signed)
      #0 0x55cbbe10daee in CBlockPolicyEstimator::processBlockTx(unsigned int, CTxMemPoolEntry const*) src/policy/fees.cpp:632:27
      bitcoin#1 0x55cbbe10e361 in CBlockPolicyEstimator::processBlock(unsigned int, std::vector<CTxMemPoolEntry const*, std::allocator<CTxMemPoolEntry const*>>&) src/policy/fees.cpp:680:13
      #2 0x55cbbd84af48 in policy_estimator_fuzz_target(Span<unsigned char const>)::$_1::operator()() const src/test/fuzz/policy_estimator.cpp:69:40
      #3 0x55cbbd84af48 in unsigned long CallOneOf<policy_estimator_fuzz_target(Span<unsigned char const>)::$_0, policy_estimator_fuzz_target(Span<unsigned char const>)::$_1, policy_estimator_fuzz_target(Span<unsigned char const>)::$_2, policy_estimator_fuzz_target(Span<unsigned char const>)::$_3>(FuzzedDataProvider&, policy_estimator_fuzz_target(Span<unsigned char const>)::$_0, policy_estimator_fuzz_target(Span<unsigned char const>)::$_1, policy_estimator_fuzz_target(Span<unsigned char const>)::$_2, policy_estimator_fuzz_target(Span<unsigned char const>)::$_3) src/./test/fuzz/util.h:43:27
      #4 0x55cbbd84af48 in policy_estimator_fuzz_target(Span<unsigned char const>) src/test/fuzz/policy_estimator.cpp:38:9
      #5 0x55cbbda1cc18 in std::function<void (Span<unsigned char const>)>::operator()(Span<unsigned char const>) const /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/std_function.h:591:9
      #6 0x55cbbda1cc18 in LLVMFuzzerTestOneInput src/test/fuzz/fuzz.cpp:178:5
      #7 0x55cbbd26a944 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/root/fuzz_dir/scratch/fuzz_gen/code/src/test/fuzz/fuzz+0x190e944) (BuildId: ffb89e0b86c093ca3bdeae6f85537737a4e3b42d)
      #8 0x55cbbd253916 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) (/root/fuzz_dir/scratch/fuzz_gen/code/src/test/fuzz/fuzz+0x18f7916) (BuildId: ffb89e0b86c093ca3bdeae6f85537737a4e3b42d)
      #9 0x55cbbd25945a in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/root/fuzz_dir/scratch/fuzz_gen/code/src/test/fuzz/fuzz+0x18fd45a) (BuildId: ffb89e0b86c093ca3bdeae6f85537737a4e3b42d)
      #10 0x55cbbd284026 in main (/root/fuzz_dir/scratch/fuzz_gen/code/src/test/fuzz/fuzz+0x1928026) (BuildId: ffb89e0b86c093ca3bdeae6f85537737a4e3b42d)
      #11 0x7fe4aa8280cf  (/lib/x86_64-linux-gnu/libc.so.6+0x280cf) (BuildId: 96ab1a8f3b2c9a2ed37c7388615e6a726d037e89)
      #12 0x7fe4aa828188 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x28188) (BuildId: 96ab1a8f3b2c9a2ed37c7388615e6a726d037e89)
      #13 0x55cbbd24e494 in _start (/root/fuzz_dir/scratch/fuzz_gen/code/src/test/fuzz/fuzz+0x18f2494) (BuildId: ffb89e0b86c093ca3bdeae6f85537737a4e3b42d)

  SUMMARY: UndefinedBehaviorSanitizer: implicit-integer-sign-change policy/fees.cpp:632:27 in
  ```

  ```
  # base64 /tmp/crash-154b42214e70781a9c1ad72d3f2693913dcf8c06
  AQEAAAAAADkFlVwAAQEAAAAAADkFlZVcACTDSSsP3746IAZrH48khwMAAQEB/QEALQAACwAAAAAA
  FgAAAAAAAQAABgAAAAAAAAAAAAAAAAAAACcQAAAAAAAAAAAAAAAAAAAAAAD6AAAAOQWVXAABAQAA
  AAAAOQWVlVwAIMNJKw/fvjogBmsfjySHAwABAQH9AQAtAAALAAAAAAAAAAABAAAGAAAAAAAAAAAA
  AAAAAAAAJxAAAAAAAAAAAAAAAAAAAAAAAPr/AAAAAAAAAAAAAAQAAAAA/wAAAAAAAAAAAAAEAAAA
  AAEBAeAIAVwBXAAA/jbSBvwBKABSKBwBYgEB2wAEkvXInHYAAAAAAAAAvgAAAAAA/9//6v8e/xIk
  MgAlAiUAOw==

ACKs for top commit:
  fanquake:
    ACK fa9dc92
  dergoegge:
    utACK fa9dc92

Tree-SHA512: 3898c17c928ecc2bcc8c7086359e9ae00da2197b4d8e10c7bf6d12415326c9bca3ef6e1d8d3b83172ccfa604ce7e7371415262ba705225f9ea4da8b1a7eb0306
adamjonas pushed a commit that referenced this pull request Mar 15, 2024
…tifications fuzz target

fab164f fuzz: Avoid signed-integer-overflow in wallet_notifications fuzz target (MarcoFalke)

Pull request description:

