401_nxcomp_bigrequests-and-genericevent-extensions.full+lite.patch

--- a/nxcomp/ClientChannel.cpp
+++ b/nxcomp/ClientChannel.cpp
@@ -447,6 +447,26 @@
         }
       }
 
+      // Get other bits of the header, so will not need to refer to them again
+      unsigned char inputDataByte = inputMessage[1];
+      unsigned int buffer2 = GetUINT(inputMessage + 2, bigEndian_);
+      unsigned int inputDataSize = buffer2 - 1;
+      if (buffer2 == 0)
+      {
+        // BIG-REQUESTS
+        inputMessage += 4;
+        inputLength -= 4;
+        inputDataSize = GetULONG(inputMessage, bigEndian_) - 2;
+      }
+      if (inputLength != (4 * (inputDataSize + 1)))
+      {
+        #ifdef WARNING
+        *logofs << "handleRead: inputLength=" << inputLength
+                << " mismatch inputDataSize=" << inputDataSize
+                << ".\n" << logofs_flush;
+        #endif
+      }
+
       //
       // Go to the message's specific encoding.
       //
@@ -455,6 +475,11 @@
       {
       case X_AllocColor:
         {
+          #ifdef WARNING
+          if (inputLength < 14)
+            *logofs << "handleRead: X_AllocColor inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                              clientCache_ -> colormapCache);
           const unsigned char *nextSrc = inputMessage + 8;
@@ -476,6 +501,11 @@
         break;
       case X_ReparentWindow:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_ReparentWindow inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8, bigEndian_),
@@ -486,6 +516,11 @@
         break;
       case X_ChangeProperty:
         {
+          #ifdef WARNING
+          if (inputLength < 24)
+            *logofs << "handleRead: X_ChangeProperty inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_ChangeProperty);
 
@@ -501,8 +536,36 @@
           encodeBuffer.encodeCachedValue(format, 8,
                              clientCache_ -> changePropertyFormatCache);
           unsigned int dataLength = GetULONG(inputMessage + 20, bigEndian_);
+
+          // Self-preserving sanity check (otherwise we crash and dump core):
+          // some clients do this when not getting their beloved BIG-REQUESTS.
+          unsigned int maxLength = 0;
+          if (format == 8)
+          {
+            maxLength = inputLength - 24;
+          }
+          else if (format == 32)
+          {
+            maxLength = (inputLength - 24) >> 2;
+          }
+          else if (format == 16)
+          {
+            maxLength = (inputLength - 24) >> 1;
+          }
+          if (dataLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_ChangeProperty bogus dataLength=" << dataLength
+                    << " set to " << maxLength
+                    << " when format=" << (int)format
+                    << " inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+            #endif
+            dataLength = maxLength;
+          }
+
           encodeBuffer.encodeValue(dataLength, 32, 6);
-          encodeBuffer.encodeValue(inputMessage[1], 2);
+          encodeBuffer.encodeValue(inputDataByte, 2);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 8, bigEndian_), 29,
@@ -533,7 +596,7 @@
               nextSrc += 4;
             }
           }
-          else
+          else if (format == 16)
           {
             for (unsigned int i = 0; i < dataLength; i++)
             {
@@ -541,6 +604,13 @@
               nextSrc += 2;
             }
           }
+          else
+          {
+            #ifdef WARNING
+            *logofs << "ChangeProperty bogus format=" << (int)format
+                    << ".\n" << logofs_flush;
+            #endif
+          }
         }
         break;
       case X_SendEvent:
@@ -551,6 +621,11 @@
           // ratio.
           //
 
+          #ifdef WARNING
+          if (inputLength < 44)
+            *logofs << "handleRead: X_SendEvent inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_SendEvent);
 
@@ -562,7 +637,7 @@
             break;
           }
 
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           unsigned int window = GetULONG(inputMessage + 4, bigEndian_);
 
           if (window == 0 || window == 1)
@@ -599,7 +674,12 @@
         break;
       case X_ChangeWindowAttributes:
         {
-          encodeBuffer.encodeValue((inputLength - 12) >> 2, 4);
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_ChangeWindowAttributes inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeValue(inputDataSize - 2, 4);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           unsigned int bitmask = GetULONG(inputMessage + 8, bigEndian_);
@@ -621,6 +701,11 @@
         break;
       case X_ClearArea:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_ClearArea inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -654,7 +739,7 @@
             break;
           }
 
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           const unsigned char *nextSrc = inputMessage + 8;
@@ -668,6 +753,11 @@
         break;
       case X_CloseFont:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_CloseFont inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int font = GetULONG(inputMessage + 4, bigEndian_);
           encodeBuffer.encodeValue(font - clientCache_ -> lastFont, 29, 5);
           clientCache_ -> lastFont = font;
@@ -675,6 +765,11 @@
         break;
       case X_ConfigureWindow:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_ConfigureWindow inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_ConfigureWindow);
 
@@ -708,6 +803,11 @@
         break;
       case X_ConvertSelection:
         {
+          #ifdef WARNING
+          if (inputLength < 24)
+            *logofs << "handleRead: X_ConvertSelection inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                              clientCache_ -> convertSelectionRequestorCache, 9);
           const unsigned char* nextSrc = inputMessage + 8;
@@ -725,6 +825,11 @@
         break;
       case X_CopyArea:
         {
+          #ifdef WARNING
+          if (inputLength < 28)
+            *logofs << "handleRead: X_CopyArea inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -793,6 +898,11 @@
         break;
       case X_CopyGC:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_CopyGC inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int s_g_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -814,6 +924,11 @@
         break;
       case X_CopyPlane:
         {
+          #ifdef WARNING
+          if (inputLength < 32)
+            *logofs << "handleRead: X_CopyPlane inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8,
@@ -833,6 +948,11 @@
         break;
       case X_CreateGC:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_CreateGC inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int g_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -917,6 +1037,11 @@
         break;
       case X_ChangeGC:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_ChangeGC inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int g_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -998,14 +1123,19 @@
         break;
       case X_CreatePixmap:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_CreatePixmap inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
-          *logofs << "handleRead: X_CreatePixmap depth " << (unsigned) inputMessage[1]
+          *logofs << "handleRead: X_CreatePixmap depth " << (unsigned) inputDataByte
                   << ", pixmap id " << GetULONG(inputMessage + 4, bigEndian_)
                   << ", drawable " << GetULONG(inputMessage + 8, bigEndian_)
                   << ", width " << GetUINT(inputMessage + 12, bigEndian_)
                   << ", height " << GetUINT(inputMessage + 14, bigEndian_)
-                  << ", size " << GetUINT(inputMessage + 2, bigEndian_) << 2
+                  << ", length " << inputLength
                   << ".\n" << logofs_flush;
 
