{"id":107119,"date":"2023-03-06T12:48:15","date_gmt":"2023-03-06T10:48:15","guid":{"rendered":"https:\/\/prohoster.info\/?p=107119"},"modified":"2023-03-06T16:13:41","modified_gmt":"2023-03-06T14:13:41","slug":"dlya-izbavleniya-glibc-ot-problemy-2038-goda-predlozheno-prekratit-ispolzovanie-utmp","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/dlya-izbavleniya-glibc-ot-problemy-2038-goda-predlozheno-prekratit-ispolzovanie-utmp","title":{"rendered":"A Glibc 2038-as probl\u00e9m\u00e1j\u00e1nak megold\u00e1s\u00e1hoz javasolt\u00e1k az utmp haszn\u00e1lat\u00e1nak megsz\u00fcntet\u00e9s\u00e9t.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Thorsten Kukuk, a SUSE Future Technology Team vezet\u0151je, aki kor\u00e1bban 10 \u00e9ven \u00e1t ir\u00e1ny\u00edtotta a SUSE LINUX Enterprise Server projektet, javasolta, hogy a disztrib\u00faci\u00f3kban hagyj\u00e1k el a \/var\/run\/utmp f\u00e1jlt a Glibc 2038-as probl\u00e9ma teljes megold\u00e1sa \u00e9rdek\u00e9ben. Minden olyan alkalmaz\u00e1st, amely utmp, wtmp \u00e9s lastlog-t haszn\u00e1l, \u00e1tt\u00e9rni javasolt a felhaszn\u00e1l\u00f3k list\u00e1j\u00e1nak megszerz\u00e9s\u00e9re a systemd-logind seg\u00edts\u00e9g\u00e9vel. <\/p>\n

2038. janu\u00e1r 19-\u00e9n a 32 bites time_t t\u00edpus \u00e1ltal defini\u00e1lt epoch id\u0151sz\u00e1ml\u00e1l\u00f3k t\u00falcsordulnak. A Glibc k\u00f6nyvt\u00e1rban, a 64 bites time_t t\u00edpus bevezet\u00e9se ellen\u00e9re, a 32 bites alkalmaz\u00e1sokkal val\u00f3 kompatibilit\u00e1s meg\u0151rz\u00e9se \u00e9rdek\u00e9ben a felhaszn\u00e1l\u00f3i t\u00e9rben bizonyos esetekben a 64 bites platformokon tov\u00e1bbra is a 32 bites time_t t\u00edpust alkalmazz\u00e1k. Az egyik ilyen eset a \/var\/run\/utmp f\u00e1jl, amely a rendszerben jelenleg fut\u00f3 felhaszn\u00e1l\u00f3k adatait t\u00e1rolja. Az utmp id\u0151mez\u0151je 32 bites time_t \u00e9rt\u00e9k felhaszn\u00e1l\u00e1s\u00e1val van meghat\u00e1rozva. <\/p>\n

Az utmp id\u0151mez\u0151 32 bites t\u00edpusr\u00f3l 64 bites t\u00edpusra val\u00f3 egyszer\u0171 cser\u00e9je nem lehets\u00e9ges, mivel ez a Glibc ABI-j\u00e1nak megv\u00e1ltoz\u00e1s\u00e1t okozza (a t\u00edpus megv\u00e1ltozik a login(), getutid() \u00e9s utmpname() funkci\u00f3kban), \u00e9s megs\u00e9rti a utmp-t haszn\u00e1l\u00f3 alkalmaz\u00e1sok, p\u00e9ld\u00e1ul a w, who, uptime, login, su, sudo, useradd, systemd, sysvinit, tcsh, xterm display menedzserek, emacs, openssh, qemu, samba, rsyslog stb. kompatibilit\u00e1s\u00e1t. A lehets\u00e9ges buktat\u00f3k b\u0151s\u00e9ge \u00e9s a neh\u00e9zkess\u00e9g miatt a Glibc fejleszt\u0151i elvetett\u00e9k a time_t t\u00edpus \u00e1tv\u00e1lt\u00e1s\u00e1nak \u00f6tlet\u00e9t az utmp-ban. Ugyanazon okb\u00f3l elvetett\u00e9k azt a lehet\u0151s\u00e9get is, hogy a utmp strukt\u00far\u00e1j\u00e1ban l\u00e9v\u0151 szabad helyet egy tov\u00e1bbi 64 bites id\u0151mez\u0151 hozz\u00e1ad\u00e1s\u00e1ra haszn\u00e1lj\u00e1k. <\/p>\n

