{"id":74882,"date":"2020-03-21T14:41:55","date_gmt":"2020-03-21T11:41:55","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/predlozhennaya-google-programmnaya-zashhita-ot-ataki-lvi-pokazala-snizhenie-proizvoditelnosti-v-14-raz"},"modified":"2020-03-21T14:41:55","modified_gmt":"2020-03-21T11:41:55","slug":"predlozhennaya-google-programmnaya-zashhita-ot-ataki-lvi-pokazala-snizhenie-proizvoditelnosti-v-14-raz","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/predlozhennaya-google-programmnaya-zashhita-ot-ataki-lvi-pokazala-snizhenie-proizvoditelnosti-v-14-raz","title":{"rendered":"Navrhnut\u00e1 programov\u00e1 ochrana od Google proti LVI \u00fatokom zaznamenala pokles v\u00fdkonu o 14-n\u00e1sobok","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Zola Bridges z Google navrhol<\/a><\/noindex> pre sadu kompil\u00e1torov LLVM pon\u00faka patch s implement\u00e1ciou ochrany SESES (Potla\u010denie ved\u013eaj\u0161\u00edch \u00fa\u010dinkov \u0161pekulat\u00edvneho vykon\u00e1vania), ktor\u00fd pom\u00e1ha blokova\u0165 \u00fatoky na mechanizmus \u0161pekulat\u00edvneho vykon\u00e1vania v CPU Intel, podobn\u00e9 LVI<\/a><\/noindex>. Ochrann\u00e1 met\u00f3da je implementovan\u00e1 na \u00farovni kompil\u00e1tora a je zalo\u017een\u00e1 na prid\u00e1van\u00ed in\u0161trukci\u00ed LFENCE<\/a><\/noindex>, ktor\u00e9 s\u00fa vlo\u017een\u00e9 pred ka\u017ed\u00fa in\u0161trukciu \u010d\u00edtania z pam\u00e4te alebo z\u00e1pisu do pam\u00e4te, ako aj pred prvou in\u0161trukciou vetvenia v skupine in\u0161trukci\u00ed ukon\u010duj\u00facej blok. <\/p>\n

In\u0161trukcia LFENCE o\u010dak\u00e1va dokon\u010denie v\u0161etk\u00fdch predch\u00e1dzaj\u00facich oper\u00e1ci\u00ed \u010d\u00edtania z pam\u00e4te a zakazuje \u0161pekulat\u00edvne vykon\u00e1vanie nasleduj\u00facich in\u0161trukci\u00ed po LFENCE, a\u017e k\u00fdm nebude dokon\u010den\u00e9. Pou\u017eitie LFENCE vedie k podstatn\u00e9mu poklesu v\u00fdkonu, preto sa odpor\u00fa\u010da pou\u017e\u00edva\u0165 ochranu len v extr\u00e9mnych pr\u00edpadoch pre mimoriadne citliv\u00fd k\u00f3d. Okrem \u00faplnej ochrany patch pon\u00faka tri argumenty, ktor\u00e9 umo\u017e\u0148uj\u00fa selekt\u00edvne vypn\u00fa\u0165 ur\u010dit\u00e9 \u00farovne ochrany s cie\u013eom zn\u00ed\u017ei\u0165 negat\u00edvny dopad na v\u00fdkon. <\/p>\n

V vykonan\u00fdch testoch aplik\u00e1cia ochrany SESES pre bal\u00edk BoringSSL viedla k poklesu po\u010dtu oper\u00e1ci\u00ed vykon\u00e1van\u00fdch kni\u017enicou za sekundu o 14-n\u00e1sobok \u2014 v\u00fdkon zostaven\u00e9ho variantu kni\u017enice s ochranou v priemere predstavoval iba 7,1 % z ukazovate\u013eov neza\u0161ifrovan\u00e9ho variantu (rozptyl v z\u00e1vislosti od testu bol od 4 % do 23 %). <\/p>\n

