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Message-Id: <20090310.042051.107256879.davem@davemloft.net>
Date: Tue, 10 Mar 2009 04:20:51 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: nicolas.dichtel@....6wind.com
Cc: netdev@...r.kernel.org
Subject: Re: XFRM state hash value
From: Nicolas Dichtel <nicolas.dichtel@....6wind.com>
Date: Tue, 10 Mar 2009 10:46:03 +0100
> this commit: [XFRM]: Hash xfrm_state objects by source address too. (http://git.kernel.org/?p=linux/kernel/git/davem/net-2.6.git;a=commitdiff;h=c1969f294e624d5b642fc8e6ab9468b7c7791fa8)
> introduces src address in hash for state.
> But in some cases, source address is a wildcard when state is inserted. For example, we can have something like this:
> # setkey -c
> add :: ff02::9 ah 0x100 -m transport -A hmac-md5 "cle3goldorakcle3";
>
> In this case, __xfrm_state_insert() will calculate the hash value with src address set to 0, but xfrm_state_find() will use the real source address to calculate this hash. At the end, no state will be found.
> The most simple way to resolve this pb is to revert the previous patch, but maybe someone has a better idea...
>
Please try this patch:
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index e25ff62..86b9078 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -748,12 +748,51 @@ static void xfrm_hash_grow_check(struct net *net, int have_hash_collision)
schedule_work(&net->xfrm.state_hash_work);
}
+static void xfrm_state_look_at(struct xfrm_policy *pol, struct xfrm_state *x,
+ struct flowi *fl, unsigned short family,
+ xfrm_address_t *daddr, xfrm_address_t *saddr,
+ struct xfrm_state **best, int *acq_in_progress,
+ int *error)
+{
+ /* Resolution logic:
+ * 1. There is a valid state with matching selector. Done.
+ * 2. Valid state with inappropriate selector. Skip.
+ *
+ * Entering area of "sysdeps".
+ *
+ * 3. If state is not valid, selector is temporary, it selects
+ * only session which triggered previous resolution. Key
+ * manager will do something to install a state with proper
+ * selector.
+ */
+ if (x->km.state == XFRM_STATE_VALID) {
+ if ((x->sel.family &&
+ !xfrm_selector_match(&x->sel, fl, x->sel.family)) ||
+ !security_xfrm_state_pol_flow_match(x, pol, fl))
+ return;
+
+ if (!*best ||
+ (*best)->km.dying > x->km.dying ||
+ ((*best)->km.dying == x->km.dying &&
+ (*best)->curlft.add_time < x->curlft.add_time))
+ *best = x;
+ } else if (x->km.state == XFRM_STATE_ACQ) {
+ *acq_in_progress = 1;
+ } else if (x->km.state == XFRM_STATE_ERROR ||
+ x->km.state == XFRM_STATE_EXPIRED) {
+ if (xfrm_selector_match(&x->sel, fl, x->sel.family) &&
+ security_xfrm_state_pol_flow_match(x, pol, fl))
+ *error = -ESRCH;
+ }
+}
+
struct xfrm_state *
xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr,
struct flowi *fl, struct xfrm_tmpl *tmpl,
struct xfrm_policy *pol, int *err,
unsigned short family)
{
+ static xfrm_address_t saddr_wildcard = { };
struct net *net = xp_net(pol);
unsigned int h;
struct hlist_node *entry;
@@ -773,38 +812,21 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr,
xfrm_state_addr_check(x, daddr, saddr, family) &&
tmpl->mode == x->props.mode &&
tmpl->id.proto == x->id.proto &&
- (tmpl->id.spi == x->id.spi || !tmpl->id.spi)) {
- /* Resolution logic:
- 1. There is a valid state with matching selector.
- Done.
- 2. Valid state with inappropriate selector. Skip.
-
- Entering area of "sysdeps".
-
- 3. If state is not valid, selector is temporary,
- it selects only session which triggered
- previous resolution. Key manager will do
- something to install a state with proper
- selector.
- */
- if (x->km.state == XFRM_STATE_VALID) {
- if ((x->sel.family && !xfrm_selector_match(&x->sel, fl, x->sel.family)) ||
- !security_xfrm_state_pol_flow_match(x, pol, fl))
- continue;
- if (!best ||
- best->km.dying > x->km.dying ||
- (best->km.dying == x->km.dying &&
- best->curlft.add_time < x->curlft.add_time))
- best = x;
- } else if (x->km.state == XFRM_STATE_ACQ) {
- acquire_in_progress = 1;
- } else if (x->km.state == XFRM_STATE_ERROR ||
- x->km.state == XFRM_STATE_EXPIRED) {
- if (xfrm_selector_match(&x->sel, fl, x->sel.family) &&
- security_xfrm_state_pol_flow_match(x, pol, fl))
- error = -ESRCH;
- }
- }
+ (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
+ xfrm_state_look_at(pol, x, fl, family, daddr, saddr,
+ &best, &acquire_in_progress, &error);
+ }
+ h = xfrm_dst_hash(net, daddr, &saddr_wildcard, tmpl->reqid, family);
+ hlist_for_each_entry(x, entry, net->xfrm.state_bydst+h, bydst) {
+ if (x->props.family == family &&
+ x->props.reqid == tmpl->reqid &&
+ !(x->props.flags & XFRM_STATE_WILDRECV) &&
+ xfrm_state_addr_check(x, daddr, saddr, family) &&
+ tmpl->mode == x->props.mode &&
+ tmpl->id.proto == x->id.proto &&
+ (tmpl->id.spi == x->id.spi || !tmpl->id.spi))
+ xfrm_state_look_at(pol, x, fl, family, daddr, saddr,
+ &best, &acquire_in_progress, &error);
}
x = best;
--
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