Ho Netfilter, sistimi e nyane ea kernel LinuxBofokodi (CVE-2022-25636) bo hlwailwe sesebelisoa sa ho sefa le ho fetola dipakete tsa marangrang se dumellang ho kenngwa tshebetsong ha khoutu boemong ba kernel. Ho phatlaladitswe sampole ya tshebediso e ka dumellang mosebelisi wa lehae ho eketsa ditokelo tsa hae. Ubuntu 21.10 ka mokhoa oa tšireletso oa KASLR o holofalitsoeng. Bothata bona bo bile teng ho tloha kernel 5.4. Tokiso e fumaneha hona joale e le patch (ha ho na litokollo tsa tlhokomelo ea kernel tse entsoeng). U ka latela litokollo tsa ntlafatso ea sephutheloana kabong maqepheng a latelang: Debian, SUSE, Ubuntu, RHEL, Fedora, Gentoo, Arch Linux.
Kotsi e bakoa ke phoso ea ho bala boholo ba phallo-> molao->action.entries array ho nft_fwd_dup_netdev_offload function (e hlalosoang ho file net/netfilter/nf_dup_netdev.c), e leng se ka lebisang ho data e laoloang ke mohlaseli e be teng. e ngotsweng sebakeng sa memori ka nqane ho moedi wa buffer e abetsweng. Phoso e hlaha ha ho hlophisoa melao ea "dup" le "fwd" ka liketane tseo ho potlakisoang ha hardware ea ho sebetsa ka lipakete (offload) ho sebelisoang. Kaha ho phalla ho etsahala pele ho theha molao oa filthara ea pakete le ho hlahloba ts'ehetso ea offload, ts'oaetso e boetse e sebetsa ho lisebelisoa tsa marang-rang tse sa tšehetseng ho potlakisa hardware, joalo ka sebopeho sa loopback.
Hoa hlokomeloa hore bothata bo bonolo haholo ho bo sebelisa, kaha litekanyetso tse fetang buffer li ka hlakola pointer ho net_device sebopeho, 'me lintlha tse mabapi le boleng bo ngotsoeng ka holimo li khutlisetsoa sebakeng sa mosebedisi, e leng se u lumellang hore u fumane liaterese. mohopolong o hlokahalang ho phethahatsa tlhaselo. Ho sebelisoa ha ts'oaetso ho hloka hore ho thehoe melao e itseng ho li-nftables, tse ka khonehang feela ka litokelo tsa CAP_NET_ADMIN, tse ka fumanoang ke mosebedisi ea se nang tokelo sebakeng se arohaneng sa mabitso a marang-rang. Bofokoli bo ka boela ba sebelisoa ho hlasela lits'ebetso tsa ho itšehla thajana.
Source: opennet.ru
