Aleksey Bragin : ntdll: Fix buffer overread in RtlNumberOfSetBits.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 4f74de5b366275ea522e269d29d2011a7b153e9e
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=4f74de5b366275ea522e269d29d2011a7b153e9e

Author: Aleksey Bragin <aleksey at reactos.org>
Date:   Wed Dec 24 06:04:25 2008 +0400

ntdll: Fix buffer overread in RtlNumberOfSetBits.

---

 dlls/ntdll/rtlbitmap.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/dlls/ntdll/rtlbitmap.c b/dlls/ntdll/rtlbitmap.c
index ef033b2..806e0e8 100644
--- a/dlls/ntdll/rtlbitmap.c
+++ b/dlls/ntdll/rtlbitmap.c
@@ -555,9 +555,12 @@ ULONG WINAPI RtlNumberOfSetBits(PCRTL_BITMAP lpBits)
       lpOut++;
     }
 
-    bMasked = *lpOut & NTDLL_maskBits[ulRemainder];
-    ulSet += NTDLL_nibbleBitCount[bMasked >> 4];
-    ulSet += NTDLL_nibbleBitCount[bMasked & 0xf];
+    if (ulRemainder)
+    {
+      bMasked = *lpOut & NTDLL_maskBits[ulRemainder];
+      ulSet += NTDLL_nibbleBitCount[bMasked >> 4];
+      ulSet += NTDLL_nibbleBitCount[bMasked & 0xf];
+    }
   }
   return ulSet;
 }