{"id":106545,"date":"2023-01-29T12:48:46","date_gmt":"2023-01-29T10:48:46","guid":{"rendered":"https:\/\/prohoster.info\/?p=106545"},"modified":"2023-02-07T12:09:03","modified_gmt":"2023-02-07T10:09:03","slug":"zavisimost-vremeni-vypolneniya-instrukczij-ot-dannyh-na-cpu-arm-i-intel","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sv\/blog\/news\/zavisimost-vremeni-vypolneniya-instrukczij-ot-dannyh-na-cpu-arm-i-intel","title":{"rendered":"K\u00f6rningstider f\u00f6r instruktioner beror p\u00e5 data p\u00e5 ARM- och Intel-CPU:er","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Eric Biggers, en av utvecklarna av Adiantum-chifferet och underh\u00e5llare av Linux fscrypt-k\u00e4rnans delsystem, har f\u00f6reslagit en upps\u00e4ttning patchar f\u00f6r att blockera s\u00e4kerhetsproblem som uppst\u00e5r p\u00e5 grund av egenskapen hos Intel-processorer, som inte garanterar konstant exekveringstid f\u00f6r olika bearbetade data. Problemet uppst\u00e5r i Intel-processorer som tillh\u00f6r Ice Lake-familjen. Ett liknande problem observeras \u00e4ven i ARM-processorer. <\/p>\n

Att exekveringstiden f\u00f6r instruktionerna beror p\u00e5 de data som bearbetas i dessa instruktioner betraktas av patcharnas f\u00f6rfattare som en s\u00e5rbarhet i processorer, eftersom ett s\u00e5dant beteende inte kan garantera s\u00e4kerheten f\u00f6r de kryptografiska operationer som utf\u00f6rs i systemet. M\u00e5nga implementeringar av kryptografiska algoritmer \u00e4r utformade s\u00e5 att data inte p\u00e5verkar exekveringstiden, och ett brott mot detta beteende kan leda till attacker via sidokanaler som \u00e5terst\u00e4ller data baserat p\u00e5 analys av tiden f\u00f6r deras behandling. <\/p>\n

Beroendet av exekveringstid fr\u00e5n data kan potentiellt \u00e4ven anv\u00e4ndas f\u00f6r att organisera attacker f\u00f6r att identifiera k\u00e4rndata fr\u00e5n anv\u00e4ndarrummet. Enligt Eric Biggers s\u00e4kerst\u00e4lls konstant exekveringstid som standard inte ens f\u00f6r instruktioner som utf\u00f6r addition och XOR-operationer, samt f\u00f6r specialiserade AES-NI-instruktioner (informationen har inte bekr\u00e4ftats av tester, men enligt andra data uppst\u00e5r det en f\u00f6rdr\u00f6jning p\u00e5 en cykel vid vektormultiplikation och bitr\u00e4kning). <\/p>\n

F\u00f6r att inaktivera det aktuella beteendet har Intel och ARM f\u00f6reslagit nya flaggor: PSTATE-bit DIT (Data Independent Timing) f\u00f6r ARM-CPU:er och MSR-bit DOITM (Data Operand Independent Timing Mode) f\u00f6r Intel-CPU:er, som \u00e5terst\u00e4ller det gamla beteendet med konstant exekveringstid. Intel och ARM rekommenderar att skydd aktiveras vid behov f\u00f6r s\u00e4rskilt viktig kod, men i praktiken kan viktiga ber\u00e4kningar f\u00f6rekomma i alla delar av k\u00e4rnan och anv\u00e4ndarrummet, varf\u00f6r m\u00f6jligheten till kontinuerlig aktivering av DOITM- och DIT-l\u00e4gena f\u00f6r hela k\u00e4rnan \u00f6verv\u00e4gs. <\/p>\n

