|Package(s):||xen||CVE #(s):||CVE-2014-3967 CVE-2014-3968|
|Created:||June 17, 2014||Updated:||June 26, 2014|
|Description:||From the xen advisory:
The implementation of the HVM control operation HVMOP_inject_msi, while checking whether a particular IRQ was already set up in the necessary way, fails to properly check all respective conditions. In particular it doesn't check the returned pointer for being non-NULL before de- referencing it. (CVE-2014-3967)
Furthermore that same code also handles certain errors by logging messages, without (under default settings) at least making these messages subject to rate limiting. (CVE-2014-3968)
The NULL pointer de-reference would lead to a host crash, and hence a denial of service would result. Since host and guest page tables are fully separated for HVM guests, the guest would not be able to leverage the vulnerability for other kinds of attacks (privilege escalation or information leak).
The spamming of the hypervisor log could similarly lead to a denial of service.
In a configuration where device models run with limited privilege (for example, stubdom device models), a guest attacker who successfully finds and exploits an unfixed security flaw in qemu-dm could leverage the other flaw into a Denial of Service affecting the whole host.
In the more general case, in more abstract terms: a malicious administrator of a domain privileged with regard to an HVM guest can cause Xen to become unresponsive leading to a Denial of Service.
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