[src/trunk]: src/sys/ufs/ffs ffs_superblock_validate(): check the number of i...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/736c8daf67c7
branches:  trunk
changeset: 806825:736c8daf67c7
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Mar 10 12:59:32 2015 +0000

description:
ffs_superblock_validate(): check the number of inodes per block. Otherwise
a malformed value could panic the system.

diffstat:

 sys/ufs/ffs/ffs_vfsops.c |  13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diffs (41 lines):

diff -r 8a16c34199b3 -r 736c8daf67c7 sys/ufs/ffs/ffs_vfsops.c
--- a/sys/ufs/ffs/ffs_vfsops.c  Tue Mar 10 12:57:56 2015 +0000
+++ b/sys/ufs/ffs/ffs_vfsops.c  Tue Mar 10 12:59:32 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ffs_vfsops.c,v 1.321 2015/03/03 17:56:51 maxv Exp $    */
+/*     $NetBSD: ffs_vfsops.c,v 1.322 2015/03/10 12:59:32 maxv Exp $    */
 
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
@@ -61,7 +61,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ffs_vfsops.c,v 1.321 2015/03/03 17:56:51 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ffs_vfsops.c,v 1.322 2015/03/10 12:59:32 maxv Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_ffs.h"
@@ -919,6 +919,7 @@
 ffs_superblock_validate(struct fs *fs)
 {
        int32_t i, fs_bshift = 0, fs_fshift = 0, fs_fragshift = 0, fs_frag;
+       int32_t fs_inopb;
 
        /* Check the superblock size */
        if (fs->fs_sbsize > SBLOCKSIZE || fs->fs_sbsize < sizeof(struct fs))
@@ -941,6 +942,14 @@
        if (fs->fs_cssize == 0)
                return 0;
 
+       /* Check the number of inodes per block */
+       if (fs->fs_magic == FS_UFS1_MAGIC)
+               fs_inopb = fs->fs_bsize / sizeof(struct ufs1_dinode);
+       else /* fs->fs_magic == FS_UFS2_MAGIC */
+               fs_inopb = fs->fs_bsize / sizeof(struct ufs2_dinode);
+       if (fs->fs_inopb != fs_inopb)
+               return 0;
+
        /* Block size cannot be smaller than fragment size */
        if (fs->fs_bsize < fs->fs_fsize)
                return 0;