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=-5.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,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 544BCC04A6B for ; Mon, 6 May 2019 14:44:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25F782087F for ; Mon, 6 May 2019 14:44:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557153862; bh=dzrOXZbco1FmGzdetEwjy6ELyX7X8qMIhoOzU6aD92k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pCmPep2qia5fBLMrwlfYsUhzG4kXB/Swt3JbGMjxjcD/XmdUOE84uzQNYtD5fjNbs 3DnFRz8S8xAIHga3+ReCXm+eErmJSSGvxt3JoWGmgABoIOaA41ZE1xDZ2yZfdgT/Hr a2E67MT/I9nF6Y4q9xW7JbanQFIYDU8WxaPWmlVc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728474AbfEFOoV (ORCPT ); Mon, 6 May 2019 10:44:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:40486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726872AbfEFOoS (ORCPT ); Mon, 6 May 2019 10:44:18 -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 9DFD621019; Mon, 6 May 2019 14:44:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557153858; bh=dzrOXZbco1FmGzdetEwjy6ELyX7X8qMIhoOzU6aD92k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sR+mQFijn+vUOaUkd8uz+hi0L7DdCBzLf7ttCsWwL5KU/z6RHPbBF3FYICLaNrwsG Q6u7BkYYQS4AYV7AlchXCEYGdWSAQsp4YTNvvau/WnDppgTbXeBx5LfnagbkZo1Nep 6cjjCwsR4VBP3ojKsxYGgdxeNegyPozxy5naO73s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , syzbot+b75b85111c10b8d680f1@syzkaller.appspotmail.com Subject: [PATCH 4.14 22/75] USB: core: Fix unterminated string returned by usb_string() Date: Mon, 6 May 2019 16:32:30 +0200 Message-Id: <20190506143055.172531958@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190506143053.287515952@linuxfoundation.org> References: <20190506143053.287515952@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Alan Stern commit c01c348ecdc66085e44912c97368809612231520 upstream. Some drivers (such as the vub300 MMC driver) expect usb_string() to return a properly NUL-terminated string, even when an error occurs. (In fact, vub300's probe routine doesn't bother to check the return code from usb_string().) When the driver goes on to use an unterminated string, it leads to kernel errors such as stack-out-of-bounds, as found by the syzkaller USB fuzzer. An out-of-range string index argument is not at all unlikely, given that some devices don't provide string descriptors and therefore list 0 as the value for their string indexes. This patch makes usb_string() return a properly terminated empty string along with the -EINVAL error code when an out-of-range index is encountered. And since a USB string index is a single-byte value, indexes >= 256 are just as invalid as values of 0 or below. Signed-off-by: Alan Stern Reported-by: syzbot+b75b85111c10b8d680f1@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/message.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -818,9 +818,11 @@ int usb_string(struct usb_device *dev, i if (dev->state == USB_STATE_SUSPENDED) return -EHOSTUNREACH; - if (size <= 0 || !buf || !index) + if (size <= 0 || !buf) return -EINVAL; buf[0] = 0; + if (index <= 0 || index >= 256) + return -EINVAL; tbuf = kmalloc(256, GFP_NOIO); if (!tbuf) return -ENOMEM;