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=-8.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,T_DKIMWL_WL_HIGH,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 3265AC04A6B for ; Mon, 6 May 2019 15:08:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 043FC2054F for ; Mon, 6 May 2019 15:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557155280; bh=7TSZU9uuESChnQZl6Z/mt6OaAgpomEHBrYCg3HwUwV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rtGQtny6wvNG+wXE1FhQ930x90jpSY/1BhvQ3XcymIKjFkZK5t7RH/TAslARI3D03 ISOUfP/KmS5RjDLXOh2JzgzOG3iD4Jdpi1MoNWKiu4Q9kGE781gW0xS8DC1CEkuDNv U9ldqrMVH1rr7uVbjx3JvN24/Mt64U/D00hLhiz0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727115AbfEFPHy (ORCPT ); Mon, 6 May 2019 11:07:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:38474 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727408AbfEFPHx (ORCPT ); Mon, 6 May 2019 11:07:53 -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 F0B362087F; Mon, 6 May 2019 15:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557155272; bh=7TSZU9uuESChnQZl6Z/mt6OaAgpomEHBrYCg3HwUwV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QQUY8HkKXayixjYnRbS9dY8i7ZdNI6za/pRKKe7+29ahKIigUPaDsIHmQ4++ZH6pa mlMIavWY+0fbxaErrFzK6pDeOam67+pFZL6++5LRMmjhhxCfFBRxv3LBj3zHdqHiK7 F1Ft80nYnBGwsJidolvupoO4ozQXDLgMo+hq2FZk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "he, bo" , "Zhang, Jun" , Jiri Kosina , Sasha Levin Subject: [PATCH 4.9 29/62] HID: debug: fix race condition with between rdesc_show() and device removal Date: Mon, 6 May 2019 16:33:00 +0200 Message-Id: <20190506143053.575546010@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190506143051.102535767@linuxfoundation.org> References: <20190506143051.102535767@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit cef0d4948cb0a02db37ebfdc320e127c77ab1637 ] There is a race condition that could happen if hid_debug_rdesc_show() is running while hdev is in the process of going away (device removal, system suspend, etc) which could result in NULL pointer dereference: BUG: unable to handle kernel paging request at 0000000783316040 CPU: 1 PID: 1512 Comm: getevent Tainted: G U O 4.19.20-quilt-2e5dc0ac-00029-gc455a447dd55 #1 RIP: 0010:hid_dump_device+0x9b/0x160 Call Trace: hid_debug_rdesc_show+0x72/0x1d0 seq_read+0xe0/0x410 full_proxy_read+0x5f/0x90 __vfs_read+0x3a/0x170 vfs_read+0xa0/0x150 ksys_read+0x58/0xc0 __x64_sys_read+0x1a/0x20 do_syscall_64+0x55/0x110 entry_SYSCALL_64_after_hwframe+0x49/0xbe Grab driver_input_lock to make sure the input device exists throughout the whole process of dumping the rdesc. [jkosina@suse.cz: update changelog a bit] Signed-off-by: he, bo Signed-off-by: "Zhang, Jun" Signed-off-by: Jiri Kosina Signed-off-by: Sasha Levin --- drivers/hid/hid-debug.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index d7179dd3c9ef..3cafa1d28fed 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -1058,10 +1058,15 @@ static int hid_debug_rdesc_show(struct seq_file *f, void *p) seq_printf(f, "\n\n"); /* dump parsed data and input mappings */ + if (down_interruptible(&hdev->driver_input_lock)) + return 0; + hid_dump_device(hdev, f); seq_printf(f, "\n"); hid_dump_input_mapping(hdev, f); + up(&hdev->driver_input_lock); + return 0; } -- 2.20.1