CVE-2019-14283: Integer Overflow

A vulnerability was found in the Linux kernels floppy disk driver implementation. A local user with permissions to access the floppy device could call setgeometry in drivers/block/floppy.c which does not validate the sect and head fields causing an integer overflow and out-of-bounds read. This may crash the system or allow an attacker to gather information allowing for successful subsequent attacks.

Systems using QEMU will likely have the virtual floppy disk controller (FDC) enabled by default, Linux guests using this configuration will auto-load the floppy kernel module and likely be affected.

Mitigation:

The kernel module named 'floppy' contains the affected code, this can be blacklisted using the standard blacklisting techniques or disabled in the systems BIOS. See https://access.redhat.com/solutions/41278 for how to blacklist a kernel module.

Virtualized guest systems can also remove the system from the guests configuration to ensure that the module does not load.

External references:

Changelog https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2.3

Upstream commit https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=da99466ac243f15fbba65bd261bfc75ffa1532b6 https://github.com/torvalds/linux/commit/da99466ac243f15fbba65bd261bfc75ffa1532b6

— Red Hat

In the Linux kernel before 5.2.3, setgeometry in drivers/block/floppy.c does not validate the sect and head fields, as demonstrated by an integer overflow and out-of-bounds read. It can be triggered by an unprivileged local user when a floppy disk has been inserted. NOTE: QEMU creates the floppy device by default.

Linux Kernel could allow a local attacker to execute arbitrary code on the system, caused by an integer overflow and out-of-bounds read in the drivers/block/floppy.c. By using a specially-crafted floppy disk, an attacker could exploit this vulnerability to execute arbitrary code on the system.

— IBM