If user has two domains, each have the same disk (configured for
RW) but each runs with different seclabel then we deny start of
the second domain because in order to do that we would need to
relabel the disk but that would cut the first domain off. Even if
we did not do that, qemu would fail to start because it would be
unable to lock the disk image for the second time. So far, this
behaviour is expected. But what is not expected is that we
increase the refcounter in XATTRs and leave it like that.
What happens is that when the second domain starts,
virSecuritySetRememberedLabel() is called, and since there are
XATTRs from the first domain it increments the refcounter and
returns it (refcounter == 2 at this point). Then callers
(virSecurityDACSetOwnership() and
virSecuritySELinuxSetFileconHelper()) realize that refcounter is
greater than 1 and desired seclabel doesn't match the one the
disk image already has and an error is produced. But the
refcounter is never decremented.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1740024
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
This effectively reverts d7420430ce and adds new code.
Here is the problem: Imagine a file X that is to be shared
between two domains as a disk. Let the first domain (vm1) have
seclabel remembering turned on and the other (vm2) has it turned
off. Assume that both domains will run under the same user, but
the original owner of X is different (i.e. trying to access X
without relabelling leads to EPERM).
Let's start vm1 first. This will cause X to be relabelled and to
gain new attributes:
trusted.libvirt.security.ref_dac="1"
trusted.libvirt.security.dac="$originalOwner"
When vm2 is started, X will again be relabelled, but since the
new label is the same as X already has (because of vm1) nothing
changes and vm1 and vm2 can access X just fine. Note that no
XATTR is changed (especially the refcounter keeps its value of 1)
because the vm2 domain has the feature turned off.
Now, vm1 is shut off and vm2 continues running. In seclabel
restore process we would get to X and since its refcounter is 1
we would restore the $originalOwner on it. But this is unsafe to
do because vm2 is still using X (remember the assumption that
$originalOwner and vm2's seclabel are distinct?).
The problem is that refcounter stored in XATTRs doesn't reflect
the actual times a resource is in use. Since I don't see any easy
way around it let's just not store original owner on shared
resources. Shared resource in world of domain disks is:
- whole backing chain but the top layer,
- read only disk (we don't require CDROM to be explicitly
marked as shareable),
- disk marked as shareable.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Just like previous commit allowed to enable or disable owner
remembering for each individual path, do the same for SELinux
driver. This is going to be needed in the next commit.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Both DAC and SELinux drivers support transactions. Each item on
the transaction list consists of various variables and @restore
is one of them. Document it so that as the list of variables grow
it's easier to spot which variable does what.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The way that virSecurityDACRecallLabel is currently written is
that if XATTRs are not supported for given path to the caller
this is not different than if the path is still in use. The value
of 1 is returned which makes secdrivers skip label restore.
This is clearly a bug as we are not restoring labels on say NFS
even though previously we were.
Strictly speaking, changes to virSecurityDACRememberLabel are not
needed, but they are done anyway so that getter and setter behave
in the same fashion.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Just like it's DAC counterpart is doing,
virSecuritySELinuxRestoreAllLabel() could print @migrated in the
debug message.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The d_type field cannot be assumed to be filled. Some filesystems, such
as older XFS, will simply report DT_UNKNOWN.
Even if the d_type is filled in, the use of it in the SELinux functions
is dubious. If labelling all files in a directory there's no reason to
skip things which are not regular files. We merely need to skip "." and
"..", which is done by virDirRead() already.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Security labeling of disks consists of labeling of the disk image
itself and it's backing chain. Modify
virSecurityManager[Set|Restore]ImageLabel to take a boolean flag that
will label the full chain rather than the top image itself.
This allows to delete/unify some parts of the code and will also
simplify callers in some cases.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The @con type security_context_t is actually a "char *", so the
correct check should be to dereference one more level; otherwise,
we could return/use the NULL pointer later in a subsequent
virSecuritySELinuxSetFileconImpl call (using @fcon).
Suggested-by: Michal Prívozník <mprivozn@redhat.com>
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
If virSecuritySELinuxRestoreFileLabel returns 0 or -1 too soon, then
the @newpath will be leaked.
Suggested-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We are setting label on kernel, initrd, dtb and slic_table files.
But we never restored it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It helps whe trying to match calls with virSecuritySELinuxSetAllLabel
if the order in which devices are set/restored is the same in
both functions.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When iterating over list of paths/disk sources to relabel it may
happen that the process fails at some point. In that case, for
the sake of keeping seclabel refcount (stored in XATTRs) in sync
with reality we have to perform rollback. However, if that fails
too the only thing we can do is warn user.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It's important to keep XATTRs untouched (well, in the same state
they were in when entering the function). Otherwise our
refcounting would be messed up.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Similarly to what I did in DAC driver, this also requires the
same SELinux label to be used for shared paths. If a path is
already in use by a domain (or domains) then and the domain we
are starting now wants to access the path it has to have the same
SELinux label. This might look too restrictive as the new label
can still guarantee access to already running domains but in
reality it is very unlikely and usually an admin mistake.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It is going to be important to know if the current transaction we
are running is a restore operation or set label operation so that
we know whether to call virSecurityGetRememberedLabel() or
virSecuritySetRememberedLabel(). That is, whether we are in a
restore and therefore have to fetch the remembered label, or we
are in set operation and therefore have to store the original
label.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
In many files there are header comments that contain an Author:
statement, supposedly reflecting who originally wrote the code.
