Key Takeaways
- Rowhammer tuaj yeem hloov cov khoom hauv RAM los ntawm hammering nrog cov ntaub ntawv.
- Blacksmith yog daim ntawv tshiab ntawm kev tawm tsam uas hla DDR4 qhov kev tiv thaiv built-in.
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Txawm tsis pom nyob rau hauv cov tsiaj qus, kev tawm tsam tuaj yeem siv tawm tsam "tus nqi siab" lub hom phiaj.
Daim ntawv tshiab qhia txog kev tawm tsam tshiab, hu ua Blacksmith, uas tuaj yeem hla kev ruaj ntseg ntawm cov cuab yeej los ntawm kev ua rau lub cim xeeb ntawm lub cuab yeej rau hauv lub xeev xav tau.
Tshaj tawm los ntawm Comsec, pab pawg tshawb fawb kev nyab xeeb los ntawm Lub Tsev Haujlwm Saib Xyuas Kev Tshawb Fawb thiab Hluav Taws Xob Hluav Taws Xob ntawm ETH Zürich, daim ntawv piav qhia txog "Rowhammer" kev tawm tsam uas ua rau lub cim xeeb nrog cov ntaub ntawv tsis txaus ntseeg kom ua rau me ntsis tig. Comsec qhov kev sib tw tshiab ntawm qhov kev tawm tsam no, Blacksmith, tuaj yeem hla kev tiv thaiv siv los ntawm DDR4 nco los tiv thaiv cov kev tawm tsam no.
"Txhua yam khoom siv uas muaj DRAM yog qhov yuav muaj qhov tsis zoo," Kaveh Razavi, tus pab xibfwb ntawm ETH Zürich thiab tus thawj coj ntawm Comsec, hais rau Lifewire hauv email.
Tsis txhob txhawj. Tej zaum
Qhov kev tawm tsam yog staggering. Thaum Razavi hais tias "txhua yam khoom siv," nws txhais tau tias "txhua yam khoom siv."
Comsec qhov kev sim, uas suav nrog DDR4 cov qauv cim xeeb los ntawm Samsung, Micron, thiab Hynix, tau ua rau cov khoos phis tawj uas khiav Ubuntu Linux, tab sis nws tuaj yeem ua haujlwm tawm tsam ze li txhua yam khoom siv uas muaj DDR4.
Txawm tias nws muaj peev xwm, feem ntau cov tib neeg tsis tas yuav txhawj xeeb txog Kev Txhaum Cai tseem tsis tau. Nov yog qhov kev tawm tsam uas xav tau kev txawj ntse thiab kev siv zog kom muaj kev vam meej.
"Vim tias qhov kev tawm tsam yooj yim dua feem ntau muaj, peb xav tias cov neeg siv nruab nrab yuav tsum tsis txhob txhawj txog qhov no ntau dhau," Razavi hais. "Zaj dab neeg sib txawv yog tias koj yog tus tshaj tawm xov xwm lossis tus neeg ua haujlwm (qhov peb hu ua 'lub hom phiaj muaj txiaj ntsig')."
Yog tias koj yog lub hom phiaj muaj txiaj ntsig, koj cov kev xaiv raug txwv. Nco nrog kev kho qhov yuam kev (ECC) ntau dua, tab sis tsis muaj zog, thiab tseem tsis muaj nyob rau ntawm cov neeg siv khoom siv feem ntau.
Qhov kev tiv thaiv zoo tshaj plaws yog kom tsis txhob muaj cov ntawv thov tsis ntseeg. Razavi kuj pom zoo kom siv qhov browser txuas ntxiv uas thaiv JavaScript, raws li cov kws tshawb fawb tau pom tias JavaScript tuaj yeem siv los tua Rowhammer.
Kev Tiv Thaiv Kev Tiv Thaiv
Rowhammer nws tus kheej tsis yog qhov kev tawm tsam tshiab. Nws tau raug coj los rau hauv ib daim ntawv xyoo 2014 los ntawm Carnegie Mellon University thiab Intel Labels, hu ua "Flipping Bits in Memory without accessing them: Ib qho Kev Tshawb Fawb Kev Tshawb Fawb ntawm DRAM cuam tshuam yuam kev." Daim ntawv ntawd tau pom qhov yuam kev hauv DDR3 nco.
