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authorLiu Shixin <liushixin2@huawei.com>2022-04-30 00:38:04 +0300
committerakpm <akpm@linux-foundation.org>2022-04-30 00:38:04 +0300
commitf6e2c20ca7604e6a267c93a511d19dda72573be1 (patch)
tree3302a5e2e1faba0acc55671c81529a4b5f07ef77 /fs/sysv
parentedc73c7261ca3ea79867437bb0b9dab0e232436c (diff)
downloadlinux-f6e2c20ca7604e6a267c93a511d19dda72573be1.tar.xz
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>
Diffstat (limited to 'fs/sysv')
-rw-r--r--fs/sysv/super.c4
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;