delegatecall safety: Implement min return size in DelegateProxy #248
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bingen
approved these changes
Mar 14, 2018
test/TestDelegateProxy.sol
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| function testFailIfReverts() { | ||
| TestDelegateProxy(throwProxy).revertIfReturnLessThanMinAndDie(); |
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Shouldn't this be revertCall?
sohkai
approved these changes
Mar 14, 2018
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| function testMinReturn0WithReturn() { | ||
| delegateFwd(target, target.returnSomething.selector.toBytes(), 0); |
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For these that don't fail, it'd be great if we could assert that their returns are the same as what Target should've returned (or nothing). But doing this would probably be easier in a separate JS-based test for the DelegateProxy.
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Adds a new param to
delegateFwd(...)to pass the minimum amount of bytes the underlying call must return, otherwise, it reverts. I kept the old function as a convenince method that just passes0as the minimum return data size.This allows things such as always forcing to return something when calling a specific type of contract to avoid a
selfdesctruct. Given that when aselfdestructoccurs the context is exited returning1(success) but always returns 0 bytes of data. Ideally this would be done at the protocol level, returning a different error code when itselfdestructs but we can't wait.This only works if you force the functions you forward to return something (setting the min to 32 and returning a boolean is enough).