CVE-2020-12657

Se detectó un problema en el kernel de Linux versiones anteriores a 5.6.5. Se presenta un uso de la memoria previamente liberada en el archivo block/bfq-iosched.c relacionado con la función bfq_idle_slice_timer_body.

A flaw was found in the Linux kernel's implementation of the BFQ IO scheduler. This flaw allows a local user able to groom system memory to cause kernel memory corruption and possible privilege escalation by abusing a race condition in the IO scheduler.

It was discovered that the btrfs implementation in the Linux kernel did not properly detect that a block was marked dirty in some situations. An attacker could use this to specially craft a file system image that, when unmounted, could cause a denial of service. It was discovered that the linux kernel did not properly validate certain mount options to the tmpfs virtual memory file system. A local attacker with the ability to specify mount options could use this to cause a denial of service. Various other issues were also addressed.