Fix crash in CModelInfoSA::MakeObjectModel with weapon-based objects#4951
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TheCrazy17 wants to merge 1 commit into
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Fix crash in CModelInfoSA::MakeObjectModel with weapon-based objects#4951TheCrazy17 wants to merge 1 commit into
TheCrazy17 wants to merge 1 commit into
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MakeObjectModel copied only sizeof(CBaseModelInfoSAInterface) bytes, including the base model's vtable pointer. For weapon models, the inherited GetAnimFileIndex() reads m_nAnimFileIndex past the allocated buffer, returning garbage used as a model ID and crashing the game. Allocate/copy a CClumpModelInfoSAInterface instead, like MakeClumpModel does, and reset m_nAnimFileIndex to -1.
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Summary
CModelInfoSA::MakeObjectModelnow allocates and copies aCClumpModelInfoSAInterface-sized buffer (instead ofCBaseModelInfoSAInterface) and resetsm_nAnimFileIndexto-1, matching the existing pattern used byMakeClumpModel.Motivation
Fixes #4241.
MakeObjectModelonly allocated and copiedsizeof(CBaseModelInfoSAInterface)bytes from the base model's interface, including its vtable pointer. When the base model is a weapon (CClumpModelInfoSAInterface-derived), the inherited vtable'sGetAnimFileIndex()readsm_nAnimFileIndexat an offset past the allocated buffer. This out-of-bounds read returns garbage, which is then used as a model ID in a recursiveCStreaming::RequestModelcall, crashing the game (e.g.engineRequestModel("object", 359)followed byengineReplaceModel).Test plan
Reproduced the crash from #4241 using
engineRequestModel("object", 359)+engineLoadTXD/engineImportTXD/engineLoadDFF/engineReplaceModelon an unpatched build. With this fix applied, the same script no longer crashes.Checklist