{"id":181666,"date":"2026-05-22T18:25:08","date_gmt":"2026-05-22T16:25:08","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/iz-af_alg-v-linux-ubirayut-zero-copy-iz-soobrazhenij-bezopasnosti"},"modified":"2026-05-22T18:25:08","modified_gmt":"2026-05-22T16:25:08","slug":"iz-af_alg-v-linux-ubirayut-zero-copy-iz-soobrazhenij-bezopasnosti","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hr\/blog\/news\/iz-af_alg-v-linux-ubirayut-zero-copy-iz-soobrazhenij-bezopasnosti","title":{"rendered":"Iz AF_ALG u Linux-u se uklanja zero-copy iz sigurnosnih razloga","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

U podsustavu kriptografije Linux se priprema uklanjanje podr\u0161ke zero-copy<\/strong> iz su\u010delja AF_ALG<\/strong> za tipove algoritama SKCIPHER<\/strong> i AEAD<\/strong>. Promjena je ve\u0107 u stablu cryptodev i o\u010dekuje se da \u0107e biti poslana u prozor spajanja Linux 7.2<\/strong>, koji bi trebao otvoriti u lipnju. Povod su rasprave o sigurnosti zero-copy mehanizama u Kernelu, posebno nakon nedavnih ranjivosti u kriptografskom kodu Linuxa.<\/p>\n

<\/p>\n

AF_ALG<\/strong> \u2014 to je korisni\u010dko su\u010delje<\/a> za kriptografski API jezgre Linuxa. Kroz njega programi mogu pristupiti implementacijama \u0161ifri, he\u0161ova i AEAD algoritama u jezgru kao socketima. Dokumentacija Linuxa posebno opisuje za AF_ALG zero-copy na\u010din kroz splice() i vmsplice(), gdje jezgra nastoji izbje\u0107i nepotrebno kopiranje podataka u memoriju jezgre.<\/p>\n

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<\/p>\n

Problem je u tome \u0161to je u slu\u010daju AF_ALG takva dobit u performansama bila manje va\u017ena, a rizici su preveliki. Autor promjene, developer kriptografske podsustave Linux, Erik Biggers iz Googlea, je naveo<\/a>, isti\u010de da zero-copy omogu\u0107ava korisni\u010dkom prostoru izvo\u0111enje kriptografskih operacija izravno na stranicama page cache datoteka, poput binarnika su, a tako\u0111er stvara uvjete za TOCTOU ranjivosti, kada se memorija mo\u017ee mijenjati istovremeno s operacijama nad njom.<\/p>\n

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Drugim rije\u010dima, mehanizam koji je koristan u mre\u017enim ili datote\u010dnim ulazno-izlaznim operacijama, u AF_ALG izgleda kao preopasna optimizacija. Sam AF_ALG, prema rije\u010dima developera, sada se u osnovi zadr\u017eava zbog unazadne kompatibilnosti s malim skupom programa, poput iwd, koji jo\u0161 nisu pre\u0161li na kriptografiju u korisni\u010dkom prostoru. Izvorno je AF_ALG zami\u0161ljen i za pristup hardverskim kriptoakceleratorima, no u praksi se pokazao kao ne previ\u0161e u\u010dinkovit su\u010delje za ovu svrhu.<\/p>\n

Va\u017eno je napomenuti da se ne radi o potpunom uklanjanju splice() ili sendfile() za AF_ALG. Promjena se opisuje kao \"softver za prekid\" kompatibilnosti: prijenos podataka u AF_ALG upitima putem splice() i sendfile() \u0107e se nastaviti, ali jezgra \u0107e sada raditi unutarnju stabilnu kopiju podataka prije kriptografske operacije. Performanse se u nekim slu\u010dajevima mogu smanjiti, ali korisni\u010dko API formalno ne propada.<\/p>\n

Posebno se nagla\u0161ava da se zero-copy za sada uklanja iz skcipher<\/strong> i aead<\/strong>. Podr\u0161ka za tip hash<\/strong> bit \u0107e razmatrana posebno.<\/p>\n

<\/p>\n

Kontekst promjena je neugodan. Krajem travnja otkrivena je ranjivost Kopiranje nije uspjelo<\/a><\/strong> (CVE-2026-31431<\/strong>) u algif_aead, \u0161to se to\u010dno odnosi na korisni\u010dko kripto su\u010delje AF_ALG. Istra\u017eiva\u010di su pokazali da povezanost AF_ALG, splice() i zna\u010dajki AEAD obrade omogu\u0107uje neprivilegiranom korisniku o\u0161te\u0107ivanje page cachea, uklju\u010duju\u0107i stranice povezane sa setuid binarnim datotekama, i stjecanje privilegija do root.<\/p>\n

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\n<\/p>\n

Pojava Kopiranje nije uspjelo<\/a> bila je povezana s optimizacijom iz 2017. godine koja je prebacila AEAD operacije na obradu 'na mjestu'; prilikom prijenosa datoteke putem splice() u AF_ALG, jezgra je radila ne s kopijom, ve\u0107 s referencama na stranice page cachea. Kao rezultat toga, dio podataka koji su se smatrali samo ulaznima mogao je zavr\u0161iti u zapisivom scatterlistu.<\/p>\n

