/dev/userfaultfd device is preferred over userfaultfd syscall for
post-copy migrations. Unless qemu driver is configured to disable mount
namespace or to forbid access to /dev/userfaultfd in cgroup_device_acl,
we will copy it to the limited /dev filesystem QEMU will have access to
and label it appropriately. So in the default configuration post-copy
migration will be allowed even without enabling
vm.unprivileged_userfaultfd sysctl.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Normally when a child process is started by libvirt, the SELinux label
of that process is set to virtd_t (plus an MCS range). In at least one
case (passt) we need for the SELinux label of a child process label to
match the label that the binary would have transitioned to
automatically if it had been run standalone (in the case of passt,
that label is passt_t).
This patch modifies virSecuritySELinuxSetChildProcessLabel() (and all
the functions above it in the call chain) so that the toplevel
function can set a new argument "useBinarySpecificLabel" to true. If
it is true, then virSecuritySELinuxSetChildProcessLabel() will call
the new function virSecuritySELinuxContextSetFromFile(), which uses
the selinux library function security_compute_create() to determine
what would be the label of the new process if it had been run
standalone (rather than being run by libvirt) - the MCS range from the
normally-used label is added to this newly derived label, and that is
what is used for the new process rather than whatever is in the
domain's security label (which will usually be virtd_t).
In order to easily verify that nothing was broken by these changes to
the call chain, all callers currently set useBinarySpecificPath =
false, so all behavior should be completely unchanged. (The next
patch will set it to true only for the case of running passt.)
https://bugzilla.redhat.com/2172267
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
When starting (some) external helpers, callers of
qemuSecurityCommandRun() pass &exitstatus variable, to learn the
exit code of helper process (with qemuTPMEmulatorStart() being
the only exception). Then, if the status wasn't zero they produce
a generic error message, like:
"Starting of helper process failed. exitstatus=%d"
or, in case of qemuPasstStart():
"Could not start 'passt': %s"
This is needless as virCommandRun() (that's called under the
hood), can do both for us, if NULL was passed instead of
@exitstatus. Not only it appends exit status, it also reads
stderr of failed command producing comprehensive error message:
Child process (${args}) unexpected exit status ${exitstatus}: ${stderr}
Therefore, pass NULL everywhere. But in contrast with one of
previous commits which removed @cmdret argument, there could be a
sensible caller which might want to process exit code. So keep
the argument for now and just pass NULL.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Every single caller of qemuSecurityCommandRun() calls the
function as:
if (qemuSecurityCommandRun(..., &cmdret) < 0)
goto cleanup;
if (cmdret < 0)
goto cleanup;
(modulo @exitstatus shenanigans)
Well, there's no need for such complication. There isn't a single
caller (and probably will never be (TM)), that would need to
distinguish the reason for the failure. Therefore,
qemuSecurityCommandRun() can be made to pass the retval of
virCommandRun() called under the hood.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The usual pattern when starting a helper daemon is:
if (qemuSecurityCommandRun(..., &exitstatus, &cmdret) < 0)
goto cleanup;
if (cmdret < 0 || exitstatus != 0) {
virReportError();
goto cleanup;
}
The only problem with this pattern is that if virCommandRun()
fails (i.e. cmdret < 0), then proper error was already reported.
But in this pattern we overwrite it (usually with less specific)
error.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
After previous cleanup this function is no longer used and thus
can be dropped.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Now that we have qemuSecurityRestoreTPMLabels() we might as well
have qemuSecuritySetTPMLabels(). The aim here is to remove
qemuSecurityStartTPMEmulator() which couples two separate things
into a single function call.
Therefore, introduce qemuSecuritySetTPMLabels() which does only
set seclabels on the TPM state.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
The qemuSecurityCleanupTPMEmulator() function calls
virSecurityManagerRestoreTPMLabels() and thus the proper name is
qemuSecurityRestoreTPMLabels(). Rename it.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Currently, qemuSecurityCleanupTPMEmulator() returns nothing which
means a caller (well, there's only one - qemuExtTPMStop()) can't
produce a warning when restoring seclabels on TPM state failed.
True, qemuSecurityCleanupTPMEmulator() does report a warning
itself, but only in one specific error path.
Make the function return an integer, just like the rest of
qemuSecurity*Restore() functions.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
This is basically just a continuation of the previous commit.
Now that the security driver APIs have a boolean flag that
controls setting/restoring seclabel of either both TPM state and
log files, or just the log file, propagate this boolean into
those APIs that start/stop swtpm emulator. For now, just pass
true. The juicy bits are soon to come.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The virSecurityDomainSetTPMLabels() and
virSecurityDomainRestoreTPMLabels() APIs set/restore label on two
files/directories:
1) the TPM state (tpm->data.emulator.storagepath), and
2) the TPM log file (tpm->data.emulator.logfile).
