Module Name: src
Committed By: maxv
Date: Sat Feb 14 07:41:40 UTC 2015
Modified Files:
src/sys/ufs/ffs: ffs_vfsops.c
Log Message:
Currently, in ffs_reload(), we don't handle the possibility that the
superblock location may have changed. But that implies that we don't
handle the possibility that its size may have changed either.
Therefore: add a check to ensure the size hasn't changed. Otherwise the
mismatch leads to a memory corruption with kmem.
To generate a diff of this commit:
cvs rdiff -u -r1.311 -r1.312 src/sys/ufs/ffs/ffs_vfsops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/ufs/ffs/ffs_vfsops.c
diff -u src/sys/ufs/ffs/ffs_vfsops.c:1.311 src/sys/ufs/ffs/ffs_vfsops.c:1.312
--- src/sys/ufs/ffs/ffs_vfsops.c:1.311 Sat Feb 14 07:20:11 2015
+++ src/sys/ufs/ffs/ffs_vfsops.c Sat Feb 14 07:41:40 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: ffs_vfsops.c,v 1.311 2015/02/14 07:20:11 maxv Exp $ */
+/* $NetBSD: ffs_vfsops.c,v 1.312 2015/02/14 07:41:40 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 1.311 2015/02/14 07:20:11 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ffs_vfsops.c,v 1.312 2015/02/14 07:41:40 maxv Exp $");
#if defined(_KERNEL_OPT)
#include "opt_ffs.h"
@@ -704,7 +704,7 @@ ffs_reload(struct mount *mp, kauth_cred_
struct fs *fs, *newfs;
struct dkwedge_info dkw;
int i, bsize, blks, error;
- int32_t *lp;
+ int32_t *lp, fs_sbsize;
struct ufsmount *ump;
daddr_t sblockloc;
struct vnode_iterator *marker;
@@ -726,15 +726,17 @@ ffs_reload(struct mount *mp, kauth_cred_
/*
* Step 2: re-read superblock from disk. XXX: We don't handle
- * possibility that superblock moved.
+ * possibility that superblock moved. Which implies that we don't
+ * want its size to change either.
*/
fs = ump->um_fs;
- error = bread(devvp, fs->fs_sblockloc / DEV_BSIZE, fs->fs_sbsize,
+ fs_sbsize = fs->fs_sbsize;
+ error = bread(devvp, fs->fs_sblockloc / DEV_BSIZE, fs_sbsize,
NOCRED, 0, &bp);
if (error)
return (error);
- newfs = kmem_alloc(fs->fs_sbsize, KM_SLEEP);
- memcpy(newfs, bp->b_data, fs->fs_sbsize);
+ newfs = kmem_alloc(fs_sbsize, KM_SLEEP);
+ memcpy(newfs, bp->b_data, fs_sbsize);
#ifdef FFS_EI
if (ump->um_flags & UFS_NEEDSWAP) {
@@ -744,15 +746,21 @@ ffs_reload(struct mount *mp, kauth_cred_
#endif
fs->fs_flags &= ~FS_SWAPPED;
+ /* We don't want the superblock size to change. */
+ if (newfs->fs_sbsize != fs_sbsize) {
+ brelse(bp, 0);
+ kmem_free(newfs, fs_sbsize);
+ return (EINVAL);
+ }
if ((newfs->fs_magic != FS_UFS1_MAGIC &&
newfs->fs_magic != FS_UFS2_MAGIC)) {
brelse(bp, 0);
- kmem_free(newfs, fs->fs_sbsize);
+ kmem_free(newfs, fs_sbsize);
return (EIO); /* XXX needs translation */
}
if (!ffs_superblock_validate(newfs, newfs->fs_sbsize, newfs->fs_bsize)) {
brelse(bp, 0);
- kmem_free(newfs, fs->fs_sbsize);
+ kmem_free(newfs, fs_sbsize);
return (EINVAL);
}
@@ -768,9 +776,9 @@ ffs_reload(struct mount *mp, kauth_cred_
newfs->fs_contigdirs = fs->fs_contigdirs;
newfs->fs_ronly = fs->fs_ronly;
newfs->fs_active = fs->fs_active;
- memcpy(fs, newfs, (u_int)fs->fs_sbsize);
+ memcpy(fs, newfs, (u_int)fs_sbsize);
brelse(bp, 0);
- kmem_free(newfs, fs->fs_sbsize);
+ kmem_free(newfs, fs_sbsize);
/* Recheck for apple UFS filesystem */
ump->um_flags &= ~UFS_ISAPPLEUFS;
