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  • Anton Anton anjo
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  1. Mar 21, 2017
  3. Mar 20, 2017
  5. Mar 17, 2017
    • Alex Bennée's avatar
      ui/console: ensure graphic updates don't race with TCG vCPUs · 8bb93c6f
      Alex Bennée authored 
      
Commit 8d04fb55..

  tcg: drop global lock during TCG code execution

..broke the assumption that updates to the GUI couldn't happen at the
same time as TCG vCPUs where running. As a result the TCG vCPU could
still be updating a directly mapped frame-buffer while the display
side was updating. This would cause artefacts to appear when the
update code assumed that memory block hadn't changed.

The simplest solution is to ensure the two things can't happen at the
same time like the old BQL locking scheme. Here we use the solution
introduced for MTTCG and schedule the update as async_safe_work when
we know no vCPUs can be running.

Reported-by: default avatarMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Message-id: 20170315144825.3108-1-alex.bennee@linaro.org
Cc: BALATON Zoltan <balaton@eik.bme.hu>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarAlex Bennée <alex.bennee@linaro.org>

[ kraxel: updated comment clarifying the display adapters are buggy
          and this is a temporary workaround ]

Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      8bb93c6f
  7. Mar 16, 2017
    • Gerd Hoffmann's avatar
      cirrus/vnc: zap bitblit support from console code. · 50628d34
      Gerd Hoffmann authored 
      
There is a special code path (dpy_gfx_copy) to allow graphic emulation
notify user interface code about bitblit operations carryed out by
guests.  It is supported by cirrus and vnc server.  The intended purpose
is to optimize display scrolls and just send over the scroll op instead
of a full display update.

This is rarely used these days though because modern guests simply don't
use the cirrus blitter any more.  Any linux guest using the cirrus drm
driver doesn't.  Any windows guest newer than winxp doesn't ship with a
cirrus driver any more and thus uses the cirrus as simple framebuffer.

So this code tends to bitrot and bugs can go unnoticed for a long time.
See for example commit "3e10c3ec vnc: fix qemu crash because of SIGSEGV"
which fixes a bug lingering in the code for almost a year, added by
commit "c7628bff vnc: only alloc server surface with clients connected".

Also the vnc server will throttle the frame rate in case it figures the
network can't keep up (send buffers are full).  This doesn't work with
dpy_gfx_copy, for any copy operation sent to the vnc client we have to
send all outstanding updates beforehand, otherwise the vnc client might
run the client side blit on outdated data and thereby corrupt the
display.  So this dpy_gfx_copy "optimization" might even make things
worse on slow network links.

Lets kill it once for all.

Oh, and one more reason: Turns out (after writing the patch) we have a
security bug in that code path ...

Fixes: CVE-2016-9603
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Message-id: 1489494419-14340-1-git-send-email-kraxel@redhat.com
      50628d34
  9. Mar 14, 2017
  11. Feb 27, 2017
  13. Feb 20, 2017
  15. Feb 09, 2017
  17. Feb 08, 2017
    • Daniel P. Berrangé's avatar
      ui: refactor VncDisplay to allow multiple listening sockets · 4ee74fa7
      Daniel P. Berrangé authored 
      
Currently there is only a single listener for plain VNC and
a single listener for websockets VNC. This means that if
getaddrinfo() returns multiple IP addresses, for a hostname,
the VNC server can only listen on one of them. This is
just bearable if listening on wildcard interface, or if
the host only has a single network interface to listen on,
but if there are multiple NICs and the VNC server needs
to listen on 2 or more specific IP addresses, it can't be
done.

This refactors the VncDisplay state so that it holds an
array of listening sockets, but still only listens on
one socket.

Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170203120649.15637-4-berrange@redhat.com
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      4ee74fa7
    • Daniel P. Berrangé's avatar
      ui: fix reporting of VNC auth in query-vnc-servers · 2a7e6857
      Daniel P. Berrangé authored 
      
Currently the VNC authentication info is emitted at the
top level of the query-vnc-servers data. This is wrong
because the authentication scheme differs between plain
and websockets when TLS is enabled. We should instead
report auth against the individual servers. e.g.

