This patch implements support for learning a VM's IP address. It uses
the pcap library to listen on the VM's backend network interface (tap)
or the physical ethernet device (macvtap) and tries to capture packets
with source or destination MAC address of the VM and learn from DHCP
Offers, ARP traffic, or first-sent IPv4 packet what the IP address of
the VM's interface is. This then allows to instantiate the network
traffic filtering rules without the user having to provide the IP
parameter somewhere in the filter description or in the interface
description as a parameter. This only supports to detect the parameter
IP, which is for the assumed single IPv4 address of a VM. There is not
support for interfaces that may have multiple IP addresses (IP
aliasing) or IPv6 that may then require more than one valid IP address
to be detected. A VM can have multiple independent interfaces that each
uses a different IP address and in that case it will be attempted to
detect each one of the address independently.
So, when for example an interface description in the domain XML has
looked like this up to now:
<interface type='bridge'>
<source bridge='mybridge'/>
<model type='virtio'/>
<filterref filter='clean-traffic'>
<parameter name='IP' value='10.2.3.4'/>
</filterref>
</interface>
you may omit the IP parameter:
<interface type='bridge'>
<source bridge='mybridge'/>
<model type='virtio'/>
<filterref filter='clean-traffic'/>
</interface>
Internally I am walking the 'tree' of a VM's referenced network filters
and determine with the given variables which variables are missing. Now,
the above IP parameter may be missing and this causes a libvirt-internal
thread to be started that uses the pcap library's API to listen to the
backend interface (in case of macvtap to the physical interface) in an
attempt to determine the missing IP parameter. If the backend interface
disappears the thread terminates assuming the VM was brought down. In
case of a macvtap device a timeout is being used to wait for packets
from the given VM (filtering by VM's interface MAC address). If the VM's
macvtap device disappeared the thread also terminates. In all other
cases it tries to determine the IP address of the VM and will then apply
the rules late on the given interface, which would have happened
immediately if the IP parameter had been explicitly given. In case an
error happens while the firewall rules are applied, the VM's backend
interface is 'down'ed preventing it to communicate. Reasons for failure
for applying the network firewall rules may that an ebtables/iptables
command failes or OOM errors. Essentially the same failure reasons may
occur as when the firewall rules are applied immediately on VM start,
except that due to the late application of the filtering rules the VM
now is already running and cannot be hindered anymore from starting.
Bringing down the whole VM would probably be considered too drastic.
While a VM's IP address is attempted to be determined only limited
updates to network filters are allowed. In particular it is prevented
that filters are modified in such a way that they would introduce new
variables.
A caveat: The algorithm does not know which one is the appropriate IP
address of a VM. If the VM spoofs an IP address in its first ARP traffic
or IPv4 packets its filtering rules will be instantiated for this IP
address, thus 'locking' it to the found IP address. So, it's still
'safer' to explicitly provide the IP address of a VM's interface in the
filter description if it is known beforehand.
* configure.ac: detect libpcap
* libvirt.spec.in: require libpcap[-devel] if qemu is built
* src/internal.h: add the new ATTRIBUTE_PACKED define
* src/Makefile.am src/libvirt_private.syms: add the new modules and symbols
* src/nwfilter/nwfilter_learnipaddr.[ch]: new module being added
* src/nwfilter/nwfilter_driver.c src/conf/nwfilter_conf.[ch]
src/nwfilter/nwfilter_ebiptables_driver.[ch]
src/nwfilter/nwfilter_gentech_driver.[ch]: plu the new functionality in
* tests/nwfilterxml2xmltest: extend testing
When comparing a CPU to host CPU, the result would be
VIR_CPU_COMPARE_SUPERSET (or even VIR_CPU_COMPARE_INCOMPATIBLE if strict
match was required) even though the two CPUs were identical.
When qemu libvirt driver doesn't support guest CPU selection with given
qemu binary, guests requiring specific CPU should fail to start instead
of being silently supplied with a default CPU.
git grep found 12 of the former but 100 of the latter in src/.
* src/remote/remote_driver.c (initialise_gnutls): Rename...
(initialize_gnutls): ...to this.
(doRemoteOpen): Adjust caller.
* src/xen/xen_driver.c (xenUnifiedOpen): Adjust output string.
* src/util/network.c: Adjust comments.
Suggested by Matthias Bolte.
* src/conf/domain_event.c (virDomainEventGraphicsNewFromDom):
Return NULL when handling out-of-memory error, rather than
falling through with ev=NULL and then assigning to ev->member.
