virSecurityManagerSetDiskLabel and virSecurityManagerRestoreDiskLabel
don't have complementary semantics. Document the semantics to avoid
possible problems.

I'm going to add functions that will deal with individual image files
rather than whole disks. Rename the security function to make room for
the new one.

I'm going to add functions that will deal with individual image files
rather than whole disks. Rename the security function to make room for
the new one.

Also remove one spurious ATTRIBUTE_UNUSED guarding the @migrated
argument.

Coverity complains about a possible leak of seclabel if
!sec_managers[i]->drv->domainGenSecurityLabel is true
and the seclabel might be overwritten by the next iteration
of the loop.

This leak should never happen, because every security driver
has domainGenSecurityLabel defined.

In order to reuse the newly-created host-side disk struct in
the virstoragefile backing chain code, I first have to move
it to util/.  This starts the process, by first moving the
security label structures.

* src/conf/domain_conf.h (virDomainDefGenSecurityLabelDef)
(virDomainDiskDefGenSecurityLabelDef, virSecurityLabelDefFree)
(virSecurityDeviceLabelDefFree, virSecurityLabelDef)
(virSecurityDeviceLabelDef): Move...
* src/util/virseclabel.h: ...to new file.
(virSecurityLabelDefNew, virSecurityDeviceLabelDefNew): Rename the
GenSecurity functions.
* src/qemu/qemu_process.c (qemuProcessAttach): Adjust callers.
* src/security/security_manager.c (virSecurityManagerGenLabel):
Likewise.
* src/security/security_selinux.c
(virSecuritySELinuxSetSecurityFileLabel): Likewise.
* src/util/virseclabel.c: New file.
* src/conf/domain_conf.c: Move security code, and fix fallout.
* src/Makefile.am (UTIL_SOURCES): Build new file.
* src/libvirt_private.syms (domain_conf.h): Move symbols...
(virseclabel.h): ...to new section.
Signed-off-by: NEric Blake <eblake@redhat.com>

Any source file which calls the logging APIs now needs
to have a VIR_LOG_INIT("source.name") declaration at
the start of the file. This provides a static variable
of the virLogSource type.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

We weren't very consistent in our use of VIR_ERR_NO_SUPPORT; many
users just passed __FUNCTION__ on, while others passed "%s" to
silence over-eager compilers that warn about __FUNCTION__ not
containing any %.  It's nicer to route all these uses through
a single macro, so that if we ever need to change the reporting,
we can do it in one place.

I verified that 'virsh -c test:///default qemu-monitor-command test foo'
gives the same error message before and after this patch:
error: this function is not supported by the connection driver: virDomainQemuMonitorCommand

Note that in libvirt.c, we were inconsistent on whether virDomain*
API used virLibConnError() (with VIR_FROM_NONE) or virLibDomainError()
(with VIR_FROM_DOMAIN); this patch unifies these errors to all use
VIR_FROM_NONE, on the grounds that it is unlikely that a caller
learning that a call is unimplemented can do anything in particular
with extra knowledge of which error domain it belongs to.

One particular change to note is virDomainOpenGraphics which was
trying to fail with VIR_ERR_NO_SUPPORT after a failed
VIR_DRV_SUPPORTS_FEATURE check; all other places that fail a
feature check report VIR_ERR_ARGUMENT_UNSUPPORTED.

* src/util/virerror.h (virReportUnsupportedError): New macro.
* src/libvirt-qemu.c: Use new macro.
* src/libvirt-lxc.c: Likewise.
* src/lxc/lxc_driver.c: Likewise.
* src/security/security_manager.c: Likewise.
* src/util/virinitctl.c: Likewise.
* src/libvirt.c: Likewise.
(virDomainOpenGraphics): Use correct error for unsupported feature.
Signed-off-by: NEric Blake <eblake@redhat.com>

virSecurityManagerGetBaseLabel queries the default settings used by
a security model.
Signed-off-by: NGiuseppe Scrivano <gscrivan@redhat.com>

Merge the functions 'virSecurityDACSetUser' and
'virSecurityDACSetGroup' into 'virSecurityDACSetUserAndGroup'.
Signed-off-by: NGiuseppe Scrivano <gscrivan@redhat.com>

A future patch wants the DAC security manager to be able to safely
get the supplemental group list for a given uid, but at the time
of a fork rather than during initialization so as to pick up on
live changes to the system's group database.  This patch adds the
framework, including the possibility of a pre-fork callback
failing.

