linux-kernel - [PATCH 3.2 60/87] crypto: af_alg - Fix socket double-free when accept fails

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Date:	Mon, 08 Feb 2016 23:53:51 +0000
From:	Ben Hutchings <ben@...adent.org.uk>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:	akpm@...ux-foundation.org,
	"Herbert Xu" <herbert@...dor.apana.org.au>,
	"Dmitry Vyukov" <dvyukov@...gle.com>
Subject: [PATCH 3.2 60/87] crypto: af_alg - Fix socket double-free when
 accept fails

3.2.77-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Herbert Xu <herbert@...dor.apana.org.au>

commit a383292c86663bbc31ac62cc0c04fc77504636a6 upstream.

When we fail an accept(2) call we will end up freeing the socket
twice, once due to the direct sk_free call and once again through
newsock.

This patch fixes this by removing the sk_free call.

Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 crypto/af_alg.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -247,10 +247,8 @@ int af_alg_accept(struct sock *sk, struc
 	security_sk_clone(sk, sk2);
 
 	err = type->accept(ask->private, sk2);
-	if (err) {
-		sk_free(sk2);
+	if (err)
 		goto unlock;
-	}
 
 	sk2->sk_family = PF_ALG;