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From:   Xiyu Yang <xiyuyang19@fudan.edu.cn>
To:     Jon Maloy <jmaloy@redhat.com>, Ying Xue <ying.xue@windriver.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        tipc-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org
Cc:     yuanxzhang@fudan.edu.cn, kjlu@umn.edu,
        Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Xin Tan <tanxin.ctf@gmail.com>
Subject: [PATCH] tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv
Date:   Wed, 15 Apr 2020 16:39:56 +0800
Message-Id: <1586939996-69937-1-git-send-email-xiyuyang19@fudan.edu.cn>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

tipc_crypto_rcv() invokes tipc_aead_get(), which returns a reference of
the tipc_aead object to "aead" with increased refcnt.

When tipc_crypto_rcv() returns, the original local reference of "aead"
becomes invalid, so the refcount should be decreased to keep refcount
balanced.

The issue happens in one error path of tipc_crypto_rcv(). When TIPC
message decryption status is EINPROGRESS or EBUSY, the function forgets
to decrease the refcnt increased by tipc_aead_get() and causes a refcnt
leak.

Fix this issue by calling tipc_aead_put() on the error path when TIPC
message decryption status is EINPROGRESS or EBUSY.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
 net/tipc/crypto.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
index c8c47fc72653..8c47ded2edb6 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -1712,6 +1712,7 @@ int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
 	case -EBUSY:
 		this_cpu_inc(stats->stat[STAT_ASYNC]);
 		*skb = NULL;
+		tipc_aead_put(aead);
 		return rc;
 	default:
 		this_cpu_inc(stats->stat[STAT_NOK]);
-- 
2.7.4