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funding: avoid dereferencing a nil localDiscoverySignal

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This commit fixes a possible panic within the funding manger’s workflow
for pending channels. We now ensure that the local discovery signal
retrieved from the localDiscoverySignals map is always non-nil.
Otherwise, we risk a server panic in the case that a node retransmits
the FundingLocked message after a channel has been fully processed, or
even just sends a FundingLocked message for a non-existent channel.
This commit is contained in:
Olaoluwa Osuntokun 2017-07-14 17:14:11 -07:00
parent 14832d8c09
commit 6128fc6971
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GPG Key ID: 9CC5B105D03521A2
1 changed files with 18 additions and 13 deletions
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31
fundingmanager.go
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@ -1008,10 +1008,12 @@ func (f *fundingManager) waitForFundingConfirmation(completeChan *channeldb.Open
shortChanID, chanID) shortChanID, chanID)
// Finally, as the local channel discovery has been fully processed, // Finally, as the local channel discovery has been fully processed,
// we'll trigger the signal indicating that it's safe foe any funding // we'll trigger the signal indicating that it's safe for any funding
// locked messages related to this channel to be processed. // locked messages related to this channel to be processed.
f.localDiscoveryMtx.Lock() f.localDiscoveryMtx.Lock()
close(f.localDiscoverySignals[chanID]) if discoverySignal, ok := f.localDiscoverySignals[chanID]; ok {
close(discoverySignal)
}
f.localDiscoveryMtx.Unlock() f.localDiscoveryMtx.Unlock()
return return
@ -1029,20 +1031,23 @@ func (f *fundingManager) processFundingLocked(msg *lnwire.FundingLocked,
// to enter normal operating mode. // to enter normal operating mode.
func (f *fundingManager) handleFundingLocked(fmsg *fundingLockedMsg) { func (f *fundingManager) handleFundingLocked(fmsg *fundingLockedMsg) {
f.localDiscoveryMtx.Lock() f.localDiscoveryMtx.Lock()
localDiscoverySignal := f.localDiscoverySignals[fmsg.msg.ChanID] localDiscoverySignal, ok := f.localDiscoverySignals[fmsg.msg.ChanID]
f.localDiscoveryMtx.Unlock() f.localDiscoveryMtx.Unlock()
// Before we proceed with processing the funding locked message, we'll if ok {
// wait for the lcoal waitForFundingConfirmation goroutine to signal // Before we proceed with processing the funding locked
// that it has the necessary state in place. Otherwise, we may be // message, we'll wait for the lcoal waitForFundingConfirmation
// missing critical information required to handle forwarded HTLC's. // goroutine to signal that it has the necessary state in
<-localDiscoverySignal // place. Otherwise, we may be missing critical information
// required to handle forwarded HTLC's.
<-localDiscoverySignal
// With the signal received, we can now safely delete the entry from // With the signal received, we can now safely delete the entry from
// the map. // the map.
f.localDiscoveryMtx.Lock() f.localDiscoveryMtx.Lock()
delete(f.localDiscoverySignals, fmsg.msg.ChanID) delete(f.localDiscoverySignals, fmsg.msg.ChanID)
f.localDiscoveryMtx.Unlock() f.localDiscoveryMtx.Unlock()
}
// First, we'll attempt to locate the channel who's funding workflow is // First, we'll attempt to locate the channel who's funding workflow is
// being finalized by this message. We got to the database rather than // being finalized by this message. We got to the database rather than