           unsigned int   p_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1042,6 +1172,11 @@
         break;
       case X_CreateWindow:
         {
+          #ifdef WARNING
+          if (inputLength < 32)
+            *logofs << "handleRead: X_CreateWindow inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int w_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1054,7 +1189,7 @@
           #endif
 
           unsigned bitmask = GetULONG(inputMessage + 28, bigEndian_);
-          encodeBuffer.encodeCachedValue((unsigned int) inputMessage[1], 8,
+          encodeBuffer.encodeCachedValue((unsigned int) inputDataByte, 8,
                                          clientCache_ -> depthCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8, bigEndian_),
                              clientCache_ -> windowCache);
@@ -1098,6 +1233,11 @@
         break;
       case X_DeleteProperty:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_DeleteProperty inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           encodeBuffer.encodeValue(GetULONG(inputMessage + 8, bigEndian_), 29, 9);
@@ -1105,6 +1245,11 @@
         break;
       case X_FillPoly:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_FillPoly inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1138,7 +1283,7 @@
             break;
           }
 
-          unsigned int numPoints = ((inputLength - 16) >> 2);
+          unsigned int numPoints = (inputDataSize - 3);
 
           if (control -> isProtoStep10() == 1)
           {
@@ -1209,7 +1354,12 @@
         break;
       case X_FreeColors:
         {
-          unsigned int numPixels = GetUINT(inputMessage + 2, bigEndian_) - 3;
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_FreeColors inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          unsigned int numPixels = inputDataSize - 2;
           encodeBuffer.encodeValue(numPixels, 16, 4);
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                                          clientCache_ -> colormapCache);
@@ -1225,12 +1375,22 @@
         break;
       case X_FreeCursor:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_FreeCursor inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_),
                                          29, clientCache_ -> cursorCache, 9);
         }
         break;
       case X_FreeGC:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_FreeGC inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int g_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1284,6 +1444,11 @@
         break;
       case X_FreePixmap:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_FreePixmap inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int p_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1318,6 +1483,11 @@
         break;
       case X_GetAtomName:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_GetAtomName inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeValue(GetULONG(inputMessage + 4, bigEndian_), 29, 9);
 
           sequenceQueue_.push(clientSequence_, inputOpcode);
@@ -1327,6 +1497,11 @@
         break;
       case X_GetGeometry:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_GetGeometry inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> drawableCache);
 
@@ -1351,6 +1526,11 @@
         break;
       case X_GetKeyboardMapping:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_GetKeyboardMapping inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeValue((unsigned int) inputMessage[4], 8);
           encodeBuffer.encodeValue((unsigned int) inputMessage[5], 8);
 
@@ -1361,6 +1541,11 @@
         break;
       case X_GetProperty:
         {
+          #ifdef WARNING
+          if (inputLength < 24)
+            *logofs << "handleRead: X_GetProperty inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_GetProperty);
 
@@ -1378,7 +1563,7 @@
             break;
           }
 
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           unsigned int property = GetULONG(inputMessage + 8, bigEndian_);
@@ -1394,6 +1579,11 @@
         break;
       case X_GetSelectionOwner:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_GetSelectionOwner inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                              clientCache_ -> getSelectionOwnerSelectionCache, 9);
 
@@ -1404,7 +1594,12 @@
         break;
       case X_GrabButton:
         {
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          #ifdef WARNING
+          if (inputLength < 24)
+            *logofs << "handleRead: X_GrabButton inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           encodeBuffer.encodeCachedValue(GetUINT(inputMessage + 8, bigEndian_), 16,
@@ -1423,7 +1618,12 @@
         break;
       case X_GrabPointer:
         {
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          #ifdef WARNING
+          if (inputLength < 24)
+            *logofs << "handleRead: X_GrabPointer inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           encodeBuffer.encodeCachedValue(GetUINT(inputMessage + 8, bigEndian_), 16,
@@ -1448,7 +1648,12 @@
         break;
       case X_GrabKeyboard:
         {
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_GrabKeyboard inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> windowCache);
           unsigned int timestamp = GetULONG(inputMessage + 8, bigEndian_);
@@ -1471,6 +1676,11 @@
         break;
       case X_PolyText8:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_PolyText8 inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1555,6 +1765,11 @@
         break;
       case X_PolyText16:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_PolyText16 inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1639,6 +1854,11 @@
         break;
       case X_ImageText8:
         {
+          #ifdef WARNING
+          if (inputLength < 16 + (unsigned int)inputDataByte)
+            *logofs << "handleRead: X_ImageText8 inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1673,7 +1893,7 @@
             break;
           }
 
-          unsigned int textLength = (unsigned int) inputMessage[1];
+          unsigned int textLength = (unsigned int) inputDataByte;
           encodeBuffer.encodeCachedValue(textLength, 8,
                              clientCache_ -> imageTextLengthCache, 4);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
@@ -1706,6 +1926,11 @@
         break;
       case X_ImageText16:
         {
+          #ifdef WARNING
+          if (inputLength < 16 + (unsigned int)inputDataByte)
+            *logofs << "handleRead: X_ImageText16 inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -1740,7 +1965,7 @@
             break;
           }
 
-          unsigned int textLength = (unsigned int) inputMessage[1];
+          unsigned int textLength = (unsigned int) inputDataByte;
           encodeBuffer.encodeCachedValue(textLength, 8,
                              clientCache_ -> imageTextLengthCache, 4);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
@@ -1773,6 +1998,11 @@
         break;
       case X_InternAtom:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_InternAtom inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_InternAtom);
 
@@ -1796,8 +2026,18 @@
           }
 
           unsigned int nameLength = GetUINT(inputMessage + 4, bigEndian_);
+          unsigned int maxLength = inputLength - 8;
+          if (nameLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_InternAtom bogus nameLength=" << nameLength
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            nameLength = maxLength;
+          }
           encodeBuffer.encodeValue(nameLength, 16, 6);
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           const unsigned char *nextSrc = inputMessage + 8;
 
