* configure.ac (with_selinux): Check for <selinux/label.h>.
* src/security/security_selinux.c (getContext): New function.
(SELinuxRestoreSecurityFileLabel): Use it to restore compilation
when using older libselinux.

https://bugzilla.redhat.com/show_bug.cgi?id=658657

* src/security/security_selinux.c
(SELinuxRestoreSecurityFileLabel): Use selabel_lookup instead of
matchpathcon.
Suggested by Daniel Walsh.

security_context_t happens to be a typedef for char*, and happens to
begin with a string usable as a raw context string.  But in reality,
it is an opaque type that may or may not have additional information
after the first NUL byte, where that additional information can
include pointers that can only be freed via freecon().

Proof is from this valgrind run of daemon/libvirtd:

==6028== 839,169 (40 direct, 839,129 indirect) bytes in 1 blocks are definitely lost in loss record 274 of 274
==6028==    at 0x4A0515D: malloc (vg_replace_malloc.c:195)
==6028==    by 0x3022E0D48C: selabel_open (label.c:165)
==6028==    by 0x3022E11646: matchpathcon_init_prefix (matchpathcon.c:296)
==6028==    by 0x3022E1190D: matchpathcon (matchpathcon.c:317)
==6028==    by 0x4F9D842: SELinuxRestoreSecurityFileLabel (security_selinux.c:382)

800k is a lot of memory to be leaking.

* src/storage/storage_backend.c
(virStorageBackendUpdateVolTargetInfoFD): Avoid leak on error.
* src/security/security_selinux.c
(SELinuxReserveSecurityLabel, SELinuxGetSecurityProcessLabel)
(SELinuxRestoreSecurityFileLabel): Use correct function to free
security_context_t.

The code in SELinuxRestoreSecurityChardevLabel() was trying to
use SELinuxSetFilecon directly for devices or file types while
it should really use SELinuxRestoreSecurityFileLabel encapsulating
routine, which avoid various problems like resolving symlinks,
making sure he file exists and work around NFS problems

* cfg.mk (sc_prohibit_sprintf): New rule.
(sc_prohibit_asprintf): Avoid false positives.
* docs/hacking.html.in (Printf-style functions): Document the
policy.
* HACKING: Regenerate.
* .x-sc_prohibit_sprintf: New exemptions.
* Makefile.am (syntax_check_exceptions): Ship new file.
* src/vbox/vbox_tmpl.c (vboxStartMachine, vboxAttachUSB): Use
virAsprintf instead.
* src/uml/uml_driver.c (umlOpenMonitor): Use snprintf instead.
* tools/virsh.c (cmdDetachInterface): Likewise.
* src/security/security_selinux.c (SELinuxGenSecurityLabel):
Likewise.
* src/openvz/openvz_driver.c (openvzDomainDefineCmd): Likewise,
and ensure large enough buffer.

If virDomainAttachDevice() was called with an image that was located
on a root-squashed NFS server, and in a directory that was unreadable
by root on the machine running libvirtd, the attach would fail due to
an attempt to change the selinux label of the image with EACCES (which
isn't covered as an ignore case in SELinuxSetFilecon())

NFS doesn't support SELinux labelling anyway, so we mimic the failure
handling of commit 93a18bba, which
just ignores the errors if the target is on an NFS filesystem (in
SELinuxSetSecurityAllLabel() only, though.)

This can be seen as a follow-on to commit
347d266c, which ignores file open
failures of files on NFS that occur directly in
virDomainDiskDefForeachPath() (also necessary), but does not ignore
failures in functions that are called from there (eg
SELinuxSetSecurityFileLabel()).

Using automated replacement with sed and editing I have now replaced all
occurrences of close() with VIR_(FORCE_)CLOSE() except for one, of
course. Some replacements were straight forward, others I needed to pay
attention. I hope I payed attention in all the right places... Please
have a look. This should have at least solved one more double-close
error.

NFS in root squash mode may prevent opening disk images to
determine backing store. Ignore errors in this scenario.

* src/security/security_selinux.c: Ignore open failures on disk
  images

NFS does not support file labelling, so ignore this error
for stdin_path when on NFS.

* src/security/security_selinux.c: Ignore failures on labelling
  stdin_path on NFS
* src/util/storage_file.c, src/util/storage_file.h: Refine
  virStorageFileIsSharedFS() to allow it to check for a
  specific FS type.

This reverts commit b8e2de88
The hooks will be re-added in the QEMU driver itself.

