From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753389AbbCaTtn (ORCPT ); Tue, 31 Mar 2015 15:49:43 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39142 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753204AbbCaTtY (ORCPT ); Tue, 31 Mar 2015 15:49:24 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Oliver Neukum , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 057/143] cdc-acm: add sanity checks Date: Tue, 31 Mar 2015 12:47:02 -0700 Message-Id: <1427831308-1854-58-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1427831308-1854-1-git-send-email-kamal@canonical.com> References: <1427831308-1854-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11-ckt18 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Oliver Neukum commit 7e860a6e7aa62b337a61110430cd633db5b0d2dd upstream. Check the special CDC headers for a plausible minimum length. Another big operating systems ignores such garbage. Signed-off-by: Oliver Neukum Reviewed-by: Adam Lee Tested-by: Adam Lee Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa --- drivers/usb/class/cdc-acm.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 6746103..82dea40 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -943,6 +943,7 @@ static int acm_probe(struct usb_interface *intf, unsigned long quirks; int num_rx_buf; int i; + unsigned int elength = 0; int combined_interfaces = 0; struct device *tty_dev; int rv = -ENOMEM; @@ -988,9 +989,12 @@ static int acm_probe(struct usb_interface *intf, dev_err(&intf->dev, "skipping garbage\n"); goto next_desc; } + elength = buffer[0]; switch (buffer[2]) { case USB_CDC_UNION_TYPE: /* we've found it */ + if (elength < sizeof(struct usb_cdc_union_desc)) + goto next_desc; if (union_header) { dev_err(&intf->dev, "More than one " "union descriptor, skipping ...\n"); @@ -999,31 +1003,38 @@ static int acm_probe(struct usb_interface *intf, union_header = (struct usb_cdc_union_desc *)buffer; break; case USB_CDC_COUNTRY_TYPE: /* export through sysfs*/ + if (elength < sizeof(struct usb_cdc_country_functional_desc)) + goto next_desc; cfd = (struct usb_cdc_country_functional_desc *)buffer; break; case USB_CDC_HEADER_TYPE: /* maybe check version */ break; /* for now we ignore it */ case USB_CDC_ACM_TYPE: + if (elength < 4) + goto next_desc; ac_management_function = buffer[3]; break; case USB_CDC_CALL_MANAGEMENT_TYPE: + if (elength < 5) + goto next_desc; call_management_function = buffer[3]; call_interface_num = buffer[4]; if ((quirks & NOT_A_MODEM) == 0 && (call_management_function & 3) != 3) dev_err(&intf->dev, "This device cannot do calls on its own. It is not a modem.\n"); break; default: - /* there are LOTS more CDC descriptors that + /* + * there are LOTS more CDC descriptors that * could legitimately be found here. */ dev_dbg(&intf->dev, "Ignoring descriptor: " - "type %02x, length %d\n", - buffer[2], buffer[0]); + "type %02x, length %ud\n", + buffer[2], elength); break; } next_desc: - buflen -= buffer[0]; - buffer += buffer[0]; + buflen -= elength; + buffer += elength; } if (!union_header) { -- 1.9.1