           if (control -> isProtoStep7() == 1)
@@ -1827,7 +2067,22 @@
         break;
       case X_ListFonts:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_ListFonts inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int textLength = GetUINT(inputMessage + 6, bigEndian_);
+          unsigned int maxLength = inputLength - 8;
+          if (textLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_ListFonts bogus textLength=" << textLength
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            textLength = maxLength;
+          }
           encodeBuffer.encodeValue(textLength, 16, 6);
           encodeBuffer.encodeValue(GetUINT(inputMessage + 4, bigEndian_), 16, 6);
           const unsigned char* nextSrc = inputMessage + 8;
@@ -1853,7 +2108,22 @@
       case X_LookupColor:
       case X_AllocNamedColor:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_AllocNamedColor inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int textLength = GetUINT(inputMessage + 8, bigEndian_);
+          unsigned int maxLength = inputLength - 12;
+          if (textLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_AllocNamedColor bogus textLength=" << textLength
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            textLength = maxLength;
+          }
           encodeBuffer.encodeValue(textLength, 16, 6);
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_),
                                          29, clientCache_ -> colormapCache);
@@ -1886,6 +2156,11 @@
       case X_QueryPointer:
       case X_QueryTree:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_MapWindow...X_QueryTree inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           if (inputOpcode == X_DestroyWindow)
@@ -1923,7 +2198,22 @@
         break;
       case X_OpenFont:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_OpenFont inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int nameLength = GetUINT(inputMessage + 8, bigEndian_);
+          unsigned int maxLength = inputLength - 12;
+          if (nameLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_InternAtom bogus nameLength=" << nameLength
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            nameLength = maxLength;
+          }
           encodeBuffer.encodeValue(nameLength, 16, 7);
           unsigned int font = GetULONG(inputMessage + 4, bigEndian_);
           encodeBuffer.encodeValue(font - clientCache_ -> lastFont, 29, 5);
@@ -1947,6 +2237,11 @@
         break;
       case X_PolyFillRectangle:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyFillRectangle inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2034,6 +2329,11 @@
         break;
       case X_PolyFillArc:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyFillArc inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2135,6 +2435,11 @@
         break;
       case X_PolyArc:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyArc inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2236,6 +2541,11 @@
         break;
       case X_PolyPoint:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyPoint inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2269,8 +2579,8 @@
             break;
           }
 
-          encodeBuffer.encodeValue(GetUINT(inputMessage + 2, bigEndian_) - 3, 16, 4);
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeValue(inputDataSize - 2, 32, 4);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> drawableCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8, bigEndian_),
@@ -2303,6 +2613,11 @@
         break;
       case X_PolyLine:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyLine inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2336,8 +2651,8 @@
             break;
           }
 
-          encodeBuffer.encodeValue(GetUINT(inputMessage + 2, bigEndian_) - 3, 16, 4);
-          encodeBuffer.encodeBoolValue((unsigned int) inputMessage[1]);
+          encodeBuffer.encodeValue(inputDataSize - 2, 32, 4);
+          encodeBuffer.encodeBoolValue((unsigned int) inputDataByte);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8,
@@ -2370,8 +2685,12 @@
         break;
       case X_PolyRectangle:
         {
-          encodeBuffer.encodeValue((GetUINT(inputMessage + 2,
-                                            bigEndian_) - 3) >> 1, 16, 3);
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolyRectangle inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeValue((inputDataSize - 2) >> 1, 32, 3);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8,
@@ -2391,6 +2710,11 @@
         break;
       case X_PolySegment:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_PolySegment inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2424,8 +2748,7 @@
             break;
           }
 
-          encodeBuffer.encodeValue((GetUINT(inputMessage + 2,
-                                            bigEndian_) - 3) >> 1, 16, 4);
+          encodeBuffer.encodeValue((inputDataSize - 2) >> 1, 32, 4);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 8,
@@ -2491,6 +2814,11 @@
         break;
       case X_PutImage:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_PutImage inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2522,7 +2850,12 @@
         break;
       case X_QueryBestSize:
         {
-          encodeBuffer.encodeValue((unsigned int)inputMessage[1], 2);
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_QueryBestSize inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
+          encodeBuffer.encodeValue((unsigned int)inputDataByte, 2);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
           encodeBuffer.encodeValue(GetUINT(inputMessage + 8, bigEndian_), 16, 8);
@@ -2535,10 +2868,15 @@
         break;
       case X_QueryColors:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_QueryColors inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           // Differential encoding.
           encodeBuffer.encodeBoolValue(1);
 
-          unsigned int numColors = ((inputLength - 8) >> 2);
+          unsigned int numColors = (inputDataSize - 1);
           encodeBuffer.encodeValue(numColors, 16, 5);
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                                          clientCache_ -> colormapCache);
@@ -2567,15 +2905,20 @@
         break;
       case X_QueryExtension:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_QueryExtension inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TEST
 
           char data[256];
 
           int length = GetUINT(inputMessage + 4, bigEndian_);
 
-          if (length > 256)
+          if (length > 255)
           {
-            length = 256;
+            length = 255;
           }
 
           strncpy(data, (char *) inputMessage + 8, length);
@@ -2588,6 +2931,16 @@
           #endif
 
           unsigned int nameLength = GetUINT(inputMessage + 4, bigEndian_);
+          unsigned int maxLength = inputLength - 8;
+          if (nameLength > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_QueryExtension bogus nameLength=" << nameLength
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            nameLength = maxLength;
+          }
           encodeBuffer.encodeValue(nameLength, 16, 6);
           const unsigned char *nextSrc = inputMessage + 8;
 
@@ -2614,6 +2967,11 @@
         break;
       case X_QueryFont:
         {
+          #ifdef WARNING
+          if (inputLength < 8)
+            *logofs << "handleRead: X_QueryFont inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int font = GetULONG(inputMessage + 4, bigEndian_);
           encodeBuffer.encodeValue(font - clientCache_ -> lastFont, 29, 5);
           clientCache_ -> lastFont = font;
@@ -2625,6 +2983,11 @@
         break;
       case X_SetClipRectangles:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_SetClipRectangles inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           MessageStore *messageStore = clientStore_ ->
                                getRequestStore(X_SetClipRectangles);
 
@@ -2636,7 +2999,7 @@
             break;
           }
 
-          unsigned int numRectangles = ((inputLength - 12) >> 3);
+          unsigned int numRectangles = ((inputDataSize - 2) >> 1);
 
           if (control -> isProtoStep9() == 1)
           {
@@ -2647,7 +3010,7 @@
             encodeBuffer.encodeValue(numRectangles, 13, 4);
           }
 
