Commit 10f04d40 authored by Jan Kara's avatar Jan Kara
Browse files

quota: Don't overflow quota file offsets 



The on-disk quota format supports quota files with upto 2^32 blocks. Be
careful when computing quota file offsets in the quota files from block
numbers as they can overflow 32-bit types. Since quota files larger than
4GB would require ~26 millions of quota users, this is mostly a
theoretical concern now but better be careful, fuzzers would find the
problem sooner or later anyway...

Reviewed-by: default avatarAndreas Dilger <adilger@dilger.ca>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent a219ee41

fs/quota/quota_tree.c

+4 −4
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static ssize_t read_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf) 


	memset(buf, 0, info->dqi_usable_bs);

	return sb->s_op->quota_read(sb, info->dqi_type, buf,

	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);

	       info->dqi_usable_bs, (loff_t)blk << info->dqi_blocksize_bits);

}



static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf)
@@ -71,7 +71,7 @@ static ssize_t write_blk(struct qtree_mem_dqinfo *info, uint blk, char *buf) 
	ssize_t ret;



	ret = sb->s_op->quota_write(sb, info->dqi_type, buf,

	       info->dqi_usable_bs, blk << info->dqi_blocksize_bits);

	       info->dqi_usable_bs, (loff_t)blk << info->dqi_blocksize_bits);

	if (ret != info->dqi_usable_bs) {

		quota_error(sb, "dquota write failed");

		if (ret >= 0)
@@ -284,7 +284,7 @@ static uint find_free_dqentry(struct qtree_mem_dqinfo *info, 
			    blk);

		goto out_buf;

	}

	dquot->dq_off = (blk << info->dqi_blocksize_bits) +

	dquot->dq_off = ((loff_t)blk << info->dqi_blocksize_bits) +

			sizeof(struct qt_disk_dqdbheader) +

			i * info->dqi_entry_size;

	kfree(buf);
@@ -559,7 +559,7 @@ static loff_t find_block_dqentry(struct qtree_mem_dqinfo *info, 
		ret = -EIO;

		goto out_buf;

	} else {

		ret = (blk << info->dqi_blocksize_bits) + sizeof(struct

		ret = ((loff_t)blk << info->dqi_blocksize_bits) + sizeof(struct

		  qt_disk_dqdbheader) + i * info->dqi_entry_size;

	}

out_buf:

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