From 4814326b59db0cfd18ac652626d955ad3f57fb0f Mon Sep 17 00:00:00 2001 From: Vlad Yasevich Date: Mon, 23 Nov 2009 15:54:01 -0500 Subject: [PATCH] sctp: prevent too-fast association id reuse We use the idr subsystem and always ask for an id at or above 1. This results in a id reuse when one association is terminated while another is created. To prevent re-use, we keep track of the last id returned and ask for that id + 1 as a base for each query. We let the idr spin lock protect this base id as well. Signed-off-by: Vlad Yasevich --- net/sctp/associola.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/net/sctp/associola.c b/net/sctp/associola.c index 6e96f83570c9..df5abbff63e2 100644 --- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -63,6 +63,12 @@ static void sctp_assoc_bh_rcv(struct work_struct *work); static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc); +/* Keep track of the new idr low so that we don't re-use association id + * numbers too fast. It is protected by they idr spin lock is in the + * range of 1 - INT_MAX. + */ +static u32 idr_low = 1; + /* 1st Level Abstractions. */ @@ -1553,7 +1559,12 @@ retry: spin_lock_bh(&sctp_assocs_id_lock); error = idr_get_new_above(&sctp_assocs_id, (void *)asoc, - 1, &assoc_id); + idr_low, &assoc_id); + if (!error) { + idr_low = assoc_id + 1; + if (idr_low == INT_MAX) + idr_low = 1; + } spin_unlock_bh(&sctp_assocs_id_lock); if (error == -EAGAIN) goto retry;