Silent deserialization exceptions

[linyinfeng]

Many deserialization exceptions are not reported to the user. These exceptions are all silently caught by catch (...) {}.

This makes troubleshooting much harder.

I follow https://docs.zerotier.com/roots/ to configure my own moon. But my moon file does not work; zerotier-cli listmoons shows nothing. I tried zerotier compiled with ZT_DEBUG=1, but no message related to moons printed. Then I read the code and tried to insert some fprintf, and it turns out that the method deserialize of World failed, throwing a ZT_EXCEPTION_INVALID_SERIALIZED_DATA_OVERFLOW, which is silently ignored.

ZeroTierOne/node/Topology.cpp

Lines 311 to 318 in 663ed73

	try {
	World w;
	w.deserialize(Buffer<ZT_WORLD_MAX_SERIALIZED_LENGTH>(tmp,(unsigned int)n));
	if ((w.type() == World::TYPE_MOON)&&(w.id() == id)) {
	addWorld(tPtr,w,true);
	return;
	}
	} catch ( ... ) {}

After reading the code of the method, I finally figured out that the problem lies in the following code. I fixed my configuration by increasing the ZT_WORLD_MAX_ROOTS to a bigger number. The process of troubleshooting is not user-friendly.

ZeroTierOne/node/World.hpp

Lines 228 to 230 in 663ed73

	if (numRoots > ZT_WORLD_MAX_ROOTS) {
	throw ZT_EXCEPTION_INVALID_SERIALIZED_DATA_OVERFLOW;
	}