Pre porovnanie, navrhnut\u00fd<\/a><\/noindex> predt\u00fdm mechanizmus pre GNU Assembler, ktor\u00fd vykon\u00e1va vkladanie LFENCE po ka\u017edej oper\u00e1cii na\u010d\u00edtania z pam\u00e4te a pred niektor\u00fdmi in\u0161trukciami vetvenia, vyk\u00e1zal pokles v\u00fdkonu pribli\u017ene 5-n\u00e1sobne (22% z k\u00f3du bez ochrany). Ochrann\u00e1 met\u00f3da bola tie\u017e je navrhnut\u00fd<\/a><\/noindex> a implementovan\u00fd<\/a><\/noindex> in\u017einiermi Intel, ale v\u00fdsledky testovania v\u00fdkonu pre \u0148u zatia\u013e neboli zverejnen\u00e9. P\u00f4vodne vedci, ktor\u00ed identifikovali \u00fatok LVI, predpokladali pokles v\u00fdkonu pri pou\u017eit\u00ed plnej ochrany v rozmedz\u00ed 2-19-n\u00e1sobne. <\/p>\n

<\/a><\/noindex><\/p>\n

Zdroj: opennet.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

Zola Bridges \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 Google \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u0434\u043b\u044f \u043d\u0430\u0431\u043e\u0440\u0430 \u043a\u043e\u043c\u043f\u0438\u043b\u044f\u0442\u043e\u0440\u043e\u0432 LLVM \u043f\u0430\u0442\u0447 \u0441 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0435\u0439 \u0437\u0430\u0449\u0438\u0442\u044b SESES (Speculative Execution Side Effect Suppression), \u043f\u043e\u043c\u043e\u0433\u0430\u044e\u0449\u0435\u0439 \u0431\u043b\u043e\u043a\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0430\u0442\u0430\u043a\u0438 \u043d\u0430 \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c \u0441\u043f\u0435\u043a\u0443\u043b\u044f\u0442\u0438\u0432\u043d\u043e\u0433\u043e \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0432 CPU Intel, \u043f\u043e\u0434\u043e\u0431\u043d\u044b\u0435 LVI. \u041c\u0435\u0442\u043e\u0434 \u0437\u0430\u0449\u0438\u0442\u044b \u0440\u0435\u0430\u043b\u0438\u0437\u043e\u0432\u0430\u043d \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 \u043a\u043e\u043c\u043f\u0438\u043b\u044f\u0442\u043e\u0440\u0430 \u0438 \u043e\u0441\u043d\u043e\u0432\u0430\u043d \u043d\u0430 \u0434\u043e\u0431\u0430\u0432\u043b\u0435\u043d\u0438\u0438 \u043a\u043e\u043c\u043f\u0438\u043b\u044f\u0442\u043e\u0440\u043e\u043c \u043f\u0440\u0438 \u0433\u0435\u043d\u0435\u0440\u0430\u0446\u0438\u0438 \u043c\u0430\u0448\u0438\u043d\u043d\u043e\u0433\u043e \u043a\u043e\u0434\u0430 \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u0439 LFENCE, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043f\u043e\u0434\u0441\u0442\u0430\u0432\u043b\u044f\u044e\u0442\u0441\u044f \u043f\u0435\u0440\u0435\u0434 \u043a\u0430\u0436\u0434\u043e\u0439 \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u0435\u0439 \u0447\u0442\u0435\u043d\u0438\u044f […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-74882","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Navrhnut\u00e1 softv\u00e9rov\u00e1 ochrana od Google proti \u00fatoku LVI vyk\u00e1zala pokles v\u00fdkonu o 14-kr\u00e1t | ProHoster","description":"Zola Bridges z Google navrhol pre sadu kompil\u00e1torov LLVM patch s implement\u00e1ciou ochrany SESES (Potla\u010denie ved\u013eaj\u0161\u00edch \u00fa\u010dinkov \u0161pekulat\u00edvneho 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