CVE-2021-3416

Se encontró un posible desbordamiento de la pila por medio de un problema de bucle infinito en varios emuladores de NIC de QEMU en versiones hasta 5.2.0 incluyéndola. El problema ocurre en el modo loopback de una NIC en donde son omitidas las comprobaciones DMA reentrantes. Un usuario y proceso invitado puede usar este fallo para consumir ciclos de CPU o bloquear el proceso QEMU en el host, resultando en un escenario DoS

A potential stack overflow via infinite loop issue was found in various NIC emulators of QEMU. The issue occurs in loopback mode of a NIC wherein reentrant DMA checks get bypassed. A guest user/process may use this flaw to consume CPU cycles or crash the QEMU process on the host resulting in DoS scenario.

Lei Sun discovered that QEMU incorrectly handled certain MMIO operations. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. Wenxiang Qian discovered that QEMU incorrectly handled certain ATAPI commands. An attacker inside the guest could possibly use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 21.04. Various other issues were also addressed.