-          encodeBuffer.encodeValue((unsigned int) inputMessage[1], 2);
+          encodeBuffer.encodeValue((unsigned int) inputDataByte, 2);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
                              clientCache_ -> gcCache);
           encodeBuffer.encodeCachedValue(GetUINT(inputMessage + 8, bigEndian_), 16,
@@ -2668,7 +3031,22 @@
         break;
       case X_SetDashes:
         {
+          #ifdef WARNING
+          if (inputLength < 12)
+            *logofs << "handleRead: X_SetDashes inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           unsigned int numDashes = GetUINT(inputMessage + 10, bigEndian_);
+          unsigned int maxLength = inputLength - 12;
+          if (numDashes > maxLength)
+          {
+            #ifdef WARNING
+            *logofs << "handleRead X_SetDashes bogus numDashes=" << numDashes
+                    << " set to " << maxLength
+                    << ".\n" << logofs_flush;
+            #endif
+            numDashes = maxLength;
+          }
           encodeBuffer.encodeCachedValue(numDashes, 16,
                              clientCache_ -> setDashesLengthCache, 5);
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4, bigEndian_),
@@ -2683,6 +3061,11 @@
         break;
       case X_SetSelectionOwner:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_SetSelectionOwner inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 4, bigEndian_), 29,
                                     clientCache_ -> setSelectionOwnerCache, 9);
           encodeBuffer.encodeCachedValue(GetULONG(inputMessage + 8, bigEndian_), 29,
@@ -2693,6 +3076,11 @@
         break;
       case X_TranslateCoords:
         {
+          #ifdef WARNING
+          if (inputLength < 16)
+            *logofs << "handleRead: X_TranslateCoords inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2764,6 +3152,11 @@
         break;
       case X_GetImage:
         {
+          #ifdef WARNING
+          if (inputLength < 20)
+            *logofs << "handleRead: X_GetImage inputLength=" << inputLength
+                    << ".\n" << logofs_flush;
+          #endif
           #ifdef TARGETS
 
           unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -2802,7 +3195,7 @@
           }
 
           // Format.
-          encodeBuffer.encodeValue((unsigned int) inputMessage[1], 2);
+          encodeBuffer.encodeValue((unsigned int) inputDataByte, 2);
           // Drawable.
           encodeBuffer.encodeXidValue(GetULONG(inputMessage + 4,
                              bigEndian_), clientCache_ -> drawableCache);
@@ -2869,6 +3262,11 @@
           }
           else if (inputOpcode == opcodeStore_ -> putPackedImage)
           {
+            #ifdef WARNING
+            if (inputLength < 24)
+              *logofs << "handleRead: putPackedImage inputLength=" << inputLength
+                      << ".\n" << logofs_flush;
+            #endif
             #ifdef TARGETS
 
             unsigned int t_id = GetULONG(inputMessage + 4, bigEndian_);
@@ -3004,7 +3402,7 @@
                     << ".\n" << logofs_flush;
             #endif
 
-            encodeBuffer.encodeCachedValue(*(inputMessage + 1), 8,
+            encodeBuffer.encodeCachedValue(inputDataByte, 8,
                          clientCache_ -> resourceCache);
           }
           else if (inputOpcode == opcodeStore_ -> freeUnpack)
@@ -3015,7 +3413,7 @@
                     << ".\n" << logofs_flush;
             #endif
 
-            encodeBuffer.encodeCachedValue(*(inputMessage + 1), 8,
+            encodeBuffer.encodeCachedValue(inputDataByte, 8,
                          clientCache_ -> resourceCache);
           }
           else if (inputOpcode == opcodeStore_ -> getControlParameters)
@@ -3130,6 +3528,11 @@
             // Enable or disable expose events
             // coming from the real server.
             //
+            #ifdef WARNING
+            if (inputLength < 8)
+              *logofs << "handleRead: setExposeParameters inputLength=" << inputLength
+                      << ".\n" << logofs_flush;
+            #endif
 
             encodeBuffer.encodeBoolValue(*(inputMessage + 4));
             encodeBuffer.encodeBoolValue(*(inputMessage + 5));
@@ -3198,10 +3601,10 @@
       {
         if (hit)
         {
-          statistics -> addRenderCachedRequest(*(inputMessage + 1));
+          statistics -> addRenderCachedRequest(inputDataByte);
         }
 
-        statistics -> addRenderRequestBits(*(inputMessage + 1), inputLength << 3, bits);
+        statistics -> addRenderRequestBits(inputDataByte, inputLength << 3, bits);
       }
 
     }  // End if (firstRequest_)... else ...
@@ -4548,10 +4951,10 @@
         //
 
 /*
-FIXME: Recover the sequence number if the proxy
+Fixed as below? - FIXME: Recover the sequence number if the proxy
        is not connected to an agent.
 */
-        if (serverSequence_ > lastSequence_ ||
+        if (SequenceNumber_x_gt_y(serverSequence_, lastSequence_) ||
                 control -> SessionMode != session_proxy)
         {
           #ifdef DEBUG
@@ -4564,7 +4967,7 @@
           lastSequence_ = serverSequence_;
         }
         #ifdef DEBUG
-        else if (serverSequence_ < lastSequence_)
+        else if (SequenceNumber_x_gt_y(lastSequence_, serverSequence_))
         {
           //
           // Use our last auto-generated sequence.
@@ -5003,6 +5406,12 @@
           break;
         default:
           {
+            // BEWARE: not only inputOpcode == GenericEvent but also
+            // others not handled above, at least:
+            //   GraphicsExpose    13
+            //   MapRequest        20
+            //   ConfigureRequest  23
+            // and any beyond LASTEvent.
             #ifdef TEST
             *logofs << "handleWrite: Using generic event compression "
                     << "for OPCODE#" << (unsigned int) outputOpcode
@@ -5014,11 +5423,51 @@
 
             for (unsigned int i = 0; i < 14; i++)
             {
-              decodeBuffer.decodeCachedValue(value, 16,
-                           *serverCache_ -> genericEventIntCache[i]);
+              //decodeBuffer.decodeCachedValue(value, 16,
+              //             *serverCache_ -> genericEventIntCache[i]);
+              if ( ! (decodeBuffer.decodeCachedValue(value, 16,
+                           *serverCache_ -> genericEventIntCache[i])) )
+              {
+                #ifdef WARNING
+                *logofs << "decodeCachedValue failed for GenEvt:"
+                        << " buffer length=" << length
+                        << " i=" << i
+                        << "\n" << logofs_flush;
+                #endif
+                break;
+              }
 
               PutUINT(value, outputMessage + i * 2 + 4, bigEndian_);
             }
+            // Handle "X Generic Event Extension"
+            // Extra data is not cached...
+            if (outputOpcode == GenericEvent && *(outputMessage+1) != 0 && outputLength == 32)
+            {
+              unsigned int extraOutputLength = (GetULONG(outputMessage + 4, bigEndian_) << 2);
+              if (extraOutputLength > 0 && extraOutputLength < 100*1024*1024)
+              {
+                // Extend buffer for the extra data
+                outputMessage = writeBuffer_.addMessage(extraOutputLength);
+                // Decode data and write into buffer at new position
+                for (unsigned int i = 0; i < (extraOutputLength>>1); i++)
+                {
+                  //decodeBuffer.decodeValue(value, 16);
+                  if ( ! (decodeBuffer.decodeValue(value, 16)) )
+                  {
+                    #ifdef WARNING
+                    *logofs << "decodeValue failed for GenEvt:"
+                            << " extraOutputLength=" << extraOutputLength
+                            << " buffer length=" << length
+                            << " i=" << i
+                            << "\n" << logofs_flush;
+                    #endif
+                    break;
+                  }
+                  PutUINT(value, outputMessage + i * 2, bigEndian_);
+                }
+              }
+            }
+
           }
         } // End of switch (outputOpcode)...
 
