Candidate: CVE-2019-18424
PublicDate: 2019-10-31 14:15:00 UTC
References:
 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-18424
 https://xenbits.xen.org/xsa/advisory-302.html
 http://www.openwall.com/lists/oss-security/2019/10/31/6
 http://xenbits.xen.org/xsa/advisory-302.html
Description:
 An issue was discovered in Xen through 4.12.x allowing attackers to gain
 host OS privileges via DMA in a situation where an untrusted domain has
 access to a physical device. This occurs because passed through PCI devices
 may corrupt host memory after deassignment. When a PCI device is assigned
 to an untrusted domain, it is possible for that domain to program the
 device to DMA to an arbitrary address. The IOMMU is used to protect the
 host from malicious DMA by making sure that the device addresses can only
 target memory assigned to the guest. However, when the guest domain is torn
 down, or the device is deassigned, the device is assigned back to dom0,
 thus allowing any in-flight DMA to potentially target critical host data.
 An untrusted domain with access to a physical device can DMA into host
 memory, leading to privilege escalation. Only systems where guests are
 given direct access to physical devices capable of DMA (PCI pass-through)
 are vulnerable. Systems which do not use PCI pass-through are not
 vulnerable.
Ubuntu-Description:
Notes:
 mdeslaur> hypervisor packages are in universe. For
 mdeslaur> issues in the hypervisor, add appropriate
 mdeslaur> tags to each section, ex:
 mdeslaur> Tags_xen: universe-binary
Mitigation:
Bugs:
Priority: untriaged
Discovered-by:
Assigned-to:
CVSS:
 nvd: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H [6.8 MEDIUM]

Patches_xen:
Tags_xen: universe-binary
upstream_xen: needs-triage
precise/esm_xen: DNE
trusty_xen: ignored (out of standard support)
trusty/esm_xen: DNE
xenial_xen: ignored (end of standard support, was needs-triage)
esm-infra/xenial_xen: needs-triage
bionic_xen: needs-triage
disco_xen: ignored (reached end-of-life)
eoan_xen: ignored (reached end-of-life)
focal_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
groovy_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
hirsute_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
impish_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
jammy_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
devel_xen: not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)