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Subject[patch 32/42] ipsec: Fix deadlock in xfrm_state management.
2.6.26-stable review patch.  If anyone has any objections, please let us know.

------------------

From: David S. Miller <davem@davemloft.net>

[ Upstream commit 37b08e34a98c664bea86e3fae718ac45a46b7276 ]

Ever since commit 4c563f7669c10a12354b72b518c2287ffc6ebfb3
("[XFRM]: Speed up xfrm_policy and xfrm_state walking") it is
illegal to call __xfrm_state_destroy (and thus xfrm_state_put())
with xfrm_state_lock held. If we do, we'll deadlock since we
have the lock already and __xfrm_state_destroy() tries to take
it again.

Fix this by pushing the xfrm_state_put() calls after the lock
is dropped.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
net/xfrm/xfrm_state.c | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)

--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -780,11 +780,13 @@ xfrm_state_find(xfrm_address_t *daddr, x
{
unsigned int h;
struct hlist_node *entry;
- struct xfrm_state *x, *x0;
+ struct xfrm_state *x, *x0, *to_put;
int acquire_in_progress = 0;
int error = 0;
struct xfrm_state *best = NULL;

+ to_put = 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) {
@@ -833,7 +835,7 @@ xfrm_state_find(xfrm_address_t *daddr, x
if (tmpl->id.spi &&
(x0 = __xfrm_state_lookup(daddr, tmpl->id.spi,
tmpl->id.proto, family)) != NULL) {
- xfrm_state_put(x0);
+ to_put = x0;
error = -EEXIST;
goto out;
}
@@ -849,7 +851,7 @@ xfrm_state_find(xfrm_address_t *daddr, x
error = security_xfrm_state_alloc_acquire(x, pol->security, fl->secid);
if (error) {
x->km.state = XFRM_STATE_DEAD;
- xfrm_state_put(x);
+ to_put = x;
x = NULL;
goto out;
}
@@ -870,7 +872,7 @@ xfrm_state_find(xfrm_address_t *daddr, x
xfrm_hash_grow_check(x->bydst.next != NULL);
} else {
x->km.state = XFRM_STATE_DEAD;
- xfrm_state_put(x);
+ to_put = x;
x = NULL;
error = -ESRCH;
}
@@ -881,6 +883,8 @@ out:
else
*err = acquire_in_progress ? -EAGAIN : error;
spin_unlock_bh(&xfrm_state_lock);
+ if (to_put)
+ xfrm_state_put(to_put);
return x;
}

@@ -1067,18 +1071,20 @@ static struct xfrm_state *__xfrm_find_ac

int xfrm_state_add(struct xfrm_state *x)
{
- struct xfrm_state *x1;
+ struct xfrm_state *x1, *to_put;
int family;
int err;
int use_spi = xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY);

family = x->props.family;

+ to_put = NULL;
+
spin_lock_bh(&xfrm_state_lock);

x1 = __xfrm_state_locate(x, use_spi, family);
if (x1) {
- xfrm_state_put(x1);
+ to_put = x1;
x1 = NULL;
err = -EEXIST;
goto out;
@@ -1088,7 +1094,7 @@ int xfrm_state_add(struct xfrm_state *x)
x1 = __xfrm_find_acq_byseq(x->km.seq);
if (x1 && ((x1->id.proto != x->id.proto) ||
xfrm_addr_cmp(&x1->id.daddr, &x->id.daddr, family))) {
- xfrm_state_put(x1);
+ to_put = x1;
x1 = NULL;
}
}
@@ -1110,6 +1116,9 @@ out:
xfrm_state_put(x1);
}

+ if (to_put)
+ xfrm_state_put(to_put);
+
return err;
}
EXPORT_SYMBOL(xfrm_state_add);
@@ -1269,10 +1278,12 @@ EXPORT_SYMBOL(xfrm_state_migrate);

int xfrm_state_update(struct xfrm_state *x)
{
- struct xfrm_state *x1;
+ struct xfrm_state *x1, *to_put;
int err;
int use_spi = xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY);

+ to_put = NULL;
+
spin_lock_bh(&xfrm_state_lock);
x1 = __xfrm_state_locate(x, use_spi, x->props.family);

@@ -1281,7 +1292,7 @@ int xfrm_state_update(struct xfrm_state
goto out;

if (xfrm_state_kern(x1)) {
- xfrm_state_put(x1);
+ to_put = x1;
err = -EEXIST;
goto out;
}
@@ -1295,6 +1306,9 @@ int xfrm_state_update(struct xfrm_state
out:
spin_unlock_bh(&xfrm_state_lock);

+ if (to_put)
+ xfrm_state_put(to_put);
+
if (err)
return err;

--


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