diff options
| author | Oliver Neukum <oneukum@suse.de> | 2015-01-28 11:14:55 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-31 08:58:38 -0800 |
| commit | 7e860a6e7aa62b337a61110430cd633db5b0d2dd (patch) | |
| tree | e5a3d99cb5cd1f66edbffd7eef694588cbcdce0d /drivers/usb/class | |
| parent | 6b629f2826419ab0fde54d04d97531fe4ce972bf (diff) | |
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')
| -rw-r--r-- | drivers/usb/class/cdc-acm.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 546a17e8ad5b..a417b738824f 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) { |