From: Eric Sandeen <sandeen@xxxxxxxxxx> commit 657bdfb7f5e68ca5e2ed009ab473c429b0d6af85 upstream. The GETNEXTQOTA ioctl takes whatever ID is sent in, and looks for the next active quota for an user equal or higher to that ID. But if we are at the maximum ID and then ask for the "next" one, we may wrap back to zero. In this case, userspace may loop forever, because it will start querying again at zero. We'll fix this in userspace as well, but for the kernel, return -ENOENT if we ask for the next quota ID past UINT_MAX so the caller knows to stop. Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> --- fs/xfs/xfs_dquot.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c index 7a30b8f..9d06cc3 100644 --- a/fs/xfs/xfs_dquot.c +++ b/fs/xfs/xfs_dquot.c @@ -710,6 +710,10 @@ xfs_dq_get_next_id( /* Simple advance */ next_id = *id + 1; + /* If we'd wrap past the max ID, stop */ + if (next_id < *id) + return -ENOENT; + /* If new ID is within the current chunk, advancing it sufficed */ if (next_id % mp->m_quotainfo->qi_dqperchunk) { *id = next_id; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html