{"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\/pt\/blog\/news\/zavisimost-vremeni-vypolneniya-instrukczij-ot-dannyh-na-cpu-arm-i-intel","title":{"rendered":"Depend\u00eancia do tempo de execu\u00e7\u00e3o de instru\u00e7\u00f5es dos dados em CPU ARM e Intel","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Eric Biggers, um dos desenvolvedores do criptograma Adiantum e mantenedor do subsistema do kernel Linux fscrypt, prop\u00f4s um conjunto de patches para bloquear problemas de seguran\u00e7a decorrentes de uma caracter\u00edstica dos processadores Intel, que n\u00e3o garante tempos de execu\u00e7\u00e3o constantes para diferentes dados processados. Nos processadores Intel, o problema se manifesta a partir da fam\u00edlia Ice Lake. Um problema similar \u00e9 observado tamb\u00e9m nos processadores ARM. <\/p>\n

A presen\u00e7a da depend\u00eancia do tempo de execu\u00e7\u00e3o das instru\u00e7\u00f5es dos dados processados \u00e9 considerada pelo autor dos patches uma vulnerabilidade nos processadores, pois esse comportamento n\u00e3o pode garantir a seguran\u00e7a das opera\u00e7\u00f5es criptogr\u00e1ficas realizadas no sistema. Muitas implementa\u00e7\u00f5es de algoritmos criptogr\u00e1ficos s\u00e3o projetadas para que os dados n\u00e3o influenciem no tempo de execu\u00e7\u00e3o das instru\u00e7\u00f5es, e a viola\u00e7\u00e3o desse comportamento pode levar \u00e0 cria\u00e7\u00e3o de ataques por canais laterais, recuperando dados com base na an\u00e1lise do tempo de seu processamento. <\/p>\n

Potencialmente, a depend\u00eancia do tempo de execu\u00e7\u00e3o dos dados tamb\u00e9m pode ser utilizada para organizar ataques que identifiquem dados do n\u00facleo a partir do espa\u00e7o do usu\u00e1rio. Segundo Eric Biggers, tempos de execu\u00e7\u00e3o constantes por padr\u00e3o n\u00e3o s\u00e3o garantidos nem mesmo para instru\u00e7\u00f5es que realizam opera\u00e7\u00f5es de soma e XOR, bem como para instru\u00e7\u00f5es especializadas AES-NI (a informa\u00e7\u00e3o n\u00e3o foi confirmada por testes; segundo outros dados, ao multiplicar vetores e contar bits, ocorre um atraso de um ciclo). <\/p>\n

Para desativar o comportamento em quest\u00e3o, as empresas Intel e ARM propuseram novas flags: o bit DIT (Data Independent Timing) para CPU ARM e o bit MSR DOITM (Data Operand Independent Timing Mode) para CPU Intel, que retornam o comportamento antigo com tempos de execu\u00e7\u00e3o constantes. As empresas Intel e ARM recomendam ativar essa prote\u00e7\u00e3o conforme necess\u00e1rio para c\u00f3digo especialmente importante, mas na pr\u00e1tica, c\u00e1lculos importantes podem ocorrer em qualquer parte do n\u00facleo e do espa\u00e7o do usu\u00e1rio, portanto, considera-se a possibilidade de ativa\u00e7\u00e3o constante dos modos DOITM e DIT para todo o n\u00facleo. <\/p>\n

Para os processadores ARM, j\u00e1 foram aceitos patches na vers\u00e3o 6.2 do n\u00facleo Linux que alteram o comportamento do n\u00facleo, mas esses patches s\u00e3o considerados insuficientes, pois abrangem apenas o c\u00f3digo do n\u00facleo e n\u00e3o afetam o comportamento do espa\u00e7o do usu\u00e1rio. Para os processadores Intel, a ativa\u00e7\u00e3o da prote\u00e7\u00e3o ainda est\u00e1 apenas na fase de revis\u00e3o. A medi\u00e7\u00e3o do impacto do patch no desempenho ainda n\u00e3o foi realizada, mas segundo a documenta\u00e7\u00e3o da Intel, a ativa\u00e7\u00e3o do modo DOITM reduz o desempenho (por exemplo, devido \u00e0 desativa\u00e7\u00e3o de algumas otimiza\u00e7\u00f5es, como o pr\u00e9-carregamento espec\u00edfico para determinados dados) e, em modelos futuros de processadores, a redu\u00e7\u00e3o do desempenho pode aumentar.
\n
Fonte: 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\udd47Depend\u00eancia do tempo de execu\u00e7\u00e3o das instru\u00e7\u00f5es em dados no CPU ARM e Intel | ProHoster","description":"Eric Biggers, um dos desenvolvedores do algoritmo Adiantum e mantenedor do subsistema fscrypt do n\u00facleo Linux, prop\u00f4s um conjunto de patches para bloquear problemas de seguran\u00e7a decorrentes das caracter\u00edsticas dos processadores.","canonical_url":"https:\/\/prohoster.info\/pt\/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":"pt_PT","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\/pt\/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\/pt\/wp-json\/wp\/v2\/posts\/106545","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/comments?post=106545"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts\/106545\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/media?parent=106545"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/categories?post=106545"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/tags?post=106545"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}