4e13fb02fe
The virNetSocketWriteSASL method has to encode the buffer it is given and then write it to the underlying socket. This write is not guaranteed to send the full amount of data that was encoded by SASL. We cache the SASL encoded data so that on the next invocation of virNetSocketWriteSASL we carry on sending it. The subtle problem is that the 'len' value passed into virNetSocketWriteSASL on the 2nd call may be larger than the original value. So when we've completed sending the SASL encoded data we previously cached, we must return the original length we encoded, not the new length. This flaw means we could potentially have been discarded queued data without sending it. This would have exhibited itself as a libvirt client never receiving the reply to a method it invokes, async events silently going missing, or worse stream data silently getting dropped. For this to be a problem libvirtd would have to be queued data to send to the client, while at the same time the TCP socket send buffer is full (due to a very slow client). This is quite unlikely so if this bug was ever triggered by a real world user it would be almost impossible to reproduce or diagnose, if indeed it was ever noticed at all. Reviewed-by: John Ferlan <jferlan@redhat.com> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
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:
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 2.1 (or later). See the files COPYING.LESSER
and COPYING for full license terms & conditions.
Installation
Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:
$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install
While to build & install as an unprivileged user
$ ./configure --prefix=$HOME/usr
$ make
$ make install
The libvirt code relies on a large number of 3rd party libraries. These will
be detected during execution of the configure script and a summary printed
which lists any missing (optional) dependencies.
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:
- libvirt-users@redhat.com (for user discussions)
- libvir-list@redhat.com (for development only)
Further details on contacting the project are available on the website: