From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: [PATCH][XFRM] Fix potential race vs xfrm_state(only)_find and xfrm_hash_resize. Date: Thu, 13 Dec 2007 13:56:14 +0300 Message-ID: <47610FCE.2000100@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Herbert Xu , Linux Netdev List , devel@openvz.org To: David Miller Return-path: Received: from sacred.ru ([62.205.161.221]:33067 "EHLO sacred.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbXLMK4e (ORCPT ); Thu, 13 Dec 2007 05:56:34 -0500 Sender: netdev-owner@vger.kernel.org List-ID: The _find calls calculate the hash value using the xfrm_state_hmask, without the xfrm_state_lock. But the value of this mask can change in the _resize call under the state_lock, so we risk to fail in finding the desired entry in hash. I think, that the hash value is better to calculate under the state lock. Signed-off-by: Pavel Emelyanov --- diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 1af522b..1face71 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -759,7 +759,7 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr, struct xfrm_policy *pol, int *err, unsigned short family) { - unsigned int h = xfrm_dst_hash(daddr, saddr, tmpl->reqid, family); + unsigned int h; struct hlist_node *entry; struct xfrm_state *x, *x0; int acquire_in_progress = 0; @@ -767,6 +767,7 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr, struct xfrm_state *best = NULL; spin_lock_bh(&xfrm_state_lock); + h = xfrm_dst_hash(daddr, saddr, tmpl->reqid, family); hlist_for_each_entry(x, entry, xfrm_state_bydst+h, bydst) { if (x->props.family == family && x->props.reqid == tmpl->reqid && @@ -868,11 +869,12 @@ struct xfrm_state * xfrm_stateonly_find(xfrm_address_t *daddr, xfrm_address_t *saddr, unsigned short family, u8 mode, u8 proto, u32 reqid) { - unsigned int h = xfrm_dst_hash(daddr, saddr, reqid, family); + unsigned int h; struct xfrm_state *rx = NULL, *x = NULL; struct hlist_node *entry; spin_lock(&xfrm_state_lock); + h = xfrm_dst_hash(daddr, saddr, reqid, family); hlist_for_each_entry(x, entry, xfrm_state_bydst+h, bydst) { if (x->props.family == family && x->props.reqid == reqid &&