Commit 11c514a9 authored by Jan Kara's avatar Jan Kara
Browse files

quota: Sanity-check quota file headers on load 



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

CC: stable@vger.kernel.org
Reported-by: default avatar <syzbot+f816042a7ae2225f25ba@syzkaller.appspotmail.com>
Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 10f04d40

fs/quota/quota_v2.c

+19 −0
Original line number Diff line number Diff line
@@ -157,6 +157,25 @@ 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);

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