[src/trunk]: src/sys/ufs/ffs Return error if we try to mount a file system wi...

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

details:   https://anonhg.NetBSD.org/src/rev/d36aefd32b80
branches:  trunk
changeset: 756988:d36aefd32b80
user:      pooka <pooka%NetBSD.org@localhost>
date:      Mon Aug 09 15:50:13 2010 +0000

description:
Return error if we try to mount a file system with block size > MAXBSIZE.

Note: there is a billion ways to make the kernel panic by trying
to mount a garbage file system and I don't imagine we'll ever get
close to fixing even half of them.  However, for this one failing
gracefully is a bonus since Xen DomU only does 32k MAXBSIZE and
the 64k MAXBSIZE file systems are out there (PR port-xen/43727).

Tested by compiling sys/rump with CPPFLAGS+=-DMAXPHYS=32768 (all
tests in tests/fs still pass).  I don't know how we're going to
translate this into an easy regression test, though.  Maybe with
a hacked newfs?

diffstat:

 sys/ufs/ffs/ffs_vfsops.c |  16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diffs (66 lines):

diff -r e5c7216d7df8 -r d36aefd32b80 sys/ufs/ffs/ffs_vfsops.c
--- a/sys/ufs/ffs/ffs_vfsops.c  Mon Aug 09 15:46:17 2010 +0000
+++ b/sys/ufs/ffs/ffs_vfsops.c  Mon Aug 09 15:50:13 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ffs_vfsops.c,v 1.260 2010/07/21 17:52:13 hannken Exp $ */
+/*     $NetBSD: ffs_vfsops.c,v 1.261 2010/08/09 15:50:13 pooka 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 1.260 2010/07/21 17:52:13 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ffs_vfsops.c,v 1.261 2010/08/09 15:50:13 pooka Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_ffs.h"
@@ -828,6 +828,7 @@
        int32_t *lp;
        kauth_cred_t cred;
        u_int32_t sbsize = 8192;        /* keep gcc happy*/
+       int32_t fsbsize;
 
        dev = devvp->v_rdev;
        cred = l ? l->l_cred : NOCRED;
@@ -886,21 +887,25 @@
                if (fs->fs_magic == FS_UFS1_MAGIC) {
                        sbsize = fs->fs_sbsize;
                        fstype = UFS1;
+                       fsbsize = fs->fs_bsize;
 #ifdef FFS_EI
                        needswap = 0;
                } else if (fs->fs_magic == bswap32(FS_UFS1_MAGIC)) {
                        sbsize = bswap32(fs->fs_sbsize);
                        fstype = UFS1;
+                       fsbsize = bswap32(fs->fs_bsize);
                        needswap = 1;
 #endif
                } else if (fs->fs_magic == FS_UFS2_MAGIC) {
                        sbsize = fs->fs_sbsize;
                        fstype = UFS2;
+                       fsbsize = fs->fs_bsize;
 #ifdef FFS_EI
                        needswap = 0;
                } else if (fs->fs_magic == bswap32(FS_UFS2_MAGIC)) {
                        sbsize = bswap32(fs->fs_sbsize);
                        fstype = UFS2;
+                       fsbsize = bswap32(fs->fs_bsize);
                        needswap = 1;
 #endif
                } else
@@ -933,6 +938,13 @@
                if (sbsize > MAXBSIZE || sbsize < sizeof(struct fs))
                        continue;
 
+               /* Check that we can handle the file system blocksize */
+               if (fsbsize > MAXBSIZE) {
+                       printf("ffs_mountfs: block size (%d) > MAXBSIZE (%d)",
+                           fsbsize, MAXBSIZE);
+                       continue;
+               }
+
                /* Ok seems to be a good superblock */
                break;
        }