Ezenk\u00edv\u00fcl a utmp t\u00edpus\u00e1nak bitm\u00e9ret\u00e9nek megv\u00e1ltoztat\u00e1sa nem oldja meg a fenn\u00e1ll\u00f3 egy\u00e9b probl\u00e9m\u00e1kat, amelyekt\u0151l szint\u00e9n meg szeretn\u00e9nk szabadulni. P\u00e9ld\u00e1ul a utmp-be val\u00f3 \u00edr\u00e1shoz speci\u00e1lis jogosults\u00e1gokra van sz\u00fcks\u00e9g, ami tov\u00e1bbi privil\u00e9giumokat k\u00f6vetel meg a folyamatokt\u00f3l. Egy m\u00e1sik probl\u00e9ma az, hogy a utmp architekt\u00far\u00e1ja lehet\u0151v\u00e9 teszi, hogy a helyi felhaszn\u00e1l\u00f3k DoS-t\u00e1mad\u00e1sokat v\u00e9gezzenek, amelyek megzavarj\u00e1k a utmp szolg\u00e1ltat\u00e1s m\u0171k\u00f6d\u00e9s\u00e9t a f\u00e1jlok lockol\u00e1s\u00e1nak manipul\u00e1l\u00e1s\u00e1val, \u00edgy nem lehet\u00fcnk biztosak abban, hogy a utmp tartalma a rendszer val\u00f3s \u00e1llapot\u00e1t t\u00fckr\u00f6zi. A utmp-hez val\u00f3 hozz\u00e1f\u00e9r\u00e9s kezel\u00e9s\u00e9re javasoltak egy h\u00e1tt\u00e9rfolyamat haszn\u00e1lat\u00e1t, de ilyen feladatokra m\u00e1r l\u00e9tezik a systemd-logind folyamat, \u00e9s egy \u00fajabb speci\u00e1lis folyamat ind\u00edt\u00e1sa nem indokolt (az alkalmaz\u00e1soknak p\u00e1rhuzamosan k\u00e9t feldolgoz\u00f3ba kell adatokat \u00e1tadniuk). <\/p>\n

A DoS-t\u00e1mad\u00e1sokkal kapcsolatos probl\u00e9m\u00e1k megold\u00e1sa eset\u00e9n is az utmp tartalma csak inform\u00e1ci\u00f3s jelleg\u0171 marad, nem garant\u00e1lva a val\u00f3s\u00e1gnak val\u00f3 megfelel\u00e9st. P\u00e9ld\u00e1ul, k\u00fcl\u00f6nb\u00f6z\u0151 emul\u00e1torok \u00e9s termin\u00e1l multiplexerek elt\u00e9r\u0151en t\u00fckr\u00f6zik saj\u00e1t \u00e1llapotukat \u2014 \u00f6t GNOME termin\u00e1l ind\u00edt\u00e1sa egy felhaszn\u00e1l\u00f3k\u00e9nt fog megjelenni az utmp-ben, m\u00edg \u00f6t konsole vagy xterm termin\u00e1l ind\u00edt\u00e1sa a KDE-ben hat felhaszn\u00e1l\u00f3t mutat. Hasonl\u00f3an elt\u00e9r\u0151en viselkedik a screen \u00e9s a tmux is, az el\u0151bbi eset\u00e9ben minden egyes session k\u00fcl\u00f6n felhaszn\u00e1l\u00f3nak sz\u00e1m\u00edt, m\u00edg az ut\u00f3bbin\u00e1l csak egy felhaszn\u00e1l\u00f3 jelenik meg az \u00f6sszes sessionre. <\/p>\n