* src/security/security_selinux.c: Remove audit hooks

A more natural auditing point would perhaps be
SELinuxSetSecurityProcessLabel, but this happens in the child after root
permissions are dropped, so the kernel would refuse the audit record.

Disk format probing is now disabled by default. A new config
option in /etc/qemu/qemu.conf will re-enable it for existing
deployments where this causes trouble

The implementation of security driver callbacks often needs
to access the security driver object. Currently only a handful
of callbacks include the driver object as a parameter. Later
patches require this is many more places.

* src/qemu/qemu_driver.c: Pass in the security driver object
  to all callbacks
* src/qemu/qemu_security_dac.c, src/qemu/qemu_security_stacked.c,
  src/security/security_apparmor.c, src/security/security_driver.h,
  src/security/security_selinux.c: Add a virSecurityDriverPtr
  param to all security callbacks

Update the QEMU cgroups code, QEMU DAC security driver, SELinux
and AppArmour security drivers over to use the shared helper API
virDomainDiskDefForeachPath().

* src/qemu/qemu_driver.c, src/qemu/qemu_security_dac.c,
  src/security/security_selinux.c, src/security/virt-aa-helper.c:
  Convert over to use virDomainDiskDefForeachPath()

Require the disk image to be passed into virStorageFileGetMetadata.
If this is set to VIR_STORAGE_FILE_AUTO, then the format will be
resolved using probing. This makes it easier to control when
probing will be used

* src/qemu/qemu_driver.c, src/qemu/qemu_security_dac.c,
  src/security/security_selinux.c, src/security/virt-aa-helper.c:
  Set VIR_STORAGE_FILE_AUTO when calling virStorageFileGetMetadata.
* src/storage/storage_backend_fs.c: Probe for disk format before
  calling virStorageFileGetMetadata.
* src/util/storage_file.h, src/util/storage_file.c: Remove format
  from virStorageFileMeta struct & require it to be passed into
  method.

Also restore the label to its original value after qemu is finished
with the file.

Prior to this patch, qemu domain restore did not function properly if
selinux was set to enforce.

When configuring serial, parallel, console or channel devices
with a file, dev or pipe backend type, it is necessary to label
the file path in the security drivers. For char devices of type
file, it is neccessary to pre-create (touch) the file if it does
not already exist since QEMU won't be allowed todo so itself.
dev/pipe configs already require the admin to pre-create before
starting the guest.

* src/qemu/qemu_security_dac.c: set file ownership for character
  devices
* src/security/security_selinux.c: Set file labeling for character
  devices
* src/qemu/qemu_driver.c: Add character devices to cgroup ACL

The restore code is done in places where errors cannot be
raised, since they will overwrite over pre-existing errors.

* src/security/security_selinux.c: Only warn about failures
  in label restore, don't report errors

When SELinux is running in MLS mode, libvirtd will have a
different security level to the VMs. For libvirtd to be
able to connect to the monitor console, the client end of
the UNIX domain socket needs a different label. This adds
infrastructure to set the socket label via the security
driver framework

* src/qemu/qemu_driver.c: Call out to socket label APIs in
  security driver
* src/qemu/qemu_security_stacked.c: Wire up socket label
  drivers
* src/security/security_driver.h: Define security driver
  entry points for socket labelling
* src/security/security_selinux.c: Set socket label based on
  VM label

Adjust args to qemudStartVMDaemon() to also specify path to stdin_fd,
so this can be passed to the AppArmor driver via SetSecurityAllLabel().

This updates all calls to qemudStartVMDaemon() as well as setting up
the non-AppArmor security driver *SetSecurityAllLabel() declarations
for the above. This is required for the following
"apparmor-fix-save-restore" patch since AppArmor resolves the passed
file descriptor to the pathname given to open().

Do not require each caller of virStorageFileGetMetadata and
virStorageFileGetMetadataFromFD to first clear the storage of the
"meta" buffer.  Instead, initialize that storage in
virStorageFileGetMetadataFromFD.
* src/util/storage_file.c (virStorageFileGetMetadataFromFD): Clear
"meta" here, not before each of the following callers.
* src/qemu/qemu_driver.c (qemuSetupDiskCgroup): Don't clear "meta" here.
(qemuTeardownDiskCgroup): Likewise.
* src/qemu/qemu_security_dac.c (qemuSecurityDACSetSecurityImageLabel):
Likewise.
* src/security/security_selinux.c (SELinuxSetSecurityImageLabel):
Likewise.
* src/security/virt-aa-helper.c (get_files): Likewise.

virFileResolveLink was returning a positive value on error,
thus confusing callers that assumed failure was < 0.  The
confusion is further evidenced by callers that would have
ended up calling virReportSystemError with a negative value
instead of a valid errno.

