The patch titled
fs/sysv: v7: adjust sanity checks for some volumes
has been added to the -mm tree. Its filename is
fs-sysv-v7-adjust-sanity-checks-for-some-volumes.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: fs/sysv: v7: adjust sanity checks for some volumes
From: Lubomir Rintel <lkundrak@xxxxx>
Newly mkfs-ed filesystems from Seventh Edition have last modification time
set to zero, but are otherwise perfectly valid.
Also, tighten up other sanity checks to filter out most filesystems with
Signed-off-by: Lubomir Rintel <lkundrak@xxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/sysv/super.c | 6 ++++--
include/linux/sysv_fs.h | 11 +++++++++++
2 files changed, 15 insertions(+), 2 deletions(-)
diff -puN fs/sysv/super.c~fs-sysv-v7-adjust-sanity-checks-for-some-volumes fs/sysv/super.c
--- a/fs/sysv/super.c~fs-sysv-v7-adjust-sanity-checks-for-some-volumes
+++ a/fs/sysv/super.c
@@ -470,7 +470,7 @@ static int v7_fill_super(struct super_bl
v7sb = (struct v7_super_block *) bh->b_data;
if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||
fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||
- fs32_to_cpu(sbi, v7sb->s_time) == 0)
+ fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)
goto failed;
/* plausibility check on root inode: it is a directory,
@@ -480,7 +480,9 @@ static int v7_fill_super(struct super_bl
v7i = (struct sysv_inode *)(bh2->b_data + 64);
if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||
(fs32_to_cpu(sbi, v7i->i_size) == 0) ||
- (fs32_to_cpu(sbi, v7i->i_size) & 017) != 0)
+ (fs32_to_cpu(sbi, v7i->i_size) & 017) ||
+ (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *
+ sizeof (struct sysv_dir_entry)))
goto failed;
brelse(bh2);
bh2 = NULL;
diff -puN include/linux/sysv_fs.h~fs-sysv-v7-adjust-sanity-checks-for-some-volumes include/linux/sysv_fs.h
--- a/include/linux/sysv_fs.h~fs-sysv-v7-adjust-sanity-checks-for-some-volumes
+++ a/include/linux/sysv_fs.h
@@ -148,6 +148,17 @@ struct v7_super_block {
char s_fname[6]; /* file system name */
char s_fpack[6]; /* file system pack name */
};
+/* Constants to aid sanity checking */
+/* This is not a hard limit, nor enforced by v7 kernel. It's actually just
+ * the limit used by Seventh Edition's ls, though is high enough to assume
+ * that no reasonable file system would have that much entries in root
+ * directory. Thus, if we see anything higher, we just probably got the
+ * endiannes wrong. */
+#define V7_NFILES 1024
+/* The disk addresses are three-byte (despite direct block addresses being
+ * aligned word-wise in inode). If the most significant byte is non-zero,
+ * something is most likely wrong (not a filesystem, bad bytesex). */
+#define V7_MAXSIZE 0x00ffffff
/* Coherent super-block data on disk */
#define COH_NICINOD 100 /* number of inode cache entries */
_
Patches currently in -mm which might be from lkundrak@xxxxx are
fs-sysv-add-v7-alias.patch
fs-sysv-v7-adjust-sanity-checks-for-some-volumes.patch
fs-sysv-v7-add-support-for-non-pdp11-v7-filesystems.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
