[PATCH] btrfs: qgroups: Fix BUG_ON condition

From: Nikolay Borisov <nborisov@suse.com>
To: linux-btrfs@vger.kernel.org
Cc: dsterba@suse.cz, rgoldwyn@suse.de, Nikolay Borisov <nborisov@suse.com>
Subject: [PATCH] btrfs: qgroups: Fix BUG_ON condition
Date: Wed, 12 Jul 2017 09:42:19 +0300	[thread overview]
Message-ID: <1499841739-18549-1-git-send-email-nborisov@suse.com> (raw)

The current code was erroneously checking for root_level > BTRFS_MAX_LEVEL. If
we had a root_level of 8 then the check won't trigger and we could
potentially hit a buffer overflow. The correct check should be
root_level >= BTRFS_MAX_LEVEL

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/qgroup.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 4ce351efe281..3b787915ef31 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1603,7 +1603,7 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
 	struct extent_buffer *eb = root_eb;
 	struct btrfs_path *path = NULL;
 
-	BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
+	BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
 	BUG_ON(root_eb == NULL);
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
@@ -2959,7 +2959,7 @@ static int __btrfs_qgroup_release_data(struct inode *inode,
 	if (free && reserved)
 		return qgroup_free_reserved_data(inode, reserved, start, len);
 	extent_changeset_init(&changeset);
-	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start, 
+	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
 			start + len -1, EXTENT_QGROUP_RESERVED, &changeset);
 	if (ret < 0)
 		goto out;
-- 
2.7.4

