Module Name: src
Committed By: christos
Date: Mon Jul 7 18:46:45 UTC 2014
Modified Files:
src/sbin/fsck_msdos: fat.c
Log Message:
From: http://marc.info/?l=openbsd-tech&m=140234174104724&w=2
Avoid off-by-one on FAT12 filesystems.
To generate a diff of this commit:
cvs rdiff -u -r1.26 -r1.27 src/sbin/fsck_msdos/fat.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sbin/fsck_msdos/fat.c
diff -u src/sbin/fsck_msdos/fat.c:1.26 src/sbin/fsck_msdos/fat.c:1.27
--- src/sbin/fsck_msdos/fat.c:1.26 Mon Jul 7 13:55:53 2014
+++ src/sbin/fsck_msdos/fat.c Mon Jul 7 14:46:45 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: fat.c,v 1.26 2014/07/07 17:55:53 christos Exp $ */
+/* $NetBSD: fat.c,v 1.27 2014/07/07 18:46:45 christos Exp $ */
/*
* Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
@@ -28,7 +28,7 @@
#include <sys/cdefs.h>
#ifndef lint
-__RCSID("$NetBSD: fat.c,v 1.26 2014/07/07 17:55:53 christos Exp $");
+__RCSID("$NetBSD: fat.c,v 1.27 2014/07/07 18:46:45 christos Exp $");
#endif /* not lint */
#include <stdlib.h>
@@ -554,13 +554,15 @@ writefat(int fs, struct bootblock *boot,
default:
if (fat[cl].next == CLUST_FREE)
boot->NumFree++;
- if (cl + 1 < boot->NumClusters
- && fat[cl + 1].next == CLUST_FREE)
- boot->NumFree++;
*p++ = (u_char)fat[cl].next;
- *p++ = (u_char)((fat[cl].next >> 8) & 0xf)
- |(u_char)(fat[cl+1].next << 4);
- *p++ = (u_char)(fat[++cl].next >> 4);
+ *p++ = (u_char)((fat[cl].next >> 8) & 0xf);
+ cl++;
+ if (cl >= boot->NumClusters)
+ break;
+ if (fat[cl].next == CLUST_FREE)
+ boot->NumFree++;
+ *p |= (u_char)(fat[cl + 1].next << 4);
+ *p++ = (u_char)(fat[cl + 1].next >> 4);
break;
}
}