  Should avoid

  ```
  policy/feerate.cpp:29:63: runtime error: signed integer overflow: 77600710321911316 * 149 cannot be represented in type 'int64_t' (aka 'long')
      #0 0x563a1775ed66 in CFeeRate::GetFee(unsigned int) const src/policy/feerate.cpp:29:63
      bitcoin#1 0x563a15913a69 in wallet::COutput::COutput(COutPoint const&, CTxOut const&, int, int, bool, bool, bool, long, bool, std::optional<CFeeRate>) src/./wallet/coinselection.h:91:57
      #2 0x563a16fa6a6d in wallet::FetchSelectedInputs(wallet::CWallet const&, wallet::CCoinControl const&, wallet::CoinSelectionParams const&) src/wallet/spend.cpp:297:17
      #3 0x563a16fc4512 in wallet::CreateTransactionInternal(wallet::CWallet&, std::vector<wallet::CRecipient, std::allocator<wallet::CRecipient>> const&, int, wallet::CCoinControl const&, bool) src/wallet/spend.cpp:1105:33
      #4 0x563a16fbec74 in wallet::CreateTransaction(wallet::CWallet&, std::vector<wallet::CRecipient, std::allocator<wallet::CRecipient>> const&, int, wallet::CCoinControl const&, bool) src/wallet/spend.cpp:1291:16
      #5 0x563a16fcf6df in wallet::FundTransaction(wallet::CWallet&, CMutableTransaction&, long&, int&, bilingual_str&, bool, std::set<int, std::less<int>, std::allocator<int>> const&, wallet::CCoinControl) src/wallet/spend.cpp:1361:16
      #6 0x563a1597b7b9 in wallet::(anonymous namespace)::FuzzedWallet::FundTx(FuzzedDataProvider&, CMutableTransaction) src/wallet/test/fuzz/notifications.cpp:162:15
      #7 0x563a15958240 in wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>)::$_0::operator()() const src/wallet/test/fuzz/notifications.cpp:228:23
      #8 0x563a15958240 in unsigned long CallOneOf<wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>)::$_0, wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>)::$_1>(FuzzedDataProvider&, wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>)::$_0, wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>)::$_1) src/./test/fuzz/util.h:43:27
      #9 0x563a15958240 in wallet::(anonymous namespace)::wallet_notifications_fuzz_target(Span<unsigned char const>) src/wallet/test/fuzz/notifications.cpp:196:9
      #10 0x563a15fdef0c in std::function<void (Span<unsigned char const>)>::operator()(Span<unsigned char const>) const /usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/bits/std_function.h:591:9
      #11 0x563a15fdef0c in LLVMFuzzerTestOneInput src/test/fuzz/fuzz.cpp:178:5
      #12 0x563a158032a4 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x19822a4) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      #13 0x563a15802999 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1981999) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      #14 0x563a15804586 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1983586) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      #15 0x563a15804aa7 in fuzzer::Fuzzer::Loop(std::vector<fuzzer::SizedFile, std::allocator<fuzzer::SizedFile>>&) (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x1983aa7) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      #16 0x563a157f21fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x19711fb) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      #17 0x563a1581c766 in main (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x199b766) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)
      bitcoin#18 0x7f499e17b0cf  (/lib/x86_64-linux-gnu/libc.so.6+0x280cf) (BuildId: 96ab1a8f3b2c9a2ed37c7388615e6a726d037e89)
      bitcoin#19 0x7f499e17b188 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x28188) (BuildId: 96ab1a8f3b2c9a2ed37c7388615e6a726d037e89)
      bitcoin#20 0x563a157e70c4 in _start (/ci_container_base/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/test/fuzz/fuzz+0x19660c4) (BuildId: 8acb42ad599d7f6d25b6f93e18fd564d80df7c06)

  SUMMARY: UndefinedBehaviorSanitizer: signed-integer-overflow policy/feerate.cpp:29:63 in
  MS: 0 ; base unit: 0000000000000000000000000000000000000000
  0x3f,0x0,0x2f,0x5f,0x5f,0x5f,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0x7d,0xff,0xff,0xff,0xff,0xff,0x53,0xff,0xff,0xff,0xff,0xff,0x0,0x0,0x0,0x0,0x0,0x0,0x13,0x5e,0x5f,0x5f,0x8,0x25,0x0,0x5f,0x5f,0x5f,0x5f,0x5f,0x5f,0x8,0x25,0xca,0x7f,0x5f,0x5f,0x5f,0x13,0x13,0x5f,0x5f,0x5f,0x2,0xdb,0xca,0x0,0x0,0xe7,0xe6,0x66,0x65,0x0,0x0,0x0,0x0,0x44,0x3f,0xa,0xa,0xff,0xff,0xff,0xff,0xff,0x61,0x76,0x6f,0x69,0x0,0xb5,0x15,
  ?\000/___}}}}}}}}}}}}}}}}}}}}\377\377\377\377\377S\377\377\377\377\377\000\000\000\000\000\000\023^__\010%\000______\010%\312\177___\023\023___\002\333\312\000\000\347\346fe\000\000\000\000D?\012\012\377\377\377\377\377avoi\000\265\025
  artifact_prefix='./'; Test unit written to ./crash-4d3bac8a64d4e58b2f0943e6d28e6e1f16328d7d
  Base64: PwAvX19ffX19fX19fX19fX19fX19fX19fX3//////1P//////wAAAAAAABNeX18IJQBfX19fX18IJcp/X19fExNfX18C28oAAOfmZmUAAAAARD8KCv//////YXZvaQC1FQ==

ACKs for top commit:
  dergoegge:
    ACK fab164f
  brunoerg:
    ACK fab164f

Tree-SHA512: f416828f4394aa7303ee437f141e9bbd23c0e0f1b830e4ef3932338858249ba68a811b9837c5b7ad8c6ab871b6354996434183597c1a910a8d8e8d829693e4b2
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