pwrite卡巴斯基授权文件
卡巴斯基授权文件 时间:2021-02-28 阅读:(
)
AllFileSystemsAreNotCreatedEqual:OntheComplexityofCraftingCrash-ConsistentApplicationsThanumalayanSankaranarayanaPillai,VijayChidambaram,RamnatthanAlagappan,SamerAl-Kiswany,AndreaC.
Arpaci-Dusseau,RemziH.
Arpaci-DusseauAllFileSystemsAreNotCreatedEqual:OntheComplexityofCraftingCrash-ConsistentApplicationsThanumalayanSankaranarayanaPillai,VijayChidambaram,RamnatthanAlagappan,SamerAl-Kiswany,AndreaC.
Arpaci-Dusseau,RemziH.
Arpaci-DusseauCrashConsistencyMaintainingdatainvariantsacrossasystemcrash‐Example:DatabasetransactionsshouldbeatomicCrashConsistencyMaintainingdatainvariantsacrossasystemcrash‐Example:DatabasetransactionsshouldbeatomicImportantinsystems‐FileSystems‐RelationalDatabases‐Key-ValueStoresCrashConsistencyMaintainingdatainvariantsacrossasystemcrash‐Example:DatabasetransactionsshouldbeatomicImportantinsystems‐FileSystems‐RelationalDatabases‐Key-ValueStoresHardtogetright:ARIESinventedonlyin1992‐ProvingARIEStook5moreyears(1997)Lotsofworkinfilesystemcrashconsistency‐Journaling,copy-on-write,softupdates.
.
.
File-SystemCrashConsistencyLotsofworkinfilesystemcrashconsistency‐Journaling,copy-on-write,softupdates.
.
.
FSconsistencyfocusesoninternalmetadata‐DodirectoriesonlycontainvaliddirectoryentriesFile-SystemCrashConsistencyLotsofworkinfilesystemcrashconsistency‐Journaling,copy-on-write,softupdates.
.
.
FSconsistencyfocusesoninternalmetadata‐DodirectoriesonlycontainvaliddirectoryentriesWhataboutuser-leveldataFile-SystemCrashConsistencyWhatguaranteesdofilesystemsgiveapplications‐Thatcanbeusedforconsistencyofuser-leveldataThisworkstudies.
.
.
Whatguaranteesdofilesystemsgiveapplications‐Thatcanbeusedforconsistencyofuser-leveldataDoapplicationsmaintainconsistencycorrectly‐Importantapplicationsrequireuser-levelconsistency‐Databases,key-valuestores,distributedsystems.
.
.
Thisworkstudies.
.
.
Filesystemguaranteesvarywidely‐Studied16configsofext2,ext3,ext4,btrfs,xfs,reiserfs‐Guaranteesvaryamongconfigsofsamefilesystem‐Guaranteesoftenside-effectsofFSimplementation‐POSIXstandardsofguarantees,ifany,aredebatedWefind.
.
.
Filesystemguaranteesvarywidely‐Studied16configsofext2,ext3,ext4,btrfs,xfs,reiserfs‐Guaranteesvaryamongconfigsofsamefilesystem‐Guaranteesoftenside-effectsofFSimplementation‐POSIXstandardsofguarantees,ifany,aredebatedApplicationsdependonguaranteesinsubtleways‐Studied11applications:Databases,Distributedsystems,Virtualizationsoftware,Key-valuestores,VCS‐60vulnerabilitiesunderaweakfilesystemmodel‐Morethan30vulnerabilitiesunderext3,ext4,btrfsWefind.
.
.
IntroductionAnExampleBOB:ExaminingFileSystemBehaviorALICE:ExaminingApplicationsConclusionOutlineIntroductionAnExampleBOB:ExaminingFileSystemBehaviorALICE:ExaminingApplicationsConclusionOutlineAfileinitiallycontainsthestring"afoo"‐Assumeeachcharacterin"afoo"isablockofdataTask:Atomicallychangethecontentsto"abar"‐Onapowerloss,wemustretrieveeither"afoo"or"abar"ToyExample:OverviewToyExample:SimpleOverwriteInitialstate/x/f1"afoo"Finalstate/x/f1"abar"Modificationpwrite(/x/f1,2,"bar")IntermediatestatespossibleoncrashToyExample:SimpleOverwriteInitialstate/x/f1"afoo"Modificationpwrite(/x/f1,2,"bar")Finalstate/x/f1"abar"Intermediatestate1/x/f1"aboo"Intermediatestate2/x/f1"afar"Intermediatestates3,4,5.
