{"id":38554,"date":"2019-10-31T22:24:30","date_gmt":"2019-10-31T19:24:30","guid":{"rendered":"https:\/\/prohoster.info\/blog\/v-yadro-linux-5-4-prinyaty-patchi-dlya-ogranicheniya-dostupa-root-k-vnutrennostyam-yadra\/"},"modified":"2019-10-31T22:24:30","modified_gmt":"2019-10-31T19:24:30","slug":"v-yadro-linux-5-4-prinyaty-patchi-dlya-ogranicheniya-dostupa-root-k-vnutrennostyam-yadra","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/v-yadro-linux-5-4-prinyaty-patchi-dlya-ogranicheniya-dostupa-root-k-vnutrennostyam-yadra","title":{"rendered":"Do j\u00e1dra Linux 5.4 byly p\u0159ijaty patche k omezen\u00ed p\u0159\u00edstupu roota k vnit\u0159nostem j\u00e1dra.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Linus Torvalds p\u0159ijal<\/a><\/noindex> do budouc\u00ed verze j\u00e1dra Linux 5.4 je zahrnuta sada patch\u016f «lockdown<\/a><\/noindex>\u201e navr\u017een\u00fd<\/a><\/noindex>\tDavidem Howells, pracuj\u00edc\u00edm v Red Hat, a Matthew Garrettem (Matthew Garrett,<\/a><\/noindex>, pracuje ve spole\u010dnosti Google) pro omezen\u00ed p\u0159\u00edstupu u\u017eivatele root k j\u00e1dru. Souvisej\u00edc\u00ed funk\u010dnost «lockdown» byla odd\u011blena do voliteln\u011b na\u010d\u00edtateln\u00e9ho LSM modulu (Linux Security Module<\/a><\/noindex>), kter\u00fd vytv\u00e1\u0159\u00ed bari\u00e9ru mezi UID 0 a j\u00e1drem, \u010d\u00edm\u017e omezuje ur\u010ditou n\u00edzko\u00farov\u0148ovou funk\u010dnost.<\/p>\n

Pokud \u00fato\u010dn\u00edk v d\u016fsledku \u00fatoku z\u00edsk\u00e1 vykon\u00e1v\u00e1n\u00ed k\u00f3du s pr\u00e1vy roota, m\u016f\u017ee prov\u00e9st sv\u016fj k\u00f3d i na \u00farovni j\u00e1dra, nap\u0159\u00edklad prost\u0159ednictv\u00edm v\u00fdm\u011bny j\u00e1dra pomoc\u00ed kexec nebo \u010dten\u00ed\/z\u00e1pisu do pam\u011bti p\u0159es \/dev\/kmem. Nejz\u0159eteln\u011bj\u0161\u00edm d\u016fsledkem takov\u00e9 aktivity m\u016f\u017ee b\u00fdt obejit\u00ed<\/a><\/noindex> UEFI Secure Boot nebo extrakce citliv\u00fdch dat ulo\u017een\u00fdch na \u00farovni j\u00e1dra.<\/p>\n

P\u016fvodn\u011b se funkce omezen\u00ed roota vyv\u00edjely v kontextu pos\u00edlen\u00ed ochrany ov\u011b\u0159en\u00e9ho spou\u0161t\u011bn\u00ed a distribuce ji\u017e del\u0161\u00ed dobu pou\u017e\u00edvaj\u00ed extern\u00ed patche k blokaci obch\u00e1zen\u00ed UEFI Secure Boot. Sou\u010dasn\u011b se v\u0161ak do hlavn\u00edho j\u00e1dra podobn\u00e1 omezen\u00ed nezahrnovala kv\u016fli n\u00e1zorov\u00fdm neshod\u00e1m<\/a><\/noindex> v jejich implementaci a obav o naru\u0161en\u00ed fungov\u00e1n\u00ed st\u00e1vaj\u00edc\u00edch syst\u00e9m\u016f. Modul «lockdown» zahrnuje ji\u017e pou\u017e\u00edvan\u00e9 patche v distribuc\u00edch, kter\u00e9 byly p\u0159epracov\u00e1ny do podoby samostatn\u00e9ho subsyst\u00e9mu, nez\u00e1visl\u00e9ho na UEFI Secure Boot. <\/p>\n

V re\u017eimu lockdown je omezen p\u0159\u00edstup k \/dev\/mem, \/dev\/kmem, \/dev\/port, \/proc\/kcore, debugfs, ladic\u00edmu re\u017eimu kprobes, mmiotrace, tracefs, BPF, PCMCIA CIS (struktura informac\u00ed o kart\u011b), n\u011bkter\u00fdm rozhran\u00edm ACPI a MSR registr\u016fm CPU, jsou blokov\u00e1ny vol\u00e1n\u00ed kexec_file a kexec_load, z\u00e1kaz p\u0159echodu do sp\u00e1nkov\u00e9ho re\u017eimu, omezen\u00ed pou\u017e\u00edv\u00e1n\u00ed DMA pro PCI za\u0159\u00edzen\u00ed, je zak\u00e1z\u00e1n import k\u00f3du ACPI z prom\u011bnn\u00fdch EFI,
\nje zak\u00e1z\u00e1no manipulovat s porty vstupu\/v\u00fdstupu, v\u010detn\u011b zm\u011bny \u010d\u00edsla p\u0159eru\u0161en\u00ed a portu vstupu\/v\u00fdstupu pro s\u00e9riov\u00fd port. <\/p>\n

