From patchwork Thu Apr 15 14:47:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 422425 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, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 A7F6CC433B4 for ; Thu, 15 Apr 2021 14:51:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 865AF613CB for ; Thu, 15 Apr 2021 14:51:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234174AbhDOOwH (ORCPT ); Thu, 15 Apr 2021 10:52:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:37126 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234106AbhDOOvX (ORCPT ); Thu, 15 Apr 2021 10:51:23 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6B6BB6137D; Thu, 15 Apr 2021 14:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498260; bh=cwZi0PoEX5UxhnDCSVxN0fDAN9c/3MRRvsCLAFqVNqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=om2Fi8LLJurG0Pqjen4CQdF+B3fMhEv9GVZIbnMzPXs4iu75PZEqNkaRfxxfb9QcL ft/vpU859IvxHeNB5zdEuE8vfgaJh3XbX2VDoHGLwYOTv7Wnti0rqsdVJJnut9mMFT k4apVuGKoSha4DvOCGO5ePVzUALCbt02r/kBt3Bg= 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 4.9 20/47] net:tipc: Fix a double free in tipc_sk_mcast_rcv Date: Thu, 15 Apr 2021 16:47:12 +0200 Message-Id: <20210415144414.108806356@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144413.487943796@linuxfoundation.org> References: <20210415144413.487943796@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 57df99ca6347..804cab8f9509 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -741,7 +741,7 @@ 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);