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Ross Golder
6a1dc8c694
virNetMessageQueuePush() appends by walking to the tail of the queue. If it is handed a message which is already in that queue, and that message happens to be the tail, it links the message to itself. The cycle then makes virNetMessageQueueServe() return the same pointer on consecutive calls, and callers which free what they are served - such as virNetServerClientDispatchWrite() - free it twice, aborting the process with "free(): invalid pointer". Refuse such a push and warn instead, so that a caller bug shows up as a diagnosable log message rather than as heap corruption some time later. The check has to walk the queue rather than just test msg->next, because virNetMessageClear() memsets the whole message: a queued message which has been cleared appears unlinked while still being referenced. Also break the cycle in virNetMessageQueueServe() if one is somehow already present, rather than handing out the same message indefinitely, and clear msg->next in virNetMessageFree() so a stale reference held by a queue is detectable instead of dangling. The accompanying test reproduces the self-cycle deterministically: with the check removed it fails with "Message linked to itself". Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Ross Golder <ross@golder.org>
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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