From: Jeffrey Czyz Date: Wed, 28 Jul 2021 19:04:10 +0000 (-0500) Subject: Use ShutdownScript to check scripts from peers X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=e1eb69aaa503c2e4657d982912838ed7998a37f9;p=rust-lightning Use ShutdownScript to check scripts from peers --- diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index e08b8af49..013c45982 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -26,6 +26,7 @@ use ln::{PaymentPreimage, PaymentHash}; use ln::features::{ChannelFeatures, InitFeatures}; use ln::msgs; use ln::msgs::{DecodeError, OptionalField, DataLossProtect}; +use ln::script::ShutdownScript; use ln::channelmanager::{PendingHTLCStatus, HTLCSource, HTLCFailReason, HTLCFailureMsg, PendingHTLCInfo, RAACommitmentOrder, BREAKDOWN_TIMEOUT, MIN_CLTV_EXPIRY_DELTA, MAX_LOCAL_BREAKDOWN_TIMEOUT}; use ln::chan_utils::{CounterpartyCommitmentSecrets, TxCreationKeys, HTLCOutputInCommitment, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT, make_funding_redeemscript, ChannelPublicKeys, CommitmentTransaction, HolderCommitmentTransaction, ChannelTransactionParameters, CounterpartyChannelTransactionParameters, MAX_HTLCS, get_commitment_transaction_number_obscure_factor}; use ln::chan_utils; @@ -43,11 +44,11 @@ use util::scid_utils::scid_from_parts; use prelude::*; use core::{cmp,mem,fmt}; +use core::convert::TryFrom; use core::ops::Deref; #[cfg(any(test, feature = "fuzztarget", debug_assertions))] use sync::Mutex; use bitcoin::hashes::hex::ToHex; -use bitcoin::blockdata::opcodes::all::OP_PUSHBYTES_0; #[cfg(test)] pub struct ChannelValueStat { @@ -822,11 +823,11 @@ impl Channel { // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything if script.len() == 0 { None - // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel - } else if is_unsupported_shutdown_script(&their_features, script) { - return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex()))); } else { - Some(script.clone()) + match ShutdownScript::try_from((script.clone(), &their_features)) { + Ok(shutdown_script) => Some(shutdown_script.into_inner()), + Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex()))), + } } }, // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel @@ -1549,11 +1550,11 @@ impl Channel { // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything if script.len() == 0 { None - // Peer is signaling upfront_shutdown and has provided a non-accepted scriptpubkey format. Fail the channel - } else if is_unsupported_shutdown_script(&their_features, script) { - return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex()))); } else { - Some(script.clone()) + match ShutdownScript::try_from((script.clone(), &their_features)) { + Ok(shutdown_script) => Some(shutdown_script.into_inner()), + Err(_) => return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided a non-accepted scriptpubkey format. script: ({})", script.to_bytes().to_hex()))), + } } }, // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel @@ -3228,16 +3229,17 @@ impl Channel { } assert_eq!(self.channel_state & ChannelState::ShutdownComplete as u32, 0); - if is_unsupported_shutdown_script(&their_features, &msg.scriptpubkey) { - return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex()))); - } + let shutdown_scriptpubkey = match ShutdownScript::try_from((msg.scriptpubkey.clone(), their_features)) { + Ok(script) => script.into_inner(), + Err(_) => return Err(ChannelError::Close(format!("Got a nonstandard scriptpubkey ({}) from remote peer", msg.scriptpubkey.to_bytes().to_hex()))), + }; if self.counterparty_shutdown_scriptpubkey.is_some() { - if Some(&msg.scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() { - return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", msg.scriptpubkey.to_bytes().to_hex()))); + if Some(&shutdown_scriptpubkey) != self.counterparty_shutdown_scriptpubkey.as_ref() { + return Err(ChannelError::Close(format!("Got shutdown request with a scriptpubkey ({}) which did not match their previous scriptpubkey.", shutdown_scriptpubkey.to_bytes().to_hex()))); } } else { - self.counterparty_shutdown_scriptpubkey = Some(msg.scriptpubkey.clone()); + self.counterparty_shutdown_scriptpubkey = Some(shutdown_scriptpubkey); } // From here on out, we may not fail! @@ -4484,24 +4486,6 @@ impl Channel { } } -fn is_unsupported_shutdown_script(their_features: &InitFeatures, script: &Script) -> bool { - // We restrain shutdown scripts to standards forms to avoid transactions not propagating on the p2p tx-relay network - - // BOLT 2 says we must only send a scriptpubkey of certain standard forms, - // which for a a BIP-141-compliant witness program is at max 42 bytes in length. - // So don't let the remote peer feed us some super fee-heavy script. - let is_script_too_long = script.len() > 42; - if is_script_too_long { - return true; - } - - if their_features.supports_shutdown_anysegwit() && script.is_witness_program() && script.as_bytes()[0] != OP_PUSHBYTES_0.into_u8() { - return false; - } - - return !script.is_p2pkh() && !script.is_p2sh() && !script.is_v0_p2wpkh() && !script.is_v0_p2wsh() -} - const SERIALIZATION_VERSION: u8 = 2; const MIN_SERIALIZATION_VERSION: u8 = 1;