OracleVM 3.2 : xen (OVMSA-2016-0172)
Low Nessus Plugin ID 95619
SynopsisThe remote OracleVM host is missing one or more security updates.
DescriptionThe remote OracleVM system is missing necessary patches to address critical security updates :
- qemu: ioport_read, ioport_write: be defensive about 32-bit addresses On x86, ioport addresses are 16-bit.
That these functions take 32-bit arguments is a mistake.
Changing the argument type to 16-bit will discard the top bits of any erroneous values from elsewhere in qemu.
Also, check just before use that the value is in range.
(This turns an ill-advised change to MAX_IOPORTS into a possible guest crash rather than a privilege escalation vulnerability.) And, in the Xen ioreq processor, clamp incoming ioport addresses to 16-bit values. Xen will never write >16-bit values but the guest may have access to the ioreq ring. We want to defend the rest of the qemu code from wrong values. This is XSA-199.
SolutionUpdate the affected xen / xen-devel / xen-tools packages.