On 20.08.2018 11:25, Dan Carpenter wrote:
> The issue here is that btrfs_commit_transaction() frees "trans" on both
> the error and the success path. So the problem would be if
> btrfs_commit_transaction() succeeds, and then qgroup_rescan_init()
> fails. That means that "ret" is non-zero and "trans" is non-NULL and it
> leads to a use after free inside the btrfs_end_transaction() macro.
>
> Fixes: 340f1aa27f36 ("btrfs: qgroups: Move transaction management inside btrfs_quota_enable/disable")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Thanks for catching it:
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
>
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 4353bb69bb86..d4917c0cddf5 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1019,10 +1019,9 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
> spin_unlock(&fs_info->qgroup_lock);
>
> ret = btrfs_commit_transaction(trans);
> - if (ret) {
> - trans = NULL;
> + trans = NULL;
> + if (ret)
> goto out_free_path;
> - }
>
> ret = qgroup_rescan_init(fs_info, 0, 1);
> if (!ret) {
>