@@ -6892,7 +7341,7 @@
   }
   else
   {
-    if (serverSequence_ > lastSequence_)
+    if (SequenceNumber_x_gt_y(serverSequence_, lastSequence_))
     {
       #ifdef DEBUG
       *logofs << "handleNotify: Updating last event's sequence "
@@ -6904,7 +7353,7 @@
       lastSequence_ = serverSequence_;
     }
     #ifdef DEBUG
-    else if (serverSequence_ < lastSequence_)
+    else if (SequenceNumber_x_gt_y(lastSequence_, serverSequence_))
     {
       //
       // Use our last auto-generated sequence.
--- a/nxcomp/ClientReadBuffer.cpp
+++ b/nxcomp/ClientReadBuffer.cpp
@@ -119,15 +119,34 @@
 
     dataLength = (GetUINT(start + 2, bigEndian_) << 2);
 
-    if (dataLength < 4)
+    if (dataLength == 0)        // or equivalently (dataLength < 4)
     {
-      #ifdef TEST
-      *logofs << "ClientReadBuffer: WARNING! Assuming length 4 "
-              << "for suspicious message of length " << dataLength
-              << ".\n" << logofs_flush;
-      #endif
+      // BIG-REQUESTS extension
+      if (size < 8)
+      {
+        remaining_ = 8 - size;
+        return 0;
+      }
 
-      dataLength = 4;
+      dataLength = (GetULONG(start + 4, bigEndian_) << 2);
+
+// See WRITE_BUFFER_OVERFLOW_SIZE elsewhere
+// and also ENCODE_BUFFER_OVERFLOW_SIZE DECODE_BUFFER_OVERFLOW_SIZE.
+      if (dataLength < 8 || dataLength > 100*1024*1024)
+      {
+        #ifdef WARNING
+        *logofs << "BIG-REQUESTS with unacceptable dataLength="
+                << dataLength << ", now set to 8.\n" << logofs_flush;
+        #endif
+        dataLength = 8;
+      }
+      else if (dataLength < 4*64*1024)
+      {
+        #ifdef WARNING
+        *logofs << "BIG-REQUESTS with silly dataLength="
+                << dataLength << ".\n" << logofs_flush;
+        #endif
+      }
     }
   }
 
--- a/nxcomp/DecodeBuffer.cpp
+++ b/nxcomp/DecodeBuffer.cpp
@@ -78,34 +78,45 @@
       {
         if (!endOkay)
         {
-          #ifdef PANIC
-          *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [A] "
-                  << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-                  << " end_ = " << (end_ - buffer_) << ".\n"
-                  << logofs_flush;
+          #ifdef WARNING
+          *logofs << "DecodeBuffer: Error [A] in decodeValue(), returning 0:"
+                  << " nextSrc_ = " << (nextSrc_ - buffer_)
+                  << " end_ = " << (end_ - buffer_)
+                  << ".\n" << logofs_flush;
           #endif
-
-          //
-          // Label "context" is just used to identify
-          // the routine which detected the problem in
-          // present source file.
-          //
-
-          cerr << "Error" << ": Failure decoding data in context [A].\n";
-
-          HandleAbort();
+          value = 0;
+          return 0;
+          //#ifdef PANIC
+          //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [A] "
+          //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+          //        << " end_ = " << (end_ - buffer_) << ".\n"
+          //        << logofs_flush;
+          //#endif
+          ////
+          //// Label "context" is just used to identify
+          //// the routine which detected the problem in
+          //// present source file.
+          ////
+          //cerr << "Error" << ": Failure decoding data in context [A].\n";
+          //HandleAbort();
         }
 
-        #ifdef PANIC
-        *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [B] "
-                << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-                << " end_ = " << (end_ - buffer_) << ".\n"
-                << logofs_flush;
+        #ifdef WARNING
+        *logofs << "DecodeBuffer: Error [B] in decodeValue(), returning 0:"
+                << " nextSrc_ = " << (nextSrc_ - buffer_)
+                << " end_ = " << (end_ - buffer_)
+                << ".\n" << logofs_flush;
         #endif
-
-        cerr << "Error" << ": Failure decoding data in context [B].\n";
-
-        HandleAbort();
+        value = 0;
+        return 0;
+        //#ifdef PANIC
+        //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [B] "
+        //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+        //        << " end_ = " << (end_ - buffer_) << ".\n"
+        //        << logofs_flush;
+        //#endif
+        //cerr << "Error" << ": Failure decoding data in context [B].\n";
+        //HandleAbort();
       }
 
       lastBit = (nextSrcChar & srcMask_);
@@ -134,28 +145,40 @@
       {
         if (!endOkay)
         {
-          #ifdef PANIC
-          *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [C] "
-                  << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-                  << " end_ = " << (end_ - buffer_) << ".\n"
-                  << logofs_flush;
+          #ifdef WARNING
+          *logofs << "DecodeBuffer: Error [C] in decodeValue(), returning 0:"
+                  << " nextSrc_ = " << (nextSrc_ - buffer_)
+                  << " end_ = " << (end_ - buffer_)
+                  << ".\n" << logofs_flush;
           #endif
-
-          cerr << "Error" << ": Failure decoding data in context [C].\n";
-
-          HandleAbort();
+          value = 0;
+          return 0;
+          //#ifdef PANIC
+          //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [C] "
+          //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+          //        << " end_ = " << (end_ - buffer_) << ".\n"
+          //        << logofs_flush;
+          //#endif
+          //cerr << "Error" << ": Failure decoding data in context [C].\n";
+          //HandleAbort();
         }
 
