From patchwork Mon May 18 17:37:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 225606 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,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 D263CC433E1 for ; Mon, 18 May 2020 18:23:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC20120643 for ; Mon, 18 May 2020 18:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589826187; bh=/HHfS83NJSn6uRGGuNfIQL/iOaixrXdIqnZA9Wc/srM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yi7qGx0LGekVIT6MX40Ja0uan9h+jOMNHssUZTz6jHor0tw/sHAcMdW9eBMiHYoS0 XFhg+DCzHKyz0iyw7M1O8yBY1svqjMlO0iQkhCqpoZ318YHccK30HdyCnOpgOE9jli yo0p1MLJ9KReo3I3NkPC5j9O9Iz/FJF5N1d/Huzo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729961AbgERRtg (ORCPT ); Mon, 18 May 2020 13:49:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:51220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730543AbgERRtd (ORCPT ); Mon, 18 May 2020 13:49:33 -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 60DDC20657; Mon, 18 May 2020 17:49:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589824172; bh=/HHfS83NJSn6uRGGuNfIQL/iOaixrXdIqnZA9Wc/srM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IMBIf8Q5sXATUsLOQdHmAYSQIuh5uRYXD+OCoKlJ8oRz7/3jx6TW4AqQSAE4fWiE5 FVG8Utt18od6rvTnEePUmL8Zao0jm5IJIb8Z4pV0CcPtmkubL8zKQJQRVP9dohfA4X K4Q20PWtESK0o4EKfGmFOhfx0Z9cNkc8LW8tMcsY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sriharsha Allenki , Mathias Nyman Subject: [PATCH 4.14 100/114] usb: xhci: Fix NULL pointer dereference when enqueuing trbs from urb sg list Date: Mon, 18 May 2020 19:37:12 +0200 Message-Id: <20200518173519.621240196@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173503.033975649@linuxfoundation.org> References: <20200518173503.033975649@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sriharsha Allenki commit 3c6f8cb92c9178fc0c66b580ea3df1fa3ac1155a upstream. On platforms with IOMMU enabled, multiple SGs can be coalesced into one by the IOMMU driver. In that case the SG list processing as part of the completion of a urb on a bulk endpoint can result into a NULL pointer dereference with the below stack dump. <6> Unable to handle kernel NULL pointer dereference at virtual address 0000000c <6> pgd = c0004000 <6> [0000000c] *pgd=00000000 <6> Internal error: Oops: 5 [#1] PREEMPT SMP ARM <2> PC is at xhci_queue_bulk_tx+0x454/0x80c <2> LR is at xhci_queue_bulk_tx+0x44c/0x80c <2> pc : [] lr : [] psr: 000000d3 <2> sp : ca337c80 ip : 00000000 fp : ffffffff <2> r10: 00000000 r9 : 50037000 r8 : 00004000 <2> r7 : 00000000 r6 : 00004000 r5 : 00000000 r4 : 00000000 <2> r3 : 00000000 r2 : 00000082 r1 : c2c1a200 r0 : 00000000 <2> Flags: nzcv IRQs off FIQs off Mode SVC_32 ISA ARM Segment none <2> Control: 10c0383d Table: b412c06a DAC: 00000051 <6> Process usb-storage (pid: 5961, stack limit = 0xca336210) <2> [] (xhci_queue_bulk_tx) <2> [] (xhci_urb_enqueue) <2> [] (usb_hcd_submit_urb) <2> [] (usb_sg_wait) <2> [] (usb_stor_bulk_transfer_sglist) <2> [] (usb_stor_bulk_srb) <2> [] (usb_stor_Bulk_transport) <2> [] (usb_stor_invoke_transport) <2> [] (usb_stor_control_thread) <2> [] (kthread) The above NULL pointer dereference is the result of block_len and the sent_len set to zero after the first SG of the list when IOMMU driver is enabled. Because of this the loop of processing the SGs has run more than num_sgs which resulted in a sg_next on the last SG of the list which has SG_END set. Fix this by check for the sg before any attributes of the sg are accessed. [modified reason for null pointer dereference in commit message subject -Mathias] Fixes: f9c589e142d04 ("xhci: TD-fragment, align the unsplittable case with a bounce buffer") Cc: stable@vger.kernel.org Signed-off-by: Sriharsha Allenki Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20200514110432.25564-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3403,8 +3403,8 @@ int xhci_queue_bulk_tx(struct xhci_hcd * /* New sg entry */ --num_sgs; sent_len -= block_len; - if (num_sgs != 0) { - sg = sg_next(sg); + sg = sg_next(sg); + if (num_sgs != 0 && sg) { block_len = sg_dma_len(sg); addr = (u64) sg_dma_address(sg); addr += sent_len;