From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35646 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732670AbeJBUSq (ORCPT ); Tue, 2 Oct 2018 16:18:46 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , syzbot+19c3aaef85a89d451eac@syzkaller.appspotmail.com Subject: [PATCH 4.14 095/137] USB: handle NULL config in usb_find_alt_setting() Date: Tue, 2 Oct 2018 06:24:56 -0700 Message-Id: <20181002132505.152243932@linuxfoundation.org> In-Reply-To: <20181002132458.446916963@linuxfoundation.org> References: <20181002132458.446916963@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit c9a4cb204e9eb7fa7dfbe3f7d3a674fa530aa193 upstream. usb_find_alt_setting() takes a pointer to a struct usb_host_config as an argument; it searches for an interface with specified interface and alternate setting numbers in that config. However, it crashes if the usb_host_config pointer argument is NULL. Since this is a general-purpose routine, available for use in many places, we want to to be more robust. This patch makes it return NULL whenever the config argument is NULL. Signed-off-by: Alan Stern Reported-by: syzbot+19c3aaef85a89d451eac@syzkaller.appspotmail.com CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/usb.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -228,6 +228,8 @@ struct usb_host_interface *usb_find_alt_ struct usb_interface_cache *intf_cache = NULL; int i; + if (!config) + return NULL; for (i = 0; i < config->desc.bNumInterfaces; i++) { if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber == iface_num) {