Ho GRUB2 bootloader 8 bofokoli. E kotsi ka ho fetisisa (), e bitsoang BootHole, Feta mochini oa UEFI Secure Boot mme o kenye malware a sa netefatsoang. Ntho e ikhethang ea ts'oaetso ena ke hore ho e felisa ha hoa lekana ho ntlafatsa GRUB2, kaha mohlaseli a ka sebelisa mecha ea phatlalatso ea bootable ka phetolelo ea khale e tlokotsing e tiisitsoeng ke signature ea digital. Mohlaseli a ka senya ts'ebetso ea netefatso eseng ea Linux feela, empa le ea litsamaiso tse ling tsa ts'ebetso, ho kenyeletsoa .
Bothata bo ka rarolloa feela ka ho nchafatsa sistimi (dbx, UEFI Revocation List), empa boemong bona bokhoni ba ho sebelisa mecha ea phatlalatso ea khale ea Linux bo tla lahleha. Baetsi ba lisebelisoa tse ling ba se ba kenyelelitse lethathamo le ntlafalitsoeng la litifikeiti tsa ho hlakoloa ho firmware ea bona; lits'ebetsong tse joalo, ke meaho e ntlafalitsoeng feela ea liphaello tsa Linux e ka jaroang ka UEFI Secure Boot mode.
Ho felisa ho ba kotsing ea ho ajoa, o tla hloka hape ho nchafatsa li-installers, bootloader, liphutheloana tsa kernel, fwupd firmware le shim layer, ho hlahisa li-signature tse ncha tsa digital bakeng sa bona. Basebedisi ba tla hlokeha ho ntlafatsa litšoantšo tsa ho kenya le lisebelisoa tse ling tsa bootable, hammoho le ho kenya lenane la ho hlakoloa ha setifikeiti (dbx) ho firmware ea UEFI. Pele o ntlafatsa dbx ho UEFI, sistimi e lula e le kotsing ho sa tsotelehe ho kenya liapdeite ho OS.
Ho ba tlokotsing buffer overflow e ka sebelisoang hampe ho etsa khoutu e sa lebelloang nakong ea ts'ebetso ea boot.
Ho ba kotsing ho etsahala ha ho arola likahare tsa faele ea tlhophiso ea grub.cfg, eo hangata e fumanehang ho ESP (EFI System Partition) 'me e ka hlophisoa ke mohlaseli ea nang le litokelo tsa batsamaisi ntle le ho tlōla botšepehi ba shim e saennoeng le lifaele tse sebetsang tsa GRUB2. Ka lebaka la ho khoutu ea litlhophiso, motho ea sebetsanang le liphoso tse bolaeang tsa ho arola YY_FATAL_ERROR o hlahisitse temoso feela, empa ha aa ka a felisa lenaneo. Kotsi ea ho ba tlokotsing e fokotsehile ka tlhokahalo ea ho ba le tokelo ea ho fumana tsamaiso; Leha ho le joalo, bothata bo ka 'na ba hlokahala ho hlahisa li-rootkits tse patehileng haeba u na le phihlelo ea' mele ho thepa (haeba ho khoneha ho bootla ho tloha mecha ea litaba ea hau).
Liphatlalatso tse ngata tsa Linux li sebelisa e nyane , e saennweng ka dijithale ke Microsoft. Lera lena le netefatsa GRUB2 ka setifikeiti sa eona, se lumellang baetsi ba kabo ho se be le kernel e 'ngoe le e' ngoe le ntlafatso ea GRUB e netefalitsoeng ke Microsoft. Ho ba kotsing ho lumella, ka ho fetola litaba tsa grub.cfg, ho fihlela ts'ebetso ea khoutu ea hau sethaleng ka mor'a netefatso e atlehileng ea shim, empa pele o kenya sistimi ea ts'ebetso, o kenelle ka har'a ketane ea ts'epo ha Secure Boot mode e sebetsa le ho fumana taolo e felletseng. nakong ea ts'ebetso e tsoelang pele ea boot, ho kenyelletsa ho kenya OS e 'ngoe, phetoho ea likarolo tsa sistimi e sebetsang le ts'ireletso e fetang .
Bofokoli bo bong ho GRUB2:
- - Buffer e phalla ka lebaka la khaello ea ho lekola boholo ba sebaka sa memori se abetsoeng ho grub_malloc;
- - palo e felletseng ea grub_squash_read_symlink, e ka lebisang hore data e ngoloe ho feta buffer e fanoeng;
- - palo e felletseng e khaphatseha ho read_section_from_string, e ka lebisang ho ngotseng data ho feta buffer e fanoeng;
- - palo e felletseng ea grub_ext2_read_link, e ka lebisang hore data e ngoloe ho feta buffer e fanoeng;
- - e u lumella ho kenya li-kernel tse sa ngolisoang nakong ea boot e tobileng ka mokhoa o sireletsehileng oa Boot ntle le lera la shim;
- - phihlello sebakeng sa memori se seng se lokolotsoe (sebelisa-kamora-mahala) ha o hlalosa ts'ebetso ka nako ea ts'ebetso;
- - palo e felletseng e khaphatseha ho "initrd size handler".
Lintlafatso tsa pakete ea Hotfix li lokollotsoe bakeng sa , , и . Bakeng sa GRUB2 sete ya maqeba.
Source: opennet.ru