{"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\/da\/blog\/news\/predlozhennaya-google-programmnaya-zashhita-ot-ataki-lvi-pokazala-snizhenie-proizvoditelnosti-v-14-raz","title":{"rendered":"Den foresl\u00e5ede Googlesoftwarebeskyttelse mod LVI-angreb har vist en pr\u00e6stationsreduktion p\u00e5 14 gange.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Zola Bridges fra Google et h\u00e5ndskrevet patch til rettelsen.<\/a><\/noindex> til LLVM compiler-s\u00e6ttet, et patch med implementering af SESES (Speculative Execution Side Effect Suppression), der hj\u00e6lper med at blokere angreb p\u00e5 mekanismen for spekulativ udf\u00f8relse i Intel CPU'er, ligesom LVI<\/a><\/noindex>. Beskyttelsesmetoden er implementeret p\u00e5 kompilatorniveau og er baseret p\u00e5, at kompilatoren ved generering af maskinkode tilf\u00f8jer instruktioner LFENCE<\/a><\/noindex>, som inds\u00e6ttes f\u00f8r hver instruktion, der l\u00e6ser fra hukommelsen eller skriver til hukommelsen, samt f\u00f8r den f\u00f8rste grene-instruktion i en gruppe instruktioner, der afslutter en blok. <\/p>\n

LFENCE-instruktionen venter p\u00e5, at alle tidligere hukommelsesl\u00e6sninger er f\u00e6rdige og forhindrer forudtagning af udf\u00f8relsen af de efterf\u00f8lgende instruktioner efter LFENCE, indtil ventingen er afsluttet. Brugen af LFENCE medf\u00f8rer en betydelig reduktion i ydeevnen, s\u00e5 beskyttelsen foresl\u00e5s kun at anvendes i s\u00e6rligt kritisk kode. Udover den fulde beskyttelse tilbyder patchen tre flag, der g\u00f8r det muligt at deaktivere specifikke niveauer af beskyttelse for at reducere den negative indvirkning p\u00e5 ydeevnen. <\/p>\n

I de udf\u00f8rte tests f\u00f8rte brugen af SESES-beskyttelse til paket BoringSSL til en reduktion af det antal operationer, der blev udf\u00f8rt af biblioteket pr. sekund, med 14 gange \u2014 den samlede ydeevne for den beskyttede version af biblioteket viste sig i gennemsnit at v\u00e6re kun 7,1 % af resultaterne for den ubeskyttede version (variation afh\u00e6ngig af testen fra 4 % til 23 %). <\/p>\n

Til sammenligning, foresl\u00e5et<\/a><\/noindex> tidligere viste mekanismen til GNU Assembler, der indsatte LFENCE efter hver hukommelsesl\u00e6sning og f\u00f8r nogle grene-instruktioner, en ydeevnedrop p\u00e5 cirka 5 gange (22% af koden uden beskyttelse). Beskyttelsesmetoden blev ogs\u00e5 er blevet foresl\u00e5et<\/a><\/noindex> og implementeret<\/a><\/noindex> udviklet af ingeni\u00f8rer fra Intel, men resultaterne af ydeevnetestene for den er endnu ikke offentliggjort. Oprindeligt foruds\u00e5 forskerne, der opdagede LVI-angrebet, en ydeevnedrop ved anvendelse af fuld beskyttelse p\u00e5 2-19 gange. <\/p>\n

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

Kilde: 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\udd47Det foresl\u00e5ede Google-softwarebeskyttelse mod LVI-angrebet viste et fald i ydeevnen p\u00e5 14 gange | ProHoster","description":"Zola Bridges fra Google har foresl\u00e5et et patch til LLVM compiler-s\u00e6ttet med implementering af SESES (Speculative Execution 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