[tdbf-cvs] SF.net SVN: tdbf:[868] trunk/src/dbf_prsdef.pas

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

Revision: 868
          http://sourceforge.net/p/tdbf/code/868
Author:   twm
Date:     2026-03-07 18:49:31 +0000 (Sat, 07 Mar 2026)
Log Message:
-----------
Guard TDynamicType.Append against negative or zero length

Add early-exit check: negative length exits without touching memory,
zero length null-terminates at the current position. Prevents undefined
behavior in Move when a negative length is passed by any caller.

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

Modified: trunk/src/dbf_prsdef.pas
===================================================================
--- trunk/src/dbf_prsdef.pas	2026-03-07 18:25:39 UTC (rev 867)
+++ trunk/src/dbf_prsdef.pas	2026-03-07 18:49:31 UTC (rev 868)
@@ -1215,6 +1215,12 @@
 
 procedure TDynamicType.Append(Source: Pointer; Length: Integer); // Was PChar
 begin
+  if Length <= 0 then
+  begin
+    if Length = 0 then
+      FMemoryPos^^ := #0;
+    exit;
+  end;
   // make room for string plus null-terminator
   AssureSpace(Length+4);
   // copy

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