Soon there will be a need to set the label on the log file but
not on the state. Therefore, extend these APIs for a boolean flag
that when set does both, but when unset does only 2).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
For QEMU_SCHED_CORE_FULL case, all helper processes should be
placed into the same scheduling group as the QEMU process they
serve. It may happen though, that a helper process is started
before QEMU (cold start of a domain). But we have the dummy
process running from which the QEMU process will inherit the
scheduling group, so we can use the dummy process PID as an
argument to virCommandSetRunAmong().
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
There's no real difference between
qemuSecurityStartVhostUserGPU() and qemuSecurityCommandRun(). The
latter is used more frequently while the former has just one
user. Therefore, drop the less frequently used one.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Attaching a newly created vhostuser port to a VM fails due to an
apparmor denial
internal error: unable to execute QEMU command 'chardev-add': Failed
to bind socket to /run/openvswitch/vhu838c4d29-c9: Permission denied
In the case of a net device type VIR_DOMAIN_NET_TYPE_VHOSTUSER, the
underlying chardev is not labeled in qemuDomainAttachNetDevice prior
to calling qemuMonitorAttachCharDev.
A simple fix would be to call qemuSecuritySetChardevLabel using the
embedded virDomainChrSourceDef in the virDomainNetDef vhostuser data,
but this incurs the risk of incorrectly restoring the label. E.g.
consider the DAC driver behavior with a vhostuser net device, which
uses a socket for the chardev backend. The DAC driver uses XATTRS to
store original labelling information, but XATTRS are not compatible
with sockets. Without the original labelling information, the socket
labels will be restored with root ownership, preventing other
less-privileged processes from connecting to the socket.
This patch avoids overloading chardev labelling with vhostuser net
devices by introducing virSecurityManager{Set,Restore}NetdevLabel,
which is currently only implemented for the apparmor driver. The
new APIs are then used to set and restore labels for the vhostuser
net devices.
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Historically, we declared pointer type to our types:
typedef struct _virXXX virXXX;
typedef virXXX *virXXXPtr;
But usefulness of such declaration is questionable, at best.
Unfortunately, we can't drop every such declaration - we have to
carry some over, because they are part of public API (e.g.
virDomainPtr). But for internal types - we can do drop them and
use what every other C project uses 'virXXX *'.
This change was generated by a very ugly shell script that
generated sed script which was then called over each file in the
repository. For the shell script refer to the cover letter:
https://listman.redhat.com/archives/libvir-list/2021-March/msg00537.html
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
The qemu_domain.c file is big as is and we should split it into
separate semantic blocks. Start with code that handles domain
namespaces.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Just like in the previous commit, the stdin_path argument of
virSecurityManagerSetAllLabel() is renamed to incomingPath.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
The only consumer was removed in the previous commit.
This reverts commit f03a38bd1d.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Currently, when restoring from a domain the path that the domain
restores from is labelled under qemuSecuritySetAllLabel() (and after
v6.3.0-rc1~108 even outside transactions). While this grants QEMU
the access, it has a flaw, because once the domain is restored, up
and running then qemuSecurityDomainRestorePathLabel() is called,
which is not real counterpart. In case of DAC driver the
SetAllLabel() does nothing with the restore path but
RestorePathLabel() does - it chown()-s the file back and since there
is no original label remembered, the file is chown()-ed to
root:root. While the apparent solution is to have DAC driver set the
label (and thus remember the original one) in SetAllLabel(), we can
do better.
Turns out, we are opening the file ourselves (because it may live on
a root squashed NFS) and then are just passing the FD to QEMU. But
this means, that we don't have to chown() the file at all, we need
to set SELinux labels and/or add the path to AppArmor profile.
And since we want to restore labels right after QEMU is done loading
the migration stream (we don't want to wait until
qemuSecurityRestoreAllLabel()), the best way to approach this is to
have separate APIs for labelling and restoring label on the restore
file.
I will investigate whether AppArmor can use the SavedStateLabel()
API instead of passing the restore path to SetAllLabel().
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1851016
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Correct the log name for qemu_security.c to qemu.qemu_security
instead of qemu.qemu_process.
Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
In a few cases we might set seclabels on a path outside of
namespaces. For instance, when restoring a domain from a file,
the file is opened, relabelled and only then the namespace is
created and the FD is passed to QEMU (see v6.3.0-rc1~108 for more
info). Therefore, when restoring the label on the restore file,
we must ignore domain namespaces and restore the label directly
in the host.
