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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 193B0C43219 for ; Thu, 9 Sep 2021 13:35:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F29A56109F for ; Thu, 9 Sep 2021 13:35:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376796AbhIINez (ORCPT ); Thu, 9 Sep 2021 09:34:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:56224 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358404AbhIINHS (ORCPT ); Thu, 9 Sep 2021 09:07:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8D7D0632A1; Thu, 9 Sep 2021 12:00:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188827; bh=w1dLWK+wKJAWn9NNIxn1pmCs0AYI824cEWgBv9Ae0k8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pU0F+M+Meq0F43uVbvayfVufTp4B8ye0yh3TlAQzAI+v4DPxjmxnfPe2VMLbf2k1x ePNZHBAKOYgZIpP1hLq1mrANZ55bC4XR6QiUibHjPRWwEIaY24lB64pj7umhdcqdUe fVUtxQIDLa6R41/xFPKKdmWeXMe19Hd5EQ1TdRbO0wOrYf8qXqi40COirMCIlWqnkX Hfs6/TCk49nFXWeOafLQ+WoI4qc0iEoEn9uTLxVb+9NZ8ZllWItwRTolQejPi9ZIbO pryD7C9CbAeDmM8mWwYEJ1PBbPSjd6k/3E2W3xMDiy/cdPoEvtM7NDiAHdzYAkG9fb m0ML5JlQAFGiw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= , Brooke Basile , "Bryan O'Donoghue" , Felipe Balbi , Greg Kroah-Hartman , Lorenzo Colitti , Sasha Levin , linux-usb@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 09/48] usb: gadget: u_ether: fix a potential null pointer dereference Date: Thu, 9 Sep 2021 07:59:36 -0400 Message-Id: <20210909120015.150411-9-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909120015.150411-1-sashal@kernel.org> References: <20210909120015.150411-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Maciej Żenczykowski [ Upstream commit 8ae01239609b29ec2eff55967c8e0fe3650cfa09 ] f_ncm tx timeout can call us with null skb to flush a pending frame. In this case skb is NULL to begin with but ceases to be null after dev->wrap() completes. In such a case in->maxpacket will be read, even though we've failed to check that 'in' is not NULL. Though I've never observed this fail in practice, however the 'flush operation' simply does not make sense with a null usb IN endpoint - there's nowhere to flush to... (note that we're the gadget/device, and IN is from the point of view of the host, so here IN actually means outbound...) Cc: Brooke Basile Cc: "Bryan O'Donoghue" Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: Lorenzo Colitti Signed-off-by: Maciej Żenczykowski Link: https://lore.kernel.org/r/20210701114834.884597-6-zenczykowski@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/u_ether.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 589d1f5fb575..5d72872310e7 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -499,8 +499,9 @@ static netdev_tx_t eth_start_xmit(struct sk_buff *skb, } spin_unlock_irqrestore(&dev->lock, flags); - if (skb && !in) { - dev_kfree_skb_any(skb); + if (!in) { + if (skb) + dev_kfree_skb_any(skb); return NETDEV_TX_OK; } -- 2.30.2