Ve v\u00fdchoz\u00edm nastaven\u00ed modul lockdown nen\u00ed aktivn\u00ed, sestavuje se po zad\u00e1n\u00ed volby v kconfig SECURITY_LOCKDOWN_LSM a aktivuje se prost\u0159ednictv\u00edm parametru j\u00e1dra «lockdown=», ovl\u00e1dac\u00edho souboru «\/sys\/kernel\/security\/lockdown» nebo sestavovac\u00edch voleb LOCK_DOWN_KERNEL_FORCE_*<\/a><\/noindex>, kter\u00e9 mohou nab\u00fdvat hodnot «integrity» a «confidentiality». V prvn\u00edm p\u0159\u00edpad\u011b jsou blokov\u00e1ny mo\u017enosti, kter\u00e9 umo\u017e\u0148uj\u00ed prov\u00e1d\u011bt zm\u011bny v b\u011b\u017e\u00edc\u00edm j\u00e1dru z u\u017eivatelsk\u00e9ho prostoru, a ve druh\u00e9m p\u0159\u00edpad\u011b je krom\u011b toho deaktivov\u00e1na funk\u010dnost, kterou lze pou\u017e\u00edt k z\u00edsk\u00e1n\u00ed d\u016fv\u011brn\u00fdch informac\u00ed z j\u00e1dra.<\/p>\n

Je d\u016fle\u017eit\u00e9 poznamenat, \u017ee lockdown pouze omezuje b\u011b\u017en\u00e9 mo\u017enosti p\u0159\u00edstupu k j\u00e1dru, ale nechr\u00e1n\u00ed p\u0159ed modifikacemi v d\u016fsledku vyu\u017eit\u00ed zranitelnost\u00ed. Pro blokov\u00e1n\u00ed prov\u00e1d\u011bn\u00ed zm\u011bn v b\u011b\u017e\u00edc\u00edm j\u00e1d\u0159e p\u0159i pou\u017eit\u00ed exploit\u016f byl projekt Openwall se vyv\u00edj\u00ed<\/a><\/noindex> samostatn\u00e9ho modulu LKRG<\/a><\/noindex> (Linux Kernel Runtime Guard).<\/p>\n

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

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

\u041b\u0438\u043d\u0443\u0441 \u0422\u043e\u0440\u0432\u0430\u043b\u044c\u0434\u0441 \u043f\u0440\u0438\u043d\u044f\u043b \u0432 \u0441\u043e\u0441\u0442\u0430\u0432 \u0431\u0443\u0434\u0443\u0449\u0435\u0433\u043e \u0432\u044b\u043f\u0443\u0441\u043a\u0430 \u044f\u0434\u0440\u0430 Linux 5.4 \u043d\u0430\u0431\u043e\u0440 \u043f\u0430\u0442\u0447\u0435\u0439 «lockdown«, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0435\u043d\u043d\u044b\u0439 \u0414\u044d\u0432\u0438\u0434\u043e\u043c \u0425\u043e\u0443\u044d\u043b\u043b\u0441\u043e\u043c (David Howells, \u0440\u0430\u0431\u043e\u0442\u0430\u0435\u0442 \u0432 Red Hat) \u0438 \u041c\u044d\u0442\u044c\u044e \u0413\u0430\u0440\u0440\u0435\u0442\u043e\u043c (Matthew Garrett, \u0440\u0430\u0431\u043e\u0442\u0430\u0435\u0442 \u0432 Google) \u0434\u043b\u044f \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u0438\u044f \u0434\u043e\u0441\u0442\u0443\u043f\u0430 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044f root \u043a \u044f\u0434\u0440\u0443. \u0421\u0432\u044f\u0437\u0430\u043d\u043d\u0430\u044f \u0441 «lockdown» \u0444\u0443\u043d\u043a\u0446\u0438\u043e\u043d\u0430\u043b\u044c\u043d\u043e\u0441\u0442\u044c \u0432\u044b\u043d\u0435\u0441\u0435\u043d\u0430 \u0432 \u043e\u043f\u0446\u0438\u043e\u043d\u0430\u043b\u044c\u043d\u043e \u0437\u0430\u0433\u0440\u0443\u0436\u0430\u0435\u043c\u044b\u0439 LSM-\u043c\u043e\u0434\u0443\u043b\u044c (Linux Security Module), \u0443\u0441\u0442\u0430\u043d\u0430\u0432\u043b\u0438\u0432\u0430\u044e\u0449\u0438\u0439 \u0431\u0430\u0440\u044c\u0435\u0440 \u043c\u0435\u0436\u0434\u0443 UID 0 \u0438 […]<\/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-38554","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\udd47Do j\u00e1dra Linux 5.4 byly p\u0159ijaty opravy pro omezen\u00ed p\u0159\u00edstupu root k nitru j\u00e1dra | ProHoster","description":"Linus Torvalds p\u0159ijal do nadch\u00e1zej\u00edc\u00ed 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