-        #ifdef PANIC
-        *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [D] "
-                << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-                << " end_ = " << (end_ - buffer_) << ".\n"
-                << logofs_flush;
+        #ifdef WARNING
+        *logofs << "DecodeBuffer: Error [D] in decodeValue(), returning 0:"
+                << " nextSrc_ = " << (nextSrc_ - buffer_)
+                << " end_ = " << (end_ - buffer_)
+                << ".\n" << logofs_flush;
         #endif
-
-        cerr << "Error" << ": Failure decoding data in context [D].\n";
-
-        HandleAbort();
+        value = 0;
+        return 0;
+        //#ifdef PANIC
+        //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [D] "
+        //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+        //        << " end_ = " << (end_ - buffer_) << ".\n"
+        //        << logofs_flush;
+        //#endif
+        //cerr << "Error" << ": Failure decoding data in context [D].\n";
+        //HandleAbort();
       }
 
       unsigned char moreData = (nextSrcChar & srcMask_);
@@ -212,16 +235,24 @@
 
   if (nextSrc_ >= end_)
   {
-    #ifdef PANIC
-    *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [E] "
-            << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-            << " end_ = " << (end_ - buffer_) << ".\n"
-            << logofs_flush;
+    #ifdef WARNING
+    *logofs << "DecodeBuffer: Error [E] in decodeCachedValue(), returning 0:"
+            << " nextSrc_ = " << (nextSrc_ - buffer_)
+            << " end_ = " << (end_ - buffer_)
+            << ".\n" << logofs_flush;
     #endif
-
-    cerr << "Error" << ": Failure decoding data in context [E].\n";
-
-    HandleAbort();
+    // Failed: return value 0
+    value = 0;
+    // Failed: return 0, though our callers do not check that...
+    return 0;
+    //#ifdef PANIC
+    //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [E] "
+    //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+    //        << " end_ = " << (end_ - buffer_) << ".\n"
+    //        << logofs_flush;
+    //#endif
+    //cerr << "Error" << ": Failure decoding data in context [E].\n";
+    //HandleAbort();
   }
 
   unsigned int index = 0;
@@ -237,30 +268,33 @@
       nextSrc_++;
       if (nextSrc_ >= end_)
       {
-        if (!endOkay)
-        {
-          #ifdef PANIC
-          *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [F] "
-                  << "in decodeCachedValue() nextSrc_ = "
-                  << (nextSrc_ - buffer_) << " end_ = "
-                  << (end_ - buffer_) << ".\n" << logofs_flush;
-          #endif
-
-          cerr << "Error" << ": Failure decoding data in context [F].\n";
-
-          HandleAbort();
-        }
-
-        #ifdef PANIC
-        *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [G] "
-                << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
-                << " end_ = " << (end_ - buffer_) << ".\n"
-                << logofs_flush;
+        #ifdef WARNING
+        *logofs << "DecodeBuffer: Error [G] in decodeCachedValue(), returning 0:"
+                << " nextSrc_ = " << (nextSrc_ - buffer_)
+                << " end_ = " << (end_ - buffer_)
+                << ".\n" << logofs_flush;
         #endif
-
-        cerr << "Error" << ": Failure decoding data in context [G].\n";
-
-        HandleAbort();
+        value = 0;
+        return 0;
+        //if (!endOkay)
+        //{
+        //  #ifdef PANIC
+        //  *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [F] "
+        //          << "in decodeCachedValue() nextSrc_ = "
+        //          << (nextSrc_ - buffer_) << " end_ = "
+        //          << (end_ - buffer_) << ".\n" << logofs_flush;
+        //  #endif
+        //  cerr << "Error" << ": Failure decoding data in context [F].\n";
+        //  HandleAbort();
+        //}
+        //#ifdef PANIC
+        //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [G] "
+        //        << "in decodeValue() nextSrc_ = " << (nextSrc_ - buffer_)
+        //        << " end_ = " << (end_ - buffer_) << ".\n"
+        //        << logofs_flush;
+        //#endif
+        //cerr << "Error" << ": Failure decoding data in context [G].\n";
+        //HandleAbort();
       }
 
       nextSrcChar = *nextSrc_;
@@ -288,15 +322,20 @@
         return 1;
       }
 
-      #ifdef PANIC
-      *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [H] "
-              << "in decodeCacheValue() with no value found.\n"
-              << logofs_flush;
+      #ifdef WARNING
+      *logofs << "DecodeBuffer: Error [H] in decodeCachedValue(), returning 0:"
+              << " no value found"
+              << ".\n" << logofs_flush;
       #endif
-
-      cerr << "Error" << ": Failure decoding data in context [H].\n";
-
-      HandleAbort();
+      value = 0;
+      return 0;
+      //#ifdef PANIC
+      //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [H] "
+      //        << "in decodeCacheValue() with no value found.\n"
+      //        << logofs_flush;
+      //#endif
+      //cerr << "Error" << ": Failure decoding data in context [H].\n";
+      //HandleAbort();
     }
     else
     {
@@ -323,15 +362,20 @@
           return 1;
         }
 
-        #ifdef PANIC
-        *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [H] "
-                << "in decodeCacheValue() with no value found.\n"
-                << logofs_flush;
+        #ifdef WARNING
+        *logofs << "DecodeBuffer: Error [F] in decodeCachedValue(), returning 0:"
+                << " no value found"
+                << " .\n" << logofs_flush;
         #endif
-
-        cerr << "Error" << ": Failure decoding data in context [H].\n";
-
-        HandleAbort();
+        value = 0;
+        return 0;
+        //#ifdef PANIC
+        //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [H] "
+        //        << "in decodeCacheValue() with no value found.\n"
+        //        << logofs_flush;
+        //#endif
+        //cerr << "Error" << ": Failure decoding data in context [H].\n";
+        //HandleAbort();
       }
     }
   }
@@ -344,16 +388,22 @@
 
     if (index > cache.getSize())
     {
-      #ifdef PANIC
-      *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [I] "
-              << "in decodeCachedValue() index = " << index
-              << " cache size = " << cache.getSize() << ".\n"
-              << logofs_flush;
+      #ifdef WARNING
+      *logofs << "DecodeBuffer: Error [I] in decodeCachedValue(), returning 0:"
+              << " index = " << index
+              << " cache size = " << cache.getSize()
+              << ".\n" << logofs_flush;
       #endif
-
-      cerr << "Error" << ": Failure decoding data in context [I].\n";
-
-      HandleAbort();
+      value = 0;
+      return 0;
+      //#ifdef PANIC
+      //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [I] "
+      //        << "in decodeCachedValue() index = " << index
+      //        << " cache size = " << cache.getSize() << ".\n"
+      //        << logofs_flush;
+      //#endif
+      //cerr << "Error" << ": Failure decoding data in context [I].\n";
+      //HandleAbort();
     }
 
     value = cache.get(index);
@@ -401,16 +451,22 @@
       {
         if (!endOkay)
         {
-          #ifdef PANIC
-          *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [K] "
-                  << "in decodeCachedValue() nextSrc_ "
-                  << (nextSrc_ - buffer_) << " end_ " << (end_ - buffer_)
+          #ifdef WARNING
+          *logofs << "DecodeBuffer: Error [K] in decodeCachedValue(), returning 0:"
+                  << " nextSrc_ " << (nextSrc_ - buffer_)
+                  << " end_ " << (end_ - buffer_)
                   << ".\n" << logofs_flush;
           #endif
-
-          cerr << "Error" << ": Failure decoding data in context [K].\n";
-
-          HandleAbort();
+          value = 0;
+          return 0;
+          //#ifdef PANIC
+          //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [K] "
+          //        << "in decodeCachedValue() nextSrc_ "
+          //        << (nextSrc_ - buffer_) << " end_ " << (end_ - buffer_)
+          //        << ".\n" << logofs_flush;
+          //#endif
+          //cerr << "Error" << ": Failure decoding data in context [K].\n";
+          //HandleAbort();
         }
 
