Bug 1905672 (CVE-2020-29480) - CVE-2020-29480 xen: xenstore watch notifications lacking permission checks (XSA-115)
Summary: CVE-2020-29480 xen: xenstore watch notifications lacking permission checks (X...
Alias: CVE-2020-29480
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1908091
Blocks: 1903644
TreeView+ depends on / blocked
Reported: 2020-12-08 19:31 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-16 18:46 UTC (History)
4 users (show)

Fixed In Version:
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Clone Of:
Last Closed: 2020-12-15 22:20:09 UTC

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Description Guilherme de Almeida Suckevicz 2020-12-08 19:31:57 UTC
Neither xenstore implementation does any permissions checks when
reporting a xenstore watch event.

A guest administrator can watch the root xenstored node, which will
cause notifications for every created, modified and deleted key.

A guest administrator can also use the special watches, which will
cause a notification every time a domain is created and destroyed.

Data may include:
 - number, type and domids of other VMs
 - existence and domids of driver domains
 - numbers of virtual interfaces, block devices, vcpus
 - existence of virtual framebuffers and their backend style (eg,
   existence of VNC service)
 - Xen VM UUIDs for other domains
 - timing information about domain creation and device setup
 - some hints at the backend provisioning of VMs and their devices

The watch events do not contain values stored in xenstore, only key

Comment 1 Guilherme de Almeida Suckevicz 2020-12-15 20:03:19 UTC
External References:


Comment 2 Guilherme de Almeida Suckevicz 2020-12-15 20:03:33 UTC
Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1908091]

Comment 3 Product Security DevOps Team 2020-12-15 22:20:09 UTC
This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.

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