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authorOliver Neukum <oneukum@suse.de>2015-01-28 11:14:55 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-31 08:58:38 -0800
commit7e860a6e7aa62b337a61110430cd633db5b0d2dd (patch)
treee5a3d99cb5cd1f66edbffd7eef694588cbcdce0d /drivers/usb/class/cdc-acm.c
parent6b629f2826419ab0fde54d04d97531fe4ce972bf (diff)
downloadlinux-7e860a6e7aa62b337a61110430cd633db5b0d2dd.tar.gz
cdc-acm: add sanity checks
Check the special CDC headers for a plausible minimum length. Another big operating systems ignores such garbage. Signed-off-by: Oliver Neukum <oneukum@suse.de> CC: stable@vger.kernel.org Reviewed-by: Adam Lee <adam8157@gmail.com> Tested-by: Adam Lee <adam8157@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class/cdc-acm.c')
-rw-r--r--drivers/usb/class/cdc-acm.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 546a17e8ad5bef..a417b738824f13 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1091,6 +1091,7 @@ 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;
@@ -1136,9 +1137,12 @@ 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");
@@ -1147,29 +1151,36 @@ 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];
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) {