The previous change to the auth scheme handling guarantees we
can never have nested TLS sessions in the VNC websockets server.
Thus we can remove the separate gnutls_session instance.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
When TLS is required, the primary VNC server considers it to be
mandatory. ie the server admin decides whether or not TLS is used,
and the client has to comply with this decision. The websockets
server, however, treated it as optional, allowing non-TLS clients
to connect to a server which had setup TLS. Thus enabling websockets
lowers the security of the VNC server leaving the admin no way to
enforce use of TLS.
This removes the code that allows non-TLS fallback in the websockets
server, so that if TLS is requested for VNC it is now mandatory for
both the primary VNC server and the websockets VNC server.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The way the websockets TLS code was integrated into the VNC server
made it essentially useless. The only time that the websockets TLS
support could be used is if the primary VNC server had its existing
TLS support disabled. ie QEMU had to be launched with:
# qemu -vnc localhost:1,websockets=5902,x509=/path/to/certs
Note the absence of the 'tls' flag. This is already a bug, because
the docs indicate that 'x509' is ignored unless 'tls' is given.
If the primary VNC server had TLS turned on via the 'tls' flag,
then this prevented the websockets TLS support from being used,
because it activates the VeNCrypt auth which would have resulted
in TLS being run over a TLS session. Of course no websockets VNC
client supported VeNCrypt so in practice, since the browser clients
cannot setup a nested TLS session over the main HTTPS connection,
so it would not even get past auth.
This patch causes us to decide our auth scheme separately for the
main VNC server vs the websockets VNC server. We take account of
the fact that if TLS is enabled, then the websockets client will
use https, so setting up VeNCrypt is thus redundant as it would
lead to nested TLS sessions.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The vnc_display_open method is quite long and complex, so
move the VNC auth scheme decision logic into a separate
method for clarity.
Also update the comment to better describe what we are
trying to achieve.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
If the VNC server is built without tls, sasl or websocket support
and the user requests one of these features, they are just silently
ignored. This is bad because it means the VNC server ends up running
in a configuration that is less secure than the user asked for.
It also leads to an tangled mass of preprocessor conditionals when
configuring the VNC server.
This ensures that the tls, sasl & websocket options are always
processed and an error is reported back to the user if any of
them were disabled at build time.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Handling of VNC audio messages results in printfs to the console.
This is of no use to anyone in production, so should be using the
normal VNC_DEBUG macro instead.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Error classes are a leftover from the days of "rich" error objects.
New code should always use ERROR_CLASS_GENERIC_ERROR. Commit 1d0d59f
added a use of ERROR_CLASS_DEVICE_NOT_FOUND. Replace it.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
vs->lsock may equal to 0, modify the check condition,
avoid possible vs->lsock leak.
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The 'x509verify' parameter is documented as taking a path to the
x509 certificates, ie the same syntax as the 'x509' parameter.
commit 4db14629c3
Author: Gerd Hoffmann <kraxel@redhat.com>
Date: Tue Sep 16 12:33:03 2014 +0200
vnc: switch to QemuOpts, allow multiple servers
caused a regression by turning 'x509verify' into a boolean
parameter instead. This breaks setup from libvirt and is not
consistent with the docs.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Use inet_listen_opts instead of inet_listen. Allows us to drop some
pointless indirection: Format strings just to parse them again later on.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Nobody cares about those strings, they are only used to check whenever
the vnc server / websocket support is enabled or not. Add bools for
this and drop the strings.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
This way the generated id will be stored in -writeconfig cfg files.
Also we can make vnc_auto_assign_id() local to vnc.c.
Tested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
vnc_display_local_addr will not be called with an invalid display id.
Add assert() to silence coverity warning about a null pointer dereference.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
in case we send and update for a complete scanline increment
the y offset to avoid running to find_next_bit for that lines
twice.
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Add new query vnc qmp command, for the lack of better ideas just name it
"query-vnc-servers". Changes over query-vnc:
* It returns a list of vnc servers, so multiple vnc server instances
are covered.
* Each vnc server returns a list of server sockets. Followup patch
will use that to also report websockets. In case we add support for
multiple server sockets server sockets (to better support ipv4+ipv6
dualstack) we can add them to the list too.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Also track the number of connections in "connecting" and "shared" state
(in addition to the "exclusive" state). Apply a configurable limit to
these connections.
The logic to apply the limit to connections in "shared" state is pretty
simple: When the limit is reached no new connections are allowed.
The logic to apply the limit to connections in "connecting" state (this
is the state you are in *before* successful authentication) is
slightly different: A new connect kicks out the oldest client which is
still in "connecting" state. This avoids a easy DoS by unauthenticated
users by simply opening connections until the limit is reached.
