X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/8ecff18117f8cabc0f515ad81aa4ad265e5e17d3..ae4ea4e862622e150a9968d7f096b1270ee3d578:/src/common/imagpcx.cpp

diff --git a/src/common/imagpcx.cpp b/src/common/imagpcx.cpp
index 0581f926fc..09a4612cbf 100644
--- a/src/common/imagpcx.cpp
+++ b/src/common/imagpcx.cpp
@@ -23,13 +23,12 @@
     #include "wx/log.h"
     #include "wx/intl.h"
     #include "wx/palette.h"
+    #include "wx/hash.h"
+    #include "wx/module.h"
 #endif
 
 #include "wx/imagpcx.h"
 #include "wx/wfstream.h"
-#include "wx/module.h"
-
-#include "wx/hash.h"
 
 //-----------------------------------------------------------------------------
 // wxPCXHandler
@@ -88,17 +87,15 @@ void RLEencode(unsigned char *p, unsigned int size, wxOutputStream& s)
 
 void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
 {
-    unsigned int i, data, cont;
-
     // Read 'size' bytes. The PCX official specs say there will be
     // a decoding break at the end of each scanline (but not at the
     // end of each plane inside a scanline). Only use this function
     // to read one or more _complete_ scanlines. Else, more than
     // 'size' bytes might be read and the buffer might overflow.
 
-    while (size > 0)
+    while (size != 0)
     {
-        data = (unsigned char)s.GetC();
+        unsigned int data = (unsigned char)s.GetC();
 
         // If ((data & 0xC0) != 0xC0), then the value read is a data
         // byte. Else, it is a counter (cont = val & 0x3F) and the
@@ -111,9 +108,11 @@ void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
         }
         else
         {
-            cont = data & 0x3F;
+            unsigned int cont = data & 0x3F;
+            if (cont > size) // can happen only if the file is malformed
+                break;
             data = (unsigned char)s.GetC();
-            for (i = 1; i <= cont; i++)
+            for (unsigned int i = 1; i <= cont; i++)
                 *(p++) = (unsigned char)data;
             size -= cont;
         }
@@ -440,7 +439,9 @@ bool wxPCXHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose
     if (!CanRead(stream))
     {
         if (verbose)
+        {
             wxLogError(_("PCX: this is not a PCX file."));
+        }
 
         return false;
     }
@@ -488,7 +489,7 @@ bool wxPCXHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
 
 bool wxPCXHandler::DoCanRead( wxInputStream& stream )
 {
-    unsigned char c = stream.GetC();
+    unsigned char c = stream.GetC();     // it's ok to modify the stream position here
     if ( !stream )
         return false;