netdev - [PATCH 2/3] xfrm: unbreak xfrm_sk_policy

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Message-ID: <1480057080-20177-3-git-send-email-steffen.klassert@secunet.com>
Date:   Fri, 25 Nov 2016 07:57:59 +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 2/3] xfrm: unbreak xfrm_sk_policy_lookup

From: Florian Westphal <fw@...len.de>

if we succeed grabbing the refcount, then
  if (err && !xfrm_pol_hold_rcu)

will evaluate to false so this hits last else branch which then
sets policy to ERR_PTR(0).

Fixes: ae33786f73a7ce ("xfrm: policy: only use rcu in xfrm_sk_policy_lookup")
Reported-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/xfrm/xfrm_policy.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index fd69866..5bf7e1bf 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1268,12 +1268,14 @@ static struct xfrm_policy *xfrm_sk_policy_lookup(const struct sock *sk, int dir,
 			err = security_xfrm_policy_lookup(pol->security,
 						      fl->flowi_secid,
 						      policy_to_flow_dir(dir));
-			if (!err && !xfrm_pol_hold_rcu(pol))
-				goto again;
-			else if (err == -ESRCH)
+			if (!err) {
+				if (!xfrm_pol_hold_rcu(pol))
+					goto again;
+			} else if (err == -ESRCH) {
 				pol = NULL;
-			else
+			} else {
 				pol = ERR_PTR(err);
+			}
 		} else
 			pol = NULL;
 	}
-- 
1.9.1