{"id":103489,"date":"2022-03-07T21:36:38","date_gmt":"2022-03-07T19:36:38","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-iskazit-fajly-dostupnye-tolko-dlya-chteniya"},"modified":"2022-03-07T21:36:38","modified_gmt":"2022-03-07T19:36:38","slug":"uyazvimost-v-yadre-linux-pozvolyayushhaya-iskazit-fajly-dostupnye-tolko-dlya-chteniya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/et\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-iskazit-fajly-dostupnye-tolko-dlya-chteniya","title":{"rendered":"Linuxi s\u00fcdamiku haavatavus, mis v\u00f5imaldab moonutada ainult lugemiseks m\u00f5eldud faile","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Linuxi tuumas avastati haavatavus (CVE-2022-0847), mis v\u00f5imaldab kirjutada lehek\u00fclje vahem\u00e4lu sisu mis tahes failide jaoks, sealhulgas lugemisre\u017eiimis olevate failide, mis on avatud O_RDONLY lipuga v\u00f5i mountitud ainult lugemisre\u017eiimis failis\u00fcsteemides. Praktikas v\u00f5ib seda haavatavust kasutada koodi sisestamiseks suvalistesse protsessidesse v\u00f5i avatud failide andmete moonutamiseks. N\u00e4iteks on v\u00f5imalik muuta faili authorized_keys sisu protsessis sshd. Ekspluateerimise protot\u00fc\u00fcp on saadaval testimiseks. <\/p>\n

Probleemile on antud koodnimi Dirty Pipe, paralleelselt 2016. aastal tuvastatud kriitilise haavatavusega Dirty COW. M\u00e4rgitakse, et ohtlikkuse tasemelt on Dirty Pipe samal tasemel nagu Dirty COW, kuid selle ekspluateerimine on oluliselt lihtsam. Haavatavus avastati seoses kaebustega perioodiliste kahjustustega v\u00f5rgu kaudu edastatud failides s\u00fcsteemis, mis laadib kokku pakitud arhiive logiserverist (37 kahjustust 3 kuu jooksul \u00fclekoormatud s\u00fcsteemis), mille ettevalmistamisel kasutati splice() operatsiooni ja anon\u00fc\u00fcmseid pipe'e. <\/p>\n

Haavatavus ilmneb alates Linuxi kernist 5.8, mis ilmus 2020. aasta augustis, st see on olemas Debian 11-s, kuid ei m\u00f5juta Ubuntu 20.04 LTS p\u00f5hikernat. RHEL 8.x ja openSUSE\/SUSE 15 kernelid p\u00f5hinevad algselt vanadel harudel, kuid pole v\u00e4listatud, et probleemiga seotud muudatus on neisse tagasi viidud (t\u00e4pset teavet ei ole hetkel). Pakettide v\u00e4rskenduste j\u00e4lgimiseks distributsioonides saab k\u00fclastada j\u00e4rgmisi lehti: Debian, SUSE, Ubuntu, RHEL, Fedora, Gentoo, Arch Linux. Haavatavuse parandamine on pakutud v\u00e4lja versioonides 5.16.11, 5.15.25 ja 5.10.102. Parandus on samuti lisatud Androidi platvormil kasutatavasse kernasse. <\/p>\n

Haavatavus tuleneb v\u00e4\u00e4rtuse «buf->flags» initsialiseerimise puudumisest funktsioonide copy_page_to_iter_pipe() ja push_pipe() koodis, kuna struktuuri eraldamisel m\u00e4lu ei puhastata ja teatud manipuleerimistega nimetamata torude korral v\u00f5ib «buf->flags» leida v\u00e4\u00e4rtusi teistest toimingutest. Kasutades seda omadust, v\u00f5ib privileegideta kohalik kasutaja saavutada lipu v\u00e4\u00e4rtuse PIPE_BUF_FLAG_CAN_MERGE, mis v\u00f5imaldab korraldada andmete kirjutamist lehe vahem\u00e4llu, kirjutades uued andmed lihtsalt ettevalmistatud nimetamata torusse. <\/p>\n

R\u00fcnnaku jaoks peab sihtfail olema loetav. Kuna torusse kirjutamisel ei kontrollita juurdep\u00e4\u00e4su\u00f5igusi, v\u00f5ib lehevahemikus asendamine toimuda ka failide jaoks, mis asuvad ainult lugemiseks monteeritud jagudes (n\u00e4iteks CD-ROM-i failide puhul). P\u00e4rast teabe asendamist lehevahemikus saab protsess lugemisel mitte tegelikke, vaid valeandmeid. <\/p>\n

