linux-kernel - [PATCH 3.16.y-ckt 121/180] crypto: af_alg - Fix socket double-free when accept fails

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Message-Id: <1454538786-12215-122-git-send-email-luis.henriques@canonical.com>
Date:	Wed,  3 Feb 2016 22:32:07 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Herbert Xu <herbert@...dor.apana.org.au>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 121/180] crypto: af_alg - Fix socket double-free when accept fails

3.16.7-ckt24 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

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: Luis Henriques <luis.henriques@...onical.com>
---
 crypto/af_alg.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index abb828a3e424..1971f3ccb09a 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -275,10 +275,8 @@ int af_alg_accept(struct sock *sk, struct socket *newsock)
 	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;