sar_ceos unsigned int wrap error

[Kurt Schwehr]

max_bytes in source:trunk/gdal/frmts/ceos2/sar_ceosdataset.cpp​ is an unsigned integer. Underflow will wrap to a large number, but the code tests for max_bytes < 0, which is never true. I'll apply this to trunk in a couple days if I get no objections.

Index: frmts/ceos2/sar_ceosdataset.cpp
===================================================================
--- frmts/ceos2/sar_ceosdataset.cpp	(revision 27011)
+++ frmts/ceos2/sar_ceosdataset.cpp	(working copy)
@@ -2160,8 +2160,9 @@
             max_records--;
         if(max_bytes > 0)
         {
-            max_bytes -= record->Length;
-            if(max_bytes < 0)
+            if(record->Length < max_bytes)
+                max_bytes -= record->Length;
+            else
                 max_bytes = 0;
         }
     }
@@ -2196,4 +2197,3 @@
         GetGDALDriverManager()->RegisterDriver( poDriver );
     }
 }

[antonio]

+1 for me

[Even Rouault]

I'm just wondering in the case where "if(record->Length < max_bytes)" is false, will max_bytes = 0 work or is it an error situation ? In which case a CPLError or CPLDebug message might be appropriate also.

[Kurt Schwehr]

Was wondering the same thing. I do think that if record->Length > max_bytes, that it is an error and I will at least add a CPLDebug message.

[Kurt Schwehr]

Added to trunk: r27017