It was used for error reporting only.

It was used for error reporting only.

The current security driver architecture has the following
split of logic

 * domainGenSecurityLabel

    Allocate the unique label for the domain about to be started

 * domainGetSecurityLabel

    Retrieve the current live security label for a process

 * domainSetSecurityLabel

    Apply the previously allocated label to the current process
    Setup all disk image / device labelling

 * domainRestoreSecurityLabel

    Restore the original disk image / device labelling.
    Release the unique label for the domain

The 'domainSetSecurityLabel' method is special because it runs
in the context of the child process between the fork + exec.

This is require in order to set the process label. It is not
required in order to label disks/devices though. Having the
disk labelling code run in the child process limits what it
can do.

In particularly libvirtd would like to remember the current
disk image label, and only change shared image labels for the
first VM to start. This requires use & update of global state
in the libvirtd daemon, and thus cannot run in the child
process context.

The solution is to split domainSetSecurityLabel into two parts,
one applies process label, and the other handles disk image
labelling. At the same time domainRestoreSecurityLabel is
similarly split, just so that it matches the style. Thus the
previous 4 methods are replaced by the following 6 new methods

 * domainGenSecurityLabel

    Allocate the unique label for the domain about to be started
    No actual change here.

 * domainReleaseSecurityLabel

   Release the unique label for the domain

 * domainGetSecurityProcessLabel

   Retrieve the current live security label for a process
   Merely renamed for clarity.

 * domainSetSecurityProcessLabel

   Apply the previously allocated label to the current process

 * domainRestoreSecurityAllLabel

    Restore the original disk image / device labelling.

 * domainSetSecurityAllLabel

    Setup all disk image / device labelling

The SELinux and AppArmour drivers are then updated to comply with
this new spec. Notice that the AppArmour driver was actually a
little different. It was creating its profile for the disk image
and device labels in the 'domainGenSecurityLabel' method, where as
the SELinux driver did it in 'domainSetSecurityLabel'. With the
new method split, we can have consistency, with both drivers doing
that in the domainSetSecurityAllLabel method.

NB, the AppArmour changes here haven't been compiled so may not
build.

The QEMU driver is doing 90% of the calls to check for static vs
dynamic labelling. Except it is forgetting todo so in many places,
in particular hotplug is mistakenly assigning disk labels. Move
all this logic into the security drivers themselves, so the HV
drivers don't have to think about it.

* src/security/security_driver.h: Add virDomainObjPtr parameter
  to virSecurityDomainRestoreHostdevLabel and to
  virSecurityDomainRestoreSavedStateLabel
* src/security/security_selinux.c, src/security/security_apparmor.c:
  Add explicit checks for VIR_DOMAIN_SECLABEL_STATIC and skip all
  chcon() code in those cases
* src/qemu/qemu_driver.c: Remove all checks for VIR_DOMAIN_SECLABEL_STATIC
  or VIR_DOMAIN_SECLABEL_DYNAMIC. Add missing checks for possibly NULL
  driver entry points.

Based off how QEMU does it, look through /sys/bus/usb/devices/* for
matching vendor:product info, and if found, use info from the surrounding
files to build the device's /dev/bus/usb path.

This fixes USB device assignment by vendor:product when running qemu
as non-root (well, it should, but for some reason I couldn't reproduce
the failure people are seeing in [1], but it appears to work properly)

[1] https://bugzilla.redhat.com/show_bug.cgi?id=542450

Replace free(virBufferContentAndReset()) with virBufferFreeAndReset().
Update documentation and replace all remaining calls to free() with
calls to VIR_FREE(). Also add missing calls to virBufferFreeAndReset()
and virReportOOMError() in OOM error cases.

Introduce a new type="dir"  mode for <disks> that allows use of
QEMU's  virtual FAT block device driver. eg

    <disk type='dir' device='floppy'>
      <source dir='/tmp/test'/>
      <target dev='fda' bus='fdc'/>
      <readonly/>
    </disk>

gets turned into

  -drive file=fat:floppy:/tmp/test,if=floppy,index=0

Only read-only disks are supported with virtual FAT mode

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add type="dir"
* docs/schemas/domain.rng: Document new disk type
* src/xen/xend_internal.c, src/xen/xm_internal.c: Raise error for
  unsupported disk types
* tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args: Fix
  empty disk file handling
* tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args,
  tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml,
  tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args,
  tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
  tests/qemuxml2argvtest.c: Test QEMU vitual FAT driver
* src/qemu/qemu_conf.c: Support generating fat:/some/dir type
  disk args
* src/security/security_selinux.c: Temporarily skip labelling
  of directory based disks

When running qemu:///system instance, libvirtd runs as root,
but QEMU may optionally be configured to run non-root. When
then saving a guest to a state file, the file is initially
created as root, and thus QEMU cannot write to it. It is also
missing labelling required to allow access via SELinux.

