From 4bda4f250d21c3e4f2a2da5f4cef829a434a4046 Mon Sep 17 00:00:00 2001
From: Pavel Emelyanov <xemul@openvz.org>
Date: Fri, 14 Dec 2007 11:38:04 -0800
Subject: [PATCH] [XFRM]: Fix potential race vs xfrm_state(only)_find and
xfrm_hash_resize.
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 <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/xfrm/xfrm_state.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index b2343d48fe96..f7c0951c9fd9 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -756,7 +756,7 @@ 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;
@@ -764,6 +764,7 @@ 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 &&
@@ -865,11 +866,12 @@ 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 &&
--
2.20.1