         #ifdef TEST
@@ -446,15 +502,20 @@
     }
     else
     {
-      #ifdef PANIC
-      *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [M] "
-              << "in decodeValue() with index = 2.\n"
-              << logofs_flush;
+      #ifdef WARNING
+      *logofs << "DecodeBuffer: Error [M] in decodeCachedValue(), returning 0:"
+              << "with index = 2"
+              << ".\n" << logofs_flush;
       #endif
-
-      cerr << "Error" << ": Failure decoding data in context [M].\n";
-
-      HandleAbort();
+      value = 0;
+      return 0;
+      //#ifdef PANIC
+      //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [M] "
+      //        << "in decodeValue() with index = 2.\n"
+      //        << logofs_flush;
+      //#endif
+      //cerr << "Error" << ": Failure decoding data in context [M].\n";
+      //HandleAbort();
     }
   }
   else
@@ -466,16 +527,22 @@
 
     if (index > cache.getSize())
     {
-      #ifdef PANIC
-      *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [N] "
-              << "in decodeCachedValue() " << "index = " << index
-              << " cache size = " << cache.getSize() << ".\n"
-              << logofs_flush;
+      #ifdef WARNING
+      *logofs << "DecodeBuffer: Error [N] in decodeCachedValue(), returning 0:"
+              << " index = " << index
+              << " cache size = " << cache.getSize()
+              << ".\n" << logofs_flush;
       #endif
-
-      cerr << "Error" << ": Failure decoding data in context [N].\n";
-
-      HandleAbort();
+      value = 0;
+      return 0;
+      //#ifdef PANIC
+      //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [N] "
+      //        << "in decodeCachedValue() " << "index = " << index
+      //        << " cache size = " << cache.getSize() << ".\n"
+      //        << logofs_flush;
+      //#endif
+      //cerr << "Error" << ": Failure decoding data in context [N].\n";
+      //HandleAbort();
     }
 
     value = cache.get(index);
@@ -538,16 +605,22 @@
   }
   else if (end_ - nextSrc_ < (int) numBytes)
   {
-    #ifdef PANIC
-    *logofs << "DecodeBuffer: PANIC! Assertion failed. Error [P] "
-            << "in decodeMemory() " << "with length " << numBytes
+    #ifdef WARNING
+    *logofs << "DecodeBuffer: Error [P] in decodeMemory(), returning NULL:"
+            << " with length " << numBytes
             << " and " << (end_ - nextSrc_)
-            << " bytes remaining.\n" << logofs_flush;
+            << " bytes remaining"
+            << ".\n" << logofs_flush;
     #endif
-
-    cerr << "Error" << ": Failure decoding data in context [P].\n";
-
-    HandleAbort();
+    return NULL;
+    //#ifdef PANIC
+    //*logofs << "DecodeBuffer: PANIC! Assertion failed. Error [P] "
+    //        << "in decodeMemory() " << "with length " << numBytes
+    //        << " and " << (end_ - nextSrc_)
+    //        << " bytes remaining.\n" << logofs_flush;
+    //#endif
+    //cerr << "Error" << ": Failure decoding data in context [P].\n";
+    //HandleAbort();
   }
 
   nextSrc_ += numBytes;
--- a/nxcomp/DecodeBuffer.h
+++ b/nxcomp/DecodeBuffer.h
@@ -30,7 +30,8 @@
 #include "ActionCacheCompat.h"
 #include "PositionCacheCompat.h"
 
-#define DECODE_BUFFER_OVERFLOW_SIZE        4194304
+// See WriteBuffer.h and EncodeBuffer.h
+#define DECODE_BUFFER_OVERFLOW_SIZE        104857600
 
 #define DECODE_BUFFER_POSTFIX_SIZE         1
 
--- a/nxcomp/EncodeBuffer.h
+++ b/nxcomp/EncodeBuffer.h
@@ -33,10 +33,10 @@
 //
 // This should match the maximum size of
 // a single message added to write buffer
-// (see WriteBuffer.h).
+// (see WriteBuffer.h and DecodeBuffer.h).
 //
 
-#define ENCODE_BUFFER_OVERFLOW_SIZE       4194304
+#define ENCODE_BUFFER_OVERFLOW_SIZE       104857600
 
 //
 // Adjust for the control messages and the
--- a/nxcomp/SequenceQueue.h
+++ b/nxcomp/SequenceQueue.h
@@ -18,6 +18,22 @@
 #ifndef SequenceQueue_H
 #define SequenceQueue_H
 
+inline int SequenceNumber_x_gt_y(unsigned int x, unsigned int y)
+{
+  // For two sequence numbers x and y, determine whether (x > y).
+  // Sequence numbers are the trailing 16 bits of a bigger number:
+  // need to handle wraparound, e.g. 0 is 65536, just after 65535.
+  if (x != (x & 0x00ffff)) return 0;
+  if (y != (y & 0x00ffff)) return 0;
+  // Closeness when comparison makes sense: arbitrarily set at 16*1024
+  if ((x > y) && ((x-y) < 16*1024)) return 1;
+  // Wrapped value
+  unsigned int w = x + 64*1024;
+  // We know that w>y but test left for symmetry
+  if ((w > y) && ((w-y) < 16*1024)) return 1;
+  return 0;
+}
+
 //
 // List of outstanding request messages which
 // are waiting for a reply. This class is used
--- a/nxcomp/ServerChannel.cpp
+++ b/nxcomp/ServerChannel.cpp
@@ -104,7 +104,8 @@
 //
 
 #define HIDE_MIT_SHM_EXTENSION
-#define HIDE_BIG_REQUESTS_EXTENSION
+// HIDE_BIG_REQUESTS_EXTENSION : No good to hide, some clients may send crap instead...
+#undef  HIDE_BIG_REQUESTS_EXTENSION
 #define HIDE_XFree86_Bigfont_EXTENSION
 #undef  HIDE_SHAPE_EXTENSION
 #undef  HIDE_XKEYBOARD_EXTENSION
@@ -1412,6 +1413,9 @@
 
         unsigned int inputSequence = GetUINT(inputMessage + 2, bigEndian_);
 