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch adds a display= parameter to the vnc options. This allows to
bind a vnc server instance to a specific display, allowing to create a
multiseat setup with a vnc server for each seat.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This patch switches vnc over to QemuOpts, and it (more or less
as side effect) allows multiple vnc server instances.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
In case the display id is "default" (which is the one you get if you
don't explicitly assign one) we keep the old name scheme, without
display, for backward compatibility reasons.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
DisplayState isn't used anywhere, drop it. Add the vnc server ID as
parameter instead, so it is possible to specify the server instance.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Replace with a vnc_displays list, so we can have multiple vnc server
instances. Add vnc_server_find function to lookup a display by id.
With no id supplied return the first vnc server, for backward
compatibility reasons.
It is not possible (yet) to actually create multiple vnc server
instances.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
At least all the ones I've tested. We make the assumption that
pixman is going to be better at conversion than we are.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[ kraxel: just hook up qemu_pixman_check_format ]
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
graphic_hw_update and vnc_refresh_server_surface aren't
need to do when no vnc client connected. It can reduce
lock contention, because vnc_refresh will hold global big
lock two millisecond every three seconds.
Signed-off-by: ChenLiang <chenliang88@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
bits_per_pixel that are less than 8 could result in accessing
non-initialized buffers later in the code due to the expectation
that bytes_per_pixel value that is used to initialize these buffers is
never zero.
To fix this check that bits_per_pixel from the client is one of the
values that the rfb protocol specification allows.
This is CVE-2014-7815.
Signed-off-by: Petr Matousek <pmatouse@redhat.com>
[ kraxel: apply codestyle fix ]
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
we currently have the Nagle algorithm enabled for all outgoing VNC updates.
This may delay sensitive updates as mouse movements or typing in the console.
As we currently prepare all data in a buffer and then send as much as we can
disabling the Nagle algorithm should not cause big trouble. Well established
VNC servers like TightVNC set TCP_NODELAY as well.
A regular framebuffer update request generates exactly one framebuffer update
which should be pushed out as fast as possible.
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
We need to remember has_updates for each vnc client. Otherwise it might
happen that vnc_update_client(has_dirty=1) takes the first exit due to
output buffers not being flushed yet and subsequent calls with
has_dirty=0 take the second exit, wrongly assuming there is nothing to
do because the work defered in the first call is ignored.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
If the client asks for !incremental frame updates, it has lost its content
so dirty doesn't matter - it has to see the full frame, so setting force_update
Signed-off-by: Stephan Kulow <coolo@suse.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
this patch makes the VNC server work correctly if the
server surface and the guest surface have different sizes.
Basically the server surface is adjusted to not exceed VNC_MAX_WIDTH
x VNC_MAX_HEIGHT and additionally the width is rounded up to multiple of
VNC_DIRTY_PIXELS_PER_BIT.
If we have a resolution whose width is not dividable by VNC_DIRTY_PIXELS_PER_BIT
we now get a small black bar on the right of the screen.
If the surface is too big to fit the limits only the upper left area is shown.
On top of that this fixes 2 memory corruption issues:
The first was actually discovered during playing
around with a Windows 7 vServer. During resolution
change in Windows 7 it happens sometimes that Windows
changes to an intermediate resolution where
server_stride % cmp_bytes != 0 (in vnc_refresh_server_surface).
This happens only if width % VNC_DIRTY_PIXELS_PER_BIT != 0.
The second is a theoretical issue, but is maybe exploitable
by the guest. If for some reason the guest surface size is bigger
than VNC_MAX_WIDTH x VNC_MAX_HEIGHT we end up in severe corruption since
this limit is nowhere enforced.
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
currently a malicious client could define a payload
size of 2^32 - 1 bytes and send up to that size of
data to the vnc server. The server would allocated
that amount of memory which could easily create an
out of memory condition.
This patch limits the payload size to 1MB max.
Please note that client_cut_text messages are currently
silently ignored.
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Since VNC_CONNECTED, VNC_DISCONNECTED, VNC_INITIALIZED share some
common functions, convert them in one patch.
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
In order to let event defines use existing types later, instead of
redefine new ones, some old type defines for spice and vnc are changed,
and BlockErrorAction is moved from block.h to qapi schema. Note that
BlockErrorAction is not merged with BlockdevOnError.
At this point, VncInfo is not made a child of VncBasicInfo, because
VncBasicInfo has mandatory fields where VncInfo makes them optional.
Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Bug was added by 38ee14f4f3.
vnc_jobs_join call is missing in one code path.
Reported-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Current code silently changes the authentication settings
in case you try to set a password without password authentication
turned on. This is bad. Return an error instead.
If we want allow changing auth settings at runtime this should
be done explicitly using a separate monitor command, not as
side effect of set_passwd.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
These errors don't seem user initiated, so forcibly printing to the
monitor doesn't seem right. Just use error_report.
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
this fixes invalid rectangle updates observed after commit 12b316d
with the vmware VGA driver. The issues occured because the server
and client surface update seems to be out of sync at some points
and the max width of the surface is not dividable by
VNC_DIRTY_BITS_PER_PIXEL (16).
Reported-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