This bug demonstrates itself when restoring a domain from a block
device. We don't create the block device inside the domain
namespace and thus the following error is reported at the end of
(otherwise successful) restore:
error : virProcessRunInFork:1236 : internal error: child reported (status=125): unable to stat: /dev/sda: No such file or directory
error : virProcessRunInFork:1240 : unable to stat: /dev/sda: No such file or directory
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
The function calls virSecurityManagerDomainRestorePathLabel()
after all.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
The new name is virSecurityManagerDomainRestorePathLabel().
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
After previous commit this function is used no more.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
As explained in the previous commit, we need to relabel the file
we are restoring the domain from. That is the FD that is passed
to QEMU. If the file is not under /dev then the file inside the
namespace is the very same as the one in the host. And regardless
of using transactions, the file will be relabeled. But, if the
file is under /dev then when using transactions only the copy
inside the namespace is relabeled and the one in the host is not.
But QEMU is reading from the one in the host, actually.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1772838
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
When preparing images for block jobs we modify their seclabels so
that QEMU can open them. However, as mentioned in the previous
commit, secdrivers base some it their decisions whether the image
they are working on is top of of the backing chain. Fortunately,
in places where we call secdrivers we know this and the
information can be passed to secdrivers.
The problem is the following: after the first blockcommit from
the base to one of the parents the XATTRs on the base image are
not cleared and therefore the second attempt to do another
blockcommit fails. This is caused by blockcommit code calling
qemuSecuritySetImageLabel() over the base image, possibly
multiple times (to ensure RW/RO access). A naive fix would be to
call the restore function. But this is not possible, because that
would deny QEMU the access to the base image. Fortunately, we
can use the fact that seclabels are remembered only for the top
of the backing chain and not for the rest of the backing chain.
And thanks to the previous commit we can tell secdrivers which
images are top of the backing chain.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1803551
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
In upcoming commits, virSecurityManagerSetAllLabel() will perform
rollback in case of failure by calling
virSecurityManagerRestoreAllLabel(). But in order to do that, the
former needs to have @migrated argument so that it can be passed
to the latter.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
See function documentation. Used in a following patch.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Add a generic way to run a command through the security management.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Set the transactionStarted to false if the commit failed. If this is not
done, then the failure path will report 'no transaction is set' and hide
more useful error reports.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190726210706.24440-2-stefanb@linux.ibm.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
The same can be achieved by using qemuSecurity[Set|Restore]ImageLabel.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The flag will control the VIR_SECURITY_DOMAIN_IMAGE_LABEL_BACKING_CHAIN
flag of the security driver image labeling APIs.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@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>
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>
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>
The TPM code currently accepts pointer to a domain definition.
This is okay for now, but in near future the security driver APIs
it calls will require domain object. Therefore, change the TPM
code to accept the domain object pointer.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Now that committing transactions using pid == -1 means that we're
not fork()-ing to run the transaction in a specific namespace, we
can utilize the transaction processing semantics in order to
start, run a or multiple commands, and then commit the
transaction without being concerned with other interactions or
transactions interrupting the processing. This will eventually
allow us to have a single place where all the paths can be
locked, followed by relabeling and unlocking again.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Even though the current use of the functions does not require full
implementation with transactions (none of the callers passes a path
somewhere under /dev), it doesn't hurt either. Moreover, in
future patches the paradigm is going to shift so that any API
that touches a file is required to use transactions.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Even though the current use of the function does not require full
implementation with transactions (none of the callers pass a path
somewhere under /dev), it doesn't hurt either. Moreover, in
future patches the paradigm is going to shift so that any API
that touches a file is required to use transactions.
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>
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>
Now that we have APIs for relabel memdevs on hotplug, fill in the
missing implementation in qemu hotplug code.
The qemuSecurity wrappers might look like overkill for now,
because qemu namespace code does not deal with the nvdimms yet.
Nor does our cgroup code. But hey, there's cgroup_device_acl
variable in qemu.conf. If users add their /dev/pmem* device in
there, the device is allowed in cgroups and created in the
namespace so they can successfully passthrough it to the domain.
It doesn't look like overkill after all, does it?
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Just like we need wrappers over other virSecurityManager APIs, we
need one for virSecurityManagerSetImageLabel and
virSecurityManagerRestoreImageLabel. Otherwise we might end up
relabelling device in wrong namespace.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
The idea is to move all the seclabel setting to security driver.
Having the relabel code spread all over the place looks very
messy.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