For now, any driver that implements a prefork callback must be
robust against the possibility of being part of a security stack
where a later element in the chain fails prefork.  This means
that drivers cannot do any action that requires a call to postfork
for proper cleanup (no grabbing a mutex, for example).  If this
is too prohibitive in the future, we would have to switch to a
transactioning sequence, where each driver has (up to) 3 callbacks:
PreForkPrepare, PreForkCommit, and PreForkAbort, to either clean
up or commit changes made during prepare.

* src/security/security_driver.h (virSecurityDriverPreFork): New
callback.
* src/security/security_manager.h (virSecurityManagerPreFork):
Change signature.
* src/security/security_manager.c (virSecurityManagerPreFork):
Optionally call into driver, and allow returning failure.
* src/security/security_stack.c (virSecurityDriverStack):
Wrap the handler for the stack driver.
* src/qemu/qemu_process.c (qemuProcessStart): Adjust caller.
Signed-off-by: NEric Blake <eblake@redhat.com>

While generating seclabels, we check the seclabel stack if required
driver is in the stack. If not, an error is returned. However, it is
possible for a seclabel to not have any model set (happens with LXC
domains that have just <seclabel type='none'>). If that's the case,
we should just skip the iteration instead of calling STREQ(NULL, ...)
and SIGSEGV-ing subsequently.

Similarly to VIR_STRDUP, we want the OOM error to be reported in
VIR_ALLOC and friends.

otherwise we crash later on if we don't find a match like:

 #0  0xb72c2b4f in virSecurityManagerGenLabel (mgr=0xb8e42d20, vm=0xb8ef40c0) at security/security_manager.c:424
 #1  0xb18811f3 in qemuProcessStart (conn=conn@entry=0xb8eed880, driver=driver@entry=0xb8e3b1e0, vm=vm@entry=0xb8ef58f0,
     migrateFrom=migrateFrom@entry=0xb18f6088 "stdio", stdin_fd=18,
     stdin_path=stdin_path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img", snapshot=snapshot@entry=0x0,
     vmop=vmop@entry=VIR_NETDEV_VPORT_PROFILE_OP_RESTORE, flags=flags@entry=2) at qemu/qemu_process.c:3364
 #2  0xb18d6cb2 in qemuDomainSaveImageStartVM (conn=conn@entry=0xb8eed880, driver=driver@entry=0xb8e3b1e0, vm=0xb8ef58f0, fd=fd@entry=0xb6bf3f98,
     header=header@entry=0xb6bf3fa0, path=path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img",
     start_paused=start_paused@entry=false) at qemu/qemu_driver.c:4843
 #3  0xb18d7eeb in qemuDomainRestoreFlags (conn=conn@entry=0xb8eed880,
     path=path@entry=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img", dxml=dxml@entry=0x0, flags=flags@entry=0)
     at qemu/qemu_driver.c:4962
 #4  0xb18d8123 in qemuDomainRestore (conn=0xb8eed880, path=0xb8ea7798 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img")
     at qemu/qemu_driver.c:4987
 #5  0xb718d186 in virDomainRestore (conn=0xb8eed880, from=0xb8ea87d8 "/var/lib/jenkins/jobs/libvirt-tck-build/workspace/tck.img") at libvirt.c:2768
 #6  0xb7736363 in remoteDispatchDomainRestore (args=<optimized out>, rerr=0xb6bf41f0, client=0xb8eedaf0, server=<optimized out>, msg=<optimized out>)
     at remote_dispatch.h:4679
 #7  remoteDispatchDomainRestoreHelper (server=0xb8e1a3e0, client=0xb8eedaf0, msg=0xb8ee72c8, rerr=0xb6bf41f0, args=0xb8ea8968, ret=0xb8ef5330)
     at remote_dispatch.h:4661
 #8  0xb720db01 in virNetServerProgramDispatchCall (msg=0xb8ee72c8, client=0xb8eedaf0, server=0xb8e1a3e0, prog=0xb8e216b0)
     at rpc/virnetserverprogram.c:439
 #9  virNetServerProgramDispatch (prog=0xb8e216b0, server=server@entry=0xb8e1a3e0, client=0xb8eedaf0, msg=0xb8ee72c8) at rpc/virnetserverprogram.c:305
 #10 0xb7206e97 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0xb8e1a3e0) at rpc/virnetserver.c:162
 #11 virNetServerHandleJob (jobOpaque=0xb8ea7720, opaque=0xb8e1a3e0) at rpc/virnetserver.c:183
 #12 0xb70f9f78 in virThreadPoolWorker (opaque=opaque@entry=0xb8e1a540) at util/virthreadpool.c:144
 #13 0xb70f94a5 in virThreadHelper (data=0xb8e0e558) at util/virthreadpthread.c:161
 #14 0xb705d954 in start_thread (arg=0xb6bf4b70) at pthread_create.c:304
 #15 0xb6fd595e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

