CVE-2019-11135

When TSX_CTRL bit of IA32_ARCH_CAPABILITIES MSR is set to 1, the CPU
supports IA32_TSX_CTRL MSR which can be used to disable and/or mask TSX.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

CVE-2019-11135

CPUs with TAA_NO bit of IA32_ARCH_CAPABILITIES MSR set to 1 are not
vulnerable to TSX Asynchronous Abort and passing this bit to a guest
may avoid unnecessary mitigations.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

To allow backups work across external snapshots we need to improve the
algorithm which calculates which bitmaps to merge.

The algorithm must look for appropriately named bitmaps in the image and
possibly descend into a backing image if the current image does not have
the bitmap.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

This function looks up a named bitmap for a virStorageSource in the data
returned from query-named-block-nodes.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The function will require the bitmap topology for the full
implementation. To facilitate testing, add the propagation of the
necessary data beforehand so that the test code can stay unchanged
during the changes.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Separate the for now incomplete code that collects the bitmaps to be
merged for an incremental backup into a separate function. This will
allow adding testing prior to the improvement of the algorithm to
include snapshots.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The object itself has no extra value and it would make testing the code
harder. Refactor it to remove just the definition pointer.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Re-create any active persistent bitmap in the snapshot overlay image so
that tracking for a checkpoint is persisted. While this basically
duplicates data in the allocation map it's currently the only possible
way as qemu can't mirror the allocation map into a dirty bitmap if we'd
ever want to do a backup.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

qemuDomainSnapshotDiskPrepareOne is already called for each disk which
is member of the snapshot so we don't need to iterate through the
snapshot list again to generate members of the 'transaction' command for
each snapshot.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Check that the value is less than 0.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

For testing purposes it will be beneficial to be able to parse the data
from JSON directly rather than trying to simulate the monitor. Extract
the worker bits and export them.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

We will need to inspect the presence and attributes for dirty bitmaps.
Extract them when processing reply of query-named-block-nodes.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The use of the parseOpaque parameter was mistakenly removed in

  commit 4a4132b4
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Tue Dec 3 10:49:49 2019 +0000

    conf: don't use passed in caps in post parse method

causing the method to re-fetch qemuCaps that were already just
fetched and put into parseOpaque.

This is inefficient when parsing incoming XML, but for live
XML this is more serious as it means we use the capabilities
for the current QEMU binary on disk, rather than the running
QEMU.

That commit, however, did have a useful side effect of fixing
a crasher bug in the qemu post parse callback introduced by

  commit 5e939cea
  Author: Jiri Denemark <jdenemar@redhat.com>
  Date:   Thu Sep 26 18:42:02 2019 +0200

    qemu: Store default CPU in domain XML

The qemuDomainDefSetDefaultCPU() method in that patch did not
allow for the possibility that qemuCaps would be NULL and thus
resulted in a SEGV.

This shows a risk in letting each check in the post parse
callback look for qemuCaps == NULL. The safer option is to
check once upfront and immediately stop (postpone) further
validation.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Don't check os type / virt type / arch in the post-parse callback
because we can't assume qemuCaps is non-NULL at this point. It
also conceptually belongs to the validation callback.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

This function will be removed in a future commit because it allows the
caller to acquire both monitor and agent jobs at the same time. Holding
both job types creates a vulnerability to denial of service from a
malicious guest agent.

qemuDomainSetVcpusFlags() always passes NONE for either the monitor job
or the agent job (and thus is not vulnerable to the DoS), so we can
simply replace this function with the functions for acquiring the
appropriate type of job.
Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

We have to assume that the guest agent may be malicious so we don't want
to allow any agent queries to block any other libvirt API. By holding
a monitor job while we're querying the agent, we open ourselves up to a
DoS.

Split the function so that the portion issuing the agent command only
holds an agent job and the portion issuing the monitor command holds
only a monitor job.
Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

We have to assume that the guest agent may be malicious so we don't want
to allow any agent queries to block any other libvirt API. By holding a
monitor job while we're querying the agent, we open ourselves up to a
DoS.

So split the function up a bit to only hold the monitor job while
querying qemu for whether the domain supports suspend. Then acquire only
an agent job while issuing the agent suspend command.
Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

We have to assume that the guest agent may be malicious so we don't want
to allow any agent queries to block any other libvirt API. By holding
a monitor job while we're querying the agent, we open ourselves up to a
DoS.

Split the function so that we only hold the appropriate type of job
while rebooting.
Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

We have to assume that the guest agent may be malicious so we don't want
to allow any agent queries to block any other libvirt API. By holding
a monitor job while we're querying the agent, we open ourselves up to a
DoS.  So split the function into separate parts: one that does the agent
shutdown and one that does the monitor shutdown. Each part holds only a
job of the appropriate type.
Signed-off-by: NJonathon Jongsma <jjongsma@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

Replace all the uses passing a single parameter as the length.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

Remove the usage where sanity of the length argument is verified
by other conditions not matching the previous patches.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

My hesitation to remove VIR_STRDUP without VIR_STRNDUP resulted
in these being able to sneak in.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

This reverts commit 7be5fe66.