* src/qemu/qemu_driver.c: Set ownership on save image before
  running migrate command in virDomainSave impl. Call out to
  security driver to set save image labelling
* src/security/security_driver.h: Add driver APIs for setting
  and restoring saved state file labelling
* src/security/security_selinux.c: Implement saved state file
  labelling for SELinux

- Don't duplicate SystemError
- Use proper error code in domain_conf
- Fix a broken error call in qemu_conf
- Don't use VIR_ERR_ERROR in security driver (isn't a valid code in this case)

Nearly all of the methods in src/util/util.h have error codes that
must be checked by the caller to correct detect & report failure.
Add ATTRIBUTE_RETURN_CHECK to ensure compile time validation of
this

* daemon/libvirtd.c: Add explicit check on return value of virAsprintf
* src/conf/domain_conf.c: Add missing check on virParseMacAddr return
  value status & report error
* src/network/bridge_driver.c: Add missing OOM check on virAsprintf
  and report error
* src/qemu/qemu_conf.c: Add missing check on virParseMacAddr return
  value status & report error
* src/security/security_selinux.c: Remove call to virRandomInitialize
  that's done in libvirt.c already
* src/storage/storage_backend_logical.c: Add check & log on virRun
  return status
* src/util/util.c: Add missing checks on virAsprintf/Run status
* src/util/util.h: Annotate all methods with ATTRIBUTE_RETURN_CHECK
  if they return an error status code
* src/vbox/vbox_tmpl.c: Add missing check on virParseMacAddr
* src/xen/xm_internal.c: Add missing checks on virAsprintf
* tests/qemuargv2xmltest.c: Remove bogus call to virRandomInitialize()

When James Morris originally submitted his sVirt patches (as seen in
libvirt 0.6.1), he did not require on disk labelling for
virSecurityDomainRestoreImageLabel. A later commit[2] changed this
behavior to assume on disk labelling, which halts implementations for
path-based MAC systems such as AppArmor and TOMOYO where
vm->def->seclabel is required to obtain the label.

* src/security/security_driver.h src/qemu/qemu_driver.c
  src/security/security_selinux.c: adds the 'virDomainObjPtr vm'
  argument back to *RestoreImageLabel

A simple misplaced break out of a switch results in:

  libvir: error : Failed to open file '/sys/bus/pci/devices/0000:00:54c./vendor': No such file or directory
  libvir: error : Failed to open file '/sys/bus/pci/devices/0000:00:54c./device': No such file or directory
  libvir: error : this function is not supported by the hypervisor: Failed to read product/vendor ID for 0000:00:54c.

when trying to passthrough a USB host device to qemu.

* src/security_selinux.c: fix a switch/break thinko

Signed-off-by: NChris Lalancette <clalance@redhat.com>

Use virStorageFileGetMetadata() to find any backing stores for images
and re-label them

Without this, qemu cannot access qcow2 backing files, see:

  https://bugzilla.redhat.com/497131

* src/security/security_selinux.c: re-label backing store files in
  SELinuxSetSecurityImageLabel()

* src/Makefile.am, src/qemu/qemu_conf.h, src/qemu/qemu_driver.c,
  tests/seclabeltest.c: Adapt for changed paths
* src/security.c: Rename to src/security/security_driver.c
* src/security.h: Rename to src/security/security_driver.h
* src/security_selinux.c, src/security_selinux.h: Move to src/security/

* src/security_selinux.c: Use virReportSystemError whereever an
  errno is involved
* src/qemu_driver.c: Don't overwrite error message from the
  security driver

* src/security.h: Driver API for relabelling host devices
* src/security_selinux.c: Implement relabelling of PCI and USB
  devices
* src/qemu_driver.c: Relabel USB/PCI devices before hotplug

* src/security_selinux.c: ignores EOPNOTSUPP when attempting to access an
  NFS share

* src/security_selinux.c: Skip relabelling of shared/readonly
  disks upon shutdown, since this breaks other VMs still active
  using those disks

Fixes startup of guest's with sourceless cdrom devices.

Patch from Cole Robinson originally posted here:

  https://bugzilla.redhat.com/499569

but never sent upstream.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>

As pointed out by Tim Waugh here:

  https://bugzilla.redhat.com/507555

We shouldn't bother trying to set the context of a file if it already
matches what we want.

(Fixed to use STREQ() and not use tabs, as pointed out by danpb)
Signed-off-by: NMark McLoughlin <markmc@redhat.com>

This patch was posted ages ago here:

  https://bugzilla.redhat.com/493692

But was never posted upstream AFAICT.

Patch from Dan Berrange
Signed-off-by: NMark McLoughlin <markmc@redhat.com>