Txhua yam khoom siv uas muaj DRAM yog qhov yuav muaj qhov tsis zoo.
DDR4 suav nrog kev tiv thaiv, Target Row Refresh (TRR), txhais tau tias tiv thaiv Rowhammer los ntawm kev kuaj pom kev tawm tsam thiab ua kom lub cim xeeb ua ntej cov ntaub ntawv kev noj nyiaj txiag tshwm sim. Blacksmith hla qhov no los ntawm kev kho qhov kev tawm tsam kom siv cov qauv tsis sib xws uas tsis ua rau DDR4 kev tiv thaiv, rov qhia Rowhammer raws li kev txhawj xeeb rau cov khoom siv tshiab xav kom muaj kev nyab xeeb.
Tseem, tsis yog txhua lub cim xeeb yog qhov sib npaug. Comsec tau sim Blacksmith nrog peb qhov kev tawm tsam ntawm 40 tus qauv ntawm DDR4 nco. Qee tus poob sai sai rau tag nrho peb, lwm tus tau tuav ntev dua, thiab qhov zoo tshaj plaws tiv thaiv ob ntawm peb tus qauv tawm tsam. Comsec cov ntawv tsis sau npe rau cov cim xeeb tshwj xeeb uas tau sim.
Dab tsi yog Rowhammer, Anyway?
Blacksmith yog ib daim ntawv ntawm Rowhammer nres-tab sis Rowhammer yog dab tsi?
Rowhammer siv qhov zoo ntawm lub cev me me ntawm lub cim xeeb ntawm lub hlwb hauv DRAM niaj hnub. Cov qauv no me me heev uas cov hluav taws xob tam sim no tuaj yeem xau nruab nrab ntawm lawv. Rowhammer pummels DRAM nrog cov ntaub ntawv uas ua rau kom xau thiab, dhau los, tuaj yeem ua rau tus nqi me ntsis khaws cia hauv lub cim xeeb kom tig. A "1" tuaj yeem hloov mus rau "0," lossis rov ua dua.
Nws zoo li Jedi lub siab ua kom yuam kev. Ib lub sijhawm lub cuab yeej paub tias tus neeg siv tsuas muaj kev nkag tau yooj yim xwb. Tom qab ntawd, nrog kev hloov pauv me ntsis, nws ntseeg tias tus neeg siv tau nkag mus rau tus thawj tswj hwm. Cov cuab yeej tsis paub tias nws tau dag vim qhov kev tawm tsam hloov nws lub cim xeeb.
Thiab nws hnyav dua. Rowhammer, zoo li Spectre vulnerability pom nyob rau hauv x86 processors, siv kom zoo dua ntawm lub cev yam ntxwv ntawm kho vajtse. Qhov ntawd txhais tau tias nws tsis yooj yim sua kom patch. Qhov kev daws teeb meem nkaus xwb yog los hloov kho vajtse.
Kev tawm tsam yog ste althy, thiab.
"Nws yuav nyuaj heev los nrhiav cov kab ntawm rowhammer nres yog tias nws tshwm sim hauv cov tsiaj qus vim tias txhua tus neeg tawm tsam yuav tsum muaj kev nkag mus tau raug cai, nrog qee qhov feng shui kom paub tseeb tias lub kaw lus tsis sib tsoo, "hais Razavi.
Tsi muaj xov xwm zoo. Tsis muaj pov thawj cov neeg tawm tsam sab nraum qhov chaw tshawb fawb siv Rowhammer. Qhov ntawd tuaj yeem hloov tau txhua lub sijhawm, txawm li cas los xij.
"Peb yuav tsum nqis peev los kho qhov teeb meem no," said Razavi, "vim cov kev hloov pauv no tuaj yeem hloov pauv yav tom ntej."
