Intel ulwazi mayelana nokuba sengozini okusha okubili kuma-Intel CPUs okubangelwa ukuvuza kwedatha kunqolobane ye-L1D (, i-L1DES - Isampula Sokukhishwa Kwe-L1D) kanye namarejista e-vector (, VRS - Vector Register Sampling). Ubungozi bungokwesigaba (I-Microarchitectural Data Sampling) futhi zisekelwe ekusetshenzisweni kwezindlela zokuhlaziya umzila oseceleni kudatha ezakhiweni zezakhiwo ezincane. I-AMD, i-ARM namanye ama-processor athintwa yizinkinga.
Ingozi enkulu kakhulu ukuba sengozini kwe-L1DES, okuyinto ukulungisa amabhulokhi wedatha egcinwe kunqolobane (umugqa wenqolobane), okhishwe kunqolobane yezinga lokuqala (L1D), ku-Fill Buffer, kulesi sigaba okufanele ingabi nalutho. Ukuze sinqume idatha esizinze kubhafa yokugcwalisa, singasebenzisa izindlela zokuhlaziya zesiteshi eseceleni ezazihlongozwe ngaphambilini ekuhlaselweni. (Microarchitectural Data Sampling) kanye (Ukuhushulwa Kwesisu Okwenziwa Ngama-Asynchronous). Ingqikithi yesivikelo esisetshenziswe ngaphambilini ngokumelene
I-MDS ne-TAA ekushayeni amabhafa ezakhiwo ezincane ngaphambi kokushintshwa komongo, kodwa kuvele ukuthi ngaphansi kwezimo ezithile idatha icatshangwa ukuthi ifakwa kumabhafa ngemva kokusebenza kokushaywa, ngakho-ke izindlela ze-MDS ne-TAA zisasebenza.
Njengomphumela walokho, umhlaseli angakwazi ukuthola idatha ekhishwe kunqolobane yeleveli yokuqala eyashintshwa ngesikhathi sokusetshenziswa kohlelo lokusebenza obekade lusebenzisa umongo wamanje we-CPU, noma izinhlelo zokusebenza ezisebenza ngokufana kolunye uchungechunge olunengqondo (hyperthread) ku-CPU efanayo. core (ukukhubaza i-HyperThreading kunciphisa ukungasebenzi kahle kokuhlasela). Ngokungafani nokuhlasela ,I-L1DES ayikuvumeli ukukhethwa kwamakheli athile aphathekayo ukuze ahlolwe, kodwa inikeza ikhono, lokungaqapheli umsebenzi kweminye imicu enengqondo ehlotshaniswa , nokulayisha noma ukugcina amanani enkumbulweni.
Ngokusekelwe ku-L1DES, amaqembu ahlukahlukene ocwaningo asungule okuhlukile okuningana kokuhlasela okungase kukhiphe ulwazi olubucayi kwezinye izinqubo, isistimu yokusebenza, imishini ebonakalayo kanye nezinsimbi ezivikelwe ze-SGX.
- Ithimba le-VUSec Indlela yokuhlasela ye-RIDL yokuba sengozini kwe-L1DES. Iyatholakala , ephinde yeqe indlela yokuvikela ehlongozwayo ye-MDS ye-Intel, esekelwe ekusebenziseni umyalo we-VERW ukusula okuqukethwe kwamabhafa e-microarchitectural lapho ibuya kusuka ku-kernel kuya endaweni yomsebenzisi noma lapho idlulisela ukulawula kusistimu yesivakashi (abacwaningi baqale bagcizelela ukuthi i-VERW (isusa i-microarchitectural iziphazamiso) ukuze kuvikelwe akwanele futhi kudinga ukushaywa okuphelele kwenqolobane ye-L1 kuswishi yomongo ngayinye).
- Ithimba ibuyekeziwe yami kucatshangelwa ukuba sengozini kwe-L1DES.
- Abacwaningi eNyuvesi yaseMichigan bazenzele eyabo indlela yokuhlasela (), okuvumela ukuthi ukhiphe ulwazi oluyimfihlo ku-kernel yesistimu yokusebenza, imishini ebonakalayo kanye ne-SGX enclaves evikelekile. Indlela isekelwe ku ngomshini wokuphazamiseka okungavumelani kokusebenza (TAA, TSX Asynchronous Abortion) ukuze kunqunywe okuqukethwe kwebhafa yokugcwalisa ngemva kokuvuza kwedatha kunqolobane ye-L1D.
Ukuba sengozini kwe-VRS yesibili (Vector Register Sampling). ngokuvuza kusigcinalwazi (Isilondolozi Sesitolo) semiphumela yemisebenzi yokufunda evela kumarejista e-vector ashintshiwe ngesikhathi kusetshenziswa imiyalelo ye-vector (SSE, AVX, AVX-512) kumongo we-CPU ofanayo. Ukuvuza kwenzeka ngaphansi kwesethi yezimo ezingavamile futhi kubangelwa iqiniso lokuthi ukusebenza kokuqagela okuholela ekuboniseni isimo samarejista e-vector ku-buffer yesitoreji kuyabambezeleka futhi kuqedwe ngemva kokuba isilondolozi sesisuliwe, futhi hhayi ngaphambi kwaso. Ngokufana nokuba sengozini kwe-L1DES, okuqukethwe kwebhafa yokugcina kunganqunywa kusetshenziswa amasu okuhlasela e-MDS ne-TAA.
Abacwaningi abavela eqenjini le-VUSec , okukuvumela ukuthi unqume amanani werejista ye-vector etholwe ngenxa yezibalo kwenye intambo enengqondo yomgogodla ofanayo we-CPU. Inkampani ye-Intel Ukuba sengozini kwe-VRS kubhekwe kuyinkimbinkimbi kakhulu ukuthi kungahlasela kwangempela futhi kwanikezwa izinga eliphansi lokuqina (2.8 CVSS).
Lezi zinkinga zabikwa ku-Intel ngoMeyi 2019 yithimba le-Zombieload lase-Technical University of Graz (Austria) kanye nethimba le-VUSec lase-Free University of Amsterdam, futhi ubungozi babuye baqinisekiswa abanye abacwaningi abaningi ngemva kokuhlaziya amanye ama-vector okuhlasela kwe-MDS. Umbiko wokuqala we-MDS awuzange uhlanganise ulwazi mayelana nezinkinga ze-L1DES ne-VRS ngenxa yokuntuleka kokulungiswa. Ukulungiswa akutholakali manje, kodwa isikhathi esingadalulwanga okuvunyelwene ngaso sesiphelelwe yisikhathi.
Njengendlela yokusebenza, kunconywa ukukhubaza i-HyperThreading. Ukuze uvimbele ukuba sengozini ohlangothini lwe-kernel, kuhlongozwa ukusetha kabusha inqolobane ye-L1 ekushintsheni kokuqukethwe ngakunye (i-MSR bit MSR_IA32_FLUSH_CMD) futhi kukhubazwe isandiso se-TSX (amabhithi e-MSR MSR_IA32_TSX_CTRL kanye ne-MSR_TSX_FORCE_ABORT).
Intel khipha isibuyekezo se-microcode ngokusetshenziswa kwezindlela zokuvimba izinkinga esikhathini esizayo esiseduze. I-Intel iphinde iphawule ukuthi ukusetshenziswa kwezindlela zokuvikela ukuhlasela ezihlongozwayo ngo-2018 (I-L1 Terminal Fault) ikuvumela ukuthi uvimbe ukuxhashazwa kokuba sengozini kwe-L1DES ezindaweni ezibonakalayo. Ukuhlasela Ama-Intel Core processors aqala esizukulwaneni sesithupha (Sky, Kaby, Coffee, Whisky, Amber Lake, njll.), kanye namanye amamodeli e-Intel Xeon kanye ne-Xeon Scalable.
Ukwengeza, kungaphawulwa , okukuvumela ukuthi usebenzise izindlela zokuhlasela ukunquma okuqukethwe kwe-hashi ye-root password kusuka ku-/etc/shadow phakathi nemizamo yokuqinisekisa ngezikhathi ezithile. Uma ukuxhashazwa okuhlongoziwe kwasekuqaleni kunqume ukuthi igama lephasiwedi lingene , futhi ngemva kokufaka ukuvuza ngesikhathi sokusebenza kwendlela yokuphazamiseka kwe-asynchronous (TAA, TSX Asynchronous Abort) yenza umsebenzi ofanayo , bese okuhlukile okusha kwenza ukuhlasela kumasekhondi angu-4.
Source: opennet.ru