{"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\/cs\/blog\/news\/predlozhennaya-google-programmnaya-zashhita-ot-ataki-lvi-pokazala-snizhenie-proizvoditelnosti-v-14-raz","title":{"rendered":"Navr\u017een\u00e1 softwarov\u00e1 ochrana proti \u00fatoku LVI od spole\u010dnosti Google vyk\u00e1zala pokles v\u00fdkonu o 14kr\u00e1t.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Zola Bridges od spole\u010dnosti Google navrhl<\/a><\/noindex> pro sadu kompil\u00e1tor\u016f LLVM patch s implementac\u00ed ochrany SESES (Speculative Execution Side Effect Suppression), kter\u00e1 pom\u00e1h\u00e1 blokovat \u00fatoky na mechanismus spekulativn\u00edho vykon\u00e1v\u00e1n\u00ed v CPU Intel, podobn\u00e9 LVI<\/a><\/noindex>. Ochrann\u00e1 metoda je realizov\u00e1na na \u00farovni kompil\u00e1toru a zakl\u00e1d\u00e1 se na p\u0159id\u00e1n\u00ed instrukc\u00ed kompil\u00e1torem p\u0159i generov\u00e1n\u00ed strojov\u00e9ho k\u00f3du LFENCE<\/a><\/noindex>, kter\u00e9 jsou vlo\u017eeny p\u0159ed ka\u017edou instrukci \u010dten\u00ed z pam\u011bti nebo z\u00e1pisu do pam\u011bti, jako\u017e i p\u0159ed prvn\u00ed instrukci v\u011btven\u00ed ve skupin\u011b instrukc\u00ed ukon\u010duj\u00edc\u00ed blok. <\/p>\n

Instrukce LFENCE o\u010dek\u00e1v\u00e1 dokon\u010den\u00ed v\u0161ech p\u0159edchoz\u00edch operac\u00ed \u010dten\u00ed z pam\u011bti a zakazuje spekulativn\u00ed vykon\u00e1v\u00e1n\u00ed n\u00e1sleduj\u00edc\u00edch instrukc\u00ed po LFENCE, dokud nebude dokon\u010deno zafixov\u00e1n\u00ed. Pou\u017eit\u00ed LFENCE vede k v\u00fdznamn\u00e9mu sn\u00ed\u017een\u00ed v\u00fdkonu, proto se doporu\u010duje pou\u017e\u00edt ochranu v krajn\u00edch p\u0159\u00edpadech pro velmi kritick\u00fd k\u00f3d. Krom\u011b \u00fapln\u00e9 ochrany patch nab\u00edz\u00ed t\u0159i p\u0159\u00edznaky, kter\u00e9 umo\u017e\u0148uj\u00ed selectively deaktivovat ur\u010dit\u00e9 \u00farovn\u011b ochrany pro sn\u00ed\u017een\u00ed negativn\u00edho dopadu na v\u00fdkon. <\/p>\n

Ve vykonan\u00fdch testech pou\u017eit\u00ed ochrany SESES pro bal\u00edk BoringSSL vedlo ke sn\u00ed\u017een\u00ed po\u010dtu operac\u00ed vykon\u00e1van\u00fdch knihovnou za sekundu o 14kr\u00e1t \u2014 v\u00fdkon varianty knihovny s ochranou byl v pr\u016fm\u011bru pouze 7,1 % v\u00fdkonu nechr\u00e1n\u011bn\u00e9 varianty (rozsah podle testu od 4 % do 23 %). <\/p>\n

Pro srovn\u00e1n\u00ed, navr\u017een\u00fd<\/a><\/noindex> d\u0159\u00edve pro GNU Assembler mechanismus, kter\u00fd prov\u00e1d\u00ed vlo\u017een\u00ed LFENCE po ka\u017ed\u00e9 operaci na\u010d\u00edt\u00e1n\u00ed z pam\u011bti a p\u0159ed n\u011bkter\u00fdmi instrukcemi v\u011btven\u00ed, prok\u00e1zal sn\u00ed\u017een\u00ed v\u00fdkonu p\u0159ibli\u017en\u011b 5kr\u00e1t (22 % k\u00f3du bez ochrany). Ochrann\u00e1 metoda byla tak\u00e9 byla navr\u017eena<\/a><\/noindex> a realizov\u00e1no<\/a><\/noindex> in\u017een\u00fdry spole\u010dnosti Intel, ale v\u00fdsledky testov\u00e1n\u00ed v\u00fdkonu pro n\u011bj zat\u00edm nebyly publikov\u00e1ny. P\u016fvodn\u011b v\u00fdzkumn\u00edci, kte\u0159\u00ed identifikovali \u00fatok LVI, p\u0159edpov\u011bd\u011bli sn\u00ed\u017een\u00ed v\u00fdkonu p\u0159i pou\u017eit\u00ed \u00fapln\u00e9 ochrany od 2 do 19kr\u00e1t. <\/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\udd47Navrhovan\u00e1 softwarov\u00e1 ochrana Google proti \u00fatoku LVI vyk\u00e1zala sn\u00ed\u017een\u00ed v\u00fdkonu o 14kr\u00e1t | ProHoster","description":"Zola Bridges od spole\u010dnosti Google navrhl pro sadu kompil\u00e1tor\u016f LLVM patch s implementac\u00ed ochrany SESES (Speculative Execution 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