[PATCH 4.4 037/162] quota: check block number when reading the block in quota file

Greg Kroah-Hartman
2021-11-24T12:02:09Z

From: Zhang Yi <yi.zhang@huawei.com>

commit 9bf3d20331295b1ecb81f4ed9ef358c51699a050 upstream.

The block number in the quota tree on disk should be smaller than the
v2_disk_dqinfo.dqi_blocks. If the quota file was corrupted, we may be
allocating an 'allocated' block and that would lead to a loop in a tree,
which will probably trigger oops later. This patch adds a check for the
block number in the quota tree to prevent such potential issue.

Link: https://lore.kernel.org/r/20211008093821.1001186-2-yi.zhang@huawei.com
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/quota/quota_tree.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

--- a/fs/quota/quota_tree.c
+++ b/fs/quota/quota_tree.c
@@ -481,6 +481,13 @@ static int remove_tree(struct qtree_mem_
goto out_buf;
}
newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
+ if (newblk < QT_TREEOFF || newblk >= info->dqi_blocks) {
+ quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
+ newblk, info->dqi_blocks);
+ ret = -EUCLEAN;
+ goto out_buf;
+ }
+
if (depth == info->dqi_qtree_depth - 1) {
ret = free_dqentry(info, dquot, newblk);
newblk = 0;
@@ -580,6 +587,13 @@ static loff_t find_tree_dqentry(struct q
blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
if (!blk) /* No reference? */
goto out_buf;
+ if (blk < QT_TREEOFF || blk >= info->dqi_blocks) {
+ quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
+ blk, info->dqi_blocks);
+ ret = -EUCLEAN;
+ goto out_buf;
+ }
+
if (depth < info->dqi_qtree_depth - 1)
ret = find_tree_dqentry(info, dquot, blk, depth+1);
else