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Patch 1.24d
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FIXES

- Fixed a client crash related to queuing too many invalid build commands ("crash hack").

The crash worked by abusing the finite stack size that the WC3 main thread had. Many people who map WC3 probably have noticed how triggers can only execute so much code in one batch before the execution stops whether or not the end of the code was reached. Getting too many operations to run at once will result in WC3 hitting its stack size limit and so prevent any further execution of actions.

The glitch that the hackers used to crash players was simply getting a unit to execute an order with a non positional exit and then que up approximately 10000 invalid build orders which will collapse instantly and so hit the main thread stack limit. When this stack limit is reached, the game crashes. The accompanying hack for this crash however made the cheater immune to the crash (by for example increasing the stack size) and then could be used to issue 1000s of invalid build orders to collapse instantly when ready. To get the orders to collapse, a building must be qued inside an existing building 1000s of times so they all the qued orders can collapse at the same time. This que is started by getting a unit to patrol or smart another unit in an order which only can finish when the unit dies and then, after queuing enough build orders, killing the followed unit so the builder tries to complete them. The hack helped here again by ordering buildings inside already built buildings which is impossible is normal WC3.

This patch prevents (or is said to) stack crash from occurring so melee ranked games should be playable again. However by fixing this bug they may have changed the mechanics behind certain systems of the game in a currently unknown way.