Tlhahisoleseding e senotsoe ka bofokoli ba bobeli ho bootloader ea GRUB2, e ka lebisang ho ts'ebetsong ea khoutu ha u sebelisa lifonti tse entsoeng ka mokhoa o khethehileng le ho sebetsana le tatellano e itseng ea Unicode. Bofokoli bo ka sebelisoa ho feta mokhoa oa boot o netefalitsoeng oa UEFI Secure Boot.
Bofokoli bo bonts'itsoeng:
- CVE-2022-2601 - Buffer e phalla ka har'a ts'ebetso ea grub_font_construct_glyph () ha e sebetsana le lifonti tse entsoeng ka mokhoa o ikhethileng ka sebopeho sa pf2, se etsahalang ka lebaka la lipalo tse fosahetseng tsa paramethara ea max_glyph_size le kabo ea sebaka sa memori seo ho hlakileng hore se nyane ho feta kamoo ho hlokahalang. amohela li-glyphs.
- CVE-2022-3775 Ho ngola ka ntle ho meeli ho etsahala ha ho etsoa tatellano e itseng ea Unicode ka fonte e hlophisitsoeng ka mokhoa o ikhethileng. Bothata bo ho khoutu ea ts'ebetso ea fonte mme bo bakoa ke khaello ea licheke tse nepahetseng ho netefatsa hore bophara le bophahamo ba glyph li lumellana le boholo ba bitmap e fumanehang. Mohlaseli a ka etsa tlhahiso ka tsela e tla etsa hore mohatla oa data o ngoloe ka ntle ho buffer e fanoeng. Hoa hlokomeloa hore ho sa tsotellehe ho rarahana ha ho sebelisa monyetla oa ho ba kotsing, ho tlisa bothata ho ts'ebetsong ea khoutu ha hoa qheleloa ka thōko.
Tokiso e phatlalalitsoe e le patch. Boemo ba ho felisa bofokoli liphatlalatsong bo ka hlahlojoa maqepheng ana: Ubuntu, SUSE, RHEL, Fedora, Debian. Ho lokisa mathata ho GRUB2, ha hoa lekana ho ntlafatsa sephutheloana feela; o tla hloka hape ho hlahisa li-signature tse ncha tsa ka hare tsa dijithale le li-installer tsa ntlafatso, li-bootloader, liphutheloana tsa kernel, fwupd firmware le shim layer.
Liphatlalatso tse ngata tsa Linux li sebelisa lesela le lenyenyane la shim le saennweng ke Microsoft bakeng sa booting e netefalitsoeng ka UEFI Secure Boot mode. 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. Bofokoli ho GRUB2 bo u lumella ho fihlela ts'ebetso ea khoutu ea hau sethaleng kamora netefatso e atlehileng ea shim, empa pele o kenya sistimi ea ts'ebetso, o kenella ka har'a ketane ea ts'epo ha Sireletsehile Boot mode e sebetsa mme o fumana taolo e felletseng mabapi le ts'ebetso e tsoelang pele ea boot, ho kenyeletsoa. ho kenya OS e 'ngoe, ho fetola sistimi ea likarolo tsa sistimi le ho feta ts'ireletso ea Lockdown.
Ho thibela ho ba kotsing ntle le ho hlakola signature ea dijithale, liphaello li ka sebelisa mochini oa SBAT (UEFI Secure Boot Advanced Targeting), o ts'ehetsoeng bakeng sa GRUB2, shim le fwupd kabong e tsebahalang haholo ea Linux. SBAT e ile ea ntlafatsoa ka kopanelo le Microsoft 'me e kenyelletsa ho kenya metadata e eketsehileng lifaeleng tse ka sebetsoang tsa likarolo tsa UEFI, tse kenyelletsang tlhahisoleseling mabapi le moetsi, sehlahisoa, karolo le mofuta. Metadata e boletsoeng e netefalitsoe ka signature ea dijithale 'me e ka kenyelletsoa ka thoko lethathamong la likarolo tse lumelletsoeng kapa tse thibetsoeng bakeng sa UEFI Secure Boot.
SBAT e u lumella ho thibela tšebeliso ea li-signature tsa dijithale bakeng sa linomoro tsa mofuta oa karolo ka 'ngoe ntle le ho hlakola linotlolo tsa Secure Boot. Ho thibela bofokoli ka SBAT ha ho hloke tšebeliso ea lenane la ho hlakoloa ha setifikeiti sa UEFI (dbx), empa ho etsoa boemong ba ho fetola senotlolo sa ka hare ho hlahisa li-signature le ho ntlafatsa GRUB2, shim le lisebelisoa tse ling tsa boot tse fanoang ke kabo. Pele ho kenyelletsoa SBAT, ho ntlafatsa lenane la ho hlakoloa ha setifikeiti (dbx, UEFI Revocation List) e ne e le ntho e hlokahalang bakeng sa ho thibela ka ho feletseng ho ba kotsing, kaha mohlaseli, ho sa tsotellehe mokhoa oa ho sebetsa o sebelisitsoeng, o ne a ka sebelisa mecha ea phatlalatso ea bootable ka phetolelo ea khale ea tlokotsing ea GRUB2, e netefalitsoeng ke signature ea dijithale, ho sekisetsa UEFI Secure Boot .
Source: opennet.ru