Luam tawm Shufflecake, ib qho khoom siv rau kev tsim cov zais encrypted disk partitions

Lub tuam txhab soj ntsuam kev ruaj ntseg Kudelski Security tau luam tawm ib lub cuab yeej hu ua Shufflecake uas tso cai rau koj los tsim cov ntaub ntawv zais cov kab ke sib faib thoob plaws qhov chaw dawb ntawm cov khoom uas twb muaj lawm thiab tsis paub qhov txawv ntawm cov ntaub ntawv seem. Partitions yog tsim nyob rau hauv xws li ib tug txoj kev uas tsis paub qhov tseem ceeb nkag mus, nws yog ib qhov nyuaj rau ua pov thawj lawv lub neej txawm tias thaum ua forensic tsom xam. Cov cai ntawm cov khoom siv hluav taws xob (shufflecake-userland) thiab Linux ntsiav module (dm-sflc) yog sau rau hauv C thiab muab faib raws li GPLv3 daim ntawv tso cai, uas ua rau nws tsis tuaj yeem suav nrog cov ntawv luam tawm hauv lub ntsiab Linux kernel vim tsis sib haum nrog GPLv2 daim ntawv tso cai nyob rau hauv uas cov ntsiav tau muab.

Lub phiaj xwm tau muab tso rau hauv qhov kev daws teeb meem ntau dua li Truecrypt thiab Veracrypt rau kev zais cov ntaub ntawv uas yuav tsum tau muaj kev tiv thaiv, uas muaj kev txhawb nqa ib txwm muaj rau Linux platform thiab tso cai rau koj tso rau 15 qhov muab zais zais ntawm lub cuab yeej, zes hauv ib leeg kom tsis meej pem qhov kev txheeb xyuas. ntawm lawv lub neej. Yog tias kev siv Shufflecake nws tus kheej tsis yog ib qho zais cia, raws li tuaj yeem txiav txim siab, piv txwv li, los ntawm kev muaj cov khoom siv sib txuas hauv lub cev, ces tag nrho cov ntaub ntawv zais tau tsim tsis tuaj yeem txiav txim siab. Cov tsim zais partitions tuaj yeem tsim los ntawm tus neeg siv qhov kev txiav txim siab kom haum rau txhua qhov system, piv txwv li, ext4, xfs lossis btrfs. Txhua qhov kev faib tawm raug kho raws li cais cov cuab yeej virtual thaiv nrog nws tus kheej tus yuam sij qhib.

Txhawm rau kom tsis meej pem cov kab, nws tau thov kom siv tus qauv "plausible deniability" tus cwj pwm, qhov tseem ceeb ntawm cov ntaub ntawv tseem ceeb yog muab zais raws li cov txheej txheem ntxiv hauv cov seem encrypted nrog cov ntaub ntawv tsis tshua muaj txiaj ntsig, tsim ib hom kev zais hierarchy ntawm ntu. Nyob rau hauv cov ntaub ntawv ntawm lub siab, tus tswv ntawm lub cuab yeej tuaj yeem nthuav qhia tus yuam sij rau encrypted partitions, tab sis lwm qhov partitions (txog 15 qib nested) tej zaum yuav muab zais rau hauv qhov kev faib no, thiab txiav txim siab lawv muaj thiab ua pov thawj tias lawv muaj teeb meem.

Kev zais yog ua tiav los ntawm kev tsim txhua qhov kev faib tawm raws li cov txheej txheem encrypted muab tso rau ntawm random txoj haujlwm ntawm lub cuab yeej cia. Txhua daim yog tsim dynamically thaum xav tau qhov chaw cia ntxiv hauv qhov muab faib. Txhawm rau ua kom qhov kev soj ntsuam nyuaj dua, cov ntu ntawm cov ntu sib txawv yog hloov pauv, piv txwv li. Shufflecake seem tsis txuas rau thaj tsam sib txuas thiab cov hlais los ntawm txhua ntu yog sib xyaw. Cov ntaub ntawv hais txog kev siv thiab pub dawb yog khaws cia rau hauv daim ntawv qhia chaw uas cuam tshuam nrog txhua qhov kev faib tawm, uas yog siv los ntawm lub taub hau encrypted. Cov ntawv teev lus thiab header yog encrypted thiab, tsis paub tus yuam sij nkag, yog qhov txawv ntawm cov ntaub ntawv random.

