{"id":102964,"date":"2022-01-14T21:37:17","date_gmt":"2022-01-14T19:37:17","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-xfs-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0%d1%8f-%d1%87%d0%b8%d1%82%d0%b0%d1%82%d1%8c-%d1%81%d1%8b%d1%80"},"modified":"2022-01-14T21:37:17","modified_gmt":"2022-01-14T19:37:17","slug":"%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-xfs-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0%d1%8f-%d1%87%d0%b8%d1%82%d0%b0%d1%82%d1%8c-%d1%81%d1%8b%d1%80","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-xfs-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0%d1%8f-%d1%87%d0%b8%d1%82%d0%b0%d1%82%d1%8c-%d1%81%d1%8b%d1%80","title":{"rendered":"Zranitelnost v XFS, kter\u00e1 umo\u017e\u0148uje \u010d\u00edst surov\u00e1 data blokov\u00e9ho za\u0159\u00edzen\u00ed.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V k\u00f3du souborov\u00e9ho syst\u00e9mu XFS byla nalezena zranitelnost (CVE-2021-4155), kter\u00e1 umo\u017e\u0148uje lok\u00e1ln\u00edmu nep\u0159id\u011blen\u00e9mu u\u017eivateli \u010d\u00edst data z nevyu\u017eit\u00fdch blok\u016f p\u0159\u00edmo z blokov\u00e9ho za\u0159\u00edzen\u00ed. V\u0161echny v\u00fdznamn\u00e9 verze j\u00e1dra Linux nad 5.16, kter\u00e9 obsahuj\u00ed ovlada\u010d XFS, jsou touto problematikou ohro\u017eeny. Oprava byla zahrnuta ve verzi 5.16, stejn\u011b jako v aktualizac\u00edch jader 5.15.14, 5.10.91, 5.4.171, 4.19.225 atd. Stav nasazen\u00ed aktualizac\u00ed opravuj\u00edc\u00edch probl\u00e9m lze sledovat na t\u011bchto str\u00e1nk\u00e1ch: Debian, RHEL, SUSE, Fedora, Ubuntu, Arch. <\/p>\n

Zranitelnost je zp\u016fsobena nespr\u00e1vn\u00fdm chov\u00e1n\u00edm dvou specifick\u00fdch pro XFS ioctl(XFS_IOC_ALLOCSP) a ioctl(XFS_IOC_FREESP), kter\u00e9 jsou funk\u010dn\u011b analogick\u00e9 k ve\u0159ejn\u00e9mu syst\u00e9mov\u00e9mu vol\u00e1n\u00ed fallocate(). P\u0159i zv\u011bt\u0161en\u00ed velikosti souboru, kter\u00e1 nen\u00ed zarovn\u00e1na na velikost bloku, ioctl XFS_IOC_ALLOCSP\/XFS_IOC_FREESP nevymaz\u00e1vaj\u00ed zb\u00fdvaj\u00edc\u00ed bajty do n\u00e1sleduj\u00edc\u00edho bloku. T\u00edm p\u00e1dem, na XFS se standardn\u00ed velikost\u00ed bloku 4096 bajt\u016f m\u016f\u017ee \u00fato\u010dn\u00edk p\u0159e\u010d\u00edst a\u017e 4095 bajt\u016f p\u0159edchoz\u00edch zapsan\u00fdch dat. Ve vymezen\u00fdch oblastech mohou b\u00fdt obsa\u017eena data odstran\u011bn\u00fdch soubor\u016f, defragmentovan\u00fdch soubor\u016f, stejn\u011b jako soubor\u016f s deduplikovan\u00fdmi bloky. <\/p>\n

Zkontrolovat svoji syst\u00e9m na p\u0159\u00edtomnost probl\u00e9mu lze pomoc\u00ed jednoduch\u00e9ho prototypu exploit. Pokud po proveden\u00ed navrhovan\u00e9 sekvence p\u0159\u00edkaz\u016f dojde k p\u0159e\u010dten\u00ed textu Shakespeara, je ovlada\u010d FS zraniteln\u00fd. P\u016fvodn\u00ed p\u0159ipojen\u00ed odd\u00edlu XFS pro demonstrov\u00e1n\u00ed vy\u017eaduje pr\u00e1va superu\u017eivatele. <\/p>\n

Jeliko\u017e ioctl(XFS_IOC_ALLOCSP) a ioctl(XFS_IOC_FREESP) se funkcionalitou prakticky neli\u0161\u00ed od standardn\u00edho fallocate(), a jejich jedin\u00fdm rozd\u00edlem je \u00fanik dat, jejich p\u0159\u00edtomnost vypad\u00e1 jako backdoor. Navzdory obecn\u00e9 politice \u2013 nem\u011bnit st\u00e1vaj\u00edc\u00ed rozhran\u00ed v j\u00e1d\u0159e \u2013 bylo na n\u00e1vrh Linuse rozhodnuto tyto ioctl zcela odstranit v dal\u0161\u00ed verzi.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u043a\u043e\u0434\u0435 \u0444\u0430\u0439\u043b\u043e\u0432\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b XFS \u043e\u0431\u043d\u0430\u0440\u0443\u0436\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-4155), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u0447\u0438\u0442\u0430\u0442\u044c \u0434\u0430\u043d\u043d\u044b\u0435 \u043d\u0435\u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c\u044b\u0445 \u0431\u043b\u043e\u043a\u043e\u0432 \u043d\u0430\u043f\u0440\u044f\u043c\u0443\u044e \u0441 \u0431\u043b\u043e\u0447\u043d\u043e\u0433\u043e \u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432\u0430. \u0412\u0441\u0435 \u0437\u043d\u0430\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u044b\u0435 \u0432\u0435\u0440\u0441\u0438\u0438 \u044f\u0434\u0440\u0430 Linux \u0441\u0442\u0430\u0440\u0448\u0435 5.16, \u0441\u043e\u0434\u0435\u0440\u0436\u0430\u0449\u0438\u0435 \u0434\u0440\u0430\u0439\u0432\u0435\u0440 XFS, \u043f\u043e\u0434\u0432\u0435\u0440\u0436\u0435\u043d\u044b \u044d\u0442\u043e\u0439 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0435. \u0418\u0441\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0438\u0435 \u0432\u043e\u0448\u043b\u043e \u0432 \u0432\u0435\u0440\u0441\u0438\u044e 5.16, \u0430 \u0442\u0430\u043a\u0436\u0435 \u0432 \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f \u044f\u0434\u0435\u0440 5.15.14, 5.10.91, 5.4.171, 4.19.225 \u0438 \u0442.\u0434. \u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0439 \u0441 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0435\u043c \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b […]<\/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-102964","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\udd47Zranitelnost v XFS, kter\u00e1 umo\u017e\u0148uje \u010d\u00edst surov\u00e1 data blokov\u00e9ho za\u0159\u00edzen\u00ed | ProHoster","description":"V k\u00f3du souborov\u00e9ho syst\u00e9mu XFS byla nalezena zranitelnost (CVE-2021-4155), kter\u00e1 umo\u017e\u0148uje lok\u00e1ln\u00edmu nep\u0159id\u011blen\u00e9mu u\u017eivateli \u010d\u00edst data z nevyu\u017eit\u00fdch blok\u016f p\u0159\u00edmo z blokov\u00e9ho za\u0159\u00edzen\u00ed.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-xfs-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0%d1%8f-%d1%87%d0%b8%d1%82%d0%b0%d1%82%d1%8c-%d1%81%d1%8b%d1%80","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","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 XFS, 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