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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 630A0C83008 for ; Tue, 28 Apr 2020 18:28:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37D2D20B1F for ; Tue, 28 Apr 2020 18:28:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588098493; bh=PDn7z5TjoQE7tSSAS//QLkvjBMmkHUo1fAqHroZxP34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yvUVkovym3gCtUiufXl9LAAl+f3clBZWTFzxqD9oeJm17NWHWE2lfvTev9cXScrsp ncCrQ6VOCUdgPH9cgyG5LVRRBYVWgUGbCAJmIWliDYCUUzVnpPtLA+jMHuNkvu3Tw7 1Yk0epeLxFWaPoEyxF1EOhWyAcIEYr4vW3nPo+60= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729152AbgD1S2M (ORCPT ); Tue, 28 Apr 2020 14:28:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:40460 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729111AbgD1S2B (ORCPT ); Tue, 28 Apr 2020 14:28:01 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 37DCF20730; Tue, 28 Apr 2020 18:28:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588098480; bh=PDn7z5TjoQE7tSSAS//QLkvjBMmkHUo1fAqHroZxP34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fl5neKqG2hCPuwXtD+DguT+0EAViexcFMc4fbabTeweWTdfnmXqS44ZSV5dWQ+Qru zbJeX/l01UYSpQ6D2xXOwjREdbwmEfihW8wC6HrDkKd6Wt+b1aT8LIx6KmwUAsiF4F 5vTK7VZ8h+S/VRZxiIO8hnp6RvOS93PaOVH4IZAc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiyu Yang , Xin Tan , "David S. Miller" Subject: [PATCH 5.6 057/167] net/x25: Fix x25_neigh refcnt leak when receiving frame Date: Tue, 28 Apr 2020 20:23:53 +0200 Message-Id: <20200428182232.201265461@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200428182225.451225420@linuxfoundation.org> References: <20200428182225.451225420@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xiyu Yang [ Upstream commit f35d12971b4d814cdb2f659d76b42f0c545270b6 ] x25_lapb_receive_frame() invokes x25_get_neigh(), which returns a reference of the specified x25_neigh object to "nb" with increased refcnt. When x25_lapb_receive_frame() returns, local variable "nb" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in one path of x25_lapb_receive_frame(). When pskb_may_pull() returns false, the function forgets to decrease the refcnt increased by x25_get_neigh(), causing a refcnt leak. Fix this issue by calling x25_neigh_put() when pskb_may_pull() returns false. Fixes: cb101ed2c3c7 ("x25: Handle undersized/fragmented skbs") Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/x25/x25_dev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/x25/x25_dev.c +++ b/net/x25/x25_dev.c @@ -115,8 +115,10 @@ int x25_lapb_receive_frame(struct sk_buf goto drop; } - if (!pskb_may_pull(skb, 1)) + if (!pskb_may_pull(skb, 1)) { + x25_neigh_put(nb); return 0; + } switch (skb->data[0]) {