Lub header tau muab faib ua cov slots, txhua tus uas txhais nws tus kheej ntu thiab cov kab sib txuas. Cov slots nyob rau hauv lub header yog stacked thiab recursively txuas - qhov tam sim no qhov muaj tus yuam sij rau decrypt cov tsis tau ntawm yav dhau los seem nyob rau hauv lub hierarchy (qhov tsawg zais ib tug), tso cai rau ib lo lus zais siv los decrypt tag nrho cov tsawg zais seem txuam nrog. ntu xaiv. Txhua qhov muab faib tsawg dua kho cov ntu ntawm cov nested partitions dawb.

Los ntawm lub neej ntawd, tag nrho Shufflecake subsections muaj qhov pom loj tib yam li cov ntu sab saum toj. Piv txwv li, yog tias muaj peb qhov kev faib tawm ntawm 1 GB ntaus ntawv, txhua tus ntawm lawv yuav pom rau lub kaw lus raws li 1 GB muab faib thiab tag nrho cov chaw muaj disk yuav muab faib rau txhua qhov kev faib tawm - yog tias tag nrho qhov loj ntawm cov ntaub ntawv khaws cia ntau dua. qhov tseeb qhov loj ntawm lub cuab yeej, nws yuav pib qhov yuam kev I / O pov tseg.

Nested seem uas tsis qhib tsis koom rau hauv qhov chaw faib, i.e. ib qho kev sim ua kom tiav qhov kev faib tawm sab saum toj yuav ua rau cov ntaub ntawv raug muab faib rau hauv cov khoom sib cais, tab sis yuav tsis ua rau nws muaj peev xwm nthuav tawm lawv lub xub ntiag los ntawm kev txheeb xyuas qhov loj ntawm cov ntaub ntawv uas tuaj yeem muab tso rau hauv qhov muab faib ua ntej qhov yuam kev pib (nws yog xav tias cov partitions sab sauv muaj immutable cov ntaub ntawv los cuam tshuam cov xim thiab yeej tsis cais tsis siv, thiab ib txwm ua hauj lwm yog ib txwm ua nrog rau feem ntau tsis ntev los no nested seem, lub tswvyim nws tus kheej txhais tau hais tias nws yog ib qho tseem ceeb heev kom muaj lub secrets ntawm lub hav zoov. cov ntaub ntawv dua li poob cov ntaub ntawv no).

Qhov tseeb, 15 Shufflecake partitions yeej ib txwm tsim - tus neeg siv lo lus zais txuas nrog rau cov khoom siv siv, thiab cov partitions tsis siv tau muab nrog tus password tsim tawm (nws tsis tuaj yeem nkag siab tias yuav siv pes tsawg partitions tiag tiag). Thaum Shufflecake partitions pib, lub disk, muab faib, lossis virtual thaiv cov cuab yeej faib rau lawv qhov kev tso kawm yog sau nrog cov ntaub ntawv random, uas ua rau nws tsis tuaj yeem txheeb xyuas Shufflecake metadata thiab cov ntaub ntawv tawm tsam keeb kwm yav dhau.

Kev siv Shufflecake muaj kev ua haujlwm siab, tab sis vim muaj cov nyiaj siv ua haujlwm, nws yog kwv yees li ob zaug qeeb hauv kev xa tawm piv rau disk encryption raws li LUKS subsystem. Siv Shufflecake kuj ua rau cov nqi ntxiv rau RAM thiab qhov chaw disk rau khaws cov ntaub ntawv pabcuam. Kev noj nco yog kwv yees li ntawm 60 MB ib qhov kev faib tawm, thiab qhov chaw disk ntawm 1% ntawm tag nrho qhov loj me. Rau kev sib piv, cov txheej txheem WORAM, zoo ib yam li lub hom phiaj, ua rau qeeb ntawm 5 txog 200 zaug nrog 75% poob ntawm qhov chaw siv tau.

Cov cuab yeej thiab cov ntsiav module tsuas yog tau sim ntawm Debian thiab Ubuntu nrog cov kernels 5.13 thiab 5.15 (txhawb ntawm Ubuntu 22.04). Nws raug sau tseg tias qhov project tseem yuav tsum tau suav tias yog tus qauv ua haujlwm, uas yuav tsum tsis txhob siv los khaws cov ntaub ntawv tseem ceeb. Nyob rau hauv lub neej yav tom ntej, peb npaj yuav ua kom optimization ntxiv rau kev ua tau zoo, kev ntseeg tau thiab kev ruaj ntseg, nrog rau muab lub peev xwm rau khau raj ntawm Shufflecake partitions.

Tau qhov twg los: opennet.ru

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