(virDomainEventGraphicsNewFromObj): Likewise.
The attached patch fixes a problem due to the mac match in iptables only
supporting --mac-source and no --mac-destination, thus it not being
symmetric. Therefore a rule like this one
<rule action='drop' direction='out'>
<all match='no' srcmacaddr='$MAC'/>
</rule>
should only have the MAC match on traffic leaving the VM and not test
for the same source MAC address on traffic that the VM receives.
* src/qemu/qemu_driver.c (qemudStartVMDaemon): Initialize "logfile"
to ensure that we don't use it uninitialized -- thus closing an
arbitrary file descriptor -- in the cleanup block.
* src/security/virt-aa-helper.c: adjust virt-aa-helper to handle pci
devices. Update valid_path() to have an override array to check against,
and add "/sys/devices/pci" to it. Then rename file_iterate_cb() to
file_iterate_hostdev_cb() and create file_iterate_pci_cb() based on it
To avoid an error when hitting the <seclabel...> definition
* src/security/virt-aa-helper.c: add VIR_DOMAIN_XML_INACTIVE flag
to virDomainDefParseString
Don't exit with error if the user unloaded the profile outside of
libvirt
* src/security/virt-aa-helper.c: check the exit error from apparmor_parser
before exiting with a failure
The calls to virExec() in security_apparmor.c when
invoking virt-aa-helper use VIR_EXEC_CLEAR_CAPS. When compiled without
libcap-ng, this is not a problem (it's effectively a no-op) but with
libcap-ng this causes MAC_ADMIN to be cleared. MAC_ADMIN is needed by
virt-aa-helper to manipulate apparmor profiles and without it VMs will
not start[1]. This patch calls virExec with the default VIR_EXEC_NONE
instead.
* src/security/security_apparmor.c: fallback to VIR_EXEC_NONE flags for
virExec of virt_aa_helper
Tested by running 'git submodule foreach git pull origin master' and
'git add .gnulib', then seeing that 'make clean' skips autogen
although 'make' properly runs it.
* cfg.mk (_clean_requested): New check, to speed up 'make clean'
even if gnulib submodule is outdated.
Suggested by Daniel P. Berrange.
Also define ESX_ERROR and ESX_VI_ERROR in a central place, instead of
defining them in each source file.
Add ESX_ERROR and ESX_VI_ERROR to the msg_gen_function list in cfg.mk.
Update po/POTFILES.in accordingly.
This patch adds a relaxng nwfilter schema along with a test that
verifies all the test output XML against the schema. The input XMLs
contain a lot of intentional out-of-range values that make them fail the
schema verification, so I am not verifying against those.
With Eric Blake's suggestions applied.
The following rule for direction 'in'
<rule direction='in' action='drop'>
<mac srcmacaddr='1:2:3:4:5:6'/>
</rule>
drops all traffic from the given mac address.
The following rule for direction 'out'
<rule direction='out' action='drop'>
<mac dstmacaddr='1:2:3:4:5:6'/>
</rule>
drops all traffic to the given mac address.
The following rule in direction 'inout'
<rule direction='inout' action='drop'>
<mac srcmacaddr='1:2:3:4:5:6'/>
</rule>
now drops all traffic from and to the given MAC address.
So far it would have dropped traffic from the given MAC address
and outgoing traffic with the given source MAC address, which is not useful
since the packets will always have the VM's MAC address as source
MAC address. The attached patch fixes this.
This is the last bug I currently know of and want to fix.
Document several missing commands. There's more work that could be
done, but incremental improvements is better than no patch at all.
* tools/virsh.pod (autostart, connect): Improve grammar.
(create): Improve example.
(domjobabort, domjobinfo, domxml-from-native, domxml-to-native):
Document.
(storage pool commands): New section.
When hitting failures in virsh, a common idiom is
to jump to a cleanup label, free some resources, and
then return a FALSE error code to vshCommandRun.
In theory, vshCommandRun is then supposed to print
out the last error. The problem is that many of
the cleanup paths have library calls to free resources,
and all of those library calls clear out the last error.
This is leading to situations where no error is being
reported at all.
This patch remedies the situation somewhat by
printing out the errors inside the command methods
themselves when we know it will go through a cleanup
path that will lose the error.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
When starting up qemu VNC autoport guests, we were
only looking through ports 5900 to 6000, meaning we
were limited to 100 total clients. Increase that
limit to 65535 (the last available port), so we can
have up to 59635 VNC autoport guests.
Signed-off-by: Chris Lalancette <clalance@redhat.com>
