IGoogle ityhiliwe kwiintsuku ezininzi ezidlulileyo iintlobo ezahlukeneyo zokuxhaphaza ezibonisa ukubakho kokuxhaphaza ukuba sesichengeni yeklasi yeSpecter xa usenza ikhowudi yeJavaScript kwisikhangeli, ngaphandle kokuya kwiindlela zokhuseleko ezongezwe apha ngasentla.
Ukuxhaphaza kunokusetyenziselwa ukufikelela kwimemori yenkqubo eqhuba umxholo wewebhu kwithebhu yangoku. Ukuvavanya ukusebenza kokuxhaphaza, iwebhusayithi yamaphepha avuzayo yasungulwa kwaye ikhowudi echaza ingcinga yokusebenza ithunyelwe kwiGitHub.
Iprototype ecetywayo yenzelwe uku iinkqubo zokuhlasela nge Iiprosesa ze-Intel Core i7-6500U kwindawo yeLinux kunye neChannel 88, nangona oku kungabandakanyi ukuba utshintsho lunokwenziwa ukusebenzisa ukuxhaphaza kwezinye iimeko.
Indlela yokusebenza ayichazwanga ngqo Iiprosesa Intel: emva kohlengahlengiso olufanelekileyo, Ukuxhaphaza kuqinisekisiwe ukusebenza kwiinkqubo ezinee-CPUs zomntu wesithathu, kubandakanya ne-Apple M1 esekwe kuyilo lwe-ARM. Emva kokulungiswa okuncinci, ukuxhaphaza kuyasebenza nakwezinye iinkqubo zokusebenza kunye nezinye izikhangeli ngokusekwe kwinjini yeChromium.
Kwimeko esekwe kumgangatho we-Chrome 88 kunye ne-Intel Skylake processors, siphumelele ukuvuza kwedatha kwinkqubo enoxanduva lokunikezela umxholo wewebhu kwithebhu yangoku ye-Chrome (inkqubo yokunikezela) ngesantya se-1 kilobyte ngomzuzwana. Ukongeza, ezinye iiprototypes zaphuhliswa, umzekelo, ukuxhaphaza okuvumela, ngexabiso lokuncipha kozinzo, ukunyusa izinga lokuvuza ukuya kwi-8kB / s xa usebenzisa intsebenzo. ). Umahluko ulungiselelwe ukuba usebenze ngokuchaneka kwesibali semilisecond enye, enokusetyenziselwa ukuhlela ukufikelela kwimemori yenye inkqubo kwinqanaba elimalunga ne-5 byte ngomzuzwana.
Ikhowudi yedemo epapashiweyo inamalungu amathathu:
- Inxalenye yokuqala linganisa isibali-xesha ukuba siqikelele ixesha lokubaleka yemisebenzi eyimfuneko yokufumana kwakhona idatha eshiyekileyo kwi-cache processor ngenxa yokuphunyezwa kwemiyalelo ye-CPU.
- Inxalenye yesibini Chaza ubume bememori obusetyenzisiweyo xa wabela uluhlu lweJavaScript.
- Inxalenye yesithathu Ixhaphaza ngokuthe ngqo ukuba sesichengeni kweSpecter ukumisela umxholo wenkumbulo yenkqubo yangoku ngenxa yokudala iimeko zokuphumeza intelekelelo yemisebenzi ethile, isiphumo sayo esilahliweyo ngumqhubekekisi emva kokumisela uqikelelo olungaphumelelanga, kodwa umkhondo wokuphunyezwa uzinzile kwi-cache ekwabelwana ngayo kwaye inokubuyiselwa isetyenziswe iindlela zokumisela imixholo ye-cache usebenzisa amajelo eqela lesithathu ahlalutya utshintsho kwixesha lokufikelela kwidatha egciniweyo kunye nengacwangciswanga.
Inkqubo yokuxhaphaza ecetywayo isusa ixesha elichanekileyo ifumaneka ngentsebenzo.now () API kwaye ngaphandle kwenkxaso yohlobo lweSharedArrayBuffer, ekuvumela ukuba wenze uluhlu kwimemori ekwabelwana ngayo.
Ukuxhaphaza kubandakanya isixhobo seSpecter, esibangela ukwenziwa kwekhowudi yokuqikelela elawulwayo, kunye nesitshisi esecaleni esivuzayo esivuzayo, esimisela ukuba yeyiphi idatha egcinwe ngexesha lokuqhutywa kwengcinga.
Igajethi iphunyezwa kusetyenziswa uluhlu lweJavaScript, apho ku kwenziwa iinzame zokufikelela kwindawo engaphandle kwemida yesixhobo sokugcina, echaphazela imeko yebhloko yokuqikelela yesebe ngenxa yobungakanani besheke lokujonga isongezo esidityaniswe ngumqokeleli (iprosesa ngokuchanekileyo yenza ukufikelela ngaphambi kwexesha, kodwa ibuyisela imeko emva kokujonga).
Ukuhlalutya imixholo ye-cache phantsi kweemeko zokuchaneka kwexesha elaneleyo, kwacetyiswa indlela yokukhohlisa iqhinga lokukhutshwa kwedatha ye-Tree-PLRU esetyenziswe kwiiprosesa kwaye ivumela, ngokwandisa inani lemijikelezo, ukwandisa kakhulu umahluko wexesha xa ixabiso ibuyisiwe kwi-cache kwaye xa kungekho xabiso kwi-cache.
UGoogle upapashe iprototype yoxhaphazo ukubonisa ukuba kwenzeka kuhlaselo usebenzisa ukuba semngciphekweni kudidi lweSpecial kwaye ukhuthaze abaphuhlisi bewebhu ukuba basebenzise iindlela zokunciphisa umngcipheko kuhlaselo olunjalo.
Kwangelo xesha, uGoogle ukholelwa ukuba ngaphandle kohlaziyo olubalulekileyo lomzekelo ocetywayo, akunakwenzeka ukwenza ukuxhaphaka kwendalo yonke okulungeleyo kungekuphela komboniso, kodwa nokusetyenziswa ngokubanzi.
Umthombo: https://security.googleblog.com