.
.
.
WhatifcrashatomicityisneededUseapplication-levellogging(a.
k.
a.
undologging/rollbackjournaling)a.
Makeacopyofolddatain"log"fileb.
Modifyactualfilec.
Deletelogfiled.
Onacrash,datacanberecoveredfromthelogToyExample:MaintainingConsistencyWhatifcrashatomicityisneededUpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);WritetologActualmodificationDeletelogToyExample:Protocol#1Worksinext3(data-journal)!
UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);ToyExample:Protocol#1Somepossibleintermediatestates/x/f1"afoo"/x/log1""/x/f1"afoo"/x/log1"2,3,f"/x/f1"aboo"/x/log1"2,3,foo"1.
2.
3.
Worksinext3(data-journal)!
UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);Somepossibleintermediatestates/x/f1"afoo"/x/log1""/x/f1"afoo"/x/log1"2,3,f"/x/f1"aboo"/x/log1"2,3,foo"1.
2.
3.
ToyExample:Protocol#1SimplydeletelogfileduringrecoveryWorksinext3(data-journal)!
UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);Somepossibleintermediatestates/x/f1"afoo"/x/log1""/x/f1"afoo"/x/log1"2,3,f"/x/f1"aboo"/x/log1"2,3,foo"1.
2.
3.
ToyExample:Protocol#1RecoverfromlogfileduringrecoveryWorksinext3(data-journal)!
Doesn'tworkinext3(data-ordered)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);ToyExample:Protocol#1Worksinext3(data-journal)!
Doesn'tworkinext3(data-ordered)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);ext3(ordered)canre-orderthesetworequests,sendingpwrite(f1)todiskfirst,beforewrite(log1)ToyExample:Protocol#1Worksinext3(data-journal)!
Doesn'tworkinext3(data-ordered)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");pwrite(/x/f1,2,"bar");unlink(/x/log1);Apossibleintermediatestate/x/f1"aboo"/x/log1""Recoverynotpossible!
ToyExample:Protocol#1Worksinext3(data-journal),(data-ordered)!
UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");fsync(/x/log1);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);ToyExample:Protocol#2Worksinext3(data-journal),(data-ordered)!
Doesn'tworkinext3(writeback)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,foo");fsync(/x/log1);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);Apossibleintermediatestates/x/f1"afoo"/x/log1"2,3,#!
@"Filesizealoneincreasesforlog1,andgarbageoccurs.
Recoverycannotdifferentiatebetweengarbageanddata!
CrashhereToyExample:Protocol#2Worksinext3(data-journal),(data-ordered),(writeback)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,checksum,foo");fsync(/x/log1);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);ToyExample:Protocol#3Worksinext3(data-journal),(data-ordered),(writeback)Notenough,accordingtoLinuxmanpagesUpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,checksum,foo");fsync(/x/log1);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);Apossibleintermediatestates/x/f1"aboo"Thelogfile'sdirectoryentrymightneverbecreatedToyExample:Protocol#3WorksinallfilesystemsUpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,checksum,foo");fsync(/x/log1);fsync(/x);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);ToyExample:Protocol#4Worksinallfilesystems(Additionalfsync()requiredfordurabilityinallFS)UpdateProtocolcreat(/x/log1);write(/x/log1,"2,3,checksum,foo");fsync(/x/log1);fsync(/x);pwrite(/x/f1,2,"bar");fsync(/x/f1);unlink(/x/log1);fsync(/x);ToyExample:Protocol#5Filesystemsvaryincrash-relatedbehavior‐ext3(ordered)re-orders,whileext3(journaled)doesnotApplicationsusuallydependonsomebehavior‐Dependonordering:Somefsync()callscanbeomittedExample:SummaryIntroductionAnExampleBOB:ExaminingFileSystemBehaviorALICE:ExaminingApplicationsConclusionOutlineTwoclassesofproperties:atomicityandordering‐Atomicityexample:Isawrite()callatomicintheFS‐Orderingexample:Arewrite()callssenttodiskin-orderStudiedext2,ext3,ext4,btrfs,xfs,reiserfs‐Westudied16configurationsofthesixfilesystemsFSBehavior:PersistenceProperties1.