Fixes Red Hat BZ #591363.

* src/util/util.c (virFileResolveLink): Live up to documentation.
* src/qemu/qemu_security_dac.c
(qemuSecurityDACRestoreSecurityFileLabel): Adjust callers.
* src/security/security_selinux.c
(SELinuxRestoreSecurityFileLabel): Likewise.
* src/storage/storage_backend_disk.c
(virStorageBackendDiskDeleteVol): Likewise.

When QEMU runs with its disk on NFS, and as a non-root user, the
disk is chownd to that non-root user. When migration completes
the last step is shutting down the QEMU on the source host. THis
normally resets user/group/security label. This is bad when the
VM was just migrated because the file is still in use on the dest
host. It is thus neccessary to skip the reset step for any files
found to be on a shared filesystem

* src/libvirt_private.syms: Export virStorageFileIsSharedFS
* src/util/storage_file.c, src/util/storage_file.h: Add a new
  method virStorageFileIsSharedFS() to determine if a file is
  on a shared filesystem (NFS, GFS, OCFS2, etc)
* src/qemu/qemu_driver.c: Tell security driver not to reset
  disk labels on migration completion
* src/qemu/qemu_security_dac.c, src/qemu/qemu_security_stacked.c,
  src/security/security_selinux.c, src/security/security_driver.h,
  src/security/security_apparmor.c: Add ability to skip disk
  restore step for files on shared filesystems.

(suggested by Daniel Berrange, tested by Dan Kenigsberg)

virStorageFileGetMetadata will fail for disk images that are stored on
a root-squash NFS share that isn't world-readable.
SELinuxSetSecurityImageLabel is called during the startup of every
domain (as long as security_driver != "none"), and it will propogate
the error from virStorageFileGetMetadata, causing the domain startup
to fail. This is, however, a common scenario when qemu is run as a
non-root user and the disk image is stored on NFS.

Ignoring this failure (which doesn't matter in this case, since the
next thing done by SELinuxSetSecurityImageLabel - setting the file
context - will also fail (and that function already ignores failures
due to root-squash NFS) will allow us to continue bringing up the
domain. The result is that we don't need to disable the entire
security driver just because a domain's disk image is stored on
root-squashed NFS.

This can be triggered by the qemuStartVMDaemon cleanup path if a
VM references a non-existent USB device (by product) in the XML.

Fixes URL installs when running virt-install as root on Fedora.

Changeset

  commit 5073aa99
  Author: Cole Robinson <crobinso@redhat.com>
  Date:   Mon Jan 11 11:40:46 2010 -0500

Added support for product/vendor based passthrough, but it only
worked at the security driver layer. The main guest XML config
was not updated with the resolved bus/device ID. When the QEMU
argv refactoring removed use of product/vendor, this then broke
launching guests.

THe solution is to move the product/vendor resolution up a layer
into the QEMU driver. So the first thing QEMU does is resolve
the product/vendor to a bus/device and updates the XML config
with this info. The rest of the code, including security drivers
and QEMU argv generated can now rely on bus/device always being
set.

* src/util/hostusb.c, src/util/hostusb.h: Split vendor/product
  resolution code out of usbGetDevice and into usbFindDevice.
  Add accessors for bus/device ID
* src/security/virt-aa-helper.c, src/security/security_selinux.c,
  src/qemu/qemu_security_dac.c: Remove vendor/product from the
  usbGetDevice() calls
* src/qemu/qemu_driver.c: Use usbFindDevice to resolve vendor/product
  into a bus/device ID

All callers now pass a NULL virConnectPtr into the USB/PCi device
iterator functions. Therefore the virConnectPtr arg can now be
removed from these functions

* src/util/hostusb.h, src/util/hostusb.c: Remove virConnectPtr
  from usbDeviceFileIterate
* src/util/pci.c, src/util/pci.h: Remove virConnectPtr arg from
  pciDeviceFileIterate
* src/qemu/qemu_security_dac.c, src/security/security_selinux.c: Update
  to drop redundant virConnectPtr arg

The virConnectPtr is no longer required for error reporting since
that is recorded in a thread local. Remove use of virConnectPtr
from all APIs in security_driver.{h,c} and update all callers to
match

It was used for error reporting only.

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