Panic if a node without PRIVATE_CONFIG set sees a private transaction

[marcosio]

System information

Geth version: 1.7.2-stable

OS & Version: Linux

Branch, Commit Hash or Release: ee498061b5a74bf1f3290139a53840345fa038cb

Expected behaviour

We are using IBFT consensus over Quorum v.2.0.1 and Constellation 0.3.1.

We don't want our validator nodes to start constellation and PRIVATE_CONFIG isn't defined because we want them to be specialized in running the consensus algorithm.

When a regular node starts a private transaction the validator node must mine the block.

Actual behaviour

When a regular node starts a private transaction, the validator node raises a runtime error and terminates.

Steps to reproduce the behaviour

Don't start constellation with Geth in one node and send a private transaction.

Backtrace

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x57a9cf]

goroutine 53 [running]:
panic(0xefb180, 0xc420012090)
	/usr/local/go/src/runtime/panic.go:500 +0x1a1
github.com/ethereum/go-ethereum/core.(*StateTransition).TransitionDb(0xc433585570, 0x1936460, 0xc42754c060, 0xc4336cf4c0, 0xc433585570, 0x1012320, 0xc42754c060, 0xc45c9d2820, 0x1012320)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/core/state_transition.go:235 +0xe2f
github.com/ethereum/go-ethereum/core.ApplyMessage(0xc42ebf9000, 0x1936460, 0xc42754c060, 0xc4336cf4c0, 0xc42754c060, 0x52c8067c, 0xc42754e020, 0x74c44c9449c37db8, 0x178a7a62de5d7774, 0x3245c91f, ...)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/core/state_transition.go:138 +0x5b
github.com/ethereum/go-ethereum/core.ApplyTransaction(0xc42025a480, 0xc420223000, 0xc45c9d52b8, 0xc4336cf4c0, 0xc42f3480f0, 0xc42f3481e0, 0xc42f346b40, 0xc42ad46630, 0xc4300fb980, 0x0, ...)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/core/state_processor.go:121 +0x571
github.com/ethereum/go-ethereum/miner.(*Work).commitTransaction(0xc42a931800, 0xc42ad46630, 0xc420223000, 0x74c44c9449c37db8, 0x178a7a62de5d7774, 0x3245c91f, 0xc4336cf4c0, 0x0, 0xc4201d6c70, 0x0, ...)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/miner/worker.go:604 +0x1d5
github.com/ethereum/go-ethereum/miner.(*Work).commitTransactions(0xc42a931800, 0xc42040fa70, 0xc45b254600, 0xc420223000, 0x74c44c9449c37db8, 0x178a7a62de5d7774, 0x3245c91f)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/miner/worker.go:549 +0x2c7
github.com/ethereum/go-ethereum/miner.(*worker).commitNewWork(0xc420296dc0)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/miner/worker.go:470 +0x9cb
github.com/ethereum/go-ethereum/miner.(*worker).update(0xc420296dc0)
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/miner/worker.go:260 +0x232
created by github.com/ethereum/go-ethereum/miner.newWorker
	/home/ubuntu/alastria-node/scripts/quorum/build/_workspace/src/github.com/ethereum/go-ethereum/miner/worker.go:159 +0x5ea

Solution proposed

We make a fork of quorum repository and change core/state_transition.go verifying if private.P is nil.

		if private.P != nil {
			data, err = private.P.Receive(st.data)
		} else {
			err = errConstellationIsntInit
		}

[markya0616]

I don't think it's an IBFT issue. It's a general issue about private transactions. @patrickmn Any thoughts?

[patrickmn]

Right, this is not a consensus issue. Quorum expects to have a Constellation node configured if it sees private transactions because it needs to check with that Constellation node to ensure it's not a recipient. This is mostly to avoid a scenario where somebody forgets to set PRIVATE_CONFIG , but it doesn't have to be that way.

@marcossanlab What if we added PRIVATE_CONFIG=ignore or similar to indicate that you explicitly want to ignore private transactions?