Runuser-levelworkloadsstressingtheproperty‐Example:write(8KB)fortestingatomicityofwrite()callsMethodology:TheBlock-OrderBreaker(BOB)1.
Runuser-levelworkloadsstressingtheproperty‐Example:write(8KB)fortestingatomicityofwrite()calls2.
Recordblock-leveltraceoftheworkloadMethodology:TheBlock-OrderBreaker(BOB)1.
Runuser-levelworkloadsstressingtheproperty‐Example:write(8KB)fortestingatomicityofwrite()calls2.
Recordblock-leveltraceoftheworkload3.
Reconstructdisk-statespossibleonapower-loss‐Allstatespossibleifdisk-cachedoesnotre-order‐Afewstateswheredisk-cachere-ordersMethodology:TheBlock-OrderBreaker(BOB)1.
Runuser-levelworkloadsstressingtheproperty‐Example:write(8KB)fortestingatomicityofwrite()calls2.
Recordblock-leveltraceoftheworkload3.
Reconstructdisk-statespossibleonapower-loss‐Allstatespossibleifdisk-cachedoesnotre-order‐Afewstateswheredisk-cachere-orders4.
RunFSrecovery,verifypropertyoneachdisk-state‐Example:Isall8KBwrittenatomicallyMethodology:TheBlock-OrderBreaker(BOB)FileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncFileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncFileSystemDifferentConfigurationsofFileSystemFileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncPersistencePropertiesconsideredFileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncIsadirectoryoperation,likerename(),atomiconasystemcrashFileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncPropertycertainlynotobeyedWedidnotseeaviolationFileSystemStudy:ResultsFilesystemconfigurationAtomicityOrderingOnesectoroverwriteAppendcontentManysectoroverwriteDirectoryoperationOverwrite→AnyopAppend→AnyopDir-op→AnyopAppend→Renameext2asyncsyncext3writebackordereddata-journalext4writebackorderedno-delallocdata-journalbtrfsxfsdefaultwsyncMainresult:FilesystemsvaryintheirpersistencepropertiesApplicationsshouldnotrelyonpersistencepropertiesTestingapplicationsonaspecificFSisnotenough‐ext3(data-journal):Re-orderingvulnerabilitiesarehiddenFileSystemStudy:ConclusionIntroductionAnExampleBOB:ExaminingFileSystemBehaviorALICE:ExaminingApplicationsConclusionOutlineALICE:Goal"Application-LevelIntelligentCrashExplorer"Goal:Tooltofindcrashvulnerabilitiesofanapplication‐Findvulnerabilitiesacrossallfilesystems‐Relatevulnerabilitiestospecificsourcelines‐RelatevulnerabilitiestofilesystembehaviorALICE:TechniqueUser-suppliedApplicationWorkloadALICEUsersuppliesALICEwithanapplicationworkload–Example:AdatabasetransactionALICE:TechniqueSystem-callTraceALICErunsworkloadandrecordssystem-calltraceALICEUser-suppliedApplicationWorkloadALICE:TechniqueSystem-callTraceAPM:AbstractPersistenceModelAPMmodelsallcrashstatesthatcanoccuronanFS–Default,weakAPMallowsmanypossiblestates–CustomAPMscanbeconfiguredbyuserforaspecificfilesystem–Eg:ext3(ordered)APMallowsstateswithoverwritesre-ordered;ext3(data-journal)APMdoesnotALICEUser-suppliedApplicationWorkloadALICE:TechniqueSystem-callTraceExplorerAPM:AbstractPersistenceModelExplorerreconstructssomestatesusingtheAPMALICEUser-suppliedApplicationWorkloadALICE:TechniqueSystem-callTraceExplorer.
.
.