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

Uklanjanje zero-copy iz AF_ALG nije to\u010dka ispravka samo jedne ranjivosti. Radije, to je poku\u0161aj da se ukloni \u010ditava klasa rizi\u010dnih scenarija iz rijetko kori\u0161tenog UAPI-a, gdje dobit od optimizacije ne opravdava slo\u017eenost i potencijalne posljedice. Za prosje\u010dne korisnike, promjena \u0107e najvjerojatnije ostati neprimije\u0107ena; za rijetke aplikacije koje aktivno koriste AF_ALG putem splice() ili sendfile(), mogu\u0107a je degradacija performansi zbog dodatnog kopiranja.<\/p>\n

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

\u0412 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u043a\u0440\u0438\u043f\u0442\u043e\u0433\u0440\u0430\u0444\u0438\u0438 Linux \u0433\u043e\u0442\u043e\u0432\u0438\u0442\u0441\u044f \u0443\u0434\u0430\u043b\u0435\u043d\u0438\u0435 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 zero-copy \u0438\u0437 \u0438\u043d\u0442\u0435\u0440\u0444\u0435\u0439\u0441\u0430 AF_ALG \u0434\u043b\u044f \u0442\u0438\u043f\u043e\u0432 \u0430\u043b\u0433\u043e\u0440\u0438\u0442\u043c\u043e\u0432 SKCIPHER \u0438 AEAD. \u0418\u0437\u043c\u0435\u043d\u0435\u043d\u0438\u0435 \u0443\u0436\u0435 \u043d\u0430\u0445\u043e\u0434\u0438\u0442\u0441\u044f \u0432 \u0434\u0435\u0440\u0435\u0432\u0435 cryptodev \u0438 \u043e\u0436\u0438\u0434\u0430\u0435\u0442\u0441\u044f \u043a \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0435 \u0432 \u043e\u043a\u043d\u043e \u0441\u043b\u0438\u044f\u043d\u0438\u044f Linux 7.2, \u043a\u043e\u0442\u043e\u0440\u043e\u0435 \u0434\u043e\u043b\u0436\u043d\u043e \u043e\u0442\u043a\u0440\u044b\u0442\u044c\u0441\u044f \u0432 \u0438\u044e\u043d\u0435. \u041f\u043e\u0432\u043e\u0434\u043e\u043c \u0441\u0442\u0430\u043b\u0438 \u0440\u0430\u0441\u0442\u0443\u0449\u0438\u0435 \u043e\u043f\u0430\u0441\u0435\u043d\u0438\u044f \u0432\u043e\u043a\u0440\u0443\u0433 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 zero-copy-\u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u043e\u0432 \u0432 \u044f\u0434\u0440\u0435, \u043e\u0441\u043e\u0431\u0435\u043d\u043d\u043e \u043f\u043e\u0441\u043b\u0435 \u043d\u0435\u0434\u0430\u0432\u043d\u0438\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 \u0432 \u043a\u0440\u0438\u043f\u0442\u043e\u0433\u0440\u0430\u0444\u0438\u0447\u0435\u0441\u043a\u043e\u043c \u043a\u043e\u0434\u0435 Linux. AF_ALG […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-181666","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\udd47Iz AF_ALG u Linuxu se uklanja zero-copy iz sigurnosnih razloga | ProHoster","description":"U subsustavu kriptografije Linux priprema se uklanjanje podr\u0161ke za zero-copy iz su\u010delja AF_ALG za tipove algoritama SKCIPHER i AEAD.","canonical_url":"https:\/\/prohoster.info\/hr\/blog\/news\/iz-af_alg-v-linux-ubirayut-zero-copy-iz-soobrazhenij-bezopasnosti","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"hr_HR","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\u0418\u0437 AF_ALG \u0432 Linux \u0443\u0431\u0438\u0440\u0430\u044e\u0442 zero-copy \u0438\u0437 \u0441\u043e\u043e\u0431\u0440\u0430\u0436\u0435\u043d\u0438\u0439 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 | ProHoster","og:description":"\u0412 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u043a\u0440\u0438\u043f\u0442\u043e\u0433\u0440\u0430\u0444\u0438\u0438 Linux \u0433\u043e\u0442\u043e\u0432\u0438\u0442\u0441\u044f \u0443\u0434\u0430\u043b\u0435\u043d\u0438\u0435 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 zero-copy \u0438\u0437 \u0438\u043d\u0442\u0435\u0440\u0444\u0435\u0439\u0441\u0430 AF_ALG \u0434\u043b\u044f \u0442\u0438\u043f\u043e\u0432 \u0430\u043b\u0433\u043e\u0440\u0438\u0442\u043c\u043e\u0432 SKCIPHER \u0438 AEAD.","og:url":"https:\/\/prohoster.info\/hr\/blog\/news\/iz-af_alg-v-linux-ubirayut-zero-copy-iz-soobrazhenij-bezopasnosti","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":"2026-05-22T16:25:08+00:00","article:modified_time":"2026-05-22T16:25:08+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\/hr\/wp-json\/wp\/v2\/posts\/181666","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/comments?post=181666"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/posts\/181666\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/media?parent=181666"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/categories?post=181666"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/tags?post=181666"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}