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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 5359DC10F11 for ; Wed, 24 Apr 2019 14:45:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20D20218FD for ; Wed, 24 Apr 2019 14:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556117128; bh=kSmBxv0RWRKApnBZxeQzBsigputrP6wEjGlv6b3v2sU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SNjbVk7ySuOaKsp9GwaxRKwYzMhlZ4r+lBVXjRjcA/Cr0Ea5AjrA7xTriRnAVImKN ynAOz0vYmOQKgpa0q2X7RY7ItFWiMJR/54dRWtq/LDCLB4pbwP0T3+YPwp7r6hztkS fL5JOUCnUryZKbWZopFe9Kl0Oh/FxccoNEuhe/z8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732151AbfDXOp0 (ORCPT ); Wed, 24 Apr 2019 10:45:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:41752 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731645AbfDXOjU (ORCPT ); Wed, 24 Apr 2019 10:39:20 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CF9A521900; Wed, 24 Apr 2019 14:39:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556116759; bh=kSmBxv0RWRKApnBZxeQzBsigputrP6wEjGlv6b3v2sU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V3vm7xUixtQf8Yx/uCzS/hi1cGSvtkWN3QnlP0fi6pCMVWRsftd3PzUq7o+Gue270 xAA5WTT6G+QbCqCWw782bhysvkZzbg7jG60/V3J4jUbqgeMJlLlsRde9Prtwa0B60W agPXFUNFqKi7BYUHpOrN1hj2VGJkNjGgrxqL3iBU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "He, Bo" , "Zhang, Jun" , Jiri Kosina , Sasha Levin , linux-input@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 03/52] HID: debug: fix race condition with between rdesc_show() and device removal Date: Wed, 24 Apr 2019 10:38:21 -0400 Message-Id: <20190424143911.28890-3-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190424143911.28890-1-sashal@kernel.org> References: <20190424143911.28890-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "He, Bo" [ 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 ebc9ffde41e9..a353a011fbdf 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -1060,10 +1060,15 @@ 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; } -- 2.19.1