V\u00e9g\u00fcl, mint a legegyszer\u0171bb megold\u00e1s, javasolj\u00e1k, hogy minden alkalmaz\u00e1st \u00e1t\u00e1ll\u00edtsanak a m\u00e1r l\u00e9tez\u0151 alternat\u00edv systemd-logind szolg\u00e1ltat\u00e1s haszn\u00e1lat\u00e1ra, \u00e9s miut\u00e1n m\u00e1r nem marad relev\u00e1ns program, amelyik a utmp-hez fordul, a utmp-be val\u00f3 \u00edr\u00e1st le\u00e1ll\u00edtani. A wtmp helyettes\u00edt\u00e9s\u00e9re programoz\u00e1si interf\u00e9szeket javasoltak az inform\u00e1ci\u00f3k felhaszn\u00e1l\u00f3k \u00e1ltali \u00edr\u00e1s\u00e1ra \u00e9s olvas\u00e1s\u00e1ra a systemd-journald seg\u00edts\u00e9g\u00e9vel. A systemd 254 k\u00f6vetkez\u0151 kiad\u00e1s\u00e1nak k\u00f3dalapj\u00e1ba m\u00e1r beleker\u00fcltek a sz\u00fcks\u00e9ges funkci\u00f3k, hogy a utmp adatait a libsystemd-n kereszt\u00fcl biztos\u00edts\u00e1k az sd-login.h API haszn\u00e1lat\u00e1val vagy a DBUS-on kereszt\u00fcl.
\n
Forr\u00e1s: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0422\u043e\u0440\u0441\u0442\u0435\u043d \u041a\u0443\u043a\u0443\u043a (Thorsten Kukuk), \u043b\u0438\u0434\u0435\u0440 \u0433\u0440\u0443\u043f\u043f\u044b \u043f\u043e \u0440\u0430\u0437\u0432\u0438\u0442\u0438\u044e \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0439 \u0431\u0443\u0434\u0443\u0449\u0435\u0433\u043e \u0432 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 SUSE (Future Technology Team, \u0440\u0430\u0437\u0432\u0438\u0432\u0430\u0435\u0442 openSUSE MicroOS \u0438 SLE Micro), \u0440\u0430\u043d\u0435\u0435 10 \u043b\u0435\u0442 \u0440\u0443\u043a\u043e\u0432\u043e\u0434\u0438\u0432\u0448\u0438\u0439 \u043f\u0440\u043e\u0435\u043a\u0442\u043e\u043c SUSE LINUX Enterprise Server, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u0438\u0437\u0431\u0430\u0432\u0438\u0442\u044c\u0441\u044f \u043e\u0442 \u0444\u0430\u0439\u043b\u0430 \/var\/run\/utmp \u0432 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 \u0434\u043b\u044f \u043f\u043e\u043b\u043d\u043e\u0433\u043e \u0440\u0435\u0448\u0435\u043d\u0438\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b 2038 \u0433\u043e\u0434\u0430 \u0432 Glibc. \u0412\u0441\u0435 \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u044f, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044e\u0449\u0438\u0435 utmp, wtmp \u0438 lastlog, \u043f\u0440\u0435\u0434\u043b\u0430\u0433\u0430\u0435\u0442\u0441\u044f \u043f\u0435\u0440\u0435\u0432\u0435\u0441\u0442\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-107119","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\udd47 A proposal to resolve the 2038 problem in Glibc suggests discontinuing the use of utmp | ProHoster","description":"Thorsten Kukuk, a leader of the Future Technology Team at SUSE, developing openSUSE MicroOS and SLE Micro, previously led the SUSE LINUX Enterprise project for 10 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\u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 utmp | ProHoster","og:description":"\u0422\u043e\u0440\u0441\u0442\u0435\u043d \u041a\u0443\u043a\u0443\u043a (Thorsten Kukuk), \u043b\u0438\u0434\u0435\u0440 \u0433\u0440\u0443\u043f\u043f\u044b \u043f\u043e \u0440\u0430\u0437\u0432\u0438\u0442\u0438\u044e \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0439 \u0431\u0443\u0434\u0443\u0449\u0435\u0433\u043e \u0432 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 SUSE (Future Technology Team, \u0440\u0430\u0437\u0432\u0438\u0432\u0430\u0435\u0442 openSUSE MicroOS \u0438 SLE Micro), \u0440\u0430\u043d\u0435\u0435 10 \u043b\u0435\u0442 \u0440\u0443\u043a\u043e\u0432\u043e\u0434\u0438\u0432\u0448\u0438\u0439 \u043f\u0440\u043e\u0435\u043a\u0442\u043e\u043c SUSE LINUX 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