Nothing but invalid shares submitted

[obigal]

I would like to see some kind of ban and/or disconnect, or maybe we could just stop putting shares into the tables after x number of invalid shares in a row, I had a couple of instances where a user was sending nothing but invalid shares but everybody else was hashing just fine, must have been something on their end messed up.

[moopless]

I have been thinking about this and I am having a hard time coming up with a way to implement this without possibly affecting normal users. This could be a big issue for attacks. Someone could submit all shares (any difficulty) and overload the server. Since stratum hashes every share that comes in, it would not be difficult to overload a cpu with a gpu.

We could cache the last X shares and then block the user if all X shares are invalid, while flushing the cache every Y seconds. We could also update the database to let the front end know that the user has been blocked.

Thoughts?

[obigal]

I've been thinking about some and I really don't know what the best course of action to take, I've even seen myself send a lot of bad shares in a row when switching pools, sometimes even until the next block is found, I think cgminer gets a little confused at times, so we would need to be very careful not to block someone unintentionally.