ALICEAPM:AbstractPersistenceModelCrashstate#1(Violatesatomicityofsyscall-1)Crashstate#2(Violatesorderingofsyscall-1and2)Explorertargetsspecificstates–Relatingtoatomicityandre-orderingofeachsyscallUser-suppliedApplicationWorkloadTheapplicationisrunoneachreconstructedstate–Usersuppliesapplicationchecker–Example:WasACIDpreservedALICE:TechniqueSystem-callTraceExplorer.
.
.
User-suppliedApplicationCheckerALICEAPM:AbstractPersistenceModelCrashstate#1(Violatesatomicityofsyscall-1)Crashstate#2(Violatesorderingofsyscall-1and2)User-suppliedApplicationWorkloadCheckershowswhichstatesarerecoveredfromcorrectlyALICE:TechniqueSystem-callTraceExplorer.
.
.
ALICEAPM:AbstractPersistenceModelCrashstate#1(Violatesatomicityofsyscall-1)Crashstate#2(Violatesorderingofsyscall-1and2)CorrectIncorrectUser-suppliedApplicationWorkloadUser-suppliedApplicationCheckerFromcheckeroutputs,wedeterminevulnerabilitiesALICE:TechniqueSystem-callTraceExplorer.
.
.
Crashvulnerability:Re-orderingsyscall-1and2ALICEAPM:AbstractPersistenceModelCrashstate#1(Violatesatomicityofsyscall-1)Crashstate#2(Violatesorderingofsyscall-1and2)CorrectIncorrectUser-suppliedApplicationWorkloadUser-suppliedApplicationCheckerHDFSZooKeeperVMWarePlayerLMDBGDBMLevelDBPostgresHSQLDBSQLiteMercurialGitVulnerabilityStudy:ApplicationsNon-relationalDatabasesRelationalDatabasesVersionControlSystemsVirtualizationSoftwareDistributedServicesExample:Gitcreat(index.
lock)mkdir(o/x)creat(o/x/tmp_y)append(o/x/tmp_y)fsync(o/x/tmp_y)link(o/x/tmp_y,o/x/y)unlink(o/x/tmp_y)append(index.
lock)rename(index.
lock,index)stdout(finishedadd)Readthefullpapertocorrectlyinterpretresults!
creat(index.
lock)mkdir(o/x)creat(o/x/tmp_y)append(o/x/tmp_y)fsync(o/x/tmp_y)link(o/x/tmp_y,o/x/y)unlink(o/x/tmp_y)append(index.
lock)rename(index.
lock,index)stdout(finishedadd)Example:GitAtomicityvulnerabilityWhichsystemcallsneedtobeatomicReadthefullpapertocorrectlyinterpretresults!
creat(index.
lock)mkdir(o/x)creat(o/x/tmp_y)append(o/x/tmp_y)fsync(o/x/tmp_y)link(o/x/tmp_y,o/x/y)unlink(o/x/tmp_y)append(index.
lock)rename(index.
lock,index)stdout(finishedadd)Example:GitAtomicityvulnerabilityOrderingvulnerabilityWhichsystem-callre-orderingscauseincorrectnessReadthefullpapertocorrectlyinterpretresults!
VulnerabilityStudy:Default(Weak)APMReadthefullpapertocorrectlyinterpretresults!
VulnerabilityStudy:Default(Weak)APM60VulnerabilitiesManyresultinsilentdataloss,inaccessibleapplicationsReadthefullpapertocorrectlyinterpretresults!
VulnerabilityStudy:BtrfsAPMReadthefullpapertocorrectlyinterpretresults!
VulnerabilityStudy:BtrfsAPM31VulnerabilitiesReadthefullpapertocorrectlyinterpretresults!
Garbageduringfile-appends‐Affects3applications‐But,partialappendswithactualdata:0vulnerabilitiesFSsafetyheuristicsseeminglydon'thelpmuch‐Only2foundvulnerabilitiesby"Flushdatabeforerename"‐HeuristicsmighthelpothertypesofapplicationsNon-synchronousdirectoryoperations‐Affectsdurabilityof6applicationsWhatFSbehavioraffectsapplicationsIn-depth:WhatFSbehaviorsaffectapplicationsVulnerabilitiesunderotherAPMsInteractionswithapplicationdevelopersHownottointerpretourresultsAnefficientFSdesignwithsafetyvalidatedbyALICEInthepaper.