This unbreaks libvirt-tck's domain/100-transient-save-restore.t with
qemu:///session and selinux compiled in but disabled.

Introduced by 8d68cbea

https://bugzilla.redhat.com/show_bug.cgi?id=947387

If a user configures a domain to use a seclabel of a specific type,
but the appropriate driver is not accessible, we should refuse to
start the domain. For instance, if user requires selinux, but it is
either non present in the system, or is just disabled, we should not
start the domain. Moreover, since we are touching only those labels we
have a security driver for, the other labels may confuse libvirt when
reconnecting to a domain on libvirtd restart. In our selinux example,
when starting up a domain, missing security label is okay, as we
auto-generate one. But later, when libvirt is re-connecting to a live
qemu instance, we parse a state XML, where security label is required
and it is an error if missing:

  error : virSecurityLabelDefParseXML:3228 : XML error: security label
  is missing

This results in a qemu process left behind without any libvirt control.

With my previous patches, we unconditionally appended a seclabel,
even if it wasn't generated but found in array of defined seclabels.
This resulted in double free later when doing virDomainDefFree
and iterating over the array of defined seclabels.

Moreover, there was another possibility of double free, if the
seclabel was generated in the last iteration of the process of
walking trough security managers array.

https://bugzilla.redhat.com/show_bug.cgi?id=923946

The <seclabel type='none'/> should be added iff there is no other
seclabel defined within a domain. This bug can be easily reproduced:
1) configure selinux seclabel for a domain
2) disable system's selinux and restart libvirtd
3) observe <seclabel type='none'/> being appended to a domain on its
   startup

The virDomainDefGetSecurityLabelDef was modifying the domain XML.
It tried to find a seclabel corresponding to given sec driver. If the
label wasn't found, the function created one which is wrong. In fact
it's security manager which should modify this part of domain XML.

The existing virSecurityManagerSetProcessLabel() API is designed so
that it must be called after forking the child process, but before
exec'ing the child. Due to the way the virCommand API works, that
means it needs to be put in a "hook" function that virCommand is told
to call out to at that time.

Setting the child process label is a basic enough need when executing
any process that virCommand should have a method of doing that. But
virCommand must be told what label to set, and only the security
driver knows the answer to that question.

The new virSecurityManagerSet*Child*ProcessLabel() API is the way to
transfer the knowledge about what label to set from the security
driver to the virCommand object. It is given a virCommandPtr, and each
security driver calls the appropriate virCommand* API to tell
virCommand what to do between fork and exec.

1) in the case of the DAC security driver, it calls
virCommandSetUID/GID() to set a uid and gid that must be set for the
child process.

2) for the SELinux security driver, it calls
virCommandSetSELinuxLabel() to save a copy of the char* that will be
sent to setexeccon_raw() *after forking the child process*.

3) for the AppArmor security drivers, it calls
virCommandSetAppArmorProfile() to save a copy of the char* that will
be sent to aa_change_profile() *after forking the child process*.

With this new API in place, we will be able to remove
virSecurityManagerSetProcessLabel() from any virCommand pre-exec
hooks.

(Unfortunately, the LXC driver uses clone() rather than virCommand, so
it can't take advantage of this new security driver API, meaning that
we need to keep around the older virSecurityManagerSetProcessLabel(),
at least for now.)

The hook scripts used by virCommand must be careful wrt
accessing any mutexes that may have been held by other
threads in the parent process. With the recent refactoring
there are 2 potential flaws lurking, which will become real
deadlock bugs once the global QEMU driver lock is removed.

Remove use of the QEMU driver lock from the hook function
by passing in the 'virQEMUDriverConfigPtr' instance directly.

