{"id":102952,"date":"2022-01-12T21:36:50","date_gmt":"2022-01-12T19:36:50","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-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0"},"modified":"2022-01-12T21:36:50","modified_gmt":"2022-01-12T19:36:50","slug":"%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","title":{"rendered":"Zranite\u013enos\u0165 v subsyst\u00e9me eBPF, ktor\u00e1 umo\u017e\u0148uje vykonanie k\u00f3du na \u00farovni jadra Linux","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V subsyst\u00e9me eBPF, ktor\u00fd umo\u017e\u0148uje sp\u00fa\u0161\u0165anie spracovate\u013eov v jadre Linux v \u0161peci\u00e1lnej virtu\u00e1lnej ma\u0161ine s JIT, bola zisten\u00e1 zranite\u013enos\u0165 (CVE-2021-4204), ktor\u00e1 umo\u017e\u0148uje lok\u00e1lnemu neopr\u00e1vnen\u00e9mu pou\u017e\u00edvate\u013eovi z\u00edska\u0165 zv\u00fd\u0161en\u00e9 opr\u00e1vnenia a spusti\u0165 svoj k\u00f3d na \u00farovni jadra Linux. Probl\u00e9m sa prejavuje od jadra Linux 5.8 a zatia\u013e zost\u00e1va neopravene (t\u00fdka sa aj vydania 5.16). Stav vytv\u00e1rania aktualiz\u00e1ci\u00ed na odstr\u00e1nenie probl\u00e9mu v distrib\u00faci\u00e1ch je mo\u017en\u00e9 sledova\u0165 na t\u00fdchto str\u00e1nkach: Debian, RHEL, SUSE, Fedora, Ubuntu, Arch. Bolo nahl\u00e1sen\u00e9 vytvorenie funguj\u00faceho exploit, ktor\u00fd pl\u00e1nuj\u00fa zverejni\u0165 18. janu\u00e1ra (pou\u017e\u00edvate\u013eom a v\u00fdvoj\u00e1rom bola poskytnut\u00e1 jedna t\u00fd\u017ede\u0148 na odstr\u00e1nenie zranite\u013enosti). <\/p>\n

Zranite\u013enos\u0165 je sp\u00f4soben\u00e1 nespr\u00e1vnou kontrolou pren\u00e1\u0161an\u00fdch eBPF programov na vykonanie. Subsyst\u00e9m eBPF poskytuje pomocn\u00e9 funkcie, ktor\u00fdch spr\u00e1vnos\u0165 pou\u017e\u00edvania kontroluje \u0161peci\u00e1lny overova\u010d. Niektor\u00e9 funkcie si vy\u017eaduj\u00fa prenos hodnoty PTR_TO_MEM ako argumentu a na zabr\u00e1nenie mo\u017en\u00fdm prete\u010deniam buffera mus\u00ed overova\u010d pozna\u0165 ve\u013ekos\u0165 pam\u00e4ti s\u00favisiacej s argumentom. Pre funkcie bpf_ringbuf_submit a bpf_ringbuf_discard neboli \u00fadaje o ve\u013ekosti prenesenej pam\u00e4te ozn\u00e1men\u00e9 overova\u010dovi, \u010do mohlo by\u0165 vyu\u017eit\u00e9 na prep\u00edsanie oblast\u00ed pam\u00e4te mimo buffera pri vykon\u00e1van\u00ed \u0161peci\u00e1lne upraven\u00e9ho eBPF k\u00f3du. <\/p>\n

Na vykonanie \u00fatoku mus\u00ed ma\u0165 pou\u017e\u00edvate\u013e mo\u017enos\u0165 nahra\u0165 svoj program BPF, a mnoh\u00e9 nov\u00e9 distrib\u00facie Linuxu t\u00fato mo\u017enos\u0165 predvolene blokuj\u00fa (vr\u00e1tane toho, \u017ee nepriviligovan\u00fd pr\u00edstup k eBPF je teraz predvolene zak\u00e1zan\u00fd aj v samotnom jadre, od vydania 5.16). Napr\u00edklad, zranite\u013enos\u0165 m\u00f4\u017ee by\u0165 vyu\u017eit\u00e1 v predvolenej konfigur\u00e1cii Ubuntu 20.04 LTS, ale v prostrediach Ubuntu 22.04-dev, Debian 11, openSUSE 15.3, RHEL 8.5, SUSE 15-SP4 a Fedora 33 sa prejavuje iba ak administr\u00e1tor nastav\u00ed parameter kernel.unprivileged_bpf_disabled na hodnotu 0. Ako obch\u00e1dzaj\u00faci prostriedok na blokovanie zranite\u013enosti je mo\u017en\u00e9 zak\u00e1za\u0165 vykon\u00e1vanie programov BPF nepriviligovan\u00fdm pou\u017e\u00edvate\u013eom pr\u00edkazom «sysctl -w kernel.unprivileged_bpf_disabled=1».
\n
Zdroj: opennet.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 eBPF, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0437\u0430\u043f\u0443\u0441\u043a\u0430\u0442\u044c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u0438 \u0432\u043d\u0443\u0442\u0440\u0438 \u044f\u0434\u0440\u0430 Linux \u0432 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0439 \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0439 \u043c\u0430\u0448\u0438\u043d\u0435 \u0441 JIT, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-4204), \u0434\u0430\u044e\u0449\u0430\u044f \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c \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 \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u0438\u044f \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0439 \u0438 \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0441\u0432\u043e\u0435\u0433\u043e \u043a\u043e\u0434\u0430 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 \u044f\u0434\u0440\u0430 Linux. \u041f\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 \u044f\u0434\u0440\u0430 Linux 5.8 \u0438 \u043f\u043e\u043a\u0430 \u043e\u0441\u0442\u0430\u0451\u0442\u0441\u044f \u043d\u0435\u0438\u0441\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u043d\u043e\u0439 (\u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u0432\u044b\u043f\u0443\u0441\u043a 5.16). \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 […]<\/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-102952","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\udd47Zranite\u013enos\u0165 v subsyst\u00e9me eBPF, ktor\u00e1 umo\u017e\u0148uje vykonanie k\u00f3du na \u00farovni jadra Linuxu | ProHoster","description":"V subsyst\u00e9me eBPF, ktor\u00fd umo\u017e\u0148uje sp\u00fa\u0161\u0165anie spracovate\u013eov v jadre Linuxu v \u0161peci\u00e1lnej virtu\u00e1lnej strojovej JIT, bola zisten\u00e1 zranite\u013enos\u0165 (CVE-2021-4204), ktor\u00e1 umo\u017e\u0148uje lok\u00e1lnemu neprivilegovaniu pou\u017e\u00edvate\u013eovi.","canonical_url":"https:\/\/prohoster.info\/sk\/blog\/news\/%d1%83%d1%8f%d0%b7%d0%b2%d0%b8%d0%bc%d0%be%d1%81%d1%82%d1%8c-%d0%b2-%d0%bf%d0%be%d0%b4%d1%81%d0%b8%d1%81%d1%82%d0%b5%d0%bc%d0%b5-ebpf-%d0%bf%d0%be%d0%b7%d0%b2%d0%be%d0%bb%d1%8f%d1%8e%d1%89%d0%b0","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sk_SK","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 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