Check input sanitization for rounded decimals

[cwgoes]

e.g. validator power (.RoundInt64() for TM power), over 2 ** 64 will cause a panic, this is a possible DoS vector.

[jackzampolin]

Is this still an issue @cwgoes? And if not, where does this need to get fixed? There are quite a few calls to .RoundInt64()...

[cwgoes]

#2958 will help, we should audit all remaining calls.

[jackzampolin]

@cwgoes @rigelrozanski can we go ahead and close this one?

[rigelrozanski]

@cwgoes how is this related to #2513 - maybe I just don't understand what's remaining in 2513 actually

[cwgoes]

It's related to #2513 in the sense that at present, validator powers over 2 ** 64 (which are possible) would cause the state machine to panic. We need to ensure that whatever changes we introduce to fix #2513 also prevent the possibility of panic.

[rigelrozanski]

got it - they're tightly related issues

[rigelrozanski]

post- #3400 AFAICT the only non test instances of RoundInt64 are:

x/auth/ante.go:311:			requiredFees[i] = sdk.NewInt64Coin(gp.Denom, fee.Ceil().RoundInt64())
x/auth/client/txbuilder/txbuilder.go:178:			fees[i] = sdk.NewInt64Coin(gp.Denom, fee.Ceil().RoundInt64())
x/slashing/params.go:110:	return sdk.NewDec(signedBlocksWindow).Mul(minSignedPerWindow).RoundInt64()