In a large collaborative project like libvirt, any non-trivial
file will have been modified by a large number of different
contributors. IOW, the Author: comments are quickly out of date,
omitting people who have made significant contribitions.
In some places Author: lines have been added despite the person
merely being responsible for creating the file by moving existing
code out of another file. IOW, the Author: lines give an incorrect
record of authorship.
With this all in mind, the comments are useless as a means to identify
who to talk to about code in a particular file. Contributors will always
be better off using 'git log' and 'git blame' if they need to find the
author of a particular bit of code.
This commit thus deletes all Author: comments from the source and adds
a rule to prevent them reappearing.
The Copyright headers are similarly misleading and inaccurate, however,
we cannot delete these as they have legal meaning, despite being largely
inaccurate. In addition only the copyright holder is permitted to change
their respective copyright statement.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Trying to use virlockd to lock metadata turns out to be too big
gun. Since we will always spawn a separate process for relabeling
we are safe to use thread unsafe POSIX locks and take out
virtlockd completely out of the picture.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
When metadata locking is enabled that means the security commit
processing will be run in a fork similar to how namespaces use fork()'s
for processing. This is done to ensure libvirt can properly and
synchronously modify the metadata to store the original owner data.
Since fork()'s (e.g. virFork) have been seen as a performance bottleneck
being able to disable them allows the admin to choose whether the
performance 'hit' is worth the extra 'security' of being able to
remember the original owner of a lock.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Return -1 and report an error message if no transaction is set and
virSecuritySELinuxTransactionCommit is called.
The function description of virSecuritySELinuxTransactionCommit says:
"Also it is considered as error if there's no transaction set and this
function is called."
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
In 4674fc6afd I've implemented transactions for selinux driver.
Well, now that I am working in this area I've noticed a subtle
bug: @ret is initialized to 0 instead of -1. Facepalm.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
This shouldn't be needed per-se. Security manager shouldn't
disappear during transactions - it's immutable. However, it
doesn't hurt to grab a reference either - transaction code uses
it after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This array is allocated in virSecuritySELinuxContextListAppend()
but never freed. This commit is essentially the same as ca25026.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Lock all the paths we want to relabel to mutually exclude other
libvirt daemons.
The only hitch here is that directories can't be locked.
Therefore, when relabeling a directory do not lock it (this
happens only when setting up some domain private paths anyway,
e.g. huge pages directory).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
So far the whole transaction handling is done
virSecuritySELinuxSetFileconHelper(). This needs to change for
the sake of security label remembering and locking. Otherwise we
would be locking a path when only appending it to transaction
list and not when actually relabelling it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Firstly, the following code pattern is harder to follow:
if (func() < 0) {
error();
} else {
/* success */
}
We should put 'goto cleanup' into the error branch and move the
else branch one level up.
Secondly, 'rc' should really be named 'ret' because it holds
return value of the function. Not some intermediate value.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This label is used in both successful and error paths. Therefore
it should be named 'cleanup' and not 'err'.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
It will be desirable to run transactions more often than we
currently do. Even if the domain we're relabeling the paths for
does not run in a namespace. If that's the case, there is no need
to fork() as we are already running in the right namespace. To
differentiate whether transaction code should fork() or not the
@pid argument now accepts -1 (which means do not fork).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
In this patch we label the swtpm process with SELinux labels. We give it the
same label as the QEMU process has. We label its state directory and files
as well. We restore the old security labels once the swtpm has terminated.
The file and process labels now look as follows:
Directory: /var/lib/libvirt/swtpm
[root@localhost swtpm]# ls -lZ
total 4
rwx------. 2 tss tss system_u:object_r:svirt_image_t:s0:c254,c932 4096 Apr 5 16:46 testvm
[root@localhost testvm]# ls -lZ
total 8
-rw-r--r--. 1 tss tss system_u:object_r:svirt_image_t:s0:c254,c932 3648 Apr 5 16:46 tpm-00.permall
The log in /var/log/swtpm/libvirt/qemu is labeled as follows:
-rw-r--r--. 1 tss tss system_u:object_r:svirt_image_t:s0:c254,c932 2237 Apr 5 16:46 vtpm.log
[root@localhost 485d0004-a48f-436a-8457-8a3b73e28567]# ps auxZ | grep swtpm | grep ctrl | grep -v grep
system_u:system_r:svirt_t:s0:c254,c932 tss 25664 0.0 0.0 28172 3892 ? Ss 16:57 0:00 /usr/bin/swtpm socket --daemon --ctrl type=unixio,path=/var/run/libvirt/qemu/swtpm/testvm-swtpm.sock,mode=0660 --tpmstate dir=/var/lib/libvirt/swtpm/testvm/tpm1.2 --log file=/var/log/swtpm/libvirt/qemu/testvm-swtpm.log
[root@localhost 485d0004-a48f-436a-8457-8a3b73e28567]# ps auxZ | grep qemu | grep tpm | grep -v grep
system_u:system_r:svirt_t:s0:c254,c932 qemu 25669 99.0 0.0 3096704 48500 ? Sl 16:57 3:28 /bin/qemu-system-x86_64 [..]
