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Daniel P. Berrangé
f74495c7a1
The remote driver client supports specifying a transport in the URI scheme component such as +ext, +unix, +tls, etc. This determines how it should connect to the daemons. It strips this transport from the scheme to create a plain driver name that it forwards on to the remote server. It also, however, supports a "name" URI parameter which can be used to override the stripped URI that gets sent to the remote server. Unfortunately there is no validation of the URI by the remote server, so the URI override could include the transport in the scheme component. When the remote server sees a transport in the URI scheme, the connection gets diverted into the remote driver which then opens another client connection. When the "ext" transport is combined with the "command" URI parameter, this allows the client to trick the server into running an arbitrary command with the same privileges as the server. This can be abused with a read-only connection to a privileged server in order to elevate local privileges. There is no a valid reason to accept a transport component in the URI scheme received by the server, so validate this condition and reject any connection that violates it. This patch is derived from a proposal made by the reporter along with their disclosure, but generalized to block all schemes, not merely +ext and apply unconditionally to all connections not merely read-only ones. Reported-by: Deutsche Telekom Red Team <redteam@telekom.de> Fixes: CVE-2026-15268 Reviewed-by: Peter Krempa <pkrempa@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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==============================
Libvirt API for virtualization
==============================
Libvirt provides a portable, long term stable C API for managing the
virtualization technologies provided by many operating systems. It
includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware
vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER
Hypervisor.
For some of these hypervisors, it provides a stateful management
daemon which runs on the virtualization host allowing access to the
API both by non-privileged local users and remote users.
Layered packages provide bindings of the libvirt C API into other
languages including Python, Perl, PHP, Go, Java, OCaml, as well as
mappings into object systems such as GObject, CIM and SNMP.
Further information about the libvirt project can be found on the
website:
https://libvirt.org
License
=======
The libvirt C API is distributed under the terms of GNU Lesser General
Public License, version 2.1 (or later). Some parts of the code that are
not part of the C library may have the more restrictive GNU General
Public License, version 2.0 (or later). See the files ``COPYING.LESSER``
and ``COPYING`` for full license terms & conditions.
Installation
============
Instructions on building and installing libvirt can be found on the website:
https://libvirt.org/compiling.html
Contributing
============
The libvirt project welcomes contributions in many ways. For most components
the best way to contribute is to send patches to the primary development
mailing list. Further guidance on this can be found on the website:
https://libvirt.org/contribute.html
Contact
=======
The libvirt project has two primary mailing lists:
* users@lists.libvirt.org (**for user discussions**)
* devel@lists.libvirt.org (**for development only**)
Further details on contacting the project are available on the website:
https://libvirt.org/contact.html