This commit broke resctrl, because it missed the fact that the
virResctrlInfoGetCache() has side-effects causing it to actually
change the virResctrlInfo parameter, not merely get data from
it.

This code will need some refactoring before we can try separating
it from virCapabilities again.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

This commit aims to fix

https://bugzilla.redhat.com/show_bug.cgi?id=1610207

The cause was apparently incorrect handling of jobs in snapshot
revert code which allowed a thread executing snapshot delete to
begin job while snapshot revert was still running on another
thread. The snapshot delete thread then waited on a condition
variable in qemuMonitorSend() while the revert thread finished,
changing (and effectively corrupting) the qemuMonitor structure
under the delete thread which led to its crash.

The incorrect handling of jobs in revert code was due to the fact
that although qemuDomainRevertToSnapshot() correctly begins a job
at the start, the job was implicitly ended when qemuProcessStop()
was called because the job lives in the QEMU driver's private
data (qemuDomainObjPrivate) that was purged during
qemuProcessStop().

This fix prevents qemuProcessStop() from clearing jobs as the
idea of qemuProcessStop() clearing jobs seems wrong in the first
place. It was (inadvertently) introduced in commit
888aa4b6, which is effectively reverted by
the second hunk of this commit. To preserve the desired effects
of the faulty commit, the first hunk is included as suggested by
Michal.
Signed-off-by: NPavel Mores <pmores@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

When QEMU uid/gid is set to non-root this is pointless as if we just
used a regular setuid/setgid call, the process will have all its
capabilities cleared anyway by the kernel.

When QEMU uid/gid is set to root, this is almost (always?) never
what people actually want. People make QEMU run as root in order
to access some privileged resource that libvirt doesn't support
yet and this often requires capabilities. As a result they have
to go find the qemu.conf param to turn this off. This is not
viable for libguestfs - they want to control everything via the
XML security label to request running as root regardless of the
qemu.conf settings for user/group.

Clearing capabilities was implemented originally because there
was a proposal in Fedora to change permissions such that root,
with no capabilities would not be able to compromise the system.
ie a locked down root account. This never went anywhere though,
and as a result clearing capabilities when running as root does
not really get us any security benefit AFAICT. The root user
can easily do something like create a cronjob, which will then
faithfully be run with full capabilities, trivially bypassing
the restriction we place.

IOW, our clearing of capabilities is both useless from a security
POV, and breaks valid use cases when people need to run as root.

This removes the clear_emulator_capabilities configuration
option from qemu.conf, and always runs QEMU with capabilities
when root.  The behaviour when non-root is unchanged.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

The keycodemap tool is told to generate docs in rst format now
instead of pod.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

This was a semi-automated conversion. First it was run through pod2rst,
and then it was manually editted to use a rst structure that matches
expectations of rst2man.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

This was a semi-automated conversion. First it was run through pod2rst,
and then it was manually editted to use a rst structure that matches
expectations of rst2man.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

This was a semi-automated conversion. First it was run through pod2rst,
and then it was manually editted to use a rst structure that matches
expectations of rst2man.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

Pull in changes which support use of RST for docs output format
instead of POD.

The generator tool has changed its command line arg handling
so all args must be after the command name. The docs title and
subtitle must be specified separately too.
Reviewed-by: NCole Robinson <crobinso@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

With all plumbing in place, we can now enable the new functionality.
Signed-off-by: NPavel Mores <pmores@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

Since blockcommit is asynchronous, libvirtd can be restarted while the
operation runs.  To ensure the information necessary to finish up the job
is not lost, serialisation to and deserialisation from the status XML is
added.

To unittest this, the new element was only added to the active commit test,
the non-active commit test doesn't have the new element so as to test its
absence.
Signed-off-by: NPavel Mores <pmores@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

When blockcommit finishes successfully, one of the
qemuBlockJobProcessEventCompletedCommit() and
qemuBlockJobProcessEventCompletedActiveCommit() event handlers is called.
This is where the delete flag (stored in qemuBlockJobCommitData since the
previous commit) can actually be used to delete the committed snapshot
images if requested.

We use virFileRemove() instead of a simple unlink() to cover the case where
the image to be removed is on an NFS volume.
Signed-off-by: NPavel Mores <pmores@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

Propagate the delete flag from qemuDomainBlockCommit() (which was just
ignoring it until now) to qemuBlockJobDiskNewCommit() where it can be
stored in the qemuBlockJobCommitData structure which holds information
necessary to finish the job asynchronously.

In the actual qemuBlockJobDiskNewCommit() in this commit, we temporarily
pass a literal 'false' to preserve the current behaviour until the whole
implementation of the feature is in place.
Signed-off-by: NPavel Mores <pmores@redhat.com>
Reviewed-by: NPeter Krempa <pkrempa@redhat.com>

Teach virt-aa-helper how to label a qcow2 data_file, tracked internally
as externalDataStore. It should be treated the same as its sibling
disk image
Reviewed-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: NCole Robinson <crobinso@redhat.com>