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Extend the DAC and SELinux modules with support for the tpm-emulator.
We label the Unix socket that QEMU connects to after starting swtmp
with DAC and SELinux labels. We do not have to restore the labels in
this case since the tpm-emulator will remove the Unix socket when it
terminates.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This patch adds support for an external swtpm TPM emulator. The XML for
this type of TPM looks as follows:
<tpm model='tpm-tis'>
<backend type='emulator'/>
</tpm>
The XML will currently only define a TPM 1.2.
Extend the documentation.
Add a test case testing the XML parser and formatter.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
virSecurityManagerDomainSetPathLabel is used to make a path known
to the security modules, but today is used interchangably for
- paths to files/dirs to be accessed directly
- paths to a dir, but the access will actually be to files therein
Depending on the security module it is important to know which of
these types it will be.
The argument allowSubtree augments the call to the implementations of
DomainSetPathLabel that can - per security module - decide if extra
actions shall be taken.
For now dac/selinux handle this as before, but apparmor will make
use of it to add a wildcard to the path that was passed.
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
SELinux and DAC drivers already have both functions but they were not
exported as public API of security manager.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Until now we ignored user-provided backing chains and while detecting
the code inherited labels of the parent device. With user provided
chains we should keep this functionality, so label of the parent image
in the backing chain will be applied if an image-specific label is not
present.
virSecuritySELinuxSetImageLabelInternal assigns different labels to
backing chain members than to the parent image. This was done via the
'first' flag. Convert it to passing in pointer to the parent
virStorageSource. This will allow us to use the parent virStorageSource
in further changes.
Add helpers that will simplify checking if a backing file is valid or
whether it has backing store. The helper virStorageSourceIsBacking
returns true if the given virStorageSource is a valid backing store
member. virStorageSourceHasBacking returns true if the virStorageSource
has a backing store child.
Adding these functions creates a central points for further refactors.
Our commit e13e8808f9 was way too generic. Currently, virtlogd is
used only for chardevs type of file and nothing else. True, we
must not relabel the path in this case, but we have to in all
other cases. For instance, if you want to have a physical console
attached to your guest:
<console type='dev'>
<source path='/dev/ttyS0'/>
<target type='virtio' port='1'/>
</console>
Starting such domain fails because qemu doesn't have access to
/dev/ttyS0 because we haven't relabelled the path.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
In the case that virtlogd is used as stdio handler we pass to QEMU
only FD to a PIPE connected to virtlogd instead of the file itself.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1430988
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
If the first console is just a copy of the first serial device we
don't need to iterate over the same device twice in order to perform
actions like security labeling, cgroup configuring, etc.
Currently only security SELinux manager was aware of this fact.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Namely, this patch is about virMediatedDeviceGetIOMMUGroup{Dev,Num}
functions. There's no compelling reason why these functions should take
an object, on the contrary, having to create an object every time one
needs to query the IOMMU group number, discarding the object afterwards,
seems odd.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
This patch updates all of our security driver to start labeling the
VFIO IOMMU devices under /dev/vfio/ as well.
Signed-off-by: Erik Skultety <eskultet@redhat.com>
A mediated device will be identified by a UUID (with 'model' now being
a mandatory <hostdev> attribute to represent the mediated device API) of
the user pre-created mediated device. We also need to make sure that if
user explicitly provides a guest address for a mdev device, the address
type will be matching the device API supported on that specific mediated
device and error out with an incorrect XML message.
The resulting device XML:
<devices>
<hostdev mode='subsystem' type='mdev' model='vfio-pci'>
<source>
<address uuid='c2177883-f1bb-47f0-914d-32a22e3a8804'>
</source>
</hostdev>
</devices>
Signed-off-by: Erik Skultety <eskultet@redhat.com>
When domain is being started up, we ought to relabel the host
side of NVDIMM so qemu has access to it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The problem is in the way how the list item is created prior to
appending it to the transaction list - the @path argument is just a
shallow copy instead of deep copy of the hostdev device's path.
Unfortunately, the hostdev devices from which the @path is extracted, in
order to add them into the transaction list, are only temporary and
freed before the buildup of the qemu namespace, thus making the @path
attribute in the transaction list NULL, causing 'permission denied' or
'double free' or 'unknown cause' errors.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1413773
Signed-off-by: Erik Skultety <eskultet@redhat.com>
There are still some systems out there that have broken
setfilecon*() prototypes. Instead of taking 'const char *tcon' it
is taking 'char *tcon'. The function should just set the context,
not modify it.
We had been bitten with this problem before which resulted in
292d3f2d and subsequently b109c09765. However, with one my latest
commits (4674fc6afd) I've changed the type of @tcon variable to
'const char *' which results in build failure on the systems from
above.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