(QEMU) query-vnc-servers
{
    "return": [
        {
            "clients": [],
            "id": "default",
            "auth": "vencrypt",
            "vencrypt": "x509-vnc",
            "server": [
                {
                    "host": "127.0.0.1"
                    "service": "5901",
                    "websocket": false,
                    "family": "ipv4",
                    "auth": "vencrypt",
                    "vencrypt": "x509-vnc"
                },
                {
                    "host": "127.0.0.1",
                    "service": "5902",
                    "websocket": true,
                    "family": "ipv4",
                    "auth": "vnc"
                }
            ]
        }
    ]
}

This also future proofs the QMP schema so that we can
cope with multiple VNC server instances, listening on
different interfaces or ports, with different auth
setup.

Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170203120649.15637-3-berrange@redhat.com
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      2a7e6857
    • Daniel P. Berrangé's avatar
      ui: fix regression handling bare 'websocket' option to -vnc · 1b1aeb58
      Daniel P. Berrangé authored 
      
The -vnc argument is documented as accepting two syntaxes for
the 'websocket' option, either a bare option name, or a port
number. If using the bare option name, it is supposed to apply
the display number as an offset to base port 5700. e.g.

  -vnc localhost:3,websocket

should listen on port 5703, however, this was broken in 2.3.0 since

  commit 4db14629
  Author: Gerd Hoffmann <kraxel@redhat.com>
  Date:   Tue Sep 16 12:33:03 2014 +0200

    vnc: switch to QemuOpts, allow multiple servers

instead qemu tries to listen on port "on" which gets looked up in
/etc/services and fails.

Fixes bug: #1455912

Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Signed-off-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 20170203120649.15637-2-berrange@redhat.com
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      1b1aeb58
    • Michael Tokarev's avatar
      vnc: do not disconnect on EAGAIN · 537848ee
      Michael Tokarev authored 
      
When qemu vnc server is trying to send large update to clients,
there might be a situation when system responds with something
like EAGAIN, indicating that there's no system memory to send
that much data (depending on the network speed, client and server
and what is happening).  In this case, something like this happens
on qemu side (from strace):

sendmsg(16, {msg_name(0)=NULL,
        msg_iov(1)=[{"\244\"..., 729186}],
        msg_controllen=0, msg_flags=0}, 0) = 103950
sendmsg(16, {msg_name(0)=NULL,
        msg_iov(1)=[{"lz\346"..., 1559618}],
        msg_controllen=0, msg_flags=0}, 0) = -1 EAGAIN
sendmsg(-1, {msg_name(0)=NULL,
        msg_iov(1)=[{"lz\346"..., 1559618}],
        msg_controllen=0, msg_flags=0}, 0) = -1 EBADF

qemu closes the socket before the retry, and obviously it gets EBADF
when trying to send to -1.

This is because there WAS a special handling for EAGAIN, but now it doesn't
work anymore, after commit 04d2529d, because
now in all error-like cases we initiate vnc disconnect.

This change were introduced in qemu 2.6, and caused numerous grief for many
people, resulting in their vnc clients reporting sporadic random disconnects
from vnc server.

Fix that by doing the disconnect only when necessary, i.e. omitting this
very case of EAGAIN.

Hopefully the existing condition (comparing with QIO_CHANNEL_ERR_BLOCK)
is sufficient, as the original code (before the above commit) were
checking for other errno values too.

Apparently there's another (semi?)bug exist somewhere here, since the
code tries to write to fd# -1, it probably should check if the connection
is open before. But this isn't important.

Signed-off-by: default avatarMichael Tokarev <mjt@tls.msk.ru>
Reviewed-by: default avatarDaniel P. Berrange <berrange@redhat.com>
Message-id: 1486115549-9398-1-git-send-email-mjt@msgid.tls.msk.ru
Fixes: 04d2529d
Cc: Daniel P. Berrange <berrange@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      537848ee
    • Peter Maydell's avatar
      ui/vnc: Drop unused vnc_has_job() and vnc_jobs_clear() · c3ff04b6
      Peter Maydell authored 
      
The functions vnc_has_job() and vnc_jobs_clear() are
never used; remove them.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarGonglei <arei.gonglei@huawei.com>
Message-id: 1486146260-8092-1-git-send-email-peter.maydell@linaro.org
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
      c3ff04b6
  19. Jan 31, 2017
  21. Jan 27, 2017