demandvista系统优化

WindowsVistaHeapManagementEnhancementsAdrianMarinescuDevelopmentLeadadrmarin@microsoft.
com2AgendaWindowsNTHeapManagementbasicsandevolutionWindowsVistaheap–majormilestone–Developmentprinciplesandguidelines–Securityfeatures–PerformancefeaturesQ&A3IntroductionSecurity–industry-wideconcernTwCdrivingmultiplesecurityinitiativesTheNTHeap–Strategicpointindefense–Improvedtorespondtoindustrytrendsinusage4PartI–Basics5HeapEvolutionTimeNT4NT4/SP4Windows2000XP/SP2Windows2003WindowsVistaBasicsPerformanceOpt-inSMPScalabilityHeapMitigationsEnhancedsecurityPerformanceQualitytoolIndustryWorkloadExploitationParallelism6NTHeapOverviewTheNTMemoryManagerSegmentManagement(forblocks1KNon-dedicatedfreelist(1–512KBytes)Segment1Segment64Segmentarray>512KVirtualBlocksList816>512K8HeapSegmentsSeg.
HB1B2UncommitedspaceBn…ByUncommitedspaceReservedspace9BlockEntryinpriorWindowsNTVersions0:018>dc04392f8004392f8000040002000000010442da6000240e68SizePreviousblocksizetagunusedbytesflagssegmentF-LinkB-Link10RoleofLinkEntryinEarlyExploitsArbitrarypointerwritemovmoveaxeax,DWORDPTR[,DWORDPTR[ecxecx]]movmovecxecx,DWORDPTR[ecx+4],DWORDPTR[ecx+4]movmovDWORDPTR[DWORDPTR[ecxecx],],eaxeaxmovmovDWORDPTR[eax+4],DWORDPTR[eax+4],ecxecxFwdLinkBkLinkValuetowriteLocationtowrite11LookasideListsNon-blockingsingle-linkedlists0-89-16Lookasidelists1016-1024HeaderLinkunusedHeaderLinkunused12TheLowFragmentationHeapArchitectureSMPUnit10-89-16Allocationbuckets1025-108815873-16384AllocationgranularitySMPUnitNSMPUnit1SegmentspoolSegmentspoolSegmentspool13LowFragmentationHeapBlockEntrySub-SegmentFlags…RelativelinkSizeLFHBlockFrees-listSub-Segment…8bytesUserdata14EarlyHeapMitigationsSafeListRemovalEntry->FwdLink->BkLink==Entry->BkLink->FwdLink==Entry8-bitcookietestedonfreeLFHblockentryencodingF(randomnumber,Blockaddress,heap)15ChangeinLandscapeNewexploitingmethodssurfacedChangeinusageoutlook–Memoryusage–IncreaseavailabilityofSMP–Increaserelevanceof64bitcomputingCodequality–higherdemandinindustry16WindowsVistaHeapManagerKeyDevelopmentDirectionsPerformanceandreliabilitySecurityCodequality17WindowsNTHeapRequirements18SecurityCorrectness–like:–Guaranteesrequestedsizes–Lifetimeofallocations–Clearingcontentwhenrequestedetc.
Defenselineinheapbasedexploits:Defenselineinheapbasedexploits:––AttemptstomitigatetheeffectofanattackAttemptstomitigatetheeffectofanattack––MakesdifficulthidingheapMakesdifficulthidingheap--basedexploitsbasedexploits19PerformanceScalefromsmalldevicestolargeserversOptimizedforvariedusagepatternsFollowtheindustrytrend–Memoryusage–IncreaseinSMPavailability–H/Warchitectureadvances20CompatibilityApplicationsmayrelyonthingslike:–Reallocreturningsamepointer–Read/writeafterreleasingablock–Doublefree–Overrunsoverunusedstructuresetc.
