From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF688C001E4 for ; Mon, 12 Apr 2021 09:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7FD416120B for ; Mon, 12 Apr 2021 09:43:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243116AbhDLJlU (ORCPT ); Mon, 12 Apr 2021 05:41:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:34724 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241020AbhDLJLY (ORCPT ); Mon, 12 Apr 2021 05:11:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 662EC61384; Mon, 12 Apr 2021 09:08:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618218514; bh=s5SvP3mWf1OFhIjbYByPvaVVhy1itZGBYCqYfZHGC1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2twJ3yIPI0xCjDVpNYk/hHY03S7he/wNqr7OOGGThe/IZvzq2+xVY5GOBj/QqTxNs HQwcgr0EGfNdVHHkm4lAegIYsv+3hCBVnveaz+ga1VZ+Cik804h2Em5Hn572iO9OPT BmdAdLiduS5f+9BD36VKKFhoTQysmVWvvC7jgupM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lv Yunlong , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 063/111] net:tipc: Fix a double free in tipc_sk_mcast_rcv Date: Mon, 12 Apr 2021 10:40:41 +0200 Message-Id: <20210412084006.360601960@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084004.200986670@linuxfoundation.org> References: <20210412084004.200986670@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lv Yunlong [ Upstream commit 6bf24dc0cc0cc43b29ba344b66d78590e687e046 ] In the if(skb_peek(arrvq) == skb) branch, it calls __skb_dequeue(arrvq) to get the skb by skb = skb_peek(arrvq). Then __skb_dequeue() unlinks the skb from arrvq and returns the skb which equals to skb_peek(arrvq). After __skb_dequeue(arrvq) finished, the skb is freed by kfree_skb(__skb_dequeue(arrvq)) in the first time. Unfortunately, the same skb is freed in the second time by kfree_skb(skb) after the branch completed. My patch removes kfree_skb() in the if(skb_peek(arrvq) == skb) branch, because this skb will be freed by kfree_skb(skb) finally. Fixes: cb1b728096f54 ("tipc: eliminate race condition at multicast reception") Signed-off-by: Lv Yunlong Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/tipc/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 66e8f89bce53..b2c36dcfc8e2 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -1210,7 +1210,7 @@ void tipc_sk_mcast_rcv(struct net *net, struct sk_buff_head *arrvq, spin_lock_bh(&inputq->lock); if (skb_peek(arrvq) == skb) { skb_queue_splice_tail_init(&tmpq, inputq); - kfree_skb(__skb_dequeue(arrvq)); + __skb_dequeue(arrvq); } spin_unlock_bh(&inputq->lock); __skb_queue_purge(&tmpq); -- 2.30.2