Kasutamine seisneb nimetu kanali loomises ja selle t\u00e4itmises juhuslike andmetega, et saavutada PIPE_BUF_FLAG_CAN_MERGE lipu seadmine k\u00f5igis seotud ringstruktuurides. Seej\u00e4rel loetakse andmed kanalist, kuid lipp j\u00e4\u00e4b seatuks k\u00f5igis pipe_buffer struktuuri eksemplarides ringstruktuurides pipe_inode_info. Seej\u00e4rel kutsutakse v\u00e4lja splice() andmete lugemiseks sihtfailist nimetusse kanalisse alates vajalikust asukohast. Kui andmeid kirjutatakse sellesse nimetusse kanali p\u00e4rast seadistatud PIPE_BUF_FLAG_CAN_MERGE lippu, siis andmed lehe vahemikus kirjutatakse \u00fcle, selle asemel et luua uus pipe_buffer struktuuri eksemplar.
\n
Allikas: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u044f\u0434\u0440\u0435 Linux \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-0847), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043f\u0435\u0440\u0435\u0437\u0430\u043f\u0438\u0441\u0430\u0442\u044c \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u0441\u0442\u0440\u0430\u043d\u0438\u0447\u043d\u043e\u0433\u043e \u043a\u044d\u0448\u0430 \u0434\u043b\u044f \u043b\u044e\u0431\u044b\u0445 \u0444\u0430\u0439\u043b\u043e\u0432, \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u043d\u0430\u0445\u043e\u0434\u044f\u0449\u0438\u0445\u0441\u044f \u0432 \u0440\u0435\u0436\u0438\u043c\u0435 \u0442\u043e\u043b\u044c\u043a\u043e \u0434\u043b\u044f \u0447\u0442\u0435\u043d\u0438\u044f, \u043e\u0442\u043a\u0440\u044b\u0442\u044b\u0445 \u0441 \u0444\u043b\u0430\u0433\u043e\u043c O_RDONLY \u0438\u043b\u0438 \u0440\u0430\u0437\u043c\u0435\u0449\u0451\u043d\u043d\u044b\u0445 \u0432 \u0444\u0430\u0439\u043b\u043e\u0432\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u0445, \u043f\u0440\u0438\u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0445 \u0432 \u0440\u0435\u0436\u0438\u043c\u0435 \u0442\u043e\u043b\u044c\u043a\u043e \u0434\u043b\u044f \u0447\u0442\u0435\u043d\u0438\u044f. \u0421 \u043f\u0440\u0430\u043a\u0442\u0438\u0447\u0435\u0441\u043a\u043e\u0439 \u0441\u0442\u043e\u0440\u043e\u043d\u044b, \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043c\u043e\u0436\u0435\u0442 \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u0442\u044c\u0441\u044f \u0434\u043b\u044f \u043f\u043e\u0434\u0441\u0442\u0430\u043d\u043e\u0432\u043a\u0438 \u043a\u043e\u0434\u0430 \u0432 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u043b\u044c\u043d\u044b\u0435 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u044b \u0438\u043b\u0438 \u0438\u0441\u043a\u0430\u0436\u0435\u043d\u0438\u044f \u0434\u0430\u043d\u043d\u044b\u0445 \u0432 \u043e\u0442\u043a\u0440\u044b\u0432\u0430\u0435\u043c\u044b\u0445 […]<\/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-103489","post","type-post","status-publish","format-standard","hentry","category-novosti-interneta"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\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\n","aioseo_head_json":{"title":"\ud83e\udd47Linuxi tuuma haavatavus, mis v\u00f5imaldab muuta ainult lugemiseks m\u00e4\u00e4ratud faile | ProHoster","description":"Linuxi tuumas on tuvastatud haavatavus (CVE-2022-0847), mis v\u00f5imaldab \u00fcle kirjutada lehe vahemiku sisu mistahes failide puhul, sealhulgas lugemiseks ainult avatud failide puhul, mis on avatud O_RDONLY lipuga v\u00f5i asuvad ainult lugemisre\u017eiimis mountitud failis\u00fcsteemides. Praktiliselt v\u00f5ib haavatavust kasutada koodi asendamiseks mis tahes protsesside seas v\u00f5i avatud andmete moonutamiseks.","canonical_url":"https:\/\/prohoster.info\/et\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-iskazit-fajly-dostupnye-tolko-dlya-chteniya","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"et_EE","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\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 \u044f\u0434\u0440\u0435 Linux, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f 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