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=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 46873C28B21 for ; Thu, 9 Sep 2021 13:19:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 30A4F61026 for ; Thu, 9 Sep 2021 13:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359710AbhIINTv (ORCPT ); Thu, 9 Sep 2021 09:19:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:35414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358466AbhIINLR (ORCPT ); Thu, 9 Sep 2021 09:11:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 11BED632CF; Thu, 9 Sep 2021 12:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631188887; bh=sjCbB48lyOSm12lMdVov5xle5CKJmy894Ol1fWAUADQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vFey2SNdhVo2dRwLLDUc4FQygsivlo1L8Ta3bcXfKdNz3Jmm4UJzADJ45xYhVZKvh Dy/OSMf/IscXBkrn/61YsuipWFFtgkf3Q+ZQOn33/BsdZxt5u0ynIV0a5TcQfubzwm KqBcceEbcozReJ/5EgrNYjIO/SpBRnUjC1KqCcxvCVyrLTaIayABQPh1zYDSOopXGI EPQ1QrPC9D9DrITUtY32TZQ3i6NOrpf5/ULrCvUVtnajUSEzIHgaUdvA+pzL93Hwf2 /B5pczN4VxdPxUtZhkDbv2uQ0GPzezwzwJUs3BC+5ShKNqxTTgGw42fwzYwVKn720t xyycghECAPkuA== 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 4.4 08/35] usb: gadget: u_ether: fix a potential null pointer dereference Date: Thu, 9 Sep 2021 08:00:49 -0400 Message-Id: <20210909120116.150912-8-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210909120116.150912-1-sashal@kernel.org> References: <20210909120116.150912-1-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: stable@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 46c50135ef9f..4bc95ac3d448 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -507,8 +507,9 @@ 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