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 84A3DC28B26 for ; Thu, 9 Sep 2021 12:39:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C5D2611EF for ; Thu, 9 Sep 2021 12:39:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354926AbhIIMjx (ORCPT ); Thu, 9 Sep 2021 08:39:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:34536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348508AbhIIM0P (ORCPT ); Thu, 9 Sep 2021 08:26:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8DEE061B1F; Thu, 9 Sep 2021 11:51:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188310; bh=qvQw3czIoSzqsNb0fcpfM4nAqg3/+tvIWVs+0JqcKCI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F+ihc+5/y1rF/YjPFgJVj1XEPdxuassvyjEXnoeVc7fJUTwCte56hLwniBZjdRUSb IoWfEnJHGMRGk13e/7U0zf8CDNDwR1gLhwbeJuE2ftzq0KYLm53h6CMxyLo2apzvmp Mv4GmcHV7EBbwk/BXIQrwh3KK45uhdwUjmsm97+PR/7LNvrGhSWODfw1F1Ov9mxqGM znKvkJL0MDO2stc3u6/9STgwPazufJLX4tvITL/jqfjDOAkdTgHuHL0zZzgxeg+ZuY N0kNuPNPT5kyM0dRHMqsXTiHsJcwW9dTKTaNZMy8Aat4DTivGQvV4CRPZapamd4NHr leR5BiY8HyI1g== 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 5.10 025/176] usb: gadget: u_ether: fix a potential null pointer dereference Date: Thu, 9 Sep 2021 07:48:47 -0400 Message-Id: <20210909115118.146181-25-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909115118.146181-1-sashal@kernel.org> References: <20210909115118.146181-1-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 c019f2b0c0af..a9cb647bac6f 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -491,8 +491,9 @@ 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