Heapchangesmayhaveunintendedeffects,suchas:–Crashes,leaksorbrokenfunctionalityinpoorlywrittenapplications–Severeperformanceregressions21PartII-WindowsVistaHeap22WindowsVistaHeapSecurityFeaturesBlockmetadatarandomizationIntegritycheckonblockentryAlgorithmvariationinresponsetousagepatternRandomrebasingFunctionpointerrandomizationAbruptapplicationterminationonerror23BlockMetadataRandomizationApartoftheheaderisXORdwitharandomvalueLowperformanceimpactShouldmakeguessingtherightvalueimpracticalFlexibleandcontainedalgorithmandimplementationAgileinupdates24EntryIntegrityCheckPrevious8-bitcookiehasbeenrepurposedtovalidatealargerpartoftheheaderValuemayberandomizedalongwiththeotherfieldsValidatedduringinternaloperationstoo25Demo–HeapHeaderLayout26Automatictuning–ShifttoLFHallocationsatarbitrarypointsonruntime–Triggersonvariouspatterns–Involvesalsode-commit/commitpoliciesRuntimeAlgorithmVariation27MoreHeapRandomizationsHeapbaserandomization–thingstoconsider:–Fragmentationoftheapplicationaddressspaceaffectinglargeserverapplications–PossibleperformanceissuesifhigherrandomizationisusedHeapfunctionpointerrandomization–Takesawayaknownplacetofacilitatethecodeexecutionalongwithrebasing28Demo29AbruptTerminationonErrorAnydatainconsistencyorinvalidheapfunctionusagedetectedmaytriggeritThescopeisprocess-wide(anyheapintheprocesshasthesamebehavior)TheprocessisterminatedviaWindowsErrorReportingDetailedinfoisavailableinthedumpfileNofunctionprovidedtodisableitOnbydefaultfor64bitplatforms&apps30TerminationonErrors(cont.
)Programmaticopt-Inmethod(newHeapEnableTerminationOnCorruptionclassdefined)BOOLHeapSetInformation(HANDLEHeapHandle,HEAP_INFORMATION_CLASSHeapInformationClass,PVOIDHeapInformation,SIZE_THeapInformationLength);LargenumberofcomponentswithWindowsVistaareoptedinTheinformationisavailableinadebuggerextension31Demo32NTHeapManager–ImprovesCodeQualityBenefitstoappdevelopersEarlyerrordetectionImproveddebuggingaidtoreducecostofinvestigatingcorruptionsReducedtolerancetomisusageWindowsVistaappswillbemoreresilienttofutureheapchanges33KnownAttackVectors&WindowsVistaRemovedlookasidelistandarrayofliststargetedbypreviousexploitsIntegritycheckonblockmetadatasignificantobstacletobruteforceattacksMostWindowsprocessesterminateonmemoryerrorsDynamic(runtime)changeinheapalgorithmsobstacletoconsistentexploitsHeapstructuresandmemorymgmtchangeslimitportabilityofexploits34SecurityenhancementsareajourneyMitigationsarenotsubstituteforgooddevelopmentpracticesWindowsVistaisjustamilestoneincontinualheapimprovements35WindowsVistaHeapPerf&ReliabilityImprovedscenariosbydefaultfor:SMPscalabilityExternalfragmentationLargeheapsImprovedreferencelocalityon64bitplatformsReducedVirtualAddressexhaustionIncreasedresiliencetopatternsinvolvinglong-termallocations36KeyPerformanceEnhancementsAutomatictuningLowergranularityofcontrolpoliciestoswitchtotheLowFragmentationHeapUseoflazyinitializationRedesignedsegmentmanagementImprovedinternallookupalgorithmsAddressedfragmentationinproblematicscenariosLoweroverheadon64bit37RandomAllocationBenchmark(0-1K)05101520253012345678MillionThreadsOps.
/secWindowsServer2003RecentWindowsVistaRandomAllocationBenchmark(4-8k)0246810121416182012345678MillionThreadsOps.
/secWindowsServer2003RecentWindowsVista38FragmentationTest(512blocks/80bytes)VirtualaddressCost010002000300040005000600070008000Runtime(sec)BytesperleakedbloRecentWindowsVistaWindowsServer2003Committedmemorycost0100200300400500600700800Runtime(sec)BytesperleakedbloRecentWindowsVistaWindowsServer200339FragmentationTest(512blocks/80bytes)Heapperformanceonheapexpansionpattern1(512blocks)(70x)0100000200000300000400000500000600000700000800000Runtime(sec)Ops.
/secRecentWindowsVistaWindowsServer200340FragmentationScenarioIIPatternPatternOps/secOps/sec(Recent(RecentWindowsWindowsVista)Vista)Ops/secOps/sec(Windows(WindowsServerServer2003SP1)2003SP1)ImprovemeImprovementntxx2562576004388663951292770915161441024403774517917204819418025776740968253412687841Memoryfootprinton2GBytesheapexpansion0500100015002000250030003500400045003264128256512102420484096BlocksizeMbytesmemorReservedMemoryInRecentWindowsVistaCommitedMemoryInRecentWindowsVistaReservedMemoryInWindowsServer2003CommitedMemoryInWindowsServer200342SummaryAttacksgetmoresophisticated…Butsodoestheheapmanagement–andnotonlyforsecurityWelaidthefoundationforincreasedagilityinheapimprovementswithreducedcompatibilityrisksImprovedscenariosforSMPandlargememoryusageDesignedtoenhancethecodequalityforapplicationsWearenotyetdone…wearelookingforwardforfurtherenhancementsasneededComeseemewithyourideas!
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