WaitingFor on not started party causes panic

[nkuba]

I initialized a keygen party but haven't started the process yet. When I call WaitingFor() for this party, I get panic runtime error.

In such a case I would expect WaitingFor() function to return either an error or a list of parties (empty or containing all parties).

Stack trace:

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x50 pc=0x4407f56]

goroutine 10 [running]:
testing.tRunner.func1(0xc0000fe300)
	/usr/local/Cellar/go/1.13.4/libexec/src/testing/testing.go:874 +0x3a3
panic(0x45aff80, 0x4bef630)
	/usr/local/Cellar/go/1.13.4/libexec/src/runtime/panic.go:679 +0x1b2
github.com/binance-chain/tss-lib/tss.(*BaseParty).WaitingFor(0xc00048f290, 0x0, 0x0, 0x0)
	/Users/(...)/binance-chain/[email protected]/tss/party.go:49 +0x86
github.com/(...)/tss.TestWaitingFor(0xc0000fe300)
	/Users/(...)/tss_test.go:46 +0x329
testing.tRunner(0xc0000fe300, 0x4795300)
	/usr/local/Cellar/go/1.13.4/libexec/src/testing/testing.go:909 +0xc9
created by testing.(*T).Run
	/usr/local/Cellar/go/1.13.4/libexec/src/testing/testing.go:960 +0x350

Test:

func TestWaitingFor(t *testing.T) {
	groupPartiesIDs := []*tss.PartyID{
		tss.NewPartyID("party-1", "", big.NewInt(1)),
		tss.NewPartyID("party-2", "", big.NewInt(2)),
		tss.NewPartyID("party-3", "", big.NewInt(3)),
	}

	params := tss.NewParameters(
		tss.NewPeerContext(tss.SortPartyIDs(groupPartiesIDs)),
		groupPartiesIDs[0],
		len(groupPartiesIDs),
		len(groupPartiesIDs)-1,
	)

	tssMessageChan := make(chan tss.Message, len(groupPartiesIDs))
	endChan := make(chan keygen.LocalPartySaveData)

	party := keygen.NewLocalParty(params, tssMessageChan, endChan)

	waitingFor := party.WaitingFor()

	t.Logf("waiting for: %v", waitingFor)
}

[cbarraford]

I've seen a similar error, same bug, different execution...

PANIC: tss_4nodes_test.go:367: TssTestSuite.TestProcessVerMessage
... Panic: runtime error: invalid memory address or nil pointer dereference (PC=0x1030D31)
/usr/local/go/src/runtime/panic.go:679
  in gopanic
/usr/local/go/src/runtime/panic.go:199
  in panicmem
/usr/local/go/src/runtime/signal_unix.go:394
  in sigpanic
/Users/yb/go/pkg/mod/github.com/binance-chain/[email protected]/tss/party.go:53
  in BaseParty.WrapError
/Users/yb/go/pkg/mod/github.com/binance-chain/[email protected]/ecdsa/keygen/local_party.go:149
  in LocalParty.UpdateFromBytes
tss.go:446
  in Tss.updateLocal
tss.go:630
  in Tss.processVerMsg
tss.go:509
  in Tss.processOneMessage
tss_4nodes_test.go:339
  in TssTestSuite.testVerMsgAndUpdate
tss_4nodes_test.go:390
  in TssTestSuite.TestProcessVerMessage
/usr/local/go/src/reflect/value.go:321
  in Value.Call
/usr/local/go/src/runtime/asm_amd64.s:1357
  in goexit

[notatestuser]

Looks like both of these can happen before the party is started and therefore before a round is set.

The round used to be set in the constructor so this might be a bit of a regression after that change.