.
.
FSvaryinbehavioraffectingapplicationconsistency‐ext2,ext3,ext4,btrfs,xfs,reiserfsvaryevenamongtheirdifferentconfigurations‐SubtleimplementationdetailsaffectbehaviorApplicationprotocolsarecomplex,vulnerable‐60vulnerabilitiesunderweakAPM‐Morethanhalfexposedunderext3,ext4,btrfs‐Depend(bydesignorunwittingly)onFSimplementationSummaryApartingnote.
.
.
.
ExperiencedApp-Developer:POSIXdoesn'tletFSesdothatCanyoupointustotheexactPOSIXdocumentationDeveloper:Ican'tfindit,butIremembersomeonesayingsoApartingnote.
.
.
.
ExperiencedApp-Developer:POSIXdoesn'tletFSesdothatCanyoupointustotheexactPOSIXdocumentationDeveloper:Ican'tfindit,butIremembersomeonesayingsoExperiencedAcademic:Realfilesystemsdon'tdothatButdoesjustthatAcademic:Mystudentswouldflunkclassiftheybuiltafilesystemthatway.
.
.
Apartingnote.
.
.
.
ExperiencedApp-Developer:POSIXdoesn'tletFSesdothatCanyoupointustotheexactPOSIXdocumentationDeveloper:Ican'tfindit,butIremembersomeonesayingsoExperiencedAcademic:Realfilesystemsdon'tdothatButdoesjustthatAcademic:Mystudentswouldflunkclassiftheybuiltafilesystemthatway.
.
.
Thankyou!
Downloadtools:http://research.
cs.
wisc.
edu/adsl/Software/alice
BuyVM针对中国客户推出了China Special - STREAM RYZEN VPS主机,带Streaming Optimized IP,帮你解锁多平台流媒体,适用于对于海外流媒体有需求的客户,主机开设在拉斯维加斯机房,AMD Ryzen+NVMe磁盘,支持Linux或者Windows操作系统,IPv4+IPv6,1Gbps不限流量,最低月付5加元起,比美元更低一些,现在汇率1加元=0.7...
华纳云(HNCloud Limited)是一家专业的全球数据中心基础服务提供商,总部在香港,隶属于香港联合通讯国际有限公司,拥有香港政府颁发的商业登记证明,保证用户的安全性和合规性。 华纳云是APNIC 和 ARIN 会员单位。主要提供数据中心基础服务、互联网业务解决方案, 以及香港服务器租用、香港服务器托管、香港云服务器、美国云服务器,云计算、云安全技术研发等产品和服务。其中云服务器基于成熟的 ...
我们对于BlueHost主机商还是比较熟悉的,早年我们还是全民使用虚拟主机的时候,大部分的外贸主机都会用到BlueHost无限虚拟主机方案,那时候他们商家只有一款虚拟主机方案。目前,商家国际款和国内款是有差异营销的,BlueHost国内有提供香港、美国、印度和欧洲机房。包括有提供虚拟主机、VPS和独立服务器。现在,BlueHost 商家周年活动,全场五折优惠。我们看看这次的活动有哪些值得选择的。 ...
卡巴斯基授权文件为你推荐
有趣的广告比较有趣的广告词有哪些如何免费开通黄钻如何免费开通黄钻??支付宝查询余额支付宝怎么查余额?!?!邮箱打不开怎么办我的邮箱打不开怎么办渗透测试渗透测试的专业服务照片转手绘如何把真人图片用photoshop做成手绘图片镜像文件是什么什么是文件镜像?什么是镜像文件?中小企业信息化中小企业如何进行企业信息化规划苹果5怎么越狱苹果5怎么越狱怎么升级ios6苹果IOS5怎么升级IOS6版本
jsp虚拟主机 花生壳动态域名 域名管理 国外服务器租用 justhost 荷兰服务器 awardspace godaddy续费优惠码 国外空间服务商 evssl 网通服务器ip 服务器架设 php空间推荐 世界测速 美国网站服务器 阿里云官方网站 qq金券 hdroad forwarder 服务器是什么意思 更多