Module Name: src
Committed By: maxv
Date: Tue Jul 8 19:34:47 UTC 2014
Modified Files:
src/sys/fs/msdosfs: msdosfs_vfsops.c
Log Message:
- Perform sanity checks not just for GEMDOSFS, but for all FAT devices. This
also fixes a division-by-zero bug that could crash the system.
- Define GEMDOSFS_BSIZE instead of a hard-coded 512 value, and remove 'bsize'.
- Rename 'tmp' to 'BlkPerSec'.
>From me, FreeBSD, OpenBSD and the FAT specification.
ok christos@
To generate a diff of this commit:
cvs rdiff -u -r1.109 -r1.110 src/sys/fs/msdosfs/msdosfs_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/fs/msdosfs/msdosfs_vfsops.c
diff -u src/sys/fs/msdosfs/msdosfs_vfsops.c:1.109 src/sys/fs/msdosfs/msdosfs_vfsops.c:1.110
--- src/sys/fs/msdosfs/msdosfs_vfsops.c:1.109 Tue Jul 8 09:21:52 2014
+++ src/sys/fs/msdosfs/msdosfs_vfsops.c Tue Jul 8 19:34:47 2014
@@ -1,4 +1,4 @@
-/* $NetBSD: msdosfs_vfsops.c,v 1.109 2014/07/08 09:21:52 hannken Exp $ */
+/* $NetBSD: msdosfs_vfsops.c,v 1.110 2014/07/08 19:34:47 maxv Exp $ */
/*-
* Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
@@ -48,7 +48,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.109 2014/07/08 09:21:52 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: msdosfs_vfsops.c,v 1.110 2014/07/08 19:34:47 maxv Exp $");
#if defined(_KERNEL_OPT)
#include "opt_compat_netbsd.h"
@@ -93,6 +93,8 @@ MODULE(MODULE_CLASS_VFS, msdos, NULL);
#define DPRINTF(a)
#endif
+#define GEMDOSFS_BSIZE 512
+
#define MSDOSFS_NAMEMAX(pmp) \
(pmp)->pm_flags & MSDOSFSMNT_LONGNAME ? WIN_MAXLEN : 12
@@ -466,8 +468,7 @@ msdosfs_mountfs(struct vnode *devvp, str
struct byte_bpb50 *b50;
struct byte_bpb710 *b710;
uint8_t SecPerClust;
- int ronly, error, tmp;
- int bsize;
+ int ronly, error, BlkPerSec;
uint64_t psize;
unsigned secsize;
@@ -496,14 +497,12 @@ msdosfs_mountfs(struct vnode *devvp, str
}
if (argp->flags & MSDOSFSMNT_GEMDOSFS) {
- bsize = secsize;
- if (bsize != 512) {
- DPRINTF(("Invalid block bsize %d for GEMDOS\n", bsize));
+ if (secsize != GEMDOSFS_BSIZE) {
+ DPRINTF(("Invalid block secsize %d for GEMDOS\n", secsize));
error = EINVAL;
goto error_exit;
}
- } else
- bsize = 0;
+ }
/*
* Read the boot sector of the filesystem, and then check the
@@ -547,19 +546,6 @@ msdosfs_mountfs(struct vnode *devvp, str
pmp->pm_Heads = getushort(b50->bpbHeads);
pmp->pm_Media = b50->bpbMedia;
- if (!(argp->flags & MSDOSFSMNT_GEMDOSFS)) {
- /* XXX - We should probably check more values here */
- if (!pmp->pm_BytesPerSec || !SecPerClust
- || pmp->pm_SecPerTrack > 63) {
- DPRINTF(("bytespersec %d secperclust %d "
- "secpertrack %d\n",
- pmp->pm_BytesPerSec, SecPerClust,
- pmp->pm_SecPerTrack));
- error = EINVAL;
- goto error_exit;
- }
- }
-
if (pmp->pm_Sectors == 0) {
pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
@@ -568,6 +554,29 @@ msdosfs_mountfs(struct vnode *devvp, str
pmp->pm_HugeSectors = pmp->pm_Sectors;
}
+ /*
+ * Sanity checks, from the FAT specification:
+ * - sectors per cluster: >= 1, power of 2
+ * - logical sector size: >= 1, power of 2
+ * - cluster size: <= max FS block size
+ * - number of sectors: >= 1
+ */
+ if ((SecPerClust == 0) || !powerof2(SecPerClust) ||
+ (pmp->pm_BytesPerSec == 0) || !powerof2(pmp->pm_BytesPerSec) ||
+ (SecPerClust * pmp->pm_BytesPerSec > MAXBSIZE) ||
+ (pmp->pm_HugeSectors == 0)) {
+ DPRINTF(("consistency checks\n"));
+ error = EINVAL;
+ goto error_exit;
+ }
+
+ if (!(argp->flags & MSDOSFSMNT_GEMDOSFS) &&
+ (pmp->pm_SecPerTrack > 63)) {
+ DPRINTF(("SecPerTrack %d\n", pmp->pm_SecPerTrack));
+ error = EINVAL;
+ goto error_exit;
+ }
+
if (pmp->pm_RootDirEnts == 0) {
unsigned short vers = getushort(b710->bpbFSVers);
/*
@@ -606,17 +615,12 @@ msdosfs_mountfs(struct vnode *devvp, str
/*
* Check a few values (could do some more):
- * - logical sector size: power of 2, >= block size
- * - sectors per cluster: power of 2, >= 1
- * - number of sectors: >= 1, <= size of partition
+ * - logical sector size: >= block size
+ * - number of sectors: <= size of partition
*/
- if ( (SecPerClust == 0)
- || (SecPerClust & (SecPerClust - 1))
- || (pmp->pm_BytesPerSec < bsize)
- || (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
- || (pmp->pm_HugeSectors == 0)
- || (pmp->pm_HugeSectors * (pmp->pm_BytesPerSec / bsize)
- > psize)) {
+ if ((pmp->pm_BytesPerSec < GEMDOSFS_BSIZE) ||
+ (pmp->pm_HugeSectors *
+ (pmp->pm_BytesPerSec / GEMDOSFS_BSIZE) > psize)) {
DPRINTF(("consistency checks for GEMDOS\n"));
error = EINVAL;
goto error_exit;
@@ -627,14 +631,14 @@ msdosfs_mountfs(struct vnode *devvp, str
* always be the same as the number of bytes per disk block
* Let's pretend it is.
*/
- tmp = pmp->pm_BytesPerSec / bsize;
- pmp->pm_BytesPerSec = bsize;
- pmp->pm_HugeSectors *= tmp;
- pmp->pm_HiddenSects *= tmp;
- pmp->pm_ResSectors *= tmp;
- pmp->pm_Sectors *= tmp;
- pmp->pm_FATsecs *= tmp;
- SecPerClust *= tmp;
+ BlkPerSec = pmp->pm_BytesPerSec / GEMDOSFS_BSIZE;
+ pmp->pm_BytesPerSec = GEMDOSFS_BSIZE;
+ pmp->pm_HugeSectors *= BlkPerSec;
+ pmp->pm_HiddenSects *= BlkPerSec;
+ pmp->pm_ResSectors *= BlkPerSec;
+ pmp->pm_Sectors *= BlkPerSec;
+ pmp->pm_FATsecs *= BlkPerSec;
+ SecPerClust *= BlkPerSec;
}
/* Check that fs has nonzero FAT size */
