f66f70acbe
Commit b647d2195 introduced a use-after-free situation when the caller is trying to delete a snapshot and its children: if the callback function deletes the parent, it is no longer safe to query the parent to learn which children also need to be deleted (where we previously saved deleting the parent for last). To fix the problem, while still maintaining support for topological visits of callback functions, we have to stash off any information needed for later traversal prior to using a callback function (virDomainMomentForEachChild already does this, it is only virDomainMomentActOnDescendant that was running into problems). Sadly, the testsuite did not cover the problem at the time. Worse, even though I later added commit 280a2b41e to catch problems like this, and even though that test is indeed sufficient to detect the problem when run under valgrind or suitable MALLOC_PERTURB_ settings, I'm guilty of not running the test in such an environment. Thus, v5.2.0 has a regression that could have been prevented had we used the testsuite to its full power. On the bright side, deleting snapshots requires ACL domain:snapshot, which is arguably as powerful as domain:write, so I don't think this use-after-free forms a security hole. At some point, it would be nice to convert virDomainMomentObj into a virObject, at which point, the solution is even simpler: add virObjectRef/Unref around the callback. But as that will require auditing even more places in the code, I went with the simplest patch for the regression fix. Fixes: b647d2195 Reported-by: Roman Bogorodskiy <bogorodskiy@gmail.com> Signed-off-by: Eric Blake <eblake@redhat.com> Tested-by: Roman Bogorodskiy <bogorodskiy@gmail.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: