diff options
| author | Liu Shixin <liushixin2@huawei.com> | 2022-04-29 14:38:04 -0700 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-04-29 14:38:04 -0700 |
| commit | f6e2c20ca7604e6a267c93a511d19dda72573be1 (patch) | |
| tree | 3302a5e2e1faba0acc55671c81529a4b5f07ef77 | |
| parent | edc73c7261ca3ea79867437bb0b9dab0e232436c (diff) | |
fs: sysv: check sbi->s_firstdatazone in complete_read_super
sbi->s_firstinodezone is initialized to 2 and sbi->s_firstdatazone is read
from sbd. There's no guarantee that sbi->s_firstdatazone must bigger than
sbi->s_firstinodezone. If sbi->s_firstdatazone less than 2, the
filesystem can still be mounted unexpetly. At this point, sbi->s_ninodes
flip to very large value and this filesystem is broken. We can observe
this by executing 'df' command. When we execute, we will get an error
message:
"sysv_count_free_inodes: unable to read inode table"
Link: https://lkml.kernel.org/r/20220330104215.530223-1-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | fs/sysv/super.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/sysv/super.c b/fs/sysv/super.c index d1def0771a40..3365a30dc1e0 100644 --- a/fs/sysv/super.c +++ b/fs/sysv/super.c @@ -312,7 +312,9 @@ static int complete_read_super(struct super_block *sb, int silent, int size) sbi->s_firstinodezone = 2; flavour_setup[sbi->s_type](sbi, &sb->s_max_links); - + if (sbi->s_firstdatazone < sbi->s_firstinodezone) + return 0; + sbi->s_ndatazones = sbi->s_nzones - sbi->s_firstdatazone; sbi->s_inodes_per_block = bsize >> 6; sbi->s_inodes_per_block_1 = (bsize >> 6)-1; |