{"id":93183,"date":"2020-09-04T07:42:02","date_gmt":"2020-09-04T05:42:02","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux"},"modified":"2020-09-04T07:42:02","modified_gmt":"2020-09-04T05:42:02","slug":"uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","title":{"rendered":"Zranitelnost v implementaci socket\u016f AF_PACKET j\u00e1dra Linuxu","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Po t\u0159ech letech od vlny zranitelnost\u00ed (1<\/a><\/noindex>, 2<\/a><\/noindex>, 3<\/a><\/noindex>, 4<\/a><\/noindex>, 5<\/a><\/noindex>) v subsyst\u00e9mu AF_PACKET j\u00e1dra Linux byla odhalena<\/a><\/noindex> se objevuje dal\u0161\u00ed probl\u00e9m (CVE-2020-14386<\/a><\/noindex>), kter\u00fd umo\u017e\u0148uje lok\u00e1ln\u00edmu nep\u0159id\u011blen\u00e9mu u\u017eivateli spustit k\u00f3d s pr\u00e1vy root nebo se dostat z izolovan\u00fdch kontejner\u016f, pokud m\u00e1 v nich root p\u0159\u00edstup.<\/p>\n

Pro vytvo\u0159en\u00ed soketu AF_PACKET a zneu\u017eit\u00ed zranitelnosti jsou pot\u0159ebn\u00e1 opr\u00e1vn\u011bn\u00ed CAP_NET_RAW. Nicm\u00e9n\u011b, toto opr\u00e1vn\u011bn\u00ed m\u016f\u017ee b\u00fdt z\u00edsk\u00e1no nep\u0159id\u011blen\u00fdm u\u017eivatelem v kontejnerech vytv\u00e1\u0159en\u00fdch v syst\u00e9mech s povolenou podporou namespaces identit u\u017eivatel\u016f (user namespaces). Nap\u0159\u00edklad, user namespaces jsou ve v\u00fdchoz\u00edm nastaven\u00ed povoleny v Ubuntu a Fedo\u0159e, ale nejsou aktivov\u00e1ny v Debi\u00e1nu a RHEL. V Androidu m\u00e1 pr\u00e1vo vytv\u00e1\u0159et sokety AF_PACKET proces mediaserver, p\u0159es kter\u00fd m\u016f\u017ee b\u00fdt zranitelnost zneu\u017eita.<\/p>\n

Zranitelnost se nach\u00e1z\u00ed ve funkci tpacket_rcv a je zp\u016fsobena chybou p\u0159i v\u00fdpo\u010dtu prom\u011bnn\u00e9 netoff. \u00dato\u010dn\u00edk m\u016f\u017ee vytvo\u0159it podm\u00ednky, za kter\u00fdch do prom\u011bnn\u00e9 netoff bude zaps\u00e1na hodnota men\u0161\u00ed ne\u017e prom\u011bnn\u00e1 maclen, co\u017e vyvol\u00e1 p\u0159et\u00e9k\u00e1n\u00ed p\u0159i v\u00fdpo\u010dtu \u201emacoff = netoff \u2014 maclen\u201c a n\u00e1sledn\u011b nespr\u00e1vn\u00e9 nastaven\u00ed ukazatele na buffer pro p\u0159\u00edchoz\u00ed data. V d\u016fsledku toho m\u016f\u017ee \u00fato\u010dn\u00edk iniciovat z\u00e1pis od 1 do 10 bajt\u016f do oblasti mimo vyhrazen\u00fd buffer. Bylo zji\u0161t\u011bno, \u017ee je ve v\u00fdvoji exploit, kter\u00fd umo\u017e\u0148uje z\u00edsk\u00e1n\u00ed root pr\u00e1v v syst\u00e9mu. <\/p>\n

Probl\u00e9m je p\u0159\u00edtomen v j\u00e1d\u0159e od \u010dervence 2008, tj. projevuje se ve v\u0161ech aktu\u00e1ln\u00edch j\u00e1drech. Oprava je zat\u00edm dostupn\u00e1 ve form\u011b patche<\/a><\/noindex>. Sledovat v\u00fdskyt aktualizac\u00ed bal\u00ed\u010dk\u016f v distribuc\u00edch lze na n\u00e1sleduj\u00edc\u00edch str\u00e1nk\u00e1ch: Ubuntu<\/a><\/noindex>, Fedora<\/a><\/noindex>, SUSE<\/a><\/noindex>, Debian<\/a><\/noindex>, RHEL<\/a><\/noindex>, Arch<\/a><\/noindex>.<\/p>\n

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

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

\u0421\u043f\u0443\u0441\u0442\u044f \u0442\u0440\u0438 \u0433\u043e\u0434\u0430 \u0441 \u043c\u043e\u043c\u0435\u043d\u0442\u0430 \u0432\u043e\u043b\u043d\u044b \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 (1, 2, 3, 4, 5) \u0432 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 AF_PACKET \u044f\u0434\u0440\u0430 Linux \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0435\u0449\u0451 \u043e\u0434\u043d\u0430 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 (CVE-2020-14386), \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 \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root \u0438\u043b\u0438 \u0432\u044b\u0439\u0442\u0438 \u0438\u0437 \u0438\u0437\u043e\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0445 \u043a\u043e\u043d\u0442\u0435\u0439\u043d\u0435\u0440\u043e\u0432, \u043f\u0440\u0438 \u043d\u0430\u043b\u0438\u0447\u0438\u0438 \u0432 \u043d\u0438\u0445 root-\u0434\u043e\u0441\u0442\u0443\u043f\u0430. \u0414\u043b\u044f \u0441\u043e\u0437\u0434\u0430\u043d\u0438\u044f \u0441\u043e\u043a\u0435\u0442\u0430 AF_PACKET \u0438 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0442\u0440\u0435\u0431\u0443\u0435\u0442\u0441\u044f \u043d\u0430\u043b\u0438\u0447\u0438\u0435 \u043f\u043e\u043b\u043d\u043e\u043c\u043e\u0447\u0438\u0439 CAP_NET_RAW. \u0422\u0435\u043c \u043d\u0435 \u043c\u0435\u043d\u0435\u0435, […]<\/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-93183","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 implementaci soket\u016f AF_PACKET j\u00e1dra Linux | ProHoster","description":"Po t\u0159ech letech od vlny zranitelnost\u00ed (1,","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","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 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u0441\u043e\u043a\u0435\u0442\u043e\u0432 AF_PACKET \u044f\u0434\u0440\u0430 Linux | ProHoster","og:description":"\u0421\u043f\u0443\u0441\u0442\u044f \u0442\u0440\u0438 \u0433\u043e\u0434\u0430 \u0441 \u043c\u043e\u043c\u0435\u043d\u0442\u0430 \u0432\u043e\u043b\u043d\u044b \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 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