+        // Sometimes we get inputSequence=0 or =256 when inputOpcode=11=X_UnmapSubwindows
+        // Seems weird... but is "normal" and is to be accepted.
+
         //
         // Check if this is an event which we can discard.
         //
@@ -1905,6 +1909,12 @@
           break;
         default:
           {
+            // BEWARE: not only inputOpcode == GenericEvent but also
+            // others not handled above, at least:
+            //   GraphicsExpose    13
+            //   MapRequest        20
+            //   ConfigureRequest  23
+            // and any beyond LASTEvent.
             #ifdef TEST
             *logofs << "handleRead: Using generic event compression "
                     << "for OPCODE#" << (unsigned int) inputOpcode
@@ -1919,6 +1929,16 @@
               encodeBuffer.encodeCachedValue(GetUINT(inputMessage + i * 2 + 4, bigEndian_),
                                  16, *serverCache_ -> genericEventIntCache[i]);
             }
+            // Handle "X Generic Event Extension"
+            // Cannot cache extra data...
+// FIXME: BUG ALERT: is it OK to have the first 32 bytes cached, but not the rest?
+            if (inputOpcode == GenericEvent && inputLength > 32)
+            {
+              for (unsigned int i = 14; i < ((inputLength-4)>>1); i++)
+              {
+                encodeBuffer.encodeValue(GetUINT(inputMessage + i * 2 + 4, bigEndian_), 16);
+              }
+            }
           }
 
         } // switch (inputOpcode)...
@@ -3756,7 +3776,7 @@
           }
 
           unsigned int numPoints;
-          decodeBuffer.decodeValue(numPoints, 16, 4);
+          decodeBuffer.decodeValue(numPoints, 32, 4);
           outputLength = (numPoints << 2) + 12;
           outputMessage = writeBuffer_.addMessage(outputLength);
           unsigned int relativeCoordMode;
@@ -3802,7 +3822,7 @@
           }
 
           unsigned int numPoints;
-          decodeBuffer.decodeValue(numPoints, 16, 4);
+          decodeBuffer.decodeValue(numPoints, 32, 4);
           outputLength = (numPoints << 2) + 12;
           outputMessage = writeBuffer_.addMessage(outputLength);
           unsigned int relativeCoordMode;
@@ -3839,7 +3859,7 @@
       case X_PolyRectangle:
         {
           unsigned int numRectangles;
-          decodeBuffer.decodeValue(numRectangles, 16, 3);
+          decodeBuffer.decodeValue(numRectangles, 32, 3);
           outputLength = (numRectangles << 3) + 12;
           outputMessage = writeBuffer_.addMessage(outputLength);
           decodeBuffer.decodeXidValue(value, clientCache_ -> drawableCache);
@@ -3869,7 +3889,7 @@
           }
 
           unsigned int numSegments;
-          decodeBuffer.decodeValue(numSegments, 16, 4);
+          decodeBuffer.decodeValue(numSegments, 32, 4);
           outputLength = (numSegments << 3) + 12;
           outputMessage = writeBuffer_.addMessage(outputLength);
           decodeBuffer.decodeXidValue(value, clientCache_ -> drawableCache);
@@ -4590,7 +4610,29 @@
 
         *outputMessage = (unsigned char) outputOpcode;
 
-        PutUINT(outputLength >> 2, outputMessage + 2, bigEndian_);
+        if (outputLength < 4*64*1024)
+          PutUINT(outputLength >> 2, outputMessage + 2, bigEndian_);
+        else
+        {
+          // Handle BIG-REQUESTS
+          PutUINT(0, outputMessage + 2, bigEndian_);
+// FIXME: BUG ALERT: following write may not work well,
+// particularly with un-flushed messages.
+if (outputMessage != writeBuffer_.getData())
+{
+*logofs << "PSz BUG handleWrite BIG-REQUESTS:"
+        << " have " << (unsigned int)(outputMessage - writeBuffer_.getData())
+        << " bytes in buffer"
+        << ", write immediate of 4-byte header will not work well"
+        << "\n" << logofs_flush;
+}
+// But, it works well enough in my testing...
+          // Write first four bytes
+          if (transport_ -> write(write_immediate, outputMessage, 4) < 0)
+              return -1;
+          // Replace with new 4-byte length
+          PutULONG(1 + (outputLength >> 2), outputMessage, bigEndian_);
+        }
 
         #if defined(TEST) || defined(OPCODES)
         *logofs << "handleWrite: Handled request OPCODE#"
@@ -5912,7 +5954,7 @@
   unsigned char opcode = *lastMotion_;
   unsigned int size = 32;
 
-  if (GetUINT(buffer + 2, bigEndian_) < serverSequence_)
+  if (SequenceNumber_x_gt_y(serverSequence_, GetUINT(buffer + 2, bigEndian_)))
   {
     PutUINT(serverSequence_, (unsigned char *) buffer + 2, bigEndian_);
   }
--- a/nxcomp/ServerReadBuffer.cpp
+++ b/nxcomp/ServerReadBuffer.cpp
@@ -108,14 +108,21 @@
     {
       dataLength = 32 + (GetULONG(start + 4, bigEndian_) << 2);
     }
+    else if (*start == GenericEvent && *(start+1) != 0)
+    {
+      // X Generic Event Extension
+      dataLength = 32 + (GetULONG(start + 4, bigEndian_) << 2);
+    }
     else
     {
       dataLength = 32;
     }
 
-    if (dataLength < 32)
+// See WRITE_BUFFER_OVERFLOW_SIZE elsewhere
+// and also ENCODE_BUFFER_OVERFLOW_SIZE DECODE_BUFFER_OVERFLOW_SIZE.
+    if (dataLength < 32 || dataLength > 100*1024*1024)
     {
-      #ifdef TEST
+      #ifdef WARNING
       *logofs << "ServerReadBuffer: WARNING! Assuming length 32 "
               << "for suspicious message of length " << dataLength
               << ".\n" << logofs_flush;
--- a/nxcomp/WriteBuffer.h
+++ b/nxcomp/WriteBuffer.h
@@ -32,8 +32,14 @@
 // This is likely to be a reply to a X_ListFonts where
 // user has a large amount of installed fonts.
 //
+// Used also for messages sent, and should accommodate any BIG-REQUESTS.
+// Value was 4MB = 4194304, changed to 100MB = 104857600.
+// See also sanity check limits (set same, to 100*1024*1024) in
+// ClientReadBuffer.cpp ServerReadBuffer.cpp and ClientChannel.cpp, and
+// ENCODE_BUFFER_OVERFLOW_SIZE DECODE_BUFFER_OVERFLOW_SIZE elsewhere.
+//
 
-#define WRITE_BUFFER_OVERFLOW_SIZE        4194304
+#define WRITE_BUFFER_OVERFLOW_SIZE        104857600
 
 class WriteBuffer
 {