netdev - [PATCH 2/2] Revert "xfrm: Fix stack-out-of-bounds read in xfrm_state

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Date:   Thu, 16 Nov 2017 11:00:40 +0100
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     David Miller <davem@...emloft.net>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        <netdev@...r.kernel.org>
Subject: [PATCH 2/2] Revert "xfrm: Fix stack-out-of-bounds read in xfrm_state_find."

This reverts commit c9f3f813d462c72dbe412cee6a5cbacf13c4ad5e.

This commit breaks transport mode when the policy template
has widlcard addresses configured, so revert it.

Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/xfrm/xfrm_policy.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 2a60938..6bc16bb 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1362,29 +1362,36 @@ 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 *local;
-		xfrm_address_t *remote;
+		xfrm_address_t *remote = daddr;
+		xfrm_address_t *local  = saddr;
 		struct xfrm_tmpl *tmpl = &policy->xfrm_vec[i];
 
-		remote = &tmpl->id.daddr;
-		local = &tmpl->saddr;
-		if (xfrm_addr_any(local, tmpl->encap_family)) {
-			error = xfrm_get_saddr(net, fl->flowi_oif,
-					       &tmp, remote,
-					       tmpl->encap_family, 0);
-			if (error)
-				goto fail;
-			local = &tmp;
+		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)) {
+				error = xfrm_get_saddr(net, fl->flowi_oif,
+						       &tmp, remote,
+						       tmpl->encap_family, 0);
+				if (error)
+					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) {
-- 
2.7.4