In newer kernels this issue has been fixed at a central location with

commit 2e1c42391ff2556387b3cb6308b24f6f65619feb
Author: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Date:   Thu Sep 21 16:58:48 2017 +0200

    USB: core: harden cdc_parse_cdc_header

on anything older the parsing had not been centralised, so a separate
fix for each driver is necessary.

Signed-off-by: Oliver Neukum <oneu...@suse.com>
---
 drivers/net/usb/cdc_ether.c | 9 ++++++++-
 drivers/usb/class/cdc-acm.c | 8 +++++++-
 drivers/usb/class/cdc-wdm.c | 2 ++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 3651f3cd474e..0f2fde0820dd 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -144,6 +144,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct 
usb_interface *intf)
                                dev_dbg(&intf->dev, "extra CDC header\n");
                                goto bad_desc;
                        }
+                       if (len < sizeof(struct usb_cdc_header_desc))
+                               break;
                        info->header = (void *) buf;
                        if (info->header->bLength != sizeof(*info->header)) {
                                dev_dbg(&intf->dev, "CDC header len %u\n",
@@ -157,6 +159,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct 
usb_interface *intf)
                         */
                        if (rndis) {
                                struct usb_cdc_acm_descriptor *acm;
+                               if (len < sizeof(struct usb_cdc_acm_descriptor))
+                                       break;
 
                                acm = (void *) buf;
                                if (acm->bmCapabilities) {
@@ -173,6 +177,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct 
usb_interface *intf)
                                dev_dbg(&intf->dev, "extra CDC union\n");
                                goto bad_desc;
                        }
+                       if (len < sizeof(struct usb_cdc_union_desc))
+                               break;
                        info->u = (void *) buf;
                        if (info->u->bLength != sizeof(*info->u)) {
                                dev_dbg(&intf->dev, "CDC union len %u\n",
@@ -231,6 +237,8 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct 
usb_interface *intf)
                                dev_dbg(&intf->dev, "extra CDC ether\n");
                                goto bad_desc;
                        }
+                       if (len < sizeof(struct usb_cdc_ether_desc))
+                               break;
                        info->ether = (void *) buf;
                        if (info->ether->bLength != sizeof(*info->ether)) {
                                dev_dbg(&intf->dev, "CDC ether len %u\n",
@@ -248,7 +256,6 @@ int usbnet_generic_cdc_bind(struct usbnet *dev, struct 
usb_interface *intf)
                                dev_dbg(&intf->dev, "extra MDLM descriptor\n");
                                goto bad_desc;
                        }
-
                        desc = (void *)buf;
 
                        if (desc->bLength != sizeof(*desc))
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index ea93b35b1c6d..8957ee57f62d 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1019,7 +1019,7 @@ static int acm_probe(struct usb_interface *intf,
                }
        }
 
-       while (buflen > 0) {
+       while (buflen >= 3) { /* minimum length making sense */
                if (buffer[1] != USB_DT_CS_INTERFACE) {
                        dev_err(&intf->dev, "skipping garbage\n");
                        goto next_desc;
@@ -1027,6 +1027,8 @@ static int acm_probe(struct usb_interface *intf,
 
                switch (buffer[2]) {
                case USB_CDC_UNION_TYPE: /* we've found it */
+                       if (buflen < sizeof(struct usb_cdc_union_desc))
+                               break;
                        if (union_header) {
                                dev_err(&intf->dev, "More than one "
                                        "union descriptor, skipping ...\n");
@@ -1035,6 +1037,8 @@ 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 (buflen < sizeof(struct 
usb_cdc_country_functional_desc))
+                               break;
                        cfd = (struct usb_cdc_country_functional_desc *)buffer;
                        break;
                case USB_CDC_HEADER_TYPE: /* maybe check version */
@@ -1043,6 +1047,8 @@ static int acm_probe(struct usb_interface *intf,
                        ac_management_function = buffer[3];
                        break;
                case USB_CDC_CALL_MANAGEMENT_TYPE:
+                       if (buflen < 4)
+                               break;
                        call_management_function = buffer[3];
                        call_interface_num = buffer[4];
                        if ((quirks & NOT_A_MODEM) == 0 && 
(call_management_function & 3) != 3)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 07133d0c971b..f61b5e138bc7 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -851,6 +851,8 @@ static int wdm_probe(struct usb_interface *intf, const 
struct usb_device_id *id)
                case USB_CDC_HEADER_TYPE:
                        break;
                case USB_CDC_DMM_TYPE:
+                       if (buflen < sizeof(struct usb_cdc_dmm_desc))
+                               break;
                        dmhd = (struct usb_cdc_dmm_desc *)buffer;
                        maxcom = le16_to_cpu(dmhd->wMaxCommand);
                        dev_dbg(&intf->dev,
-- 
2.13.6

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