Sehlopha sa bafuputsi ba Vrije Universiteit Amsterdam se khethile e ncha (CVE-2020-0543) meahong e menyenyane ea meralo ea Intel processors, e hlokomelehang ka hore e o lumella ho khutlisa liphetho tsa ts'ebetso ea litaelo tse ling tse entsoeng motheong o mong oa CPU. Ena ke ts'oaetso ea pele ea mokhoa o inahaneloang oa ho etsa litaelo o lumellang ho lutla ha data lipakeng tsa li-cores tsa CPU (tseo pele li neng li lutla li ne li lekantsoe likhoele tse fapaneng tsa mantlha a tšoanang). Bafuputsi ba ile ba reha bothata CROSTalk, empa Kotsi e bitsoa SRBDS (Special Register Buffer Data Sampling).
Kotsi e amana le selemo se fetileng ho sehlopha sa mathata a MDS (Microarchitectural Data Sampling) 'me e itšetlehile ka tšebeliso ea mekhoa ea ho hlahloba mahlakoreng a marang-rang ho data ka mehaho e menyenyane ea meralo. CROSSTalk e haufi le ho ba kotsing , empa e fapana ka mohloli oa ho lutla.
Kotsi e ncha e laola ho lutla ha buffer ea mahareng e neng e sa ngolisoe pele e arolelanoang ke li-cores tsohle tsa CPU.
ke hore litaelo tse ling tsa microprocessor, ho kenyeletsoa RDRAND, RDSEED le SGX EGETKEY, li kenngoa ts'ebetsong ho sebelisoa ts'ebetso ea ka hare ea microarchitectural SRR (Special Register Reads). Ho li-processor tse amehileng, lintlha tse khutliselitsoeng bakeng sa SRR li kenngoa ka har'a buffer e bohareng e tloaelehileng ho li-cores tsohle tsa CPU, ka mor'a moo e fetisetsoa ho buffer e tlatsitsoeng e amanang le motheo o itseng oa 'mele oa CPU oo mosebetsi oa ho bala o qalileng ho oona. Ka mor'a moo, boleng bo tsoang ho buffer ea ho tlatsa bo kopitsoa ho li-registas tse bonahalang ho likopo.
Boholo ba "buffer" e arolelanoang lipakeng bo tsamaellana le mohala oa "cache", oo hangata o leng kholo ho feta boholo ba data e baloang, 'me lipalo tse fapaneng li ama li-offsets tse fapaneng ho buffer. Kaha "buffer" e arolelanoang e kopitsoa ka botlalo ho buffer ea ho tlatsa, ha se feela karolo e hlokahalang bakeng sa ts'ebetso ea hajoale e sisinyehang, empa hape le data e setseng ho tsoa lits'ebetsong tse ling, ho kenyeletsoa le tse etsoang ho li-cores tse ling tsa CPU.
Haeba tlhaselo e atlehile, mosebelisi oa lehae ea netefalitsoeng ka har'a sistimi a ka tseba sephetho sa ho phethahatsa litaelo tsa RDRAND, RDSEED le EGETKEY ts'ebetsong ea kantle ho naha kapa kahare ho Intel SGX enclave, ho sa tsotelehe motheo oa CPU oo khoutu e etsoang ho ona.
Bafuputsi ba hlokometseng bothata Sebetsa sa mohlala se bonts'ang bokhoni ba ho hlahisa tlhahisoleseling mabapi le boleng bo sa reroang bo fumanoeng ka RDRAND le RDSEED litaelo tsa ho khutlisa senotlolo sa lekunutu sa ECDSA se sebetsitsoeng ka har'a Intel SGX enclave kamora ho etsa ts'ebetso e le 'ngoe feela ea signature ea dijithale sistimi.
bothata mefuta e mengata ea li-desktop, mobile le server Intel processors, ho kenyelletsa Core i3, i5, i7, i9, m3, Celeron (J, G le N series), Atom (C, E le X series), Xeon (E3, E5, Malapa a E7 , W le D), Xeon Scalable, joalo-joalo. Hoa hlokomeleha hore Intel e ile ea tsebisoa ka tlokotsi ka Loetse 2018, mme ka Phupu 2019 ho ile ha fanoa ka mohlala oa tšebeliso e mpe e bonts'ang ho lutla ha data lipakeng tsa li-CPU cores, empa ntlafatso ea tokiso e ile ea lieha ka lebaka la ho rarahana ha ts'ebetsong ea eona. Nchafatso e reriloeng ea kajeno ea microcode e rarolla bothata ka ho fetola boitšoaro ba litaelo tsa RDRAND, RDSEED, le EGETKEY ho hlakola data ho buffer e arolelanoang ho thibela tlhahisoleseling e setseng ho lula moo. Ho feta moo, phihlello ea buffer e emisitsoe ho fihlela litaba li baloa le ho ngoloa bocha.
Litla-morao tsa mofuta ona oa ts'ireletso li eketsa latency ha ho etsoa RDRAND, RDSEED, le EGETKEY, le ho fokotsa ts'ebetso ha u leka ho phethahatsa litaelo tsena ka nako e le 'ngoe ho li-processor tse fapaneng tse utloahalang. Ho sebelisa RDRAND, RDSEED, le EGETKEY ho boetse ho emisa phihlello ea memori ho tsoa ho li-processor tse ling tse utloahalang. Likarolo tsena li ka ama ts'ebetso ea lits'ebetso tse ling tsa seva hampe, kahoo firmware e fana ka mochini (RNGDS_MITG_DIS) ho tima ts'ireletso bakeng sa litaelo tsa RDRAND le RDSEED tse etsoang kantle ho Intel SGX enclave.
Source: opennet.ru