USB Gadget, kachitidwe kakang'ono ka Linux kernel yomwe imapereka mawonekedwe opangira zida zamakasitomala a USB ndi mapulogalamu omwe amatengera zida za USB, ali pachiwopsezo (CVE-2021-39685) chomwe chingayambitse kutayikira kwa chidziwitso kuchokera ku kernel, kuwonongeka, kapena kupha. mosinthana malamulo pa mlingo maso. Kuwukiraku kumachitika ndi wogwiritsa ntchito wamba wopanda mwayi pogwiritsa ntchito zida zosiyanasiyana zomwe zimagwiritsidwa ntchito potengera USB Gadget API, monga rndis, hid, uac1, uac1_legacy ndi uac2.
Vutoli lidakonzedwa muzosintha zaposachedwa za Linux kernel 5.15.8, 5.10.85, 5.4.165, 4.19.221, 4.14.258, 4.9.293 ndi 4.4.295. Vuto limakhalabe losakhazikika pakugawa (Debian, Ubuntu, RHEL, SUSE, Fedora, Arch). Chitsanzo chogwiritsa ntchito chakonzedwa kuti chiwonetsetse kusatetezeka.
Vutoli limadza chifukwa cha kusefukira kwa bafa muzoyendetsa zopempha zotumizira ma data mu ma driver a gadget rndis, hid, uac1, uac1_legacy ndi uac2. Chifukwa chogwiritsa ntchito pachiwopsezo, wowukira wopanda mwayi atha kupeza mwayi wokumbukira kernel potumiza pempho lapadera lowongolera lomwe lili ndi gawo la wLength lomwe limaposa kukula kwa static buffer, pomwe ma byte 4096 amaperekedwa nthawi zonse (USB_COMP_EP0_BUFSIZ). Panthawi yachiwonongeko, njira yopanda mwayi pamalo ogwiritsira ntchito imatha kuwerenga kapena kulemba mpaka 65 KB ya data mu kernel memory.
Source: opennet.ru