Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

Steffen Klassert says:

====================
pull request (net): ipsec 2017-11-09

1) Fix a use after free due to a reallocated skb head.
   From Florian Westphal.

2) Fix sporadic lookup failures on labeled IPSEC.
   From Florian Westphal.

3) Fix a stack out of bounds when a socket policy is applied
   to an IPv6 socket that sends IPv4 packets.

Please pull or let me know if there are problems.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/xfrm/xfrm_input.c

@@ -266,8 +266,6 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 		goto lock;
 	}
 
-	daddr = (xfrm_address_t *)(skb_network_header(skb) +
-				   XFRM_SPI_SKB_CB(skb)->daddroff);
 	family = XFRM_SPI_SKB_CB(skb)->family;
 
 	/* if tunnel is present override skb->mark value with tunnel i_key */
@@ -294,6 +292,8 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 		goto drop;
 	}
 
+	daddr = (xfrm_address_t *)(skb_network_header(skb) +
+				   XFRM_SPI_SKB_CB(skb)->daddroff);
 	do {
 		if (skb->sp->len == XFRM_MAX_DEPTH) {
 			XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);

net/xfrm/xfrm_policy.c

@@ -1361,18 +1361,14 @@ xfrm_tmpl_resolve_one(struct xfrm_policy *policy, const struct flowi *fl,
 	struct net *net = xp_net(policy);
 	int nx;
 	int i, error;
-	xfrm_address_t *daddr = xfrm_flowi_daddr(fl, family);
-	xfrm_address_t *saddr = xfrm_flowi_saddr(fl, family);
 	xfrm_address_t tmp;
 
 	for (nx = 0, i = 0; i < policy->xfrm_nr; i++) {
 		struct xfrm_state *x;
-		xfrm_address_t *remote = daddr;
-		xfrm_address_t *local  = saddr;
+		xfrm_address_t *local;
+		xfrm_address_t *remote;
 		struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
 
-		if (tmpl->mode == XFRM_MODE_TUNNEL ||
-		    tmpl->mode == XFRM_MODE_BEET) {
 		remote = &tmpl->id.daddr;
 		local = &tmpl->saddr;
 		if (xfrm_addr_any(local, tmpl->encap_family)) {
@@ -1383,14 +1379,11 @@ xfrm_tmpl_resolve_one(struct xfrm_policy *policy, const struct flowi *fl,
 				goto fail;
 			local = &tmp;
 		}
-		}
 
 		x = xfrm_state_find(remote, local, fl, tmpl, policy, &error, family);
 
 		if (x && x->km.state == XFRM_STATE_VALID) {
 			xfrm[nx++] = x;
-			daddr = remote;
-			saddr = local;
 			continue;
 		}
 		if (x) {
@@ -1787,19 +1780,23 @@ void xfrm_policy_cache_flush(void)
 	put_online_cpus();
 }
 
-static bool xfrm_pol_dead(struct xfrm_dst *xdst)
+static bool xfrm_xdst_can_reuse(struct xfrm_dst *xdst,
+				struct xfrm_state * const xfrm[],
+				int num)
 {
-	unsigned int num_pols = xdst->num_pols;
-	unsigned int pol_dead = 0, i;
+	const struct dst_entry *dst = &xdst->u.dst;
+	int i;
 
-	for (i = 0; i < num_pols; i++)
-		pol_dead |= xdst->pols[i]->walk.dead;
+	if (xdst->num_xfrms != num)
+		return false;
 
-	/* Mark DST_OBSOLETE_DEAD to fail the next xfrm_dst_check() */
-	if (pol_dead)
-		xdst->u.dst.obsolete = DST_OBSOLETE_DEAD;
+	for (i = 0; i < num; i++) {
+		if (!dst || dst->xfrm != xfrm[i])
+			return false;
+		dst = dst->child;
+	}
 
-	return pol_dead;
+	return xfrm_bundle_ok(xdst);
 }
 
 static struct xfrm_dst *
@@ -1813,26 +1810,28 @@ xfrm_resolve_and_create_bundle(struct xfrm_policy **pols, int num_pols,
 	struct dst_entry *dst;
 	int err;
 
+	/* Try to instantiate a bundle */
+	err = xfrm_tmpl_resolve(pols, num_pols, fl, xfrm, family);
+	if (err <= 0) {
+		if (err != 0 && err != -EAGAIN)
+			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
+		return ERR_PTR(err);
+	}
+
 	xdst = this_cpu_read(xfrm_last_dst);
 	if (xdst &&
 	    xdst->u.dst.dev == dst_orig->dev &&
 	    xdst->num_pols == num_pols &&
-	    !xfrm_pol_dead(xdst) &&
 	    memcmp(xdst->pols, pols,
 		   sizeof(struct xfrm_policy *) * num_pols) == 0 &&
-	    xfrm_bundle_ok(xdst)) {
+	    xfrm_xdst_can_reuse(xdst, xfrm, err)) {
 		dst_hold(&xdst->u.dst);
+		while (err > 0)
+			xfrm_state_put(xfrm[--err]);
 		return xdst;
 	}
 
 	old = xdst;
-	/* Try to instantiate a bundle */
-	err = xfrm_tmpl_resolve(pols, num_pols, fl, xfrm, family);
-	if (err <= 0) {
-		if (err != 0 && err != -EAGAIN)
-			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTPOLERROR);
-		return ERR_PTR(err);
-	}
 
 	dst = xfrm_bundle_create(pols[0], xfrm, err, fl, dst_orig);
 	if (IS_ERR(dst)) {