4feeb2d986
The virt-login-shell binary is a setuid program that takes no arguments. When invoked it looks at the invoking uid, resolves it to a username, and finds an LXC guest with the same name. It then starts the guest and runs the shell in side the namespaces of the container. Given this set of tasks the virt-login-shell binary needs to connect to libvirtd, make various other libvirt API calls. This is a problem for setuid binaries as various libraries that libvirt.so links to are not safe. For example, they have constructor functions which execute an unknown amount of code that can be influenced by env variables. For this reason virt-login-shell doesn't use libvirt.so, but instead links to a custom, cut down, set of source files sufficient to be a local client only. This introduces a problem for integrating glib2 into libvirt though, as once integrated, there would be no way to build virt-login-shell without an external dependancy on glib2 and this is definitely not setuid safe. To resolve this problem, we split the virt-login-shell binary into two parts. The first part is setuid and does almost nothing. It simply records the original uid+gid, and then invokes the virt-login-shell-helper binary. Crucially when it does this it completes scrubs all environment variables. It is thus safe for virt-login-shell-helper to link to the normal libvirt.so. Any things that constructor functions do cannot be influenced by user control env vars or cli args. Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> |
||
|---|---|---|
| .ctags.d | ||
| .gnulib@8089c00979 | ||
| build-aux | ||
| docs | ||
| examples | ||
| gnulib | ||
| include/libvirt | ||
| m4 | ||
| po | ||
| src | ||
| tests | ||
| tools | ||
| .color_coded.in | ||
| .ctags | ||
| .dir-locals.el | ||
| .gitignore | ||
| .gitlab-ci.yml | ||
| .gitmodules | ||
| .gitpublish | ||
| .mailmap | ||
| .travis.yml | ||
| .ycm_extra_conf.py.in | ||
| ABOUT-NLS | ||
| AUTHORS.in | ||
| autogen.sh | ||
| bootstrap | ||
| bootstrap.conf | ||
| cfg.mk | ||
| ChangeLog | ||
| config-post.h | ||
| configure.ac | ||
| COPYING | ||
| COPYING.LESSER | ||
| gitdm.config | ||
| libvirt-admin.pc.in | ||
| libvirt-lxc.pc.in | ||
| libvirt-qemu.pc.in | ||
| libvirt.pc.in | ||
| libvirt.spec.in | ||
| Makefile.am | ||
| Makefile.ci | ||
| Makefile.nonreentrant | ||
| mingw-libvirt.spec.in | ||
| README | ||
| README-hacking | ||
| README.md | ||
| run.in | ||
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 2.0 (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: