Litlhaselo tse peli ho mochini oa ho bolela esale pele oa "cache" ho li-processor tsa AMD

Sehlopha sa bafuputsi ba tsoang Technical University of Graz (Austria), pele e ne e tsejoa ka ho hlahisa mekhoa ea tlhaselo MDS, NetSpecter, Sehlapi и ZombieLoad, e entse lipatlisiso mabapi le lisebelisoa tsa lisebelisoa tse khethehileng ho li-processor tsa AMD le ntshetswa pele mekhoa e 'meli e mecha ea litlhaselo tsa li-channel tse ka thōko tse laolang ho lutla ha data nakong ea ts'ebetso ea mochine oa ho bolela esale pele oa "cache" oa LXNUMX oa li-processor tsa AMD. Mekhoa e ka sebelisoa ho fokotsa katleho ea ts'ireletso ea ASLR, ho khutlisa linotlolo ts'ebetsong ea AES e tlokotsing, le ho ntlafatsa katleho ea tlhaselo ea Specter.

Mathata a ile a bonoa ts'ebetsong ea mokhoa oa ho bolela esale pele mocha (mochine o bolelang esale pele) ka har'a cache ea data ea boemo ba pele ba CPU (L1D), e sebelisetsoang ho bolela esale pele hore na ke mocha ofe oa cache o nang le aterese e itseng ea memori. Ntlafatso e sebelisoang ho li-processor tsa AMD e ipapisitse le ho hlahloba μ-tag (μTag). μTag e baloa ka ho sebelisa ts'ebetso e itseng ea hash ho aterese ea sebele. Nakong ea ts'ebetso, enjine ea ho bolela esale pele ea seteishene e sebelisa μTag ho tseba mocha oa cache o tsoang tafoleng. Kahoo, μTag e lumella processor hore e ikemisetse ho fihlella mocha o itseng feela, ntle le ho batla likhetho tsohle, tse fokotsang ts'ebeliso ea matla a CPU haholo.

Nakong ea boenjineri ba morao-rao ba ts'ebetsong ea sistimi ea ho bolela esale pele melokong e fapaneng ea li-processor tsa AMD tse lokollotsoeng ho tloha 2011 ho isa 2019, ho ile ha tsejoa mekhoa e 'meli e mecha ea tlhaselo ea lehlakore:

• Collide+Probe - e lumella mohlaseli ho latela phihlello ea memori bakeng sa lits'ebetso tse sebetsang motheong o tšoanang o utloahalang oa CPU. Moko oa mokhoa ona ke ho sebelisa liaterese tsa sebele tse bakang likhohlano mosebetsing oa hash o sebelisetsoang ho bala μTag ho lekola phihlello ea memori. Ho fapana le tlhaselo ea Flush + Reload le Prime + Probe e sebelisoang ho li-processor tsa Intel, Collide + Probe ha e sebelise mohopolo o arolelanoang mme e sebetsa ntle le tsebo ea liaterese tsa 'mele.
• Load + Reload - e u lumella ho tseba ka nepo lintlha tsa phihlello ea memori mokokotlong o tšoanang oa 'mele oa CPU. Mokhoa o ipapisitse le taba ea hore sele ea memori ea 'mele e ka ba ka har'a cache ea L1D hang. Tseo. ho fihlella sele e le 'ngoe ea memori atereseng e fapaneng ea virtual ho tla etsa hore sele e ntšoe ka har'a cache ea L1D, ho lumella phihlello ea memori ho lateloa. Leha tlhaselo e its'etleha mohopolong o arolelanoeng, ha e otlolle likhoele tsa cache, e lumellang litlhaselo tsa bolotsana tse sa lelekeng data ho cache ea boemo ba ho qetela.

Ho ipapisitsoe le mekhoa ea Collide+Probe le Load+Reload, bafuputsi ba bontšitse maemo a' maloa a tlhaselo ea likanale tse lehlakoreng:

• Monyetla oa ho sebelisa mekhoa ea ho hlophisa mocha oa puisano o patiloeng o sa tobang pakeng tsa lits'ebetso tse peli, ho lumella ho fetisoa ha data ka lebelo la ho fihla ho 588 kB motsotsoana.
• Ho sebelisa likhohlano ho μTag, ho ile ha khonahala ho fokotsa entropy bakeng sa mefuta e fapaneng ea ASLR (Adress Space Layout Randomization) le ho feta tšireletso ea ASLR kernel ho sistimi e ntlafalitsoeng ka botlalo ea Linux. Monyetla oa ho etsa tlhaselo ea ho fokotsa ASLR entropy ka bobeli ho tsoa lits'ebetsong tsa basebelisi le ho sebelisa khoutu ea JavaScript e etsoang sebakeng sa sandbox le khoutu e sebetsang sebakeng se seng sa baeti e bonts'itsoe.
  

• Ho ipapisitsoe le mokhoa oa Collide + Probe, tlhaselo e ile ea kengoa ts'ebetsong ho khutlisa senotlolo sa encryption ts'ebetsong e tlokotsing (e ipapisitse le T-tafole) AES encryption.
• Ka ho sebelisa mokhoa oa Collide + Probe e le mocha oa ho fumana lintlha, tlhaselo ea Specter e ile ea khona ho ntša boitsebiso ba lekunutu ho kernel ntle le ho sebelisa mohopolo o arolelanoang.

Ho ba kotsing ho etsahala ho li-processor tsa AMD tse ipapisitseng le li-microarchitectures
Bulldozer, Piledriver, Steamroller, Zen (Ryzen, Epic), Zen+ le Zen2.
AMD e ile ea tsebisoa ka taba ena ka Phato 23, 2019, empa ho fihlela joale ha ea ka ea lokolla tlaleho ka tlhahisoleseding e mabapi le ho thibela bofokodi. Ho ea ka bafuputsi, bothata bo ka thijoa boemong ba ntlafatso ea microcode ka ho fana ka li-bits tsa MSR ho thibela mokhoa oa ho bolela esale pele oa mocha, o tšoanang le seo Intel a se entseng ho laola ho thibela mekhoa ea ho bolela esale pele ea lekala.

Source: opennet.ru