Chiwopsezo cha Linux kernel chomwe chingayambitse ngozi potumiza paketi ya UDP

Mu Linux kernel kudziwika kusatetezeka (CVE-2019-11683), zomwe zimakupatsani mwayi woletsa ntchito patali potumiza mapaketi opangidwa mwapadera a UDP (paketi-yakufa). Vutoli limayamba chifukwa cha cholakwika pa udp_gro_receive_segment handler (net/ipv4/udp_offload.c) ndikukhazikitsa ukadaulo wa GRO (Generic Receive Offload) ndipo zitha kuwononga zomwe zili m'malo okumbukira kernel pokonza mapaketi a UDP okhala ndi zero padding. (katundu wopanda kanthu).

Vutoli limakhudza kernel yokha 5.0popeza kuthandizira kwa GRO kwa soketi za UDP kunali zakhazikitsidwa mu Novembala chaka chatha ndipo adangokwanitsa kulowa mumtundu waposachedwa wa kernel. Ukadaulo wa GRO umakupatsani mwayi wofulumizitsa kukonza kwa mapaketi ambiri omwe akubwera pophatikiza mapaketi angapo kukhala midadada yayikulu yomwe safuna kusinthidwa kwa paketi iliyonse.
Kwa TCP, vuto silichitika, chifukwa protocol iyi sichirikiza kuphatikizika kwa paketi popanda kulipira.

Chiwopsezochi mpaka pano chakhazikitsidwa mwa mawonekedwe okha chigamba, zosintha zowongolera sizinasindikizidwe (zosintha dzulo 5.0.11 kukonza osaphatikizidwa). Kuchokera ku zida zogawa, kernel 5.0 idakwanitsa kuphatikizidwa Fedora 30, Ubuntu 19.04, Arch Linux, Gentoo ndi magawo ena omwe akusinthidwa mosalekeza. Debian, Ubuntu 18.10 ndi kale, RHEL/CentOS и SUSE/OpenSUSE vuto silikhudza.

Vuto linapezeka chifukwa chake ntchito Makina oyesera a fuzzing opangidwa ndi Google syzbot ndi analyzer KASAN (KernelAddressSanitizer), yomwe cholinga chake ndi kuzindikira zolakwika mukamagwira ntchito ndi kukumbukira komanso zowona zolowera molakwika, monga kupeza malo okumbukira omasulidwa ndikuyika ma code m'malo okumbukira omwe sanapangidwe kuti asinthe.

Source: opennet.ru