[tdbf-cvs] SF.net SVN: tdbf:[864] trunk/src/dbf_idxfile.pas

[<tw...@us...>]

Revision: 864
          http://sourceforge.net/p/tdbf/code/864
Author:   twm
Date:     2026-03-07 16:59:41 +0000 (Sat, 07 Mar 2026)
Log Message:
-----------
Fix nil pointer dereference in GetKeyDataFromEntry

TMdxPage.GetKeyDataFromEntry and TNdxPage.GetKeyDataFromEntry both
dereference the result of GetEntry() without checking for nil. GetEntry
returns nil when the entry number is out of range (e.g. corrupt index).
Add nil check to return nil instead of causing an Access Violation.

Modified Paths:
--------------
    trunk/src/dbf_idxfile.pas

Modified: trunk/src/dbf_idxfile.pas
===================================================================
--- trunk/src/dbf_idxfile.pas	2025-09-12 15:57:13 UTC (rev 863)
+++ trunk/src/dbf_idxfile.pas	2026-03-07 16:59:41 UTC (rev 864)
@@ -1720,8 +1720,14 @@
 end;
 
 function TMdxPage.GetKeyDataFromEntry(AEntry: Integer): PAnsiChar;
+var
+  EntryPtr: Pointer;
 begin
-  Result := @PMdxEntry(GetEntry(AEntry))^.KeyData;
+  EntryPtr := GetEntry(AEntry);
+  if EntryPtr <> nil then
+    Result := @PMdxEntry(EntryPtr)^.KeyData
+  else
+    Result := nil;
 end;
 
 function TMdxPage.GetRecNo: Integer;
@@ -1797,8 +1803,14 @@
 end;
 
 function TNdxPage.GetKeyDataFromEntry(AEntry: Integer): PAnsiChar;
+var
+  EntryPtr: Pointer;
 begin
-  Result := @PNdxEntry(GetEntry(AEntry))^.KeyData;
+  EntryPtr := GetEntry(AEntry);
+  if EntryPtr <> nil then
+    Result := @PNdxEntry(EntryPtr)^.KeyData
+  else
+    Result := nil;
 end;
 
 function TNdxPage.GetNumEntries: Integer;

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