F\u00f6r ARM-processorer har patchar redan antagits i Linux-k\u00e4rnans version 6.2 som \u00e4ndrar beteendet f\u00f6r k\u00e4rnan, men dessa patchar betraktas som otillr\u00e4ckliga eftersom de bara t\u00e4cker k\u00e4rnkoden och inte \u00e4ndrar beteendet f\u00f6r anv\u00e4ndarutrymmet. F\u00f6r Intel-processorer \u00e4r aktiveringen av skyddet fortfarande endast under granskning. M\u00e4tningar av patchens inverkan p\u00e5 prestanda har \u00e4nnu inte genomf\u00f6rts, men enligt information fr\u00e5n Intels dokumentation s\u00e4nker aktiveringen av DOITM-l\u00e4get prestandan (till exempel p\u00e5 grund av inaktivering av vissa optimeringar, s\u00e5som specifik f\u00f6r vissa data f\u00f6rhandsladdning), och i framtida processor-modeller kan prestandaf\u00f6rlusten f\u00f6rst\u00e4rkas.
\n
K\u00e4lla: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u042d\u0440\u0438\u043a \u0411\u0438\u0433\u0433\u0435\u0440\u0441 (Eric Biggers), \u043e\u0434\u0438\u043d \u0438\u0437 \u0440\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u043e\u0432 \u0448\u0438\u0444\u0440\u0430 Adiantum \u0438 \u043c\u044d\u0439\u043d\u0442\u0435\u0439\u043d\u0435\u0440 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u044b \u044f\u0434\u0440\u0430 Linux fscrypt, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u043d\u0430\u0431\u043e\u0440 \u043f\u0430\u0442\u0447\u0435\u0439 \u0434\u043b\u044f \u0431\u043b\u043e\u043a\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c \u0441 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u044c\u044e, \u0432\u043e\u0437\u043d\u0438\u043a\u0430\u044e\u0449\u0438\u0445 \u0438\u0437-\u0437\u0430 \u043e\u0441\u043e\u0431\u0435\u043d\u043d\u043e\u0441\u0442\u0438 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u043e\u0432 Intel, \u043d\u0435 \u0433\u0430\u0440\u0430\u043d\u0442\u0438\u0440\u0443\u044e\u0449\u0435\u0439 \u043f\u043e\u0441\u0442\u043e\u044f\u043d\u043d\u043e\u0435 \u0432\u0440\u0435\u043c\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u0439 \u0434\u043b\u044f \u0440\u0430\u0437\u043d\u044b\u0445 \u043e\u0431\u0440\u0430\u0431\u0430\u0442\u044b\u0432\u0430\u0435\u043c\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445. \u0412 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u0430\u0445 Intel \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u043d\u0430\u0447\u0438\u043d\u0430\u044f \u0441 \u0441\u0435\u043c\u0435\u0439\u0441\u0442\u0432\u0430 Ice Lake. \u0410\u043d\u0430\u043b\u043e\u0433\u0438\u0447\u043d\u0430\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043d\u0430\u0431\u043b\u044e\u0434\u0430\u0435\u0442\u0441\u044f \u0438 \u0432 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u0430\u0445 ARM. […]<\/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-106545","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\udd47Beroende av exekveringstid f\u00f6r instruktioner p\u00e5 ARM- och Intel-CPU:er | ProHoster","description":"Eric Biggers, en av utvecklarna bakom Adiantum-krypteringen och underh\u00e5llets f\u00f6rest\u00e5ndare f\u00f6r Linux-k\u00e4rnans fscrypt, har f\u00f6reslagit en upps\u00e4ttning patchar f\u00f6r att blockera s\u00e4kerhetsproblem som uppst\u00e5r p\u00e5 grund av processorns egenskaper.","canonical_url":"https:\/\/prohoster.info\/sv\/blog\/news\/zavisimost-vremeni-vypolneniya-instrukczij-ot-dannyh-na-cpu-arm-i-intel","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sv_SE","og:site_name":"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b","og:type":"article","og:title":"\ud83e\udd47\u0417\u0430\u0432\u0438\u0441\u0438\u043c\u043e\u0441\u0442\u044c \u0432\u0440\u0435\u043c\u0435\u043d\u0438 \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0438\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u0439 \u043e\u0442 \u0434\u0430\u043d\u043d\u044b\u0445 \u043d\u0430 CPU ARM \u0438 Intel | ProHoster","og:description":"\u042d\u0440\u0438\u043a \u0411\u0438\u0433\u0433\u0435\u0440\u0441 (Eric Biggers), \u043e\u0434\u0438\u043d \u0438\u0437 \u0440\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u043e\u0432 \u0448\u0438\u0444\u0440\u0430 Adiantum \u0438 \u043c\u044d\u0439\u043d\u0442\u0435\u0439\u043d\u0435\u0440 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u044b \u044f\u0434\u0440\u0430 Linux fscrypt, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u043d\u0430\u0431\u043e\u0440 \u043f\u0430\u0442\u0447\u0435\u0439 \u0434\u043b\u044f \u0431\u043b\u043e\u043a\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c \u0441 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u044c\u044e, \u0432\u043e\u0437\u043d\u0438\u043a\u0430\u044e\u0449\u0438\u0445 \u0438\u0437-\u0437\u0430 \u043e\u0441\u043e\u0431\u0435\u043d\u043d\u043e\u0441\u0442\u0438 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u043e\u0432.","og:url":"https:\/\/prohoster.info\/sv\/blog\/news\/zavisimost-vremeni-vypolneniya-instrukczij-ot-dannyh-na-cpu-arm-i-intel","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2023-01-29T10:48:46+00:00","article:modified_time":"2023-02-07T10:09:03+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":[],"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts\/106545","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/comments?post=106545"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts\/106545\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/media?parent=106545"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/categories?post=106545"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/tags?post=106545"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}