Add functions to the virSecurityManager to be invoked before
and after fork, to ensure the mutex is held by the current
thread. This allows it to be safely used in the hook script
in the child process.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Add locking to virSecurityManagerXXX APIs, so that use of the
security drivers is internally serialized. This avoids the need
to rely on the global driver locks to achieve serialization
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

To enable locking to be introduced to the security manager
objects later, turn virSecurityManager into a virObjectLockable
class
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When LXC labels USB devices during hotplug, it is running in
host context, so it needs to pass in a vroot path to the
container root.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

When a qemu domain is backed by huge pages, apparmor needs to grant the domain
rw access to files under the hugetlbfs mount point.  Add a hook, called in
qemu_process.c, which ends up adding the read-write access through
virt-aa-helper.  Qemu will be creating a randomly named file under the
mountpoint and unlinking it as soon as it has mmap()d it, therefore we
cannot predict the full pathname, but for the same reason it is generally
safe to provide access to $path/**.
Signed-off-by: NSerge Hallyn <serge.hallyn@ubuntu.com>

The impls of virSecurityManagerGetMountOptions had no way to
return errors, since the code was treating 'NULL' as a success
value. This is somewhat pointless, since the calling code did
not want NULL in the first place and has to translate it into
the empty string "". So change the code so that the impls can
return "" directly, allowing use of NULL for error reporting
once again
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

BZ:https://bugzilla.redhat.com/show_bug.cgi?id=851981
When using macvtap, a character device gets first created by
kernel with name /dev/tapN, its selinux context is:
system_u:object_r:device_t:s0

Shortly, when udev gets notification when new file is created
in /dev, it will then jump in and relabel this file back to the
expected default context:
system_u:object_r:tun_tap_device_t:s0

There is a time gap happened.
Sometimes, it will have migration failed, AVC error message:
type=AVC msg=audit(1349858424.233:42507): avc:  denied  { read write } for
pid=19926 comm="qemu-kvm" path="/dev/tap33" dev=devtmpfs ino=131524
scontext=unconfined_u:system_r:svirt_t:s0:c598,c908
tcontext=system_u:object_r:device_t:s0 tclass=chr_file

This patch will label the tapfd device before qemu process starts:
system_u:object_r:tun_tap_device_t:MCS(MCS from seclabel->label)

https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.

* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/;  If/.  If/

Recent changes in the security driver discarded changes that fixed
labeling un-confined guests.

If no 'security_driver' config option was set, then the code
just loaded the 'dac' security driver. This is a regression
on previous behaviour, where we would probe for a possible
security driver. ie default to SELinux if available.

This changes things so that it 'security_driver' is not set,
we once again do probing. For simplicity we also always
create the stack driver, even if there is only one driver
active.

The desired semantics are:

 - security_driver not set
     -> probe for selinux/apparmour/nop
     -> auto-add DAC driver
 - security_driver set to a string
     -> add that one driver
     -> auto-add DAC driver
 - security_driver set to a list
     -> add all drivers in list
     -> auto-add DAC driver

It is not allowed, or possible to specify 'dac' in the
security_driver config param, since that is always
enabled.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

These changes make the security drivers able to find and handle the
correct security label information when more than one label is
available. They also update the DAC driver to be used as an usual
security driver.
Signed-off-by: NMarcelo Cerri <mhcerri@linux.vnet.ibm.com>

This patch updates the structures that store information about each
domain and each hypervisor to support multiple security labels and
drivers. It also updates all the remaining code to use the new fields.
Signed-off-by: NMarcelo Cerri <mhcerri@linux.vnet.ibm.com>

If a domain is explicitly configured with <seclabel type="none"/> we
correctly ensure that no labeling will be done by setting
norelabel=true. However, if no seclabel element is present in domain XML
and hypervisor is configured not to confine domains by default, we only
set type to "none" without turning off relabeling. Thus if such a domain
is being started, security driver wants to relabel resources with
default label, which doesn't make any sense.

Moreover, with SELinux security driver, the generated image label lacks
"s0" sensitivity, which causes setfilecon() fail with EINVAL in
enforcing mode.

Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)

  You should have received a copy of the GNU General Public License
  along with Foobar.  If not, see <http://www.gnu.org/licenses/>.

This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').

Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:

  src/security/security_selinux.h
  src/security/security_driver.h
  src/security/security_selinux.c
  src/security/security_apparmor.h
  src/security/security_apparmor.c
  src/security/security_driver.c