{"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\/hu\/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":"Az eBPF alrendszer egy sebezhet\u0151s\u00e9ge, amely lehet\u0151v\u00e9 teszi a Linux kernel szint\u0171 k\u00f3d v\u00e9grehajt\u00e1s\u00e1t","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Az eBPF alrendszer\u00e9ben, amely lehet\u0151v\u00e9 teszi az \u00edr\u00f3k ind\u00edt\u00e1s\u00e1t a Linux kernel\u00e9n bel\u00fcl egy speci\u00e1lis virtu\u00e1lis g\u00e9pen JIT-tel, egy sebezhet\u0151s\u00e9get (CVE-2021-4204) fedeztek fel, amely lehet\u0151v\u00e9 teszi, hogy egy helyi, nem privilegiz\u00e1lt felhaszn\u00e1l\u00f3 jogosults\u00e1gokat szerezzen \u00e9s k\u00f3dot futtasson a Linux kernel szintj\u00e9n. A probl\u00e9ma a Linux 5.8-as verzi\u00f3j\u00e1t\u00f3l kezd\u0151d\u0151en jelentkezik \u00e9s egyel\u0151re m\u00e9g nem jav\u00edtott\u00e1k (\u00e9rinti a 5.16 kiad\u00e1st is). A probl\u00e9m\u00e1val kapcsolatos friss\u00edt\u00e9sek \u00e1llapot\u00e1t a k\u00f6vetkez\u0151 oldalakon lehet nyomon k\u00f6vetni: Debian, RHEL, SUSE, Fedora, Ubuntu, Arch. Bejelentett\u00e9k egy m\u0171k\u00f6d\u0151 exploit elk\u00e9sz\u00edt\u00e9s\u00e9t, amelyet janu\u00e1r 18-\u00e1n terveznek k\u00f6zz\u00e9tenni (a felhaszn\u00e1l\u00f3knak \u00e9s fejleszt\u0151knek egy h\u00e9t \u00e1ll rendelkez\u00e9s\u00fckre a sebezhet\u0151s\u00e9g megsz\u00fcntet\u00e9s\u00e9re). <\/p>\n

A sebezhet\u0151s\u00e9get a v\u00e9grehajt\u00e1sra sz\u00e1nt eBPF programok helytelen ellen\u0151rz\u00e9se okozza. Az eBPF alrendszer seg\u00e9dfunkci\u00f3kat biztos\u00edt, amelyek haszn\u00e1lat\u00e1t egy speci\u00e1lis ellen\u0151r ellen\u0151rzi. N\u00e9h\u00e1ny funkci\u00f3 megk\u00f6veteli, hogy a PTR_TO_MEM \u00e9rt\u00e9k ker\u00fclj\u00f6n \u00e1tad\u00e1sra argumentumk\u00e9nt, \u00e9s hogy elker\u00fclj\u00fck a potenci\u00e1lis puffert\u00falfut\u00e1sokat, az ellen\u0151rnek ismernie kell az argumentumhoz kapcsol\u00f3d\u00f3 mem\u00f3ria m\u00e9ret\u00e9t. A bpf_ringbuf_submit \u00e9s bpf_ringbuf_discard funkci\u00f3kn\u00e1l a mem\u00f3ria m\u00e9ret\u00e9re vonatkoz\u00f3 inform\u00e1ci\u00f3k nem voltak k\u00f6z\u00f6lve az ellen\u0151rrel, ami lehet\u0151s\u00e9get adott a mem\u00f3ria ter\u00fcletek fel\u00fcl\u00edr\u00e1s\u00e1ra a pufforon k\u00edv\u00fcl, a speci\u00e1lisan megform\u00e1lt eBPF k\u00f3d v\u00e9grehajt\u00e1sa sor\u00e1n. <\/p>\n

A t\u00e1mad\u00e1s v\u00e9grehajt\u00e1s\u00e1hoz a felhaszn\u00e1l\u00f3nak lehet\u0151s\u00e9ge kell legyen, hogy felt\u00f6ltse a saj\u00e1t BPF-programj\u00e1t, \u00e9s sok \u00faj Linux disztrib\u00faci\u00f3 alap\u00e9rtelmez\u00e9s szerint blokkolja ezt a lehet\u0151s\u00e9get (t\u00f6bbek k\u00f6z\u00f6tt az eBPF-hez val\u00f3 nem privil\u00e9giz\u00e1lt hozz\u00e1f\u00e9r\u00e9s most m\u00e1r alap\u00e9rtelmez\u00e9s szerint betiltva van mag\u00e1ban a kernelben is, a 5.16-os verzi\u00f3 \u00f3ta). P\u00e9ld\u00e1ul, a sebezhet\u0151s\u00e9g kiakn\u00e1zhat\u00f3 az alap\u00e9rtelmezett konfigur\u00e1ci\u00f3ban az Ubuntu 20.04 LTS-ben, de az Ubuntu 22.04-dev, Debian 11, openSUSE 15.3, RHEL 8.5, SUSE 15-SP4 \u00e9s Fedora 33 k\u00f6rnyezetekben csak akkor jelentkezik, ha az adminisztr\u00e1tor a kernel.unprivileged_bpf_disabled param\u00e9tert 0 \u00e9rt\u00e9kre \u00e1ll\u00edtotta. A sebezhet\u0151s\u00e9g blokkol\u00e1s\u00e1nak egyik megker\u00fcl\u00e9si m\u00f3dszere lehet az BPF-programok v\u00e9grehajt\u00e1s\u00e1nak megtilt\u00e1sa nem privil\u00e9giz\u00e1lt felhaszn\u00e1l\u00f3k sz\u00e1m\u00e1ra a «sysctl -w kernel.unprivileged_bpf_disabled=1» parancs kiad\u00e1s\u00e1val.
\n
Forr\u00e1s: 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\udd47Sebezhet\u0151s\u00e9g az eBPF alrendszer\u00e9ben, amely lehet\u0151v\u00e9 teszi k\u00f3d v\u00e9grehajt\u00e1s\u00e1t a Linux kernel szintj\u00e9n | ProHoster","description":"Az eBPF alrendszer\u00e9ben, amely lehet\u0151v\u00e9 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\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 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 eBPF, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 \u044f\u0434\u0440\u0430 Linux | ProHoster","og:description":"\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 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