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quota: Sanity-check quota file headers on load 

commit 11c514a99b upstream.

Perform basic sanity checks of quota headers to avoid kernel crashes on
corrupted quota files.

CC: stable@vger.kernel.org
Reported-by: syzbot+f816042a7ae2225f25ba@syzkaller.appspotmail.com
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Jan Kara 2020-11-02 16:16:29 +01:00 committed by Greg Kroah-Hartman
parent df95ea1228
commit 0118204534
1 changed files with 19 additions and 0 deletions
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19
fs/quota/quota_v2.c
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@ -159,6 +159,25 @@ static int v2_read_file_info(struct super_block *sb, int type)
qinfo->dqi_entry_size = sizeof(struct v2r1_disk_dqblk);
qinfo->dqi_ops = &v2r1_qtree_ops;
}
ret = -EUCLEAN;
/* Some sanity checks of the read headers... */
if ((loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits >
i_size_read(sb_dqopt(sb)->files[type])) {
quota_error(sb, "Number of blocks too big for quota file size (%llu > %llu).",
(loff_t)qinfo->dqi_blocks << qinfo->dqi_blocksize_bits,
i_size_read(sb_dqopt(sb)->files[type]));
goto out;
}
if (qinfo->dqi_free_blk >= qinfo->dqi_blocks) {
quota_error(sb, "Free block number too big (%u >= %u).",
qinfo->dqi_free_blk, qinfo->dqi_blocks);
goto out;
}
if (qinfo->dqi_free_entry >= qinfo->dqi_blocks) {
quota_error(sb, "Block with free entry too big (%u >= %u).",
qinfo->dqi_free_entry, qinfo->dqi_blocks);
goto out;
}
ret